I’ve posted extensively about Oncolytic virus trials, focused on the ongoing Neuroendocrine Cancer trial in Uppsala Sweden. I wanted to incorporate this information into a single article ready for future news, whilst at the same time updating you on further developments in the field of Oncolytic Viruses for Neuroendocrine Cancer. The excitement of the Uppsala work has dampened in recent years, not helped by the fact that one of the first patients unfortunately died. In the absence of any news, I suspect there has been no real progress and/or the funding has run out.
What exactly are Oncolytic Viruses?
Oncolytic Viruses infects and breaks down cancer cells but not normal cells. Oncolytic viruses can occur naturally or can be made in the laboratory by changing other viruses. Certain oncolytic viruses are being studied in the treatment of cancer. Some scientists say they are another type of immunotherapy whilst others say it’s too early to classify as such. The good news is that Neuroendocrine Cancer seems to figure in this work with two of these viruses apparently working on mice to date. Listed below are two active projects involving NETs, one directly and one indirectly.
The Uppsala Trial – AdVince
The Oncolytic Virus AdVince is removed from the freezer ready for the Neuroendocrine Cancer Trial
I’ll briefly describe what’s happening and then you can link to my Facebook article if you need more background.
The trial is called AdVince after Vince Hamilton who funded it. Unfortunately he died before he saw any output but his forward thinking and benevolence lives on and might hopefully help NET patients in the longer term. It’s quite a small trial and is being conducted in Uppsala University Sweden, a famous European NET Centre of Excellence and where many people from across the world attend to take advantage of PRRT availability and experience and is home to famous NET specialist Kjell Öberg, MD, PhD, a professor of endocrine oncology.
A Swedish man (Jan-Erik Jannsson) was the first to get the virus to their cancer (NETs) using a genetically modified virus.
Unfortunately, I was given the news from a source close to the trial that Jan died last year of pneumonia. I have no evidence to suggest his death is in anyway connected to the trial but I’m told he was an ill man prior to the trial commencing. I have therefore dedicated this post to him. RIP Jan.
The initial data presented by the trial indicated that AdVince can be safely evaluated in a phase I/IIa clinical trial for patients with liver-dominant NET. The last I heard from the trial is that they are trying to recruit a further 12 patients to Phase IIa (the trial document allows for up to 36).
Read more background on my Facebook post here: Click here
The trial document on Clinical Trials Website: Click here
Then read this status update from the trial sponsors released in March 2018
Pexa-Vec Oncolytic Virus Trials
This is an oncolytic viral therapy currently in phase III and phase Ib/II clinical trials for use against primary liver (Hepatocellular Carcinoma) and Colorectal cancers, respectively. Pexa-Vec is a weakened (or attenuated) virus that is based on a vaccine used in the eradication of smallpox. The modified virus is injected directly into the cancer tumour, to grow inside these rapidly growing cancer cells and hopefully kill them.
According to the Colorectal Clinical Trial, the aim of the study is to evaluate whether the anti-tumor immunity induced by Pexa-Vec oncolytic viral therapy can be enhanced by immune checkpoint inhibition i.e. they are testing it in conjunction with Immunotherapy drugs (in the case of Colorectal, Durvalumab, and a combination of Durvalumab and Tremelimumab).
The Hepatocellular Carcinoma trial (Phocus) is at Phase III where the sponsors are evaluating Pexa-Vec to determine if it can slow the progression of advanced liver cancer and improve quality of life. I can other trials appearing such as this one for Colorectal Cancer and this one for any solid tumour type.
The work is a collaboration forged between University of California San Francisco (UCSF) vascular researcher Donald McDonald, MD, PhD, and researchers at San Francisco-based biotech SillaJen Biotherapeutics Inc. (formerly Jennerex Biotherapeutics, Inc.), a subsidiary of SillaJen, Inc., headquartered in Korea.
A tumor with green patches of vaccinia virus infection surrounded by red blood vessels. Image by Donald McDonald Lab
So what’s the Neuroendocrine Connection with Pexa-Vec?
As part of the research, McDonald’s lab injected it intravenously into mice genetically modified to develop pancreatic neuroendocrine cancer. They found that the virus failed to infect healthy organs or make the animals ill, but succeeded in infecting blood vessels within tumors. These initial infections caused the vessels to leak and expose the tumor cells to the virus. In these experiments, the virus managed to infect and destroy only a small proportion of tumor cells directly, the researchers found, but within five days of the initial infection, the rest of the tumor began to be killed by a powerful immune reaction. Live human trials have commenced in 2018 and the “patient 1” is a pancreatic NET patient. Read more here. Interestingly they added Keytruda (an immunotherapy) to the mix. It’s only been four months since ‘Patient 1’ (Tamara) began the trial, but a mid-treatment CT scan was said to be “promising”. I will keep this article live and bring you updates as I receive them.
Summary
Clearly it’s still early days in the Oncolytic Virus field with minimum breakthrough in terms of success on humans. In terms of the Neuroendocrine connection, it is exciting that two programmes are showing results (albeit in mice). We wait to hear from Uppsala on how the human test of AdVince is coming along. My agents are scanning the internet every day looking for any comment.
If you want to learn more about Oncolytic Viruses in general – there’s a great summary here.
After 7 years of avoiding pancreatic enzyme replacement therapy (PERT), I finally asked for some on a trial basis at the end of 2017. To be honest, for some time, I thought they were really only needed in the NET world for those with pancreatic issues (pNETs). I’ve always known I’ve had some digestive issues related to malabsorption. However, I’m not losing weight – this has been stable for some years (but see below). Plus my key vitamin levels (B12 and D) are in range. However, I had been struggling with a lot of bloating issues, thus the trial. You know me, I like to research and analyse such things! I’ve actually written about a lot of these issues in my Nutrition series ….. so this is now ‘Article Number 5’.
Crash Course.We eat food, but our digestive system doesn’t absorb food, it absorbs nutrients. Food has to be broken down from things like steak and broccoli into its nutrient pieces: amino acids (from proteins), fatty acids and cholesterol (from fats), and simple sugars (from carbohydrates), as well as vitamins, minerals, and a variety of other plant and animal compounds. Digestive enzymes, primarily produced in the pancreas and small intestine, break down our food into nutrients so that our bodies can absorb them.
Background
Some of the common symptoms of NETs are gas, bloating, cramping and abdominal pain and the root cause of these issues can sometimes be as a result of insufficient ‘digestive’ enzymes. They are primarily produced in the pancreas (an exocrine function) and the small intestine but also in the saliva glands and the stomach. This post will focus on pancreas and to a certain extent, the small intestine. There are actually some key tell-tale signs of a pancreatic enzyme deficiency, such as steatorrhoea which is described as an excess of fat in faeces, the stool may float due to trapped air, the stool can be pale in colour, may be foul-smelling, and you may also notice droplets of oil or a ‘slick’ in the toilet pan. Steatorrhoea is mainly (but not always) due to malabsorption of fat from the diet and this can actually be caused or made worse by somatostatin analogues which are known to inhibit the supply of pancreatic enzymes. Of course if fat is not being absorbed, then the key nutrients your body needs to function properly might not be either. The signs from that might not be so noticeable but can be even more problematic over time. Please see Article 1.
Those who have had surgery, in particular, in GI tract/digestive system, are at risk of malabsorption; as are those prescribed somatostatin analogues (Lanreotide/Octreotide) as these drugs can inhibit digestive enzymes, causing or adding to the malabsorption effect. For those who need to read more, see Article 2.
One way to combat these issues when they are caused by pancreatic insufficiency is with Pancreatic Enzyme Replacement Therapy (PERT) which can mimic the normal digestive process. However, this is not the whole story as there could be numerous reasons for these issues, perhaps even some which are unrelated to NETs. If you are in doubt about whether you suffer from malabsorption and/or any form of digestive enzyme insufficiency, you should consult your doctors.
Pancreatic Enzyme Replacement Therapy
Many NET patients succumb to malabsorption due to pancreatic insufficiency and are prescribed Pancreatic Enzyme Replacement Therapy, or PERT for short. There are various brands available (e.g. Creon®, Nutrizym®, Pancrease HL® or Pancrex®). Most are in capsule form in various doses.
How does PERT work? Most people experiencing the issues above are going to benefit from a multiple-enzyme replacement which tend to include the key ones such as:
lipase which break down fats (e.g from many different foods)
amylase which breaks down starchy carbohydrates (e.g. potatoes, bread, rice, pasta, cereals, fruits, fibre, etc).
The dose sizes tend to be based on the amount of lipase, i.e. a 25,000 strength would mean 25,000 units of lipase and (normally) a lesser amount of amylase and protease. The entire mix of enzymes may be given a name, e.g. ‘Pancreatin’ or ‘Pancrealipase’. You will be given a number of capsules to be used from your prescribing doctor.
The pancreatic enzyme capsule is swallowed along with food and digests food as they pass through the gut. If your capsules contain an enteric coat or enteric coated granules (delayed release), they should not be affected by stomach acid. The replacement enzymes will help to break down food allowing the nutrients to be absorbed beyond the stomach (i.e. in the small intestine). Do not be alarmed at the dose sizes, a healthy pancreas will release about 720,000 lipase units during every meal!
Frequently Asked Questions (FAQ)
When I first started taking the supplements, I thought of numerous questions, many of which I could not find definitive answers to! Different sites say different (and contradictory) things. Clearly, you should always consult your prescribing doctor and the medicine patient information leaflet. That said, I found the patient information leaflet which came with the capsules is just not detailed enough for an inquisitive patient such as myself!
I always like to refer to best practice which is why I’ve consulted one of the top NET Dietitians, Tara Whyand of Royal Free London. She agreed to an online Q&A session on 28 Feb 2018. This took place on my private Facebook group click here or search Facebook for this group “Neuroendocrine Cancer – Ronny Allan’s Group“. Join, answer some simple questions and then your application will be processed.
The output from the online with with Tara Whyand is below:
Thanks for attending the online event. Here is a tidy summary of the many comments. I hope this is also useful for those who were unable to attend.
Why would I need PERT and are there any tests that can be done to validate this?
“Somatostatin analogues, pancreatic surgery, pancreatitis and cystic fibrosis can cause exocrine pancreatic insufficiency (EPI). This means that the pancreas does not produce enough enzymes to break down food. It results in fatty loose stools called steatorrhoea.
Patients who have exocrine pancreatic insufficiency (EPI) require PERT (pancreatic enzyme replacement therapy) to break down food (fat, protein and carbohydrate). There are many brands of pancreatic enzymes, the most commonly used are Creon and Nutrizyme. Both have different dose levels to choose from.
The fecal elastase test was traditionally used to test the function of the pancreas, although it may not be that useful in NETs. This is because a NET team in Wales found that some NET patients who reported steatorrhoea had a false negative result.
Steatorrhoea may also be a result of bile acid malabsorption and small intestinal bacterial overgrowth which can co-exist and are common especially after surgery. They can both be tested for at a hospital.”
Supplementary Questions:
1a. Would the treatment be different for both EPI and bile acid malabsorption? If not how different?
“Yes BAM requires bile acid sequestrants rather than PERT”.
1b. would this be something you would take in general to help overall digestion and absorption of nutrients?
“No only if you have reasons for EPI to occur”.
PERT dosage. Is there a set dosage for all patients or does it depend on type of NET or surgery? And can I overdose on PERT?
“It depends on what you eat. PERT dose is normally tailored on fat content (the more fat you have, the more enzymes you need), but patients who have had a total pancreatectomy will have to have PERT for all food and drink (apart from water) as carbohydrate and protein needs to be broken down too.”
Supplementary Questions
2a. “What about when taking medication such as Cholesteramine or pills in the morning and evening. Do I need to take it to absorb these?”
“see question 5”.
2b. I had a total pancreatectomy and was told I do not need PERT for fruit and veg?
“there’s carbs in all fruit and veg and often fat and protein too, so no different really.”
Some sources say to take the capsules at the beginning of a meal, some say it’s also at the end of a meal is also OK. How critical is this?
“You must always take the capsules at the beginning of the meal and if the meal goes on longer than ~30 minutes, or there are several courses, you will need to have another capsule/tablet/scoop of enzymes. If you don’t, food will pass by the pancreas undigested and ‘malabsorption occurs. This leads to fatty stools (steatorrhoea), fat soluble vitamin deficiency and weight loss. Unbroken down food can also feed bacteria and you can develop small intestinal bacterial overgrowth as a result.”
Supplementary Questions
3a. so if my oncologist says to take four capsules per meal, then I should take all four at the same time?
“see question 11”
3b. if you have had a total gastrectomy (total removal of the stomach), is there a different procedure for taking PERT? I am on Creon and have heard that perhaps I need to open up the capsules as I can not break down the gelatin casing. Not sure if this is true or not.
“See question 11”
What is a meal? Is it multiple courses, or is there a strategy for each individual course? What about snacks? (i.e. a single biscuit with a cup of tea)
“The standard starting dose for snacks: 22-25,000 units lipase, titrating up when symptoms have not resolved. Most people end up taking 44,000-50,000 for snacks.
For main meals start on 44,000/50,000 and most people will need 66,000-100,000 units lipase/meal for the long term.”
Supplementary Questions:
4a. I have to eat multiple small meals a day (like every 3 hours, so 7 to 8 small meals). Is there a limit on the amount of Creon I can take in a day?
“see question 11”
4b. What is a snack?
“No official definition. Something with a little fat and maybe 50-200kcals.
Are there any problems taking PERT at the same time as other drugs? e.g. I like to take my vitamin supplements with food. And it’s recommended that some drugs be taken with food.
“PERT only breaks down food, but it is important to take your PERT to ensure food and drugs are absorbed. If you do not take you PERT with the meal, it is likely that food and drugs will rush through your bowel without being absorbed. There is no problem taking vitamins and minerals with food and PERT.
Supplementary Questions:
5a. I take a probiotic also, when is best time to take this, before, during or after food?
“Timing doesn’t matter”
I heard PERT is a porcine produce but I’m a vegan? Is there anything else for me?
“There are no other recommended products, and you should only have prescription PERT’s. This is for safety and reliability. Other off the shelf enzymes are unlikely to work.
Pigs are not slaughtered for PERT, they are slaughtered for meat and enzymes are a by-product if that makes anyone feel more comfortable with the idea.”
I heard PERT is a porcine produce but my religion does not allow me to eat such produces. Is there anything else for me?
“PERT are only sourced from a pigs pancreas but Jewish and Muslim patients have been granted approval to take the enzymes on medical grounds from their religious leaders because there is no alternative.”
Some doctors are prescribing PPIs along with PERT claiming that they help the PERT do the job. Do you have a view on this and are there any general diet tips to support the job of PERT without resorting to other drugs?
“Yes if you have had a whipples operation or you have acid reflux you must take an anti-acid (proton-pump inhibitor-PPI) drug to reduce the acid level. If left untreated it can cause ulcers, and when they bleed it can sometimes lead to a life threatening situation. PERT are gastro-resistant-they do not work in too high an acid environment. Sometimes a PPI / H2 blocker can decrease the acid level and allow the PERT to work better. There is no other reliable way of reducing stomach acid.
Note: Ronny Allan input that there is information published about the over-subscribing of PPI for long term use. Additionally that some NET specialists are suggesting a preference for H2 Blockers rather than PPI for NET Patients. H2 Receptor Blockers include Nizatidine (Axid), Famotidine (Pepcid, Pepcid AC), Cimetidine (Tagamet, Tagamet HB), Ranitidine (Zantac). The exceptions would be for PPI therapy necessary for Barrett’s Esophagus and Zollinger Ellison Syndrome (Gastrinoma). Read my article on PPIs by clicking here.
Supplementary Questions:
8a. I had a whipples two and a half years ago and have recently stopped taking omperazole as I didn’t seem to need them. Do you think I should still be taking something to reduce acid level anyway?
“yep think you should be on Ranitadine or a PPI long term.”
8b. Is it possible to suffer from excess acid without even knowing it? I also take probiotics, is it possible they could be minimising any excess acid? Also, I seem to be able to eat whatever I want without consequence but am worried now in case I am doing wrong and storing up trouble for myself.
“yes you can have silent reflux but after a total pancreatectomy you needs lots of adjustments and insulin dosing advice.”
