Neuroendocrine Cancer: a needle in a haystack, primary vs secondary


needle in a haystack

It’s no secret that Neuroendocrine Cancer can be difficult to diagnose. Although earlier diagnosis is improving (as reported in the SEER database report issued in 2017), there is still a lot of ground to cover. There are a number of reasons why these Neoplasms are often difficult to correctly and quickly  diagnose including but not limited to: – they grow silently, they often produce vague symptoms which can be mistaken for much more common illnesses, and their complexity is not fully understood.

I wanted to cover two different aspects of the problem of finding NETs. Firstly, in finding the primary tumour so that the type of NET can be properly established – this drives the best treatment regime. Secondly in finding all the tumours, as this establishes the correct and most detailed staging declaration – this drives treatment plans and surveillance regimes that need to be put into place.

Hunting Tumours – Primary vs Secondary

It’s really important to determine which tumours are primary and which are secondary (metastasis). There’s a number of ways to help work this out and knowledge of NETs epidemiology studies can help.

Specialist Knowledge – certain things are known about the behaviour of NETs

Specialists and in particular NET specialists will be aware of the vagaries of NETs in terms of what tumours are normally a primary and which are normally secondary and many of the pitfalls involved in working that out. Many NETs will have metastasized to the liver at diagnosis, so whilst it is not impossible to have a primary liver NET, the vast majority of liver tumours found will be secondary (metastases). NET Specialists are more likely to have the experience than generalists. They know that the varying metastatic potential depending on the primary site clearly indicates differing biology and genetics across sites and they know that NETs are indeed a heterogeneous group of tumours.

The differences cannot be explained by whether the NET is situated in the foregut, midgut, or hindgut. For example, Appendiceal NET is known to be less prone to metastasis. This may be due to the high rate of incidental findings during appendectomies, or because the appendix is an immunological organ where malignant cells can therefore be expected to be frequently recognized by the immune system.

The majority of the digestive tract is drained by the portal venous system, explaining the dominance of liver metastases in this group of tumours. This also explains the finding that many nervous system and bone metastases originate from NETs in the lungs. Disseminated tumour cells may directly reach the systemic circulation from the lungs, whereas if originating from the midgut region, they need to first pass both the liver and the lungs.

As an example of this heuristic knowledge, one Swedish study indicated that two-thirds of peritoneal metastases will be attributed to Small Intestine NETs (SI NETs). SI NETs and Pancreatic NETs (pNETs) are the most likely to metastasize. The least likely sites to metastasize are the Appendix and Rectum. The same study indicated that in addition to the common metastatic locations of lymph nodes and liver, Lung NETs are more likely to metastasize to the brain and bone than other types. I believe the findings from this study more or less correlates to other information I’ve had access to and also confirms the technical behaviour paragraph above.

Multiple Primary Tumours

With NETs there are two scenarios:

1. Multiple primaries in same organ/location (multicentric). This is fairly common in small intestine (SI NETs), stomach/gastric NETs (gNETs), and also found in Lung and pNETs too. NET experts will be aware of the issue and know to look for the possibility. This is an important point with SI NETs as the small intestine is a long and winding organ, although held together by the mesentery. So a ‘Mark 1 eyeball’ can normally be more efficient in finding NETs in this organ than scans.  There is a very well known surgical technique called “running the bowel” where they check the small intestine for signs of other primary tumours – they can do the same with the large intestine.  Additional surgeries due to this lack of knowledge could come with significant morbidity. Multiple ‘nodes’ and ‘lesions’ are common in the thyroid.

2. Multiple primaries in different locations. This is common with Multiple Endocrine Neoplasia (MEN) syndromes (the name gives it away) and these may be metasynchronous. MEN1 for example can have tumours in what is called the ‘3 P’ locations, pituitary, pancreas and parathyroid. Of course MEN guys may also have multiple primaries in the same organ (multicentric).  Read more about MEN by clicking here.

There’s probably a third scenario (for all cancers) and that is multiple primaries with different cancers (i.e a second, third and fourth cancer etc). Synchronous would be really unlucky but metasynchonous is more likely and there are many NET patients with a second cancer.

What else helps find a NET? 

There are many other clues open to those involved in diagnosing a NET:

Patient. Very often the patient plays a big part of determining where the primary and other tumours might be by carefully describing symptoms.

Incidental Finds. NETs are very often found incidentally during trips to the ER/A&E and also during tests for something else. This is particularly the case with Appendiceal NETs and might explain why the average age of a patient is significantly lower in this type of NET.

Blood tests and Hormone Markers. We are not yet in a position where these types of tests can diagnose (but we are moving in that direction). In the case of unknown primaries (CUP), sometimes test results can help to find where some of these cancers started. With NETs, symptomatic patients can often test to confirm an elevated hormone marker which may narrow it down to a specific organ or gland. Read more here.

Scans and Endoscopies. Most cancers of a certain size may show up on conventional scanning such as CT, MRI and Ultrasound. Nuclear scans are now playing a bigger part in finding tumours which betray their location through functional behaviour by lighting up or glowing on these imaging devices. Endoscopies (e.g. gastroscopies, colonoscopies, even gastro intestinal pill cameras can be used) can help but like scans are not foolproof). Generally with NETs, if you can see it, you can detect it. Read more here.

Hereditary Conditions. Around 5-10% of NETs are hereditary in nature, mostly involving the MEN group of syndromes. Many of those people will know