9. How will I know the PERT is working for me? And are there any tests to validate this?
“You will know if your PERT is working well if your symptoms improve – i.e. you get normal (mid brown and formed) stools.
Patients taking enough PERT will not become fat soluble vitamin deficient or lose weight in the long term.
You could do a fecal elastase test (if stools are not liquid), but this is not a very reliable test especially for patients with NETs.
If symptoms do not resolve entirely, there may be a co-existing cause of malabsorption e.g. bile acid malabsorption or small intestinal bacterial overgrowth.”
Supplementary Questions:
9a. With regards to Question 9, how would you know if you have bile acid malabsorption or SIBO? Can you be tested for those?
“If PERT doesn’t resolve things, SIBO testing is another thing to look at using a lactulose drink and hydrogen breath test. If the NET is in the terminal ileum, bile acid malabsorption (BAM) is likely. The test is a SeHCAT scan and treatment usually Questran or Colesevelam.
If I need to stop taking PERT, do I just stop or do I need to taper off consumption over time?
“No, just stop. But only do so if it has caused a side effect and report the reaction to the doctor and pharmaceutical company. If you don’t think they are working, speak with a specialist Dietitian and you may need a PPI or H2 blocker or change brand/dose.”
If someone has had a total gastrectomy, can they take Creon? If so, do they need to open up the pill to remove the gelatin to help the enzymes to work?
“They are to be taken as normally directed. You can open capsules but only into an acidic fruit juice (a pH of 4.5 or below) and swallow immediately. It could be argued that PERT will work most easily in patients having a gastrectomy as you cannot get too high a stomach acid level without stomach P-cells. By the way, shouldn’t be any gelatin in the prescribed PERT”
Supplementary Questions:
11a. Are there any problems with taking too much in a day? I have to have 7 to 8 meals (minimum). I am losing weight. Take with every snack and meal?
“You can overdose – for Creon this is 6000 units lipase per kg of body weight. If you are still losing weight, PERT is not working or something else is the cause of malabsorption”
SUPPLEMENTARY QUESTIONS AT THE END
12A. My steatorrhoea only occurs once/twice a month. Is PERT indicated if steatorrhoea is not chronic?
“Yes, probably need to take all month as steatorrhoea is only a sign of extreme malabsorption, small amounts of malabsorption aren’t noticeable visibly but will reflect in weight and blood vitamin levels.”
12B. I do not need Creon as I am a Lung NET; although I have had my gall bladder removed.
“May need PERT if on somatostatin analogues. Some people take a bile acid sequestrants after gall bladder removal. PERT won’t work for that.”
Summary
I’ve always known about issues such as steatorrhoea and vitamin/mineral deficiency. My weight is fine but very happy to trial PERT to see the differences. I made a mistake of starting the capsules on Dec 23rd just before Christmas – it made for an interesting week! Early days so far but I’m getting used to taking them (and remembering to take them ….). Still seeing signs of steatorrhoea but am tracking this against diet. Not seeing any change to stool frequency. I would appear to be belching more though! I will keep this post live as I learn more.
You may wish to see the output from an online chat I carried out, the link is above.
UPDATE 1st Feb 2019. After 1 year, I’m not sure if there has been any difference to signs of malabsorption with Creon, although the supplement did help with weight gain in the period Oct – Dec 2018 after a dose increase. I had lost weight earlier in 2018 due to a bad chest infection and was having trouble regaining it. Despite the success with the weight gain, that is no long an issue, so I commenced a 3 month trial of Nutrizym to see any change in intermittent but frequent steatorrhea, which potentially indicates a continuing malabsorption issue.
ASCO (American Society of Clinical Oncology) is one of the biggest cancer conferences in the world normally bringing together more than 30,000 oncology professionals from around the world to discuss state-of-the-art treatment modalities, new therapies, and ongoing controversies in the field. As Neuroendorine Tumors is on a roll in terms of new treatments and continued research, we appear to be well represented with over 20 ‘extracts’ submitted for review and display. This is fairly complex stuff but much of it will be familiar to many. I’ve filtered and extracted all the Neuroendocrine stuff into one list providing you with an easy to peruse table of contents, complete with relevant linkages if you need to read more. For many the extract title and conclusion will be sufficiently educational or at least prompt you to click the link to investigate further. Remember, these are extracts so do not contain all the details of the research or study. However, some are linked to bigger trials and linkages are shown where relevant. I’ve also linked to some of my blog posts to add context and detail.
I’m hoping to capture any presentations or other output from the meeting which appears to be relevant and this will follow after the meeting. I will also be actively tweeting any output from the live event (for many cancers, not just NETs).
There’s something for everyone here – I hope it’s useful.
Conclusions: Objective response to PRRT defines a subset of patients with markedly improved PFS. SUVave 21.6 defines a threshold below which patients have a poor response to PRRT. This threshold should be taken forward into prospective study.
Check out my recent blog discussing ‘Theranostic pairing” – click here
Conclusions: The duration of SSA use was positively associated with QoL benefit among CS patients. This may be explained by long-term effectiveness of SSAs or selection bias favoring patients with more indolent disease. Future studies will be needed to distinguish between these possibilities.
Conclusions: The incidence of weight gain was dose-related on TE and was greater than that on pbo. It was possibly related to a reduction in diarrhea severity, and it may be a relevant aspect of TE efficacy among patients with functioning metastatic NETs. Clinical trial information: NCT01677910
Conclusions: A pre-PRRT analysis of circulating NET genes, the predictive quotient index comprising “omic” analysis and grading, is validated to predict the efficacy of PRRT therapy in GEP and lung NETs.
Conclusions: CAPTEM shows activity in neuroendocrine tumor of unknown primary. Currently FDA approved treatment options for grade I and grade II GI NETs includes somatostatin analogs and everolimus. Both of which are cytostatic and of limited use in case of visceral crisis or bulky disease where disease shrinkage is required. CAPTEM should be considered for grade II NETS of unknown primary.
Conclusions: This is the first multi-center study in Mexico. Which reflects the clinical characteristics of the NET_GET. The results differ in their epidemiology from that reported in other countries. However, the clinical and therapeutic results are very similar.
Conclusions: These data suggest that serotonin is secreted by nonfunctioning tumors, but does not reach the threshold required for clinical carcinoid symptoms. Monitoring 5HIAA and CgA may be useful during LAN treatment of nonfunctional GEP NETs. Clinical trial information: NCT00353496
Conclusions: CLARINET OLE suggests sustained antitumor effects with LAN 120 mg in enteropancreatic NETs irrespective of tumor origin, and suggests benefits with LAN as early treatment. Clinical trial information: NCT00842348
Conclusions: Pts showed improvement in CS symptoms of flushing and diarrhea and reduction in 5HIAA levels with LAN treatment, indicating efficacy of LAN regardless of prior OCT use. Transition from OCT to LAN was well tolerated among prior OCT pts in ELECT. Clinical trial information: NCT00774930
Conclusions: These findings highlight the utility of molecular classification to identify distinct NET tumor types/subtypes to improve diagnostic precision and treatment decision-making. In addition, significant differences in the distribution of molecular diagnoses of NET subtype by age and gender were identified.
Conclusions: In PNETS, multi-omic profiling through the KYT program identified targetable alterations in several key pathways. Outcome data will be explored.
Conclusions: In this poor prognosis G3 NET cohort of whom 77% had received prior chemotherapy, a median OS of 18 months from start of PRRT is encouraging and warrants further study. PRRT is a promising treatment option for patients with G3 NET with high somatostatin-receptor expression selected by SSRI.
Conclusions: Occurrence of documented carcinoid crisis was low in this high-risk population. However, a significant proportion of patients developed hemodynamic instability, suggesting that carcinoid crisis is a spectrum diagnosis and may be clinically under-recognized. Use of octreotide was not associated with risk of carcinoid crisis or hemodynamic instability; however, this analysis was limited by our modest sample size at a single institution. There remains a need to establish an objective definition of carcinoid crisis and to inform standardization of periprocedural use of octreotide for at-risk patients.
Conclusions: By assessing patients with GI NET from two independent US claim databases, this study suggested that patients diagnosed with CS were 2-3 times more likely to be diagnosed with liver disorder, enlargement of lymph nodes, or abdominal mass, than those without CS during the one year prior to CS diagnosis. Future studies using patient medical charts are warranted to validate and interpret the findings. These findings, when validated, may aid physicians to diagnose CS patients earlier.
Conclusions: Radiological progression within 12 months of completion of PRRT is associated with a worse outcome in terms of OS. Patients with greater liver involvement and highest CgA levels are more likely to progress within 12 months of treatment completion. Earlier treatment with PRRT in patients with radiological progression not meeting RECIST criteria may need to be considered. There may be a greater survival benefit if PRRT is given prior to the development of large volume disease.
Conclusions: To the best of our knowledge, this is the first population-based study to examine potentially relevant pre-existing symptoms, resource utilization and healthcare costs before NET diagnosis. NET patients were more likely to have certain conditions and incurred higher resource utilizations and costs in the year preceding diagnosis of NET.
Conclusions: This population-based study showed that elderly NET pts have significantly different prevalence of co-morbidities compared to non-cancer controls. The impact of these conditions on survival and therapeutic decisions is being evaluated.
Conclusions: In patients with SBNET with liver metastasis, higher tumor grade and post-operative chemotherapy increased risk of death. However, resection of the primary tumor along with liver metastasis improves the 5-year OS with complete cytoreduction providing the most benefit.
Role of 92 gene cancer classifier assay in neuroendocrine tumor of unknown primary. | 2017 ASCO Annual Meeting Abstracts
Conclusions: Tissue type ID was able to identify a primary site in NETs of unknown primary in majority (94.7%) of cases. The result had direct implication in management of patients with regards to FDA approved treatment options in 13/38 patients (pNETs, merkel cell and pheochromocytoma).
Conclusions: Radical loco-regional surgery for primary tumours combined with PRRT provides a novel, highly efficacious approach in metastasised NET. The NETest accurately measures the effectiveness of treatment.
Conclusions: Grade 3 GEP-NECs could be morphologically classified into well and poorly differentiated NETs. Additionally, among grade 3 GEP-NECs, there was a significant difference in ranges of Ki67 index between well and poorly differentiated NECs. Higher levels ( > 60%) of Ki67 index might be a predictive marker for efficacy of EP as a standard regimen in grade 3 GEP-NECs.
Check out my blog post on Gradingwhich has incorporated latest thinking in revised grade 3 classification
Seung Tae Kim
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Theranostic trial of well differentiated neuroendocrine tumors (NETs) with somatostatin antagonists 68Ga-OPS202 and 177Lu-OPS201.
Conclusions: In this trial of heavily treated NETs, preliminary data are promising for the use of 68Ga-OPS202/177Lu-OPS201 as a theranostic combination for imaging and therapy. Additional studies are planned to determine an optimal therapeutic dose and schedule. Clinical trial information: NCT02609737
Conclusions: SREs in NEN patients with BM were not uncommon, especially in patients with grade 3 NEN and osteolytic metastases. Application of ART did not significantly alter median OS or TTSRE, no subgroup with a benefit of ART could be identified. The use of ART in NEN should be questioned and evaluated prospectively.
Conclusions: Rhenium Re 188 P2045, a radiolabeled somatostatin analog, may be used to both identify and treat lung cancer tumors. The ability to image and dose patients with the same targeted molecule enables a personalized medicine approach and this highly targeted patient therapy may significantly improve treatment of tumors that over express somatostatin receptor.
Cabozantinib is an oral drug which works by blocking the growth of new blood vessels that feed a tumour. In addition to blocking the formation of new blood cells in tumours, Cabozantinib also blocks pathways that may be responsible for allowing cancers cells to become resistant to other “anti-angiogenic” drugs. It is a type of drug called a growth blocker. Cabozantinib has been studied or is already in research studies as a possible treatment for various types of cancer, including prostate cancer, ovarian cancer, brain cancer, thyroid cancer, lung cancer, and kidney cancer. During my research, I found that it has a connection to Medullary Thyroid Cancer (MTC) which is a type of Neuroendocrine Cancer, frequently associated with Multiple Endocrine Neoplasia (MEN). Cabozantinib, under the brand name of ‘Cometriq’ was approved by the FDA in 2012 for use in MTC. Read more about Cometriq here. It’s also been approved by the FDA for advanced renal cell carcinoma (RCC) (branded as Cabometyx). I also discovered that there is an exclusive licensing Agreement with the manufacturers (Elelixis) and Ipsen (of Lanreotide fame) to commercialize and develop Cabozantinib in regions outside the United States, Canada and Japan
Growth blockers are a type of biological therapy and include tyrosine kinase inhibitors, proteasome inhibitors, mTOR inhibitors, PI3K inhibitors, histone deacetylase inhibitors and hedgehog pathway blockers. Cabozantinib is a tyrosine kinase inhibitor (TKI). They block chemical messengers (enzymes) called tyrosine kinases. Tyrosine kinases help to send growth signals in cells so blocking them stop the cell growing and dividing. Some TKIs can block more than one tyrosine kinase and these are known as multi-TKIs.
Example action of Cabozantinib
So Capozantinib is a tyrosine kinase inhibitor and is therefore a biological therapy and growth blocker just like Everolimus (Afinitor) and Sunitinib (Sutent) – some texts describe thelattero two as chemotherapy but this is just not accurate.
Very technical process but in the simplest of terms, Cabozantinib is designed to disrupt the actions of VEGF (a growth factor) and MET (a growth factor receptor) which promote spread of cancerous cells through the growth of new blood vessels. Whilst we are on this subject, please note Everolimus (Afinitor) is an mTOR inhibitor and Sunitinib (Sutent) is a tyrosine kinase inhibitor. Many people think these drugs are a type of chemo – that is incorrect, these are targeted biological therapies. See more on this by clicking here.
What is the current trial status of Capozantinib?
A Phase III trial is now recruiting entitled “Cabozantinib S-malate in Treating Patients With Neuroendocrine Tumors Previously Treated With Everolimus That Are Locally Advanced, Metastatic, or Cannot Be Removed by Surgery”.
The trial has 172 locations across the US (see link below). The primary study (final data) is scheduled Jan 1st 2021.
You can read the trial documentation by clicking here.
A funded piece of research by the NET Research Foundation – check it out here – looks like they are trying to figure out what patients might benefit from Cabozantinib using biomarker data to predict response.
BOSTON — Cabozantinib (Cabometyx) may benefit patients with malignant pheochromocytomas and paragangliomas, according to results of a phase II trial presented here.
Patients receiving cabozantinib (Cometriq) treatment experienced notable tumor shrinkage in the lymph nodes, liver, and lung metastases, according to Camilo Jimenez, MD, of the MD Anderson Cancer Center in Houston, and colleagues.
Additionally, progression-free survival significantly increased after treated to 12.1 months (range 0.9-28) compared with just 3.2 months prior to treatment, they reported at the American Association of Clinical Endocrinologists (AACE) annual meeting.
Cabozantinib treatment was also tied to an improvement in blood pressure and performance status, as well as remission of diabetes among these patients.
“Malignant pheochromocytomas and paragangliomas are frequently characterized by an excessive secretion of catecholamines. [Patients] have a large tumor burden and they have a decreased overall survival,” explained Jimenez. “Tumors are frequently very vascular and frequently associated with bone metastases. In fact, up to 20% of patients who have malignancy of pheochromocytomas and paragangliomas may have predominant bone metastases.”
He added that “an interesting aspect of this tumor is that C-MET receptor mutation have been found in occasional patients with malignant pheochromocytomas and paragangliomas.”
Cabozantinib is an anti-angiogenic tyrosine kinase inhibitor, which also targets RET, MET, and AXL. It is approved for metastatic medullary thyroid cancer, and was more recently approved for first-line treatment of advanced renal cell carcinoma.
“MET pathway is also involved in the development of bone metastases. In fact, cabozantinib is a very effective medications for patients who have bone metastases in the context of cancer of different origins,” Jimenez said.
In order to be eligible for the trial, patients with confirmed pheochromocytoma or paraganglioma had to be ineligible for curative surgery, have ≥3 months life expectancy, no risk for perforation or fistula, and adequate organ functioning. Prior to cabozantinib initiation, patients could not receive chemotherapy or biologic agents within 6 weeks, radiation within 4 weeks, or MIBG within 6 months.
Following histological confirmation of disease progression >1 year according to RECIST 1.1, the trial included 14 patients with measurable disease and eight patients with predominant/exclusive bone metastases. Fifteen patients subsequently enrolled into the trial, six of whom had germline mutations of the SDHB gene.
All participants were all started at an initial daily dose of 60 mg of cabozantinib, which was subsequently reduced down to between 40 to 20 mg due to toxicity in 13 patients based on tolerance.
The majority of these patients with measurable disease experienced some level of disease response. Six patients reported a partial response, defined as over a 30% reduction, while three patients achieved moderate response, marked by a 15%-30% reduction. Five of the patients with predominant bone metastases reported disease stabilization, according to results of an FDG-PET scan. One patient experienced disease progression while on treatment.
Overall, cabozantinib was generally well-tolerated without any grade 4 or 5 treatment-related adverse events reported. Some of the most common adverse events reported included grade mild dysgeusia, hand and foot syndrome, mucositis, fatigue, weight loss, and hypertension, according to the authors.
Primary Source – American Association of Clinical Endocrinologists meeting – AACE 2018; Abstract 142. attended my Medscape writers
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Summary
I generated this blog article to add value rather than just post the outputs for your own perusal. I hope you find it useful.
Please note that taking part in a clinical trial is a big decision and must be considered carefully in conjunction with your specialists if necessary. This article is not suggesting this trial is right for you. Please check the inclusion and exclusion criteria in the trials document carefully. (Pheo/Para patients see other clinical trial link above)
Courtesy of Pashtoon Kasi MD on Twitter https://twitter.com/pashtoonkasi/status/1078675398601396224
Theranostics is a joining of the words therapeutics and diagnostics. You may also see it conveyed as ‘Theragnostics’ and these terms are interchangeable. The basic aim of theranotistics is to find and then destroy the ‘bad guys‘. With Neuroendocrine Cancer, finding the tumours (the bad guys) can often be a challenge – they can be small and/or difficult to find – they are sometimes expert at camouflage. Moreover, once found, they can then be difficult to treat (destroy), as they can often prove resistant to conventional cancer drugs and many are inoperable due to sheer quantity, spread and positioning. When they are found and identified, it’s also really helpful to know from the intelligence gathered, how successful the destroy (therapeutic) part of the mission might be.
The nuclear scan uses the same targetin agent as the therapy, therefore if you cancer lights up on the nuclear scan, then the therapy will find its way to the cancer and hopefully work well. That is the beauty of theranostic pairing, i.e. the use of the same agent in the diagnostics – the ability to find, estimate likely success criteria and then hopefully destroy – or at least reduce the capability of the tumours and extend life.
A great example of an approved Theranostic Pairin Neuroendocrine Cancer, is the combination of the Somatostatin Receptor based Ga68 PET scan using NETSPOT or SomaKit TOC™ (US/Europe respectively) and Peptide Receptor Radiotherapy (PRRT) using Lutathera which both target NETs expressing the same somatostatin receptor, with PRRT intended to kill tumor cells by emitting a different kind of low-energy, short-range radiation than that of the diagnostic version. As mentioned above, the Ga68 PET scan can give a reasonably indication of therapeutic success using PRRT based on measurements taken during the scan (too complex for this article).
Nuclear medicine makes it possible by using the same molecular targeting compound to create diagnostic and therapeutic drugs, which work as theranostic pairings. Advanced Accelerator Applications’ theranostic platform is based on radiolabelling a single targeting molecule with either gallium Ga-68 for diagnostic use or lutetium Lu-177 for therapeutic use. AAA’s pipeline now includes several theranostic drug pairings for oncology indications including prostate and breast cancer; and gastrointestinal stromal tumors (GIST).
Newer imaging agents targeting somatostatin receptors (SSTR) labelled with 68 Ga have been developed, namely, DOTATATE, DOTATOC and DOTANOC. They are collectively referred to as SSTR PET.
The main difference among these three tracers (DOTA-TOC, DOTA-NOC, and DOTA-TATE) is their variable affinity to SSTR subtypes. All of them can bind to SSTR2 and SSTR5, while only DOTA-NOC shows good affinity for SSTR3.
These agents have several benefits over In111-pentetreotide (Octreotide scan), including improved detection sensitivity, improved patient convenience due to the 2 hour length of the study (compared to 2 or 3 days with Octreoscan), decreased radiation dose, decreased biliary excretion due to earlier imaging after radiotracer administration, and the ability to quantify uptake. The quantification of the uptake can help decide whether a patient is suitable for PRRT. Eventually, all Octreotide scans should be replaced with SSTR PET. To confirm the advantages of SSTR PET over Octreotide scans, a study comprising 1,561 patients reported a change in tumour management occurred in over a third of patients after SSTR PET/CT even when performed after an Octreotide scan. Worth pointing out that SSTR PET is replacing the ageing Octreotide scan and not conventional imaging (CI). You can see the recommended scenarios for use of SSTR PET in this article published by the Journal of Nuclear Medicine
Ga68 PET scans have been in many locations for some time. Current excitement is focused on USA locations with Ga68 PET (NETSPOT) only recently approved (DOTATATE). Other countries/scan centres may use one of the other types of imaging agent.
Read much more about this scan in my detailed article on Ga68 PET here.
So SSTR PETs above have the ability to find and estimate likely success criteria for therapy. We are now in a position to move on to ‘THERApy’ – e.g. Peptide Receptor Radiotherapy or PRRT.
THERANOSTICS – DESTROY
click on picture to watch video
Lutathera® (note the ‘THERA’ which makes up the brand name)
Definitions:
Europe Approval: LUTATHERA®(lutetium (177Lu) Oxodotreotide) is indicated for the treatment of unresectable or metastatic, progressive, well differentiated (G1 and G2), somatostatin receptor positive gastroenteropancreatic neuroendocrine tumours (GEPNETs) in adults.
USA Approval: LUTATHERA® (lutetium Lu 177 dotatate) is indicated for the treatment of somatostatin receptor-positive gastroenteropancreatic neuroendocrine tumors (GEP-NETs), including foregut, midgut and hindgut neuroendocrine tumors in adults.
For commercial purposes, the drug may be slightly different on a regional basis. For all intents and purposes it does the same job.
PRRT with LUTATHERA®
LUTATHERA® solution for infusion is a ‘radiolabelled somatostatin analog (SSA)’ comprised of a radionuclide (Lutetium-177) and a peptide (differs between Europe and USA)
The relevant SSA binds with high affinity to the somatostatin receptors (SSTR) overexpressed in malignant neuroendocrine cells such as the ones found in GEP-NETs.
Lutetium-177 is a β particle emitting radionuclide, with a mean penetration range of 0.67 millimetres in tissue (maximum penetration range of 2.2 mm) which is sufficient to kill targeted tumour cells with a limited effect on neighbouring normal cells.
The affinity for SSTRs and the specificity of binding ensures a high level of specificity in the delivery of radiation to the tumour. Before starting treatment with LUTATHERA®, imaging must confirm the presence of these receptors in tumour tissues.
As an example of how the drug is administered, please watch this short video from the European site:
Video courtesy of Advanced Accelerator Applications Please see the following post for a summary of PRRT activity worldwide. Please note this linked article is not designed to contain a list of every single location or country available – please bear that in mind when you read it – CLICK HERE
I’m very grateful to the team at Advanced Accelerator Applications (a Novartis Company) for allowing me to use their site for graphics and videos.
In another ‘theranostic’ development, check out my article on the Satoreotide trial (Ops 201/202) from Ipsen (of Lanreotide fame) – click here to read – the trial is recruiting.
The last few years have reminded me that life is fragile
Steve Jobs died 5 Oct 2011. RIP Steve, you certainly made a difference to the world of technology and that is still being felt today. I have a number of google alerts setup and every day the emails arrive in my inbox. The longest email is always the Steve Jobs one, i.e. Steve Jobs is written about more than Neuroendocrine Cancer and other connected subjects. That’s interesting because Neuroendocrine Cancer is the type Steve had, not Pancreatic as is frequently reported.
There are huge differences between Pancreatic Cancer and Neuroendocrine Cancer with a pancreatic primary – click here to read more.
I’ve mentioned Steve Jobs a few times previously, mainly in my blog The Human Anatomy of Neuroendocrine Cancer. I wrote that blog when I was frustrated about the constant misreporting of Neuroendocrine Cancer as other types of cancer. Others included Nick Robinson (see blog The Devil is in the Detail) and Wilko Johnson (The Ecstasy of Wilko Johnson). I’ve also suggested in my blog ‘Every Day is NET Cancer Day’ that we need high-profile patient Ambassadors and despite his death, Steve Jobs would have been quite a catch, had he been willing. Curiously, the same thing is happening with Dag Kittlaus (Siri creator) who was diagnosed with a pNET last year. To add insult to injury, the 2018 death of Aretha Franklin is gong the same way.
A lot has been written about Steve’s cancer experience and much of it is full of ‘what ifs’. However, I’d like to focus on the facts that are known and we can be almost certain about. That said, the precise detail that we (as NET patients) might want, is probably only to be found in Steve Jobs’s medical documents. Many people say that Steve Jobs had a right to personal privacy and I agree, nothing I put here isn’t already in the public domain.
Diagnosis
How was it found? In 2003, Steve was having a CT scan to examine his kidneys and ureter, as he had developed recurrent kidney stones beginning in the late 1990s. A suspicious lesion was spotted on his pancreas. To cut a long story short, he eventually had more specialist scans and then a biopsy which diagnosed a type of Neuroendocrine Tumour. There are many mentions of Insulinoma, a pNET which is reported to have a 10% malignancy rate (ISI Book – Woltering et al). It isn’t clear whether Steve had any presentational symptoms of an Insulinoma at this point (i.e. hypoglycemia). There is also some chatter online about his tumour being a Glucagonoma (another type of pNET).
Initial Treatment
Steve initially tried alternative medicine before having surgery 9 months after diagnosis. There are reports of his medical team urging surgery earlier and his biographer stated that Steve had later regretted this delay. One of his Doctors is reported to have said “Steve was a very thoughtful person. In deciding whether or not to have major surgery, and when, he spent a few months consulting with a number of physicians and scientists worldwide as well as his team of superb physicians. It was his decision to do this”. He is reported to have gone on to have a ‘Whipple’ type operation in 2004. It was only then, that his condition was made public. During that operation, 3 lesions were reported on his liver.
Ongoing Treatment and Surveillance
Most NET patients enter this phase after their initial treatment, it’s also the period where you learn about the cancer and how best to live with it. There’s not much written about Jobs’ illness between his surgery and his liver transplant but my research uncovered a useful timeline from Bloomberg and other sources:
June 12, 2005: Jobs talks about his fight with cancer during a commencement speech at Stanford University. He says he was diagnosed about a year earlier and that doctors told him he wouldn’t live longer than six months. The cancer turned out to be a form that was treatable with surgery, “and I’m fine now,” he says. Source Bloomberg. {Author’s note: an indication he had been told, or his doctors knew, it was a Neuroendocrine Tumor}
January 24, 2006: Walt Disney chief executive Bob Iger knew early on that Steve Jobs’s cancer had returned and kept it a secret before it became public knowledge, a new biography of Apple’s late chief executive reveals. The day the deal was officially announced, Mr Iger said he was at Pixar’s headquarters for the ceremony when Jobs asked to go for a private walk. On a secluded part of the Californian campus Jobs put his arm around Mr Iger’s shoulder and revealed his cancer was back. “Frankly, they tell me I’ve got a 50-50 chance of living five years,” the Disney CEO quoted Jobs as saying.
2007: Not much out there except that he was busy launching what might be regarded as Apple’s most successful and iconic product ever – the iPhone.
June 9, 2008: Jobs, while introducing the iPhone 3G at Apple’s developers’ conference, appears thinner and frail. The company blames a “common bug.”
July 21, 2008: Responding to concerns about Jobs’s appearance, Apple says he has no plans to leave the company and that his health is a private matter. Investors aren’t reassured, and the shares fall 10 percent.
July 23, 2008: The New York Times reports that Jobs has been telling associates and Apple’s board he is cancer-free. Jobs had a surgical procedure earlier in the year to address a problem that contributed to his weight loss, the newspaper reports, citing unnamed people close to the executive. The shares climb 2.6 percent.
July 26, 2008: New York Times columnist Joe Nocera writes that he spoke two days earlier on the phone with Jobs, who said his health problems weren’t life-threatening. Jobs declines to go on the record about the nature of his ailment.
Sept. 9, 2008: Jobs, introducing new iPod media players at an event in San Francisco, still looks thin. “Reports of my death are greatly exaggerated,” Jobs jokes. Munster says that while the CEO’s appearance is unchanged since June, “Just the fact that Steve Jobs was up there was a positive.”
Oct. 3, 2008: A posting on CNN’s citizen journalist Web site, called iReport.com, says Jobs has been rushed to the hospital after a “major heart attack.” The shares fall 5.4pc. The stock rebounds after Apple says the report is false.
Dec. 16, 2008: Apple says that Jobs won’t be giving his usual speech at the Macworld conference, renewing concerns about his health. Jobs had used the forum to introduce new products for 11 straight years.
Jan. 5, 2009: Jobs says he is suffering from a hormone imbalance, causing him to lose weight. Jobs vows to remain CEO during treatment. “The remedy for this nutritional problem is relatively simple and straightforward,” Jobs says in an open letter.
Jan. 14, 2009: Jobs gives up day-to-day operations to Cook until June, saying his health problems are more complex than originally thought. Jobs says he will remain involved in major strategic decisions. “I look forward to seeing all of you this summer,” he says in a letter to employees.
By this stage, his cancer is already starting to take its toll on how he looks.
The disease takes its toll over the years
Liver Transplant 2009
It is common knowledge that Jobs had a liver transplant in 2009 in Tennessee (he was on the list in California and Tennessee). In between his Whipple and then, he appears to have lived (and worked) with his disease and it’s consequences. His issues appear to have been exacerbated by his excessive vegan diet/fads and the effects of the Whipple surgery (many of you will be aware of these effects). For example, he would spend weeks eating the same thing and then suddenly change his mind and stop eating it. He’d also go on fasts. His condition immediately prior to the liver transplant was said to be ‘poor’ and losing more weight (he had been noticeably thinner for some time).
Did Steve Jobs get ‘experimental’ PRRT?
Jobs took a second medical absence for roughly six months in 2009. It wasn’t until June 20th, two months after the fact, that the Wall Street Journal uncovered the fact that Jobs had undergone a secret liver transplant at Methodist University Hospital in Memphis, Tennessee. However, during that absence, Fortune reported Jobs also took an unpublicized flight to Switzerland to undergo an ‘unusual radiological treatment’ (PRRT) at the University of Basel for neuroendocrine cancer, according to Jerry York, the Apple director who died in March 2010.
Post-Liver Transplant
In 2010, Jobs started to feel sick again. He would lose his appetite and begin to feel pains throughout his body. His doctors would do tests, detect nothing, and reassure him that he still seemed clear. In early November 2010, he was in pain, stopped eating and had to be fed intravenously by a nurse who came to his house. The doctors found no sign of more tumours, and they assumed that this was just another of his periodic cycles of fighting infections and digestive maladies.
Heres’ a great bunch of TV interviews (something Jobs didn’t do very often). “The last few years have reminded me that life is fragile”. Click here (worth watching the whole 10 minutes). His final TV appearance was in June 2011 to the Cupertino City Council about the acquisition of land for their new campus. Worth watching some of it: Click here.
The End
In early 2011, doctors detected the recurrence that was causing these symptoms. Ultimately, he developed liver, bone, and other metastases. He had a further extended leave of absence from his job before stepping down as Apple CEO in Aug, Steve Jobs eventually died 5 Oct 2011.
The last few years have reminded me that life is fragile
References
Notwithstanding the Pancreatic Cancer vs Neuroendocrine Cancer issue, I carried out my research mainly using two articles of the many you can find out there:
A Tumor Is No Clearer in Hindsight. This article comes to similar conclusions than the one above but it’s shorter and easier to read. It’s from the New York times and was written after the dust settled on Jobs’ death (i.e. when more facts were available). There is also input to this article from NET specialists Dr Wolin and Dr Libutti.
“A tumor is no clearer in hindsight” is a good summary on the basis that I would have liked much more detail! During my research, I found many mentions of Insulin as stated above but only one or two mentioning Glucagon, a hormone associated with another pNET type – Glucagonoma. However, looking at this tumor type in the ISI Book (Woltering et al) and the Jobs diagnostic and treatment story, I have some doubts whether this was the precise tumor type. I have some other searches in progress hoping to find something concrete.
“Thinking Differently“ There is no doubt that Steve Jobs was an amazing and very interesting character. You just can’t see Apple being the Apple it is today without his intervention. He was famous for being ‘unconventional’ and ‘thinking different’ and I get that element of his character. I just can’t help thinking that perhaps he should have been more ‘conventional’ with this thinking and approach to treating his cancer. However, we just don’t know what advice he was receiving and what advice he accepted or rejected. As for the ‘Pancreatic Cancer’ thing – I’ve said this before, I believe patients only say or interpret what their doctors say to them in regards cancer type.
“The most famous patient ambassador we never had”. I don’t mean any disrespect by that, I’m just emphasising that we need so much more awareness of our cancer and a high-profile patient could do so much to help in this area. If he was so inclined, Steve would have been a fantastic advocate for Neuroendocrine Cancer and there’s an area where perhaps thinking different might be the way ahead. However, I have a suspicion that very famous people don’t really want to talk about their illness and Steve Jobs might even perceive that as a weakness.
And one more thing ……. you may also find this article useful. It’s titled “And one more thing”
There’s a saying that the patient is the most underused person in healthcare and I think there’s a lot of truth in that. However, I would suggest with Neuroendocrine Cancer, it’s less true than for many other cancers. There are so many NET Cancer patients out there who know quite a lot about their cancer, and in some detail. Even the great Dr Liu once said that NET Patients frequently know more about NET Cancer than their doctors.
If you go onto Twitter, if you go onto Facebook, if you read newspaper stories, you will find cancer patient stories in abundance and they will normally be patients diagnosed with the big 4 cancers. This is not surprising as these tend to affect more people. However, the ratio of NET Cancer patient stories still does not seem to be right. I’m not ‘dissing’ breast, lung, bowel and prostate cancer patients, all credit to them for pushing their cancer awareness – respect!
I truly believe that patient stories, whether they are written, presented live or recorded for mass media, are an extremely valuable tool in spreading awareness of NET Cancer. A ‘human being’ talking is a thousand times more potent than the endless stream of ‘memes’ and cartoons that seem to pervade our community – one reason why I don’t use them on my own site. It’s also the reason why I always jump at the opportunity to tell my story, because it’s real, it’s factual and I’m sensing an increasing willingness from the medical and healthcare communities to use patients in this way. Quite right too, patients have a lot to offer.
I’ve been video’d several times in the past 12 months and one day you might actually get to see those, there are some contractual reasons why I cannot yet share them with you. It’s quite a scary thing to do and I found it mentally exhausting – but very worthwhile.
I was therefore delighted to find this recently published group of videos from Cure Connect. Within the clips, there are 2 patients stories, one Pancreatic NET (pNET) and one Carcinoid and they are interspersed and integrated by input from NET specialist Dr. Reidy-Lagunes (a very knowledgeable and enthusiastic speaker). Each clip is only around 5 minutes long so not too taxing. The pNET patient, Michael, is a great supporter of my blog and one of the first NET patients I met on twitter. I’m very thankful to him for alerting me to the videos. Dr Reidy-Lagunes is fast becoming a ‘fav’ of mine and I note she emphasises some of the things I’ve been consistently saying in my blogs; i.e. this cancer can be treated and it’s not as rare as people think.
Another bonus is the addition of Carcinoid Cancer Foundation (CCF) and my friend Grace Goldstein. CCF is the largest and most respected NET Cancer organisation on the planet and Grace works tirelessly to spread awareness and help patients including me! CCF was the first site I found and remains my go-to site today.
Well done Michael and Brenda. Thanks also to Dr. Reidy-Lagunes, Grace Goldstein/CCF and Cure Connect for once again highlighting our cancer.
I think most people have had a form of medical testing at some point in their life, i.e. the sampling and testing of blood, urine, saliva, stool or body tissue. In a nutshell, the medical staff are just measuring the content of a ‘substance’ and then taking a view whether this is normal or not based on pre-determined ranges. These tests are normally done as a physician’s reaction to symptom presentation or maintenance/surveillance of an existing diagnosed condition. Sometimes, abnormal results will lead to more specialist tests.
In cancer, these tests are frequently called ‘markers’. Most tumour markers are made by normal cells as well as by cancer cells; however, they are produced at much higher levels in cancerous conditions. These substances can be found in the blood, urine, stool, tumour tissue, or other tissues or bodily fluids of some patients with cancer. Most tumour markers are proteins. However, more recently, patterns of gene expression and changes to DNA have also begun to be used as tumour markers. Many different tumour markers have been characterized and are in clinical use. Some are associated with only one type of cancer, whereas others are associated with two or more cancer types. No “universal” tumour marker that can detect any type of cancer has been found.
There are some limitations to the use of tumor markers. Sometimes, noncancerous conditions can cause the levels of certain tumor markers to increase. In addition, not everyone with a particular type of cancer will have a higher level of a tumour marker associated with that cancer. Moreover, tumour markers have not been identified for every type of cancer. Tumour markers are not foolproof and other tests and checks are usually needed to learn more about a possible cancer or recurrence.
I’d also like to talk about a group of associated tests, in particular, hormone levels as these tests are really important to help determine the type of Neuroendocrine Tumour. NETs will sometimes oversecrete hormones and this can give clues to the type. The constraints mentioned above apply to hormone levels and other tests to a certain extent.
What this article will not cover
Routine Testing – the post will not cover routine blood tests (i.e. complete blood count etc). Although they may point to a problem, these tests do not necessarily indicate a particular type of NET without other supporting evidence.
Biopsy Testing – Technically, the Immunohistochemical ‘stains’ used in biopsy testing are tumour markers but I’ll not be discussing that today. I did cover the output of biopsies in my blog on NETs – Stages and Grades.
Genetic Testing. This is very specialised but you may find my Genetics and NETs article is of interest.
Sequencing of marker testing – diagnosis
The sequencing of marker testing may have been different for many patients. In my own experience, I had a biopsy and then the biochemical checks were carried out. So regardless of the results of my marker tests, I was to be diagnosed with NETs. Those with lengthy and difficult diagnostic phases will perhaps have had a different sequence with the biochemical markers providing evidence for further tests to formally diagnose. Markers alone will normally not be enough for a diagnosis but they do, however, feed into the treatment plan and provide a baseline at diagnosis and for tracking going forward.
Interpreting test results – International/National/Regional differences
The use of markers tends to be different on an international basis, e.g. specific marker tests can be developed in-country by independent labs. Testing can also vary in the same country as in-country labs use different commercially available ‘testing kits’. Not all tests are available in all countries.
Reference ranges can be dependent on many factors, including patient age, gender, sample population, and test method, and numeric test results can have different meanings in different laboratories. The lab report containing your test results should include the relevant reference range for your test(s). Please consult your doctor or the laboratory that performed the tests to obtain the reference range if you do not have the lab report. Moreover, the ‘normal’ test range can vary from hospital to hospital, even within the same tests. I suspect clinical staff have their own versions of risk thresholds when dealing with test results. Even when results are just above or below, individual physicians can take their own view in a subjective manner. Testing is best done at the same lab each time if possible.
There’s a great website called LabTestsOnlinewhich can describe each test. It’s peer-reviewed, non-commercial and patient-focused but just please note you should always refer to your own lab ‘normal ranges’ which will be printed on your test results. For these reasons, you will not find reference ranges for the majority of tests described on this web site. The link above will take you to the list of ‘country’ affiliated versions with specific information on a country basis.
Here’s some tips I always give people:
1 – Always try to get your own copy of results (preferably on paper) and track them yourself (I use a spreadsheet).
2 – When comparing results inside patient forums, always add the range and if possible, the unit of measurement (i.e. g/L, mmol/L, umol/L etc etc). Failure to do this can at best confuse, and at worst frighten patients. Compare apples with apples not with pears! (this is why it’s important to know the unit of measure and the reference range in addition to the figure).
3 – Don’t get too excited about rises if the test is still inside the normal range – normal is normal!
4 – Don’t get too excited about rises taking you just outside of normal range – your doctors are looking for bigger spikes.
5. Don’t get too excited about a single test result, your doctors are looking for trends, a single test result is not much to go on.
NET Markers
Although some routine blood markers (complete blood count etc) are useful in NETs, it’s pretty much impossible to cover these in any general detail. I’m going to focus on tumor and hormone associated markers
There are many markers involved with NETs. Some do different jobs and some are just variants measuring the same thing (more or less efficiently). You may also see something called ‘gold standard’ in reference to NET Tumour markers. Although thinking is changing (more on this below) and can vary from country to country, it is generally accepted that Chromogranin A and 5HIAA are the gold standard markers for tumour bulk and tumour functionality respectively. These gold standard tests may not be applicable to every type of NET, particularly 5HIAA. I’m also aware that US doctors are reducing the dependency on CgA and using Pancreastatin instead (although many are measuring both).
NETs are known to be heterogeneous in nature (i.e. consisting of or composed of dissimilarelements;nothaving a uniformqualitythroughout). Whilst some markers can be used widely, it follows that there are many very specialist marker tests for individual types of NET. I think this applies to 3 broad categories of NETs: Tumours known to potentially oversecrete Serotonin and and perhaps others (mainly midgut), Pancreatic NETs (or pNETs) secreting various hormones by type; and other less common types and/or syndromes which might be considered by some to be even more complex than the former two and in some cases there are big overlaps.
Another interesting thing about NET markers is that an undiagnosed patient may undergo several specialist tests to eliminate the many possibilities that are being presented as vague and common symptoms. Sometimes this is necessary to eliminate or ‘home in’ on a tumour type or syndrome/hormone involved (it’s that jigsaw thing again!).
Markers too can be divided into broad categories, those measuring how much tumour is in your body and its growth potential and those measuring how functional (or not) those tumours are. The latter can probably be expanded to measure/assess excess hormone secretion and syndromes.
The Anatomy
Certain tests can be anatomy related so to add context and to prevent big repetitive lists when using the terms ‘foregut’, ‘midgut’ and ‘hindgut’, you may find this graphic useful.
Markers for measuring Tumour bulk or load/growth prediction
Chromogranin (plasma/blood test)
Chromogranin is an acidic protein released along with catecholamines from chromaffin cells and nerve terminals. This statement alone might explain why it is a good marker to use with NETs. Depending on the test kit being used, you may see test results for Chromogranin A (CgA) and Chromogranin B (CgB) – the inclusion of CgB tends to be confined to Europe. There is also mention of Chromogranin C (CgC) in places but I’ve never heard of this being used in conjunction with NETs.
One of the disadvantages of CgA is that the results can be skewed by those taking Proton Pump Inhibitors(PPIs). Many NET patients are taking PPIs to treat GERD (….and Zollinger-Ellison Syndrome). In the long-term, this has the result of increasing gastrin levels which can lead to an increase of CgA in the blood including for some months after discontinuing. Opinions differ but many texts I found did suggest stopping PPIs for 2 weeks before the CgA blood test. CgB is said not be as influenced by the use of PPI as CgA. In addition to the issue with PPIs, CgA levels may also be elevated in other illnesses including severe hypertension and renal insufficiency. CgB is also said to be more sensitive to Pheochromocytoma.
Elevated CgA is a constant and somewhat excitable discussion point on patient forums and not just because of the lack of unit of measurement use I discussed above. Some people get quite excited about a single test result. I refer to Dr Woltering et al (ISI Book) where it clearly states that changes in CgA levels of more than 25% over baseline are considered significant and a trend in serial CgA levels over time has been proven to be a useful predictor of tumour growth (i.e. a single test result with an insignificant rise may not be important on its own). Dr Woltering also gives good advice on marker tests when he says “normal is normal” (i.e. an increased result which is still in range is normal).
Here is a nice graphic explaining what else could be the cause of elevated CgA:
CgA appears to be a widely used tumour marker and is effective in most NETs (foregut, midgut and hindgut). It is also sensitive to Pheochromocytoma, particularly when correlated with a 131I-MIBG scan. Interestingly Chromogranin can also be used in the immunohistochemical staining of NET biopsy samples (along with other methods).
As for my own experience, my CgA was only elevated at diagnosis, remained elevated after intestinal surgery but returned to normal after liver surgery (indicating the effect of liver tumour bulk on results). It also spiked out of range when some growth in a distant left axillary node was reported in Jan 2012. Following a lymphadenectomy, it returned to normal again and has remained in range to this day. It has been a good predictor of tumour bulk for me and I’m currently tested every 6 months.
Pancreastatin
In effect, this marker does the same job as CgA. Interestingly, Pancreastatin is actually a fragment of the CgA molecule. There have been many studies (mainly in the US) indicating this is a more efficient marker than CgA, and not only because it is not influenced by the use of PPI. It has also been suggested that it’s more sensitive than CgA and therefore capable of detecting early increases in tumour burden. It has also been suggested it can be an indication of tumour ‘activity’ (whatever that means). It is widely used in the US and some physicians will use it in preference to CgA (…..although from what I read, CgA also seems to be tested alongside). I’m starting to see this mentioned in the UK.
Neurokinin A (NKA)
This is not a well publicised test. However, it is something used in USA but I’d like to hear from others to validate its use elsewhere. In a nutshell, this test, which only applies to well differentiated midgut NETs, appears to have some prognostic indication. I discovered this test in the ISI NET Guidance and it’s backed up by a study authored by names such as Woltering, O’Dorisio, Vinik, et al. This is not a one-off test but one designed to be taken serially, i.e. a number of consecutive tests. These authors believe that NKA can also aid in the early identification of patients with more aggressive tumors, allowing for better clinical management of these patients. NKA is sometimes called Substance K.
Neuron-Specific Enolase (NSE)
In patients with suspected NET who have no clear elevations in the primary tumor markers used to diagnose these conditions, an elevated serum NSE level supports the clinical suspicion.
Markers for measuring Tumour functionality/hormone/peptide levels
So far, I’ve covered basic tumor markers which have a tumor bulk and/or prognostic indication. This section is a slightly more complex area and many more tests are involved. There’s often a correlation between CgA/Pancreastatin and these type of markers in many patients i.e. a serial high level of CgA might indicate a high level of tumour bulk and therefore increased production of a hormone in patients with a syndrome or oversecreting tumor. However, it frequently does not work out like that, particularly when dealing with non-functioning tumours.
The type of marker for this element of NET diagnosis and surveillance will vary depending on the type of NET and its location (to a certain extent). Like tumour bulk/growth, there might be different options or test variants on an international basis. There are too many to list here, so I’ll only cover the most common.
Serotonin Secreting Tumors
There are a few markers in use for measuring the functionality of this grouping of tumours. This tumour group has a tendency to secrete excess amounts of the hormone Serotoninalthough it differs depending on the area of the primary. For example, hindgut tumours tend to secret lower levels than foregut and midgut and therefore this test may present within range. Please also note there may be other hormones of note involved. The antiquated and misleading term ‘Carcinoid’ is sometimes used as a descriptor for these tumours and more and more NET scientific organisations and specialists are now avoiding use of this term.
Lug the Jug
5HIAA. 5HIAA is a metabolite of Serotonin thus why it’s a useful thing to measure to assess functionality in this grouping of tumours. 5HIAA is actually the ‘gold standard’ test for functioning serotonin secreting tumours. It’s a key measure of the effects of carcinoid syndrome and the risk of succumbing to carcinoid heart disease. However, there are two methods of testing: Urine and Plasma. The rather obvious key difference between the two is practicality. With the 24 hour urine, there are two key issues: 1. The logistics (i.e. lug the jug). 2. Fasting for up to 3 days prior to the test (4 if you count the day of the test). There are numerous variations on the fasting theme but most labs tend to say not to eat at least the following foods that contain high levels of serotonin producing amines: avocados, bananas, chocolate, kiwi fruit, pineapple, plums, tomatoes, and walnuts. Some lists contain additional items. With the plasma version, the fasting period is reduced to 8 hours (although I’ve seen some labs increase that to 10 or 12). There are also medicinal limitations including drugs that can also alter 5-HIAA urine values, such as acetanilide, phenacetin, glyceryl guaiacolate (found in many cough syrups), methocarbamol, and reserpine. Drugs that can decrease urinary 5-HIAA levels include heparin, isoniazid, levodopa, monoamine oxidase inhibitors, methenamine, methyldopa, phenothiazines, and tricyclic antidepressants. Patients should talk to their doctor before decreasing or discontinuing any medications. Taking 5HTP supplements are possibly not advised either prior to the test either.
As for my own experience, my 5HIAA (urine) was elevated at diagnosis only returning to normal after removal of my primary and commencement of Lanreotide. It has been a good measure of tumour functionality for me and I’m currently tested every 6 months.
Other tests for the tumour subgroup include but not limited to:
Serum Serotonin (5-HydroxyTryptamine; 5-HT). Firstly let’s deconflict between 5HIAA above and the serotonin (5-HT) blood test. 5HIAA is a metabolite of serotonin but the serotonin test is a measure of pure serotonin in the blood. Morning specimens are preferred and this is a fasting test (10-12 hours). There is always debate on forums about Serum Serotonin results. I have Dr Liu on record as saying “a high serotonin level measured in the blood in isolation really isn’t that dangerous. It’s the 5HIAA (a breakdown product of serotonin, which is easily measured in the blood and urine) that is considered to be more indicative of persistent elevated hormone. It’s this test that is most closely related to the carcinoid heart disease”.
Substance P. A substance associated with foregut and midgut tumours. It is a vasoactive protein that can cause wheezing, diarrhea, tachycardia, flushing
Histamines – Usually associated with foregut tumors. Appears to be involved in patchy rashes and flushing. The advice in the ISI NET book is no anti-histamine medication to be taken for 48 hours prior to blood draw.
Gastric NETs (Stomach)
Testing will be different depending on the Type:
Type 1 – Typical Low Grade, tends to be caused by atrophic gastritis.
Type 2 – Atypical Intermediate Grade and tends to be caused by gastrin secreting tumours. Type 2 normally needs a check for MEN1/Zollinger-Ellison Syndrome.
Type 3 – Tend to be larger and more aggressive tumours.
The key makers are CgA and Gastrin although Gastrin may not be elevated in Type 3. Gastrin ph is useful to differentiate between Type 1 and Type 2. 5HIAA can be considered but Carcinoid Syndrome is rare in Gastric NETs.
NETs of the Pancreas (pNETs)
There are many different types of cells in the pancreas
pNETs can be very difficult to diagnose and not only because they share some presentational similarities to their exocrine counterparts. Some pNETs actually comprise tumours arising in the upper part of the duodenum (small intestine) close to the Pancreas. Moreover, more than half of pNETs are non-functional which increases the difficulty in suspecting and then finding the tumours. However, where there is clinical presentation or suspicion, these symptoms can lead to the appropriate testing to support the output of scans. The fasting gut profile mentioned above can be useful in identifying the offending hormones when the type of NET is not yet known.
Gut Hormones (Glucagon, Gastrin, VIP, Somatostatin, Pancreatic Polypeptide)
A gut hormone screen is used for the diagnosis of a variety of endocrine tumours of the pancreas area. Analysis includes gastrin, VIP, somatostatin, pancreatic polypeptide, and glucagon, but there may be others depending on processes used by your ordering specialist or hospital.
Notes:
1. You may see this referred to as a ‘Fasting Gut Profile’ or a ‘Fasting Gut Hormone Profile’.
2. The individual hormones measured seem to differ between hospital labs.
3. The fasting conditions also vary between hospitals and labs but all agree the conditions are critical to the most accurate results. Always ask for instructions if you’re offered this test.
The gastrin test is usually requested to help detect high levels of gastrin and stomach acid. It is used to help diagnose gastrin-producing tumours called gastrinomas, Zollinger-Ellison (ZE) syndrome, and hyperplasia of G-cells, specialised cells in the stomach that produce gastrin. It may be measured to screen for the presence of multiple endocrine neoplasia type I (MEN) It may be used if a person has abdominal pain, diarrhoea, and recurrent peptic ulcers. A gastrin test may also be requested to look for recurrence of disease following surgical removal of a gastrinoma.
Vasoactive intestinal peptide (VIP) measurement is required for diagnosis of pancreatic tumour or a ganglioneuroma which secretes VIP. Administration of VIP to animals causes hyperglycaemia, inhibition of gastric acid, secretion of pancreatic bicarbonate and of small intestinal juice, and a lowering of systemic blood pressure with skin flush. These features are seen in patients with a tumour of this type which is secreting VIP.
Glucagon is measured for preoperative diagnosis of a glucagon-producing tumour of the pancreas in patients with diabetes and a characteristic skin rash (necrolytic migratory erythema).
Pancreatic polypeptide (PP) production is most commonly associated with tumours producing vasoactive intestinal polypeptide and with carcinoid syndrome and, less commonly, with insulinomas and gastrinomas.
When secreted by endocrine tumours, somatostatin appears to produce symptoms similar to those seen on pharmacological administration, i.e. steatorrhoea, diabetes mellitus and gall stones.
There are several types of pNETs, each with their own syndrome or hormone issue. When they are suspected due to the presentational symptoms, the markers that could be used are listed below. These types of tumours are complex and can be related to one or more syndromes. A patient may be tested using multiple markers to include or exclude these. Depending on other factors, some physicians may recommend additional marker testing in addition to the most common types below.
Somatostatinoma – Somatostatin (plasma somatostatin like immunoreactivity)
PPoma – Pancreatic Polypeptide (PP)
Other NETs/Syndromes
Pheochromocytoma/Paraganglioma – Adrenaline-producing tumours. Plasma and urine catecholamines, plasma free total metanephrines, urine total metanephrines, vanillylmandelic acid (VMA)
Medullary Thyroid Cancer. Medullary thyroid cancer (MTC) starts as a growth of abnormal cancer cells within the thyroid – the parafollicular C cells. In the hereditary form of medullary thyroid cancer (~20% of cases, often called Familial MTC or FMTC), the growth of these cells is due to a mutation in the RET gene which was inherited. This mutated gene may first produce a premalignant condition called C cell hyperplasia. The parafollicular C cells of the thyroid begin to have unregulated growth. In the inherited forms of medullary thyroid cancer, the growing C cells may form a bump or nodule in any portion of the thyroid gland. Unlike papillary and follicular thyroid cancers, which arise from thyroid hormone-producing cells, medullary thyroid cancer originates in the parafollicular cells (also called C cells) of the thyroid. These cancer cells make a different hormone called calcitonin, which has nothing to do with the control of metabolism in the way thyroid hormone does. The other test often seen in MTC is Carcinoembryonic Antigen (CEA). CEA is a protein that is usually found in the blood at a very low level but might rise in certain cancers, such as medullary thyroid cancer. There is no direct relationship between serum calcitonin levels and extent of medullary thyroid cancer. However, trending serum calcitonin and CEA levels can be a useful tool for doctors to consider in determining the pace of change of a patient’s medullary cancer.
[please note there are extremely rare occurrences of elevated calcitonin from places outside the thyroid – read more here.
Parathyroid– Parathyroid hormone (PTH), Serum Calcium. Parathyroid hormone (PTH) is secreted from four parathyroid glands, which are small glands in the neck, located behind the thyroid gland. Parathyroid hormone regulates calcium levels in the blood, largely by increasing the levels when they are too low. A primary problem in the parathyroid glands, producing too much parathyroid hormone causes raised calcium levels in the blood (hypercalcaemia – primary hyperparathyroidism). You may also be offered an additional test called Parathyroid Hormone-Related Peptide (PTHrP). They would probably also measure Serum Calcium in combination with these type of tests. The parathyroid is one of the ‘3 p’ locations often connected to Multiple Endocrine Neoplasia – MEN 1 – see MEN below.
HPA AXIS – It’s important to note something called the HPA axis when discussing pituitary hormones as there is a natural and important connection and rhythm between the Hypothalamus, Pituitary and the Adrenal glands.
Adrenocorticotropic hormone (ACTH) is made in the corticotroph cells of the anterior pituitary gland. It’s production is stimulated by receiving corticotrophin releasing hormone (CRH) from the Hypothalamus. ACTH is secreted in several intermittent pulses during the day into the bloodstream and transported around the body. Like cortisol (see below), levels of ACTH are generally high in the morning when we wake up and fall throughout the day. This is called a diurnal rhythm. Once ACTH reaches the adrenal glands, it binds on to receptors causing the adrenal glands to secrete more cortisol, resulting in higher levels of cortisol in the blood. It also increases production of the chemical compounds that trigger an increase in other hormones such as adrenaline and noradrenaline. If too much is released, The effects of too much ACTH are mainly due to the increase in cortisol levels which result. Higher than normal levels of ACTH may be due to:
Cushing’s disease – this is the most common cause of increased ACTH. It is caused by a tumor in the pituitary gland (PitNET), which produces excess amounts of ACTH. (Please note, Cushing’s disease is just one of the numerous causes of Cushing’s syndrome). It is likely that a Cortisol test will also be ordered if Cushing’s is suspected.
Cortisol
This is a steroid hormone, one of the glucocorticoids, made in the cortex of the adrenal glands and then released into the blood, which transports it all round the body. Almost every cell contains receptors for cortisol and so cortisol can have lots of different actions depending on which sort of cells it is acting upon. These effects include controlling the body’s blood sugar levels and thus regulating metabolism acting as an anti-inflammatory, influencing memory formation, controlling salt and water balance, influencing blood pressure. Blood levels of cortisol vary dramatically, but generally are high in the morning when we wake up, and then fall throughout the day. This is called a diurnal rhythm. In people who work at night, this pattern is reversed, so the timing of cortisol release is clearly linked to daily activity patterns. In addition, in response to stress, extra cortisol is released to help the body to respond appropriately. Too much cortisol over a prolonged period of time can lead to Cushing’s syndrome. Cortisol oversecretion can be associated with Adrenal Cortical Carcinoma (ACC) which can sometimes be grouped within the NET family.
Other hormones related to ACC include:
Androgens (e.g. Testosterone) – increased facial and body hair, particularly females. Deepened voice in females.
Estrogen – early signs of puberty in children, enlarged breast tissue in males.
Aldosterone – weight gain, high blood pressure.
Adrenal Insufficiency (Addison’s Disease) occurs when the adrenal glands do not produce enough of the hormone cortisol and in some cases, the hormone aldosterone. For this reason, the disease is sometimes called chronic adrenal insufficiency, or hypocortisolism.
A tumour outside the pituitary gland, producing ACTH (also called ectopic ACTH). With NETs, this is normally a pNET, Lung/Bronchial NET or Pheochromocytoma.
Multiple Endocrine Neoplasia (MEN). Please note MEN is a group of distinct syndrome not a tumor. Complex area and tends to be multiple instances of some of the tumours above. For a breakdown of MEN types and locations, check out my MEN blog ‘Running in the Family’
Carcinoid Heart Disease(CHD) (Hedinger syndrome)I’m not really talking directly about a tumour here but thought it would be useful to include a blood test called NT-proBNP. I’ve left a link to my CHD article in the paragraph heading for those who wish to learn more about CHD in general. For those not offered an annual Echocardiogram or are ‘non-syndromic’ there is a screening test that can give an indication of any heart issue which might then need further checks.
The Future – Molecular Markers?
This is testing using DNA and genes. Exciting but complex – check out this article which involved some NETs.
Tumour Markers and Hormone levels – complex subject!
This article is designed for patients to understand in a simple way and only covers the basics. If you are a medical professional, I recommend this artilcle:
Herrera-Martínez, A., Hofland, L., Gálvez Moreno, M., Castaño, J., de Herder, W., & Feelders, R. (2019). Neuroendocrine neoplasms: current and potential diagnostic, predictive and prognostic markers, Endocrine-Related Cancer. Retrieved Apr 5, 2019, from CLICK HERE
This is the second article in the Neuroendocrine Cancer Nutrition series. In the first article, I focused on Vitamin and Mineral deficiency risks for patients and there is a big overlap with the subject of Gastrointestinal Malabsorption. Those who remember the content will have spotted the risks pertaining to the inability to absorb particular vitamins and minerals. This comes under the general heading of Malabsorption and in Neuroendocrine Cancer patients, this can be caused or exacerbated by one or more of a number of factors relating to their condition. It’s also worth pointing out that malabsorption issues can be caused by other reasons unrelated to NETs. Additionally, malabsorption and nutrient deficiency issues can form part of the presenting symptoms which eventually lead to a diagnosis of Neuroendocrine Cancer; e.g. in my own case, I was initially diagnosed with Iron Deficiency Anemia in association with some weight loss. Even after diagnosis, these issues still need to be carefully monitored as they can manifest as part of the consequences of having cancer and cancer treatment.
Malabsorption will present via several symptoms which may be similar to other issues (i.e. they could masquerade as, or appear to worsen the effect of a NET Syndrome). These symptoms may include (but are not limited to) tiredness/fatigue/lethargy, stomach cramps, diarrhea, steatorrhea (see below), weight loss. Some of these symptoms could be a direct result of nutrient deficiencies caused by the malabsorption. Some patients (and perhaps physicians?) could mistake these for symptoms of Neuroendocrine disease including certain syndromes, perhaps leading to prescribing expensive and unnecessary drugs when a different (and cheaper) strategy might be better.
Crash Course……. We eat food, but our digestive system doesn’t absorb food, it absorbs nutrients. Food has to be broken down from things like steak and broccoli into its nutrient pieces: amino acids (from proteins), fatty acids and cholesterol (from fats), and simple sugars (from carbohydrates), as well as vitamins, minerals, and a variety of other plant and animal compounds. Digestive enzymes, primarily produced in the pancreas and small intestine (they’re also made in saliva glands and the stomach), break down our food into nutrients so that our bodies can absorb them. If we don’t have enough digestive enzymes, we can’t break down our food—which means even though we’re eating well, we aren’t absorbing all that good nutrition.
What is malabsorption?
The malabsorption associated with Neuroendocrine Cancer is most prevalent with the inability to digest fat properly which can lead to steatorrhea. Patients will recognise this in their stools. They may be floating, foul-smelling and greasy (oily) and frothy looking. Many patients confuse steatorrhea with diarrhea but technically it’s a different issue although both issues may present concurrently. Whilst we all need some fat in our diets (e.g. for energy), if a patient is not absorbing fat, it ends up being wasted in their stools and in addition to the steatorrhea, it can also potentially lead to (unwanted) weight loss and micronutrient deficiencies of the fat-soluble vitamins A, D, E and K. Certain water-soluble vitamins, particularly B3 and B12, are also at risk. Many NET Patients are prescribed a supplement of pancreatic enzymes to combat these issues – see Article 5 in this series – Pancreatic Enzyme Replacement Therapy (PERT).
What causes it with NET Patients?
Structural Changes (i.e. Surgery)
This can play a very big part in malabsorption issues. For example, if a patient has undergone Pancreatic surgery, this will most likely effect the availability of pancreatic (digestive) enzymes needed to break down food. Many Small Intestine NET (SI NET) patients will suffer due to the removal of sections of their ileum, an area where absorption of water-soluble vitamins and other nutrients take place. In fact, the terminal ileum is really the only place where B12 is efficiently absorbed. Low B12 is known to cause fatigue. Some patients with Gastric tumours succumb to pernicious anemia with the most common cause being the loss of stomach cells that make intrinsic factor. Intrinsic factor helps the body absorb vitamin B12 in the intestine. Although a less common tumour location, jejunum surgery could result in loss of nutrients as this section of the small intestine is active in digestive processes. Malabsorption issues for SI NETs are an added complication to the issues caused by a shorter bowel (e.g. faster transit time), something which is regularly assumed to be the effects of one of theNET Syndromes (particularly diarrhea and fatigue), when in actual fact, it’s a simple consequence of cancer treatment and may need a different treatment regime.
Evidence of the problems being caused by the effects of small intestinal surgery can be found in a recently published Swedish study which you can read here: Click here. This particular study recommends supplementation of B12 and D3 for those affected. If you’re having trouble getting your physician to monitor your vitamin levels, show them these studies. I get these vitamins checked annually.
The Gallbladder and Liver
The Gallbladder plays an important part in the digestive system – particularly in fat breakdown. The liver continually manufactures bile, which travels to the gallbladder where it is stored and concentrated. Bile helps to digest fat and the gallbladder automatically secretes a lot of bile into the small intestine after a fatty meal. However, when the gallbladder is removed, the storage of bile is no longer possible and to a certain extent, neither is the ‘on demand automation’. This results in the bile being constantly delivered/trickled into the small intestine making the digestion of fat less efficient. One of the key side effects of Somatostatin Analogues (Octreotide and Lanreotide) is the formation of gall stones and many Neuroendocrine Cancer patients have their gallbladder removed to offset the risk of succumbing to these issues downstream. However, the removal of the gallbladder increases the risk of Bile Acid Malabsorption (BAM) as described below. Any issues with Bile Ducts can also have a similar effect.
The Liver has multiple functions including the production of bile as stated above. However, one of its key functions within the digestive system is to process the nutrients absorbed from the small intestine. If this process is affected by disease, it can potentially worsen the issues outlined above.
Bile Acids Malabsorption
Another risk created by the lack of terminal ileum is Bile Acids Malabsorption (BAM) (sometimes known as Bile Salts Malabsorption and some texts described the resultant diarrhea as ‘Bile Acid Diarrhea”). Bile Acids are produced in the liver and have major roles in the absorption of lipids in the small intestine. Following a terminal ileum resection which includes a right hemicolectomy, there is a risk that excess Bile Acids will leak into the large intestine (colon) via the anastomosis (the new joint between small and large intestines). This leakage can lead to increased motility, shortening the colonic transit time, and so producing watery diarrhea (or exacerbating an existing condition).
Somatostatin Analogues
Somatostatin Analogues can also impact (or worsen) the ability to digest fat as they inhibit the production of pancreatic digestive enzymes (amongst other things). This is a well-known side effect of both Octreotide and Lanreotide. The levels of the fat-soluble vitamins (ADEK) and B vitamins such as B12, need to be monitored through testing and/or in reaction to symptoms of malabsorption. If necessary these issues need to be offset with the use of supplements as directed by your dietician or doctor. Supplements are less affected by malabsorption of nutrients but their efficiency can be impacted by fast gut transit times (thus why testing is important). The evidence and recommendations for malabsorption caused by somatostatin analogues is here: Click Here.
Overlapping Areas
Deficiencies of these vitamins and certain minerals can lead to other conditions/comorbidities, some more serious than others. For a list of the vitamins and minerals most at risk for Neuroendocrine Cancer patients, have a read of my article which was co-authored by Tara Whyand – Vitamin and Mineral deficiency risks.
There is a third article in this series discussing a related issue with Neuroendocrine Cancer, particularly where gut surgery has been performed. You can link directly to this article here – “Gut Health” – (Gut Health, Probiotics and Small Intestinal Bacterial Overgrowth (SIBO)).
The fourth article looks at Amines and why they can cause food reactions or exacerbate syndromes.
Many people also confuse steatorrhea with diarrhea (although these issues can appear simultaneously), again leading to wrong conclusions about the causes and effects, and worryingly, the treatment required. Check out my diarrhea article – click here.
Read a Gut Surgery Diet Booklet authored by Tara – CLICK HERE
Summary
A common problem in patients and from what I see, many just assume this is part of their various syndromes leading to the wrong therapy or no therapy as it’s simply ignored. Again, I remain very grateful to Tara Whyandfor some assistance.
This is a big and complex subject and I only intended to cover the basics. Everyone is different and nothing in here should be accepted as medical advice for you or anyone you know. If you need professional advice, you should speak to your doctor or registered dietitian.
Although initially considered rare tumours up until 10 years ago, the most recent data indicates the incidence of Neuroendocrine Neoplasms (NENs) has increased exponentially over the last 4 decades and they are as common as Myeloma, Testicular Cancer, and Hodgkin’s Lymphoma. In terms of prevalence, NENs represent the second most common gastrointestinal malignancy after colorectal cancer. Consequently, many experts are now claiming NENs are not rare (see below).
A recent study published on 5 Dec 2018 reports that even if you isolate Small Intestine NETs in the USA population, the incidence rate is 9/100,000. Contrast this against the US incidence rate as at 2012 of 7/100,000 for all NETs. The rare threshold in Europe is 5/100,000 and below. They’re not common (in incidence rate terms which means the numbers diagnosed each year) but they are certainly no longer rare, a more accurate description would be ‘uncommon’.
However, on 7th January 2019, an internationally known NET Specialist described NETs as very common but he was talking in terms of the prevalence (how many people are living with the disease)
In fact, the graph of the SEER database figures for NETs in both 2004 and 2012 indicates the rate of incidence increase is faster than any other cancer on the planet, particularly attributed to lung, small intestine, and rectal NETs. The World Health Organisation’s revised classification of Neuroendocrine Neoplasms in 2010, abandoned the division between benign and malignant NET as all NETs have malignant potential and should be graded accordingly. The 2004 SEER data compiled did not take into account what might have been considered to be benign NETs.
However, the most recent USA study up to 2012 has confirmed the incidence beyond 2004 has continued to rise (and rise, and rise, and rise) and this is covered below in the section entitled “Meanwhile inUSA”. One of the principal authors of both database studies has now gone public and said NETs are no longer rare.
Incidence and Prevalence
Before I continue, it’s important to understand the difference between incidence and prevalence. In the crudest of terms, incidence is the number of new cases of a disease being diagnosed (normally aligned to a specific quota of the population per year, generally 100,000). Prevalence normally indicates an amount of people living at any one time with a disease. It’s also important to note that different nations or groups of nations classify ‘rare’ in different ways – not really helpful when looking at worldwide statistics.
So why the increase? I suspect the reasons include (but are not limited to), more awareness (population and medical staff), better detection techniques and probably more accurate reporting systems, at least in USA, Norway, Canada and now in the UK i.e. a mixture of underdiagnoses and misreporting. The Canadian study is important as it also noted the proportion of metastases at presentation decreased from 29% to 13%. This is the first study that suggests an increased incidence of NETs may be due to an increased (and earlier?) detection. This has the knock on effect of increasing prevalence as most NET Cancer patients will normally live for longer periods. Add to this the plethora of better treatments available today, you have a highly prevalent cancer. Most of that is good news.
However, their true incidence may be higher owing to the lack of diagnosis until after death. For example, in USA, a respected NET specialist stated that the autopsy find for (excuse the outdated terminology) ‘carcinoid‘ is 4 times the recorded diagnosis rate. In Australia, one study claimed that 0.05% of all autopsies found a Pheochromocytoma or Paraganglioma. A very interesting slideshow from a well respected NET expert claimed there are 200,000 undiagnosed NET patients in USA. Slide below: You may also wish to check out my article “The Invisible NET Patient Population” where this is explored further.
US SEER 2004 – The Trigger and Turning Point
In the largest study of its kind up to that point, well-known Neuroendocrine Cancer expert James C. Yao researched the Surveillance, Epidemiology and End Results (SEER) database. His team studied 35,825 cases of Neuroendocrine Cancers in the United States covering data between 1973 and 2004. The report concluded that in 2004 there were 5.25 new cases of NETs per 100,000 people, compared with 1.09 per 100,000 in 1973 [1]. This is in contrast to the overall incidence of malignancies, which has remained relatively constant since 1992 (see the yellow line on the graph).The study also pointed out that due to increased survival durations over time, NETs are more prevalent than previously reported. If you analyse the NET data for 1994 (10 years before the end of the study period), you will see an incidence rate of approx 3.25/100,000. In 2004, the incidence rate had risen to 5.25/100,000. Although not an exact science, it does suggest the potential incidence rate at 2014 (10 years after the study period) might possibly have climbed well beyond 6/100,000 and even further if the same rate of increase displayed by the study had continued (spoiler alert – it actually came out as 7/100,000 see below under ‘Meanwhile in USA’). This study also confirmed a prevalence of 103,000 NET patients as at 2004. As this is regarded as the most accurate NET statistic ever produced, it is interesting to note that was at a time when the prognostics for NET were not as good as they are today indicating there must be a very significant increase if extrapolated to the current time. Moreover, this was prior to the WHO 2010 reclassification of NETs so more diagnoses will be counted today that were not counted in 2004. See below to see the significance of this figure (see section ‘Do the math’).
The 2004 data was an astonishing set of statistics – particularly as they were based on 12 year old data. However, there is now new data up to 2012 that overtakes the above-mentioned groundbreaking study and confirmed the incidence is now even higher. See section entitled “Meanwhile inUSA …….”
SEER study 2004 – NETs
Rare but collectively common?
Some will claim that some of the individual types of Neuroendocrine Neoplasm are rare so the disease is rare. That’s clutching at straws really, there’s a rare type of breast cancer but that disease is hardly rare. On that subject let’s talk about something no-one really talks about, Small Cell Lung Cancer (SCLC) which is a type of Neuroendocrine Carcinoma. On it’s own this type is not rare (around 15% of all cancers of the lung).
Pheochromocytoma/Paraganglioma
I suspect on their own, these types of Neuroendocrine Tumours are rare based on the numbers but things are changing. Check out this short video clip from the Pheo/Para Alliance. Let’s do some maths: Based on the US population of 320,000,000, that’s 106,666.
A few more facts about Pheochromoctyoma/Paraganglioma:
In Australia, one study claimed that 0.05% of all autopsies found a Pheochromocytoma or Paraganglioma.
The Mayo Clinic experience shows that in up to 50% of cases of pheochromocytoma, the correct diagnosis is made at autopsy (ergo the incidence rate could be double what is published).
Here is an article claiming that former US President Dwight D Eisenhower had a biopsy confirming he had a Pheochromocytoma. Click here.
Meanwhile in Norway ……
Data from the Norwegian Registry of Cancer showed a similar incidence of Neuroendocrine Cancers with a 72% increase between 2000 and 2004 compared with 1993–1997[2]. Also in Norway, an article published in 2015 entitled “Epidemiology and classification of gastroenteropancreatic neuroendocrine neoplasms using current coding criteria” indicated a high crude incidence of GEP-NEN, at 5·83 per 100 000 inhabitants over the period 2003-2013 (adjusting to 7.64 for Europe in 2013 – see diagram below extracted from cited article 2a). It was also noted together with the statement “….a significant increasing trend over time”. [2a] Citation [2b]
Meanwhile in Canada …….
CNETs have highlighted an article published in the magazine ‘Cancer’, February 15, 2015, showing that the incidence of Neuroendocrine Tumours has markedly increased in Canada over the course of 15 years (1994-2009). The results showed that the incidence of Neuroendocrine Tumours has increased from 2.48 to 5.86 per 100,000 per year.[3] [4]
Meanwhile in UK …….
The latest figures from Public Health England (PHE) indicate the incidence of NETs has risen to almost 9/100,000 (i.e. not rare) using the latest International Classification of Diseases for Oncology (ICD-O) methodology version 3 – ICD-O-3. Even that figure is understated because it does not include Lung Neuroendocrine Carcinomas (i.e. SCLC and LCNEC). As at 31 Mar 2016, the age-standardised incidence rate for NETs in England (excluding small and large cell neuroendocrine carcinomas, SCLC and LCNEC respectively) was 8.84, 8.37 in males and 9.30 in females – rising from 3.9 in 2001. These figures are from the NET Patient Foundation and were issued as a result of a NPF and PHE (NCRAS) partnership project which has been compiling statistics on the incidence, prevalence and survival of NET Patients in England using English cancer registry data. They also have an aim to also access the rest of UK cancer registry data to get UK wide figures.
A slide from the recent UKINETS 2017 conference indicating an agreement from UK and Ireland NET Specialists.
as presented at UKINETS 2017
Meanwhile in New Zealand …….
as presented by Unicorn Foundation NZ on 11 Mar 2017
Meanwhile in USA …….
The latest evidence of its rise is contained in the largest ever study ever conducted. It is based on data up to 2012 so it’s worth noting that in 2019, this data is now 7 years old (5 years for the project prevalence figure), so even these figures may still be conservative. The document, which was published in 2017 can be found here: Click here. A short summary follows:
In this population-based study that included 64 971 patients with neuroendocrine tumors, age-adjusted incidence rates increased 6.4-fold between 1973 and 2012, mostly for early stage tumors. Survival for all neuroendocrine tumors has improved, especially for distant stage gastrointestinal and pancreatic neuroendocrine tumors.
Of the 64 971 cases of NETs, 34 233 (52.7%) were women. The age-adjusted incidence rate increased 6.4-fold from 1973 (1.09 per 100 000) to 2012 (6.98 per 100 000). This increase occurred across all sites, stages, and grades. In the SEER 18 registry grouping (2000-2012), the highest incidence rates were 1.49 per 100 000 in the lung, 3.56 per 100 000 in gastroenteropancreatic sites, and 0.84 per 100 000 in NETs with an unknown primary site. The estimated 20-year limited-duration prevalence of NETs in the United States on January 1, 2014, was 171 321
Conclusion: The incidence and prevalence of NETs have continued to rise in the United States, owing to the increased diagnosis of early-stage disease and possibly stage migration. The survival of patients with NETs has improved, and this improvement has been greater for those with distant gastrointestinal NETs and, in particular, distant pancreatic NETs.
Combine that with a revised annual incidence rate of 23,000 and the very well known fact that NETs is a highly prevalent disease, it must be mathematically impossible for the figure not to be above the USA rare threshold of 200,000 in 2017. As you can see from the graph below, the incidence rate for NETs continues to outstrip the incidence rate for all malignant neoplasms (another word for tumour). Amazingly, the report authors even state “…….. it is likely that we have underestimated their true incidence and prevalence”.
NET Cancer diagnoses continues to outstrip all other cancer diagnoses
The NET Research Foundation published an amazing infographic which summarises the output of the SEER 2012 study (although it does omit the prevalence figure ‘as at’ date). See it below and you can read the accompanying text here.
Graphic from the NET Research Foundation – https://netrf.org/study-shows-rising-rates-of-net-incidence-prevalence-and-survival/
Let’s do the Math
Neuroendocrine Cancer is not only the fastest growing cancer in incidence terms but as a group of cancers, given the mounting epidemiological evidence, it can no longer be rare as a grouping of cancers. Neuroendocrine disease IS NOT RARE.
For example, if you roughly extrapolate the US SEER data graph above to 2017 and recalculate the prevalence rate based on 23 000 per year from the 2014 figure of 171 321. Unfortunately, some people will have passed, but it’s well documented as a highly prevalent cancer and therefore more people live. The prevalence of neuroendocrine tumors in USA was higher than the combined estimated prevalence of esophageal cancer (n = 36,857), gastric adenocarcinoma (n = 79,843) and pancreatic adenocarcinoma (n = 49,620) in 2013. In fact, one of the conclusions of the 2012 SEER report is that we are living longer with NETs. This is in line with many other cancers due to improved diagnostic and treatment regimes. Cleary more work still needs doing.
Dr Kunz has done the mathDr Hendifar has done the mathDr Yao has done the mathDr Singh has done the mathDr Strosberg has done the math
The heading of this section is my name for those who have not yet been diagnosed with NETs but are walking around having been either misdiagnosed, diagnosed with another cancer in the same part of the anatomy, living and putting up with the symptoms whilst the tumours grow. Read my Invisible NET Patient Population article here. To add to this part of the underdiagnoses of NETs is this most amazing piece of research published in 2018 – Pan-cancer molecular classes transcending tumor lineage across 32 cancer types, multiple data platforms, and over 10,000 cases. It was published in the American Association of Cancer Research (AACR) journal ‘Clinical Cancer Research and authored by Chad Creighton et al. DOI: 10.1158/1078-0432.CCR-17-3378. This was a pan cancer piece of research which indicated that Neuroendocrine disease may be more prevalent than anyone had ever thought. There’s a summary article here which I suggest you read fully. The rather explosive extract is as follows:
Go figure
Whilst reporting has been improved, it is most likely still not 100% accurate. Therefore, even the figures above may be understated due to an incorrect cause of death reporting and incorrect diagnosis/recording of the wrong cancers (e.g. pNETs recorded as Pancreatic Cancer, Lung NETs recorded as Lung Cancer, etc). This is certainly still happening in UK and I suspect in most other countries. Add to that the regular reports of Neuroendocrine Tumours being found during autopsies and you have the potential for an even further unrecorded increase had these been found prior to death. In fact, according to SEER 2012, the true incidence and prevalence is most likely underestimated. In fact here is a statement straight from the horse’s mouth:
more math
The issue is also complicated by the method used in USA for naming a disease ‘rare’. Rather than use incidence rates, the USA uses the number of people living with the disease at any one time (i.e. essentially the prevalence). This is currently 200,000 as a threshold – anything below that is considered rare. It seems mathematically impossible for NETs to be less than 200,000 given the data provided above.
When I first started researching NETs back in 2010, the US figure (which varies from source to source) was around 125-150,000. Why are people quoting figures less than this in 2017 when the 2014 figure has now been confirmed above? There also seems to be a selective omission of the new US incidence rate of 7/100,000.
You will also see that Dana Farber is estimating more than 200,000 people are as yet undiagnosed. Even if that were 50% accurate, it would put the current prevalence figure in US over 300,000.
Let’s cut to the chase – NETs are not rare, they are just less common
Are we shouting loud enough about this? I don’t think so. ‘Rare’ is very frequently used within the NET community almost to the point of being a status symbol. Based on these figures, this looks like an outdated approach along with its associated icons. The evidence above is so compelling that saying the group of cancers officially called Neuroendocrine Neoplasms is rare is starting to sound like fake news.
“A neoplasm on the rise. More prevalent than you may think. Incidence increased dramatically during past 3 decades” (Novartis)
“it’s less rare than we used to think. It’s more malignant than we previously thought” (Dr Richard Warner)
“…..it is one of the most rapidly increasing cancers in the U.S. There has been a 500-percent increase in the last 30 years” (Dr Edward Wolin)
“Estimated more than 200,000 undiagnosed cases in the US” (Dana Farber)
“I actually think NETs are not a rare cancer” (Dr James Yao)
“NETS will no longer be rare” (UKINETS 2017 one of the opening slides)
“NETs are no longer rare” (Dr Andrew Hendifar)
“…..when you think of prevalence, NETs are actually quite common” (Dr Jonathan Strosberg)
“One study showed that the number of people diagnosed has risen 50% over the last decade and unfortunately, I worry that is an underestimate” (Dr Eric Liu)
“Neuroendocrine Cancer – NETs are not rare, just less common. We need a new paradigm” (Ronny Allan since 2015)
At the end of 2014, I was feeling pretty good celebrating 4 years since my first ‘big’ surgery in 2010. It prompted me to write an article Surgery – the gift that keeps on giving. In that particlar article, I really just wanted to say I was grateful for the early surgical treatment and as I was just about to spend another Christmas with my family, I was reminiscing what a wonderful gift it was at the time. Other than some detail of the surgery, I didn’t get too technical, I just wanted to generate a thankful and festive mood. However, a recent private message from a subscriber prompted me to study the current benefits of surgery for Neuroendocrine Tumours (NETs) in more detail just to ensure my understanding was still in line with best practice.
It’s very well known that NETs can present a major challenge to physicians in their recognition and treatment requirements. For example, NETs can cause various syndromes, not only for requiring treatment for primary and loco-regional tumours to minimise the risk of abdominal complications and future growth; but also for removal of tumour including liver and other metastases to palliate hormonal symptoms. Some tumours can be quite large and require extensive surgery to remove.
I searched reputable websites and European and North American NET treatment guidelines to find that surgical treatment of these tumours still appears to remain an important intervention, not just for curative treatment (where this is possible) but also for symptom palliation and survival. Although more treatment modalities are available than ever before (e.g. radiotherapy including PRRT, liver embolisation, liver ablation, somatostatin analogues and other new drugs, some with chemo combinations), surgery still appears to be the mainstay treatment to be offered when it is appropriate. For some it isn’t appropriate or will be held in reserve for watch and wait scenarios or as ‘adjuvant’ treatment downstream. On paper, it appears to be the only current option for a curative scenario if the cancer is caught early enough.
I had an amazing surgeon with an impressive CV in Neuroendocrine disease. He believes in early and aggressive surgery (within normal guidelines) and always in conjunction with other treatment modalities and only when required. I found a video of one of his lectures which you may find useful. Another surgeon who talks with knowledge and passion is Dr Pommier and one of his videos can be viewed here. I’m sure there are many others. They are different characters but they both seem to believe in getting as much tumour out as early as possible and also emphasise that sometimes it can be too risky so the focus moves to other treatment. Both presentations provide statistical evidence that debulking/cytoreductive surgery can often offer a better outlook even for those with advanced neuroendocrine disease.
I think I have a soft spot for surgeons – they also seem to love their job despite it being particularly ‘gory’. On the subject of ‘gory’, I recently came across another surgical video which I found totally fascinating. This one contains amazing footage of real surgery and if you are like me, you will find this very educational. It’s also fairly recent (2014) so perhaps offers more up to date techniques. It’s also a very well structured presentation. Some of you may have seen it before and some of you could even have even been at the presentation! If you don’t have time, skip forward to approximately ’19 minutes’ and watch them take out large and small tumours of the liver using a technique called enucleation! (Click here to watch).
Hope you enjoyed this session as much as I enjoyed writing it!
Until I was diagnosed with metastatic Neuroendocrine Cancer, I didn’t have a clue about hormones – it’s one of those things you just take for granted. However, hormones are vital to human health (male and female) and it’s only when things go wrong you suddenly appreciate how important they are ……..like a lot of other things in life I suppose! The presence of over-secreting hormones (often called peptides throughout) is useful to aid diagnosis albeit it often means the tumours have metastasized. It’s also a frequent indication that the person has an associated NET syndrome.
This is a really complex area and to understand the hormone problems associated with Neuroendocrine Cancer, you need to have a basic knowledge of the endocrine and neuroendocrine systems. I’ve no intention of explaining that (!) – other than the following high level summary:
Glands in the endocrine system use the bloodstream to monitor the body’s internal environment and to communicate with each other through substances called hormones, which are released into the bloodstream. Endocrine glands include; Pituitary, Hypothalmus, Thymus, Pineal, Testes, Ovaries Thyroid, Adrenal, Parathyroid, Pancreas.
A Hormone is a chemical that is made by specialist cells, usually within an endocrine gland, and it is released into the bloodstream to send a message to another part of the body. It is often referred to as a ‘chemical messenger’. In the human body, hormones are used for two types of communication. The first is for communication between two endocrine glands, where one gland releases a hormone which stimulates another target gland to change the levels of hormones that it is releasing. The second is between an endocrine gland and a target organ, for example when the pancreas releases insulin which causes muscle and fat cells to take up glucose from the bloodstream. Hormones affect many physiological activities including growth, metabolism, appetite, puberty and fertility.
The Endocrine system. The complex interplay between the glands, hormones and other target organs is referred to as the endocrine system.
The Neuroendocrine System. The diffuse neuroendocrine system is made up of neuroendocrine cells scattered throughout the body. These cells receive neuronal input and, as a consequence of this input, release hormones to the blood. In this way they bring about an integration between the nervous system and the endocrine system (i.e. Neuroendocrine). A complex area but one example of what this means is the adrenal gland releasing adrenaline to the blood when the body prepares for the ‘fight or flight’ response in times of stress, ie, for vigorous and/or sudden action.
Hormones – the NET Effect
At least one or more hormones will be involved at various sites and even within certain syndromes, the dominant and offending hormone may differ between anatomical tumour sites. For example, NETs of the small intestine may overproduce serotonin and other hormones which can cause a characteristic collection of symptoms currently called carcinoid syndrome. The key symptoms are flushing,diarrhea and general abdominal pain, loss of appetite, fast heart rate and shortness of breath and wheezing. The main symptom for me was facial flushing and this was instrumental in my eventual diagnosis. The fact that I was syndromic at the point of diagnosis made it easier to discover, albeit the trigger for the investigation was a fairly innocuous event. Other types of NETs are also affected by the overproduction of hormones including Insulinomas, Gastrinomas, Glucagonomas, VIPomas, Somatostatinomas, and others. These can cause their own syndromes and are not part of carcinoid syndrome as some organisations incorrectly state. For more on NET syndromes – Read Here.
So are hormones horrible?
Absolutely not, they are essential to the normal function of the human body. For example if you didn’t have any of the hormone Serotonin in your system, you would become extremely ill. On the other hand, if your glands start secreting too much of certain hormones, your body could become dysfunctional and in some scenarios, this situation could become life threatening. So hormones are good as long as the balance is correct. NET patients with an oversecreting tumor may be classed as “functional”.
Functional tumors make extra amounts of hormones, such as gastrin, insulin, and glucagon, that cause signs and symptoms.
Nonfunctional tumors do not make extra amounts of hormones. Signs and symptoms are caused by the tumor as it spreads and grows. Many NET patients are deemed to be “non-functioning” with normal hormone levels. It’s also accurate to say that many can move from one stage to the other.
Location Location Location
It’s accurate to say that the type and amount of hormone secretion differs between locations or sites of the functional tumor and this can also create different effects. The division of NETs into larger anatomical regions appears to differ depending on where you look but they all look something likes this:
Foregut NETs: In the respiratory tract, thymus, stomach, duodenum, and pancreas. This group mostly lack the enzyme aromatic amino decarboxylase that converts 5-HTP (5-Hydroxytryptophan – a precursor to serotonin) to serotonin (5-HT); such tumours tend to produce 5-HTP and histamine instead of serotonin.
The Pancreas is a particularly prominent endocrine organ and can produce a number of different syndromes each with their associated hormone oversecretion – although many can be non-functional (at least to begin with), (see below for more detail). It’s also possible to see predominantly serotonin secreting tumors in places such as the pancreas (although what you would call that type of NET is open for debate).
Lung NETs rarely produce serotonin, but may instead secrete histamine causing an ‘atypical’ carcinoid syndrome with generalized flushing, diarrhea, periorbital oedema, lacrimation and asthma. They may also produce adrenocorticotropic hormone (ATCH) or corticotropin-releasing factor (CRP), resulting in an ectopic Cushing’s syndrome. Please note the respiratory tract and thymus are not really anatomically pure ‘Foregut’ – but in NETs, grouped there for convenience.
Gastric (Stomach) NETs. Gastrin is the main hormone but there can also be histamine producing an atypical carcinoid syndrome effect.
Midgut NETs: In the small intestine, appendix, and ascending colon. For example, serotonin secreting tumors tend to be associated with carcinoid syndrome which tends to be associated with midgut NETs and this is normally the case. Many texts will also tell you that a syndrome only occurs at a metastatic stage. Both are a good rule of thumb but both are technically incorrect. For example, ovarian NETs can have a form of carcinoid syndrome without liver metastasis (tends to be described as atypical carcinoid syndrome).
Hindgut NETs (transverse, descending colon and rectum) cannot convert tryptophan to serotonin and other metabolites and therefore rarely cause carcinoid syndrome even if they metastasise to the liver.
Less Common Locations – there are quite a few less common NET locations which may involve less common hormones – some are covered below including the key glands contributing to NETs.
Unknown Primary? – One clue to finding the primary might be by isolating an offending hormone causing symptoms.
The key NET hormones
Serotonin
I used the example of Serotoninabove because it is the most cited problem with NET Cancer although it does tend to be most prevalent in midgut tumors. Serotonin is a monoamine neurotransmitter synthesized from Tryptophan, one of the eight essential amino acids (defined as those that cannot be made in the body and therefore must be obtained from food or supplements). About 90% of serotonin produced in the body is found in the enterochromaffin cells of the gastrointestinal (GI) tract where it is used mainly to regulate intestinal movements amongst other functions. The remainder is synthesized in the central nervous system where it mainly regulates mood, appetite, and sleep. Please note there is no transfer of serotonin across the blood-brain barrier.
Alterations in tryptophan metabolism may account for many symptoms that accompany carcinoid syndrome. Serotonin in particular is the most likely cause of many features of carcinoid syndrome as it stimulates intestinal motility and secretion and inhibits intestinal absorption. Serotonin may also stimulate fibroblast growth and fibrogenesis and may thus account for peritoneal and valvular fibrosis encountered in such tumours; serotonin, however, it is said not to be associated with flushing. The diversion of tryptophan to serotonin may lead to tryptophan deficiency as it becomes unavailable for nicotinic acid synthesis, and is associated with reduced protein synthesis and hypoalbuminaemia; this may lead to the development of pellagra (skin rash, glossitis, stomatitis, confusion/dementia).
Serotonin is also thought to be responsible for ‘right sided’ heart disease (Carcinoid Heart Disease). It is thought that high levels of serotonin in the blood stream damages the heart, leading to lesions which cause fibrosis, particularly of the heart valves. This generally affects the right side of the heart when liver metastases are present. The left side of the heart is usually not affected because the lungs can break down serotonin. Right sided heart failure symptoms include swelling (edema) in the extremities and enlargement of the heart.
Whilst serotonin can be measured directly in the blood, it’s said to be more accurate to measure 5HIAA (the output of serotonin) via blood or urine, the latter is said to be the most accurate.
Tachykinins
Tackykinins include Substance P, Neurokinin A, Neuropeptide K and others. They are active in the enterochromaffin cells of the GI tract but can also be found in lung, appendiceal and ovarian NETs, and also in Medullary Thyroid Carcinoma and Pheochromocytomas. They are thought to be involved in flushing and diarrhea in midgut NETs. The most common tachykinin is Substance P, which is a potent vasodilator (substances which open up blood vessels). Telangiectasias are collections of tiny blood vessels which can develop superficially on the faces of people who have had NETs for several years. They are most commonly found on the nose or upper lip and are purplish in color. They are thought to be due to chronic vasodilatation.
Histamine
Histamine is a hormone that is chemically similar to the hormones serotonin, epinephrine, and norepinephrine. After being made, the hormone is stored in a number of cells (e.g., mast cells, basophils, enterochromaffin cells). Normally, there is a low level of histamine circulating in the body. However (and as we all know!), the release of histamine can be triggered by an event such as an insect bite. Histamine causes the inconvenient redness, swelling and itching associated with the bite. For those with severe allergies, the sudden and more generalized release of histamine can be fatal (e.g., anaphylactic shock). Mast cell histamine has an important role in the reaction of the immune system to the presence of a compound to which the body has developed an allergy. When released from mast cells in a reaction to a material to which the immune system is allergic, the hormone causes blood vessels to increase in diameter (e.g., vasodilation) and to become more permeable to the passage of fluid across the vessel wall. These effects are apparent as a runny nose, sneezing, and watery eyes. Other symptoms can include itching, burning and swelling in the skin, headaches, plugged sinuses, stomach cramps, and diarrhea. Histamine can also be released into the lungs, where it causes the air passages to become constricted rather than dilated. This response occurs in an attempt to keep the offending allergenic particles from being inhaled. Unfortunately, this also makes breathing difficult. An example of such an effect of histamine occurs in asthma. Histamine has also been shown to function as a neurotransmitter (a chemical that facilitates the transmission of impulses from one neural cell to an adjacent neural cell).
In cases of an extreme allergic reaction, adrenaline is administered to eliminate histamine from the body. For minor allergic reactions, symptoms can sometimes be lessened by the use of antihistamines that block the binding of histamine to a receptor molecule. Histamine is thought to be involved with certain types and locations of NET, including Lung and foregut NETs where they can cause pulmonary obstruction, atypical flush and hormone syndromes.
Histamine, another amine produced by certain NETs (particularly foregut), may be associated with an atypical flushing and pruritus; increased histamine production may account for the increased frequency of duodenal ulcers observed in these tumours.
Kallikrein
Kallikrein is a potent vasodilator and may account for the flushing and increased intestinal mobility.
Prostaglandins
Although prostaglandins are overproduced in midgut tumours, their role in the development of the symptoms of carcinoid syndrome is not well established but triggering peristalsis is mentioned in some texts.
Bradykinin
Bradykinin acts as a blood vessel dilator. Dilation of blood vessels can lead to a rapid heartbeat (tachycardia) and a drop in blood pressure (hypotension). Dilation of blood vessels may also be partly responsible for the flushing associated with carcinoid syndrome.
Gastrin
Gastrin is a hormone that is produced by ‘G’ cells in the lining of the stomach and upper small intestine. During a meal, gastrin stimulates the stomach to release gastric acid. This allows the stomach to break down proteins swallowed as food and absorb certain vitamins. It also acts as a disinfectant and kills most of the bacteria that enter the stomach with food, minimising the risk of infection within the gut. Gastrin also stimulates growth of the stomach lining and increases the muscle contractions of the gut to aid digestion. Excess gastrin could indicate a NET known as a Gastric NET (stomach) or a pNET known as Gastrinoma (see pancreatic hormones below).
Endocrine Organs
Thyroid Gland
Calcitonin is a hormone that is produced in humans by the parafollicular cells (commonly known as C-cells) of the thyroid gland. Calcitonin is involved in helping to regulate levels of calcium and phosphate in the blood, opposing the action of parathyroid hormone. This means that it acts to reduce calcium levels in the blood. This hormone tends to involve Medullary Thyroid Carcinoma and Hyperparathyroidism in connection to those with Multiple Endocrine Neoplasia. Worth also pointing out the existence of Calcitonin Gene-Related Peptide (CGRP) which is a member of the calcitonin family of peptides and a potent vasodilator. Please note that hypothyroidism is often a side effect of NETs or treatment for NETs – please click here to read about the connection.
Pituitary Gland
HPA AXIS – It’s important to note something called the HPA axis when discussing pituitary hormones as there is a natural and important connection and rhythm between the Hypothalamus, Pituitary and the Adrenal glands. However, I’m only covering the pituitary and adrenal due to their strong connection with NETs.
Adrenocorticotropic hormone (ATCH) is made in the corticotroph cells of the anterior pituitary gland. It’s production is stimulated by receiving corticotrophin releasing hormone (CRH) from the Hypothalamus. ATCH is secreted in several intermittent pulses during the day into the bloodstream and transported around the body. Like cortisol (see below), levels of ATCH are generally high in the morning when we wake up and fall throughout the day. This is called a diurnal rhythm. Once ACTH reaches the adrenal glands, it binds on to receptors causing the adrenal glands to secrete more cortisol, resulting in higher levels of cortisol in the blood. It also increases production of the chemical compounds that trigger an increase in other hormones such as adrenaline and noradrenaline. If too much is released, The effects of too much ATCH are mainly due to the increase in cortisol levels which result. Higher than normal levels of ATCH may be due to:
Cushing’s disease – this is the most common cause of increased ATCH. It is caused by a tumor in the pituitary gland (PitNET), which produces excess amounts of ATCH. (Please note, Cushing’s disease is just one of the numerous causes of Cushing’s syndrome). It is likely that a Cortisol test will also be ordered if Cushing’s is suspected.
A tumour outside the pituitary gland, producing ATCH is known as an ectopic ATCH. With NETs, this is normally a pNET, Lung/Bronchial/Pulmonary NET or Pheochromocytoma.
Adrenal Glands
Adrenaline and Noradrenline
These are two separate but related hormones and neurotransmitters, known as the ‘Catecholamines’. They are produced in the medulla of the adrenal glands and in some neurons of the central nervous system. They are released into the bloodstream and serve as chemical mediators, and also convey the nerve impulses to various organs. Adrenaline has many different actions depending on the type of cells it is acting upon. However, the overall effect of adrenaline is to prepare the body for the ‘fight or flight’ response in times of stress, i.e. for vigorous and/or sudden action. Key actions of adrenaline include increasing the heart rate, increasing blood pressure, expanding the air passages of the lungs, enlarging the pupil in the eye, redistributing blood to the muscles and altering the body’s metabolism, so as to maximise blood glucose levels (primarily for the brain). A closely related hormone, noradrenaline, is released mainly from the nerve endings of the sympathetic nervous system (as well as in relatively small amounts from the adrenal medulla). There is a continuous low-level of activity of the sympathetic nervous system resulting in release of noradrenaline into the circulation, but adrenaline release is only increased at times of acute stress. These hormones are normally related to adrenal and extra adrenal NETs such as Pheochromocytoma and Paraganglioma. Like serotonin secreting tumours, adrenal secreting tumours convert the offending hormone into something which comes out in urine. In fact, this is measured (amongst other tests) by 24 hour urine test very similar to 5HIAA (with its own diet and drug restrictions). It’s known as 24-hour urinary catacholamines and metanephrines. Worth noting that adrenaline is also known as Epinephrine (one of the 5 E’s of Carcinoid Syndrome).
Cortisol
This is a steroid hormone, one of the glucocorticoids, made in the cortex of the adrenal glands and then released into the blood, which transports it all round the body. Almost every cell contains receptors for cortisol and so cortisol can have lots of different actions depending on which sort of cells it is acting upon. These effects include controlling the body’s blood sugar levels and thus regulating metabolism acting as an anti-inflammatory, influencing memory formation, controlling salt and water balance, influencing blood pressure. Blood levels of cortisol vary dramatically, but generally are high in the morning when we wake up, and then fall throughout the day. This is called a diurnal rhythm. In people who work at night, this pattern is reversed, so the timing of cortisol release is clearly linked to daily activity patterns. In addition, in response to stress, extra cortisol is released to help the body to respond appropriately. Too much cortisol over a prolonged period of time can lead to Cushing’s syndrome. Cortisol oversecretion can be associated with Adrenal Cortical Carcinoma (ACC) which can sometimes be grouped within the NET family.
Other hormones related to ACC include:
Androgens (e.g. Testosterone) – increased facial and body hair, particularly females. Deepened voice in females.
Estrogen – early signs of puberty in children, enlarged breast tissue in males.
Aldosterone – weight gain, high blood pressure.
Adrenal Insufficiency (Addison’s Disease) occurs when the adrenal glands do not produce enough of the hormone cortisol and in some cases, the hormone aldosterone. For this reason, the disease is sometimes called chronic adrenal insufficiency, or hypocortisolism.
Parathyroid
Parathyroid hormone (PTH) is secreted from four parathyroid glands, which are small glands in the neck, located behind the thyroid gland. Parathyroid hormone regulates calcium levels in the blood, largely by increasing the levels when they are too low. A primary problem in the parathyroid glands, producing too much parathyroid hormone causes raised calcium levels in the blood (hypercalcaemia – primary hyperparathyroidism). You may also be offered an additional test called Parathyroid Hormone-Related Peptide (PTHrP). They would probably also measure Serum Calcium in combination with these type of tests. The parathyroid is one of the ‘3 p’ locations often connected to Multiple Endocrine Neoplasia – MEN 1
Pancreatic Hormones (Syndromes)
Pancreatic neuroendocrine tumors form in hormone-making cells of the pancreas. You may see these described as ‘Islet Cells’ or ‘Islets of Langerhans’ after the scientist who discovered them. Pancreatic NETs may also be functional or non-functional:
Functional tumors make extra amounts of hormones, such as gastrin, insulin, and glucagon, that cause signs and symptoms.
Nonfunctional tumors do not make extra amounts of hormones. Signs and symptoms are caused by the tumor as it spreads and grows.
There are different kinds of functional pancreatic NETs. Pancreatic NETs make different kinds of hormones such as gastrin, insulin, and glucagon. Functional pancreatic NETs include the following:
Gastrinoma: A tumor that forms in cells that make gastrin. Gastrin is a hormone that causes the stomach to release an acid that helps digest food. Both gastrin and stomach acid are increased by gastrinomas. When increased stomach acid, stomach ulcers, and diarrhea are caused by a tumor that makes gastrin, it is called Zollinger-Ellison syndrome. A gastrinoma usually forms in the head of the pancreas and sometimes forms in the small intestine. Most gastrinomas are malignant (cancer).
Insulinoma: A tumor that forms in cells that make insulin. Insulin is a hormone that controls the amount of glucose (sugar) in the blood. It moves glucose into the cells, where it can be used by the body for energy. Insulinomas are usually slow-growing tumors that rarely spread. An insulinoma forms in the head, body, or tail of the pancreas. Insulinomas are usually benign (not cancer).
Glucagonoma: A tumor that forms in cells that make glucagon. Glucagon is a hormone that increases the amount of glucose in the blood. It causes the liver to break down glycogen. Too much glucagon causes hyperglycemia (high blood sugar). A glucagonoma usually forms in the tail of the pancreas. Most glucagonomas are malignant (cancer).
Pancreatic Polypeptide (PPoma). A pancreatic polypeptide is a polypeptide hormone secreted by the pancreatic polypeptide (PP) cells of the islets of Langerhans in the endocrine portion of the pancreas. Its release is triggered in humans by protein-rich meals, fasting, exercise, and acute hypoglycemia and is inhibited by somatostatin and intravenous glucose. The exact biological role of pancreatic polypeptide remains uncertain. Excess PP could indicate a pNET known as PPoma.
Other types of tumors: There are other rare types of functional pancreatic NETs that make hormones, including hormones that control the balance of sugar, salt, and water in the body. These tumors include:
VIPomas, which make vasoactive intestinal peptide. VIPoma may also be called Verner-Morrison syndrome, pancreatic cholera syndrome, or the WDHA syndrome (Watery Diarrhea, Hypokalemia (low potassium)and Achlorhydria).
Somatostatinomas, which make somatostatin. Somatostatin is a hormone produced by many tissues in the body, principally in the nervous and digestive systems. It regulates a wide variety of physiological functions and inhibits the secretion of other hormones, the activity of the gastrointestinal tract and the rapid reproduction of normal and tumour cells. Somatostatin may also act as a neurotransmitter in the nervous system.
Having certain syndromes can increase the risk of pancreatic NETs.
Anything that increases your risk of getting a disease is called a risk factor. Having a risk factor does not mean that you will get cancer; not having risk factors doesn’t mean that you will not get cancer. Talk with your doctor if you think you may be at risk. Multiple endocrine neoplasia type 1 (MEN1) syndrome is a risk factor for pancreatic NETs.
Signs and symptoms of pancreatic NETs
Signs or symptoms can be caused by the growth of the tumor and/or by hormones the tumor makes or by other conditions. Some tumors may not cause signs or symptoms. Check with your doctor if you have any of these problems.
Signs and symptoms of a non-functional pancreatic NET
A non-functional pancreatic NET may grow for a long time without causing signs or symptoms. It may grow large or spread to other parts of the body before it causes signs or symptoms, such as:
Diarrhea.
Indigestion.
A lump in the abdomen.
Pain in the abdomen or back.
Yellowing of the skin and whites of the eyes.
Signs and symptoms of a functional pancreatic NET
The signs and symptoms of a functional pancreatic NET depend on the type of hormone being made.
Too much gastrin may cause:
Stomach ulcers that keep coming back.
Pain in the abdomen, which may spread to the back. The pain may come and go and it may go away after taking an antacid.
The flow of stomach contents back into the esophagus (gastroesophageal reflux).
Diarrhea.
Too much insulin may cause:
Low blood sugar. This can cause blurred vision, headache, and feeling lightheaded, tired, weak, shaky, nervous, irritable, sweaty, confused, or hungry.
Fast heartbeat.
Too much glucagon may cause:
Skin rash on the face, stomach, or legs.
High blood sugar. This can cause headaches, frequent urination, dry skin and mouth, or feeling hungry, thirsty, tired, or weak.
Blood clots. Blood clots in the lung can cause shortness of breath, cough, or pain in the chest. Blood clots in the arm or leg can cause pain, swelling, warmth, or redness of the arm or leg.
Diarrhea.
Weight loss for no known reason.
Sore tongue or sores at the corners of the mouth.
Too much vasoactive intestinal peptide (VIP) may cause:
Very large amounts of watery diarrhea.
Dehydration. This can cause feeling thirsty, making less urine, dry skin and mouth, headaches, dizziness, or feeling tired.
Low potassium level in the blood. This can cause muscle weakness, aching, or cramps, numbness and tingling, frequent urination, fast heartbeat, and feeling confused or thirsty.
Cramps or pain in the abdomen.
Facial flushing.
Weight loss for no known reason.
Too much somatostatin may cause:
High blood sugar. This can cause headaches, frequent urination, dry skin and mouth, or feeling hungry, thirsty, tired, or weak.
Diarrhea.
Steatorrhea (very foul-smelling stool that floats).
Gallstones.
Yellowing of the skin and whites of the eyes.
Weight loss for no known reason.
Too much pancreatic polypeptide may cause:
belly pain.
an enlarged liver.
Testing hormones
Clearly the presenting symptoms will give doctors a clue to the oversecreting hormone (see list above). Excessive secretions or high levels of hormones and other substances can be measured in a number of ways. For example:
Well known tests for the most common types of NET include 5-Hydroxyindoleacetic Acid (5-HIAA) 24 hour urine test which is also measured by a blood draw. Note: -tumor markers can be measured simultaneously e.g. Chromogranin A (CgA) blood test and/or Pancreastatin as there can very often be a correlation between tumour mass and tumour secreting activity. CgA / Pancreastatin is a blood test which measures a protein found in many NET tumour cells. These marker tests are normally associated with tumour mass rather than tumour functionality.
By measuring the level of 5-HIAA in the urine or blood, healthcare providers can calculate the amount of serotonin in the body (5-HIAA is a by-product of serotonin). 5-HIAA test is the most common biochemical test for carcinoid syndrome or the degree of how ‘functional’ tumours are. If you’ve understood the text above, you can now see why there are dietary and drug restrictions in place prior to the test.
Pancreatic Hormone testing. There are other tests for other hormones and there is a common test which measured the main hormones seen in NETs. It may be called different things in different countries, but in UK, it’s known as a ‘Fasting Gut Hormone Profile‘.
Scratching the surface here so for a comprehensive list of marker tests for NETs, have aread here.
Treatment for Over-secreting Hormones
Of course, reducing tumour bulk through surgery and other treatment modalities, should technically reduce over-secretion (I suspect that doesn’t work for all). Other treatments may have the dual effect of reducing tumour burden and the effects of hormone oversecretions.
One of the key treatment breakthroughs for many NET cancer patients, is the use of ‘Somatostatin Analogues’ mainly branded as Octreotide (Sandostatin) or Lanreotide (Somatuline). People tend to associate these drugs with serotonin related secretions and tumours but they are in actual fact useful for many others including the pancreatic NETs listed above. Patients will normally be prescribed these drugs if they are displaying these symptoms but some people may be more avid to the drug than others and this may influence future use and dosages. This is another complex area but I’ll try to describe the importance here in basic terms. Somatostatin is a naturally occurring protein in the human body. It is an inhibitor of various hormones secreted from the endocrine system (some of which were listed above) and it binds with high affinity to the five somatostatin receptors found on secretory endocrine cells. NETs have membranes covered with receptors for somatostatin. However, the naturally occurring Somatostatin has limited clinical use due to its short half-life (<3 min). Therefore, specific somatostatin analogues (synthetic versions) have been developed that bind to tumours and block hormone release. Thus why Octreotide and Lanreotide do a good job of slowing down hormone production, including many of the gut hormones controlling emptying of the stomach and bowel. It also slows down the release of hormones made by the pancreas, including insulin and digestive enzymes – so there can be side effects including fat malabsorption.
The recent introduction of Telotristat Ethyl(XERMELO) is interesting as that inhibits a precursor to serotonin and reduces diarrhea in those patients where it is not adequately controlled by somatostatin analogues.
Other than the effects of curative or cytoreductive surgery, some NETs may have very specialist drugs for inhibiting the less common hormone types. This is not an exhaustive list.
Worth also noting that oversecreting hormones can contribute to a phenomenon (currently) known as Carcinoid Crisis – read more here. For catacholamine secreting tumors (Pheochromocytoma/Paraganglioma), this may be known as Intraoperative Hypertensive Crisis
Sorry about the long article – it’s complex and you should always consult your specialist about issues involving hormones, testing for hormones and treating any low or high scores.
There’s a saying that the patient is the most underused person in healthcare and I think there’s a lot of truth in that. However, I would suggest with Neuroendocrine Cancer, it’s less true than for many other cancers. There are so many NET Cancer patients out there who know quite a lot about their cancer, and in some detail. Even the great Dr Liu once said that NET Patients frequently know more about NET Cancer than their doctors.
Chromogranin is an acidic protein released along with catecholamines from chromaffin cells and nerve terminals. This statement alone might explain why it is a good marker to use with NETs. Depending on the test kit being used, you may see test results for Chromogranin A (CgA) and Chromogranin B (CgB) – the inclusion of CgB tends to be confined to Europe. There is also mention of Chromogranin C (CgC) in places but I’ve never heard of this being used in conjunction with NETs.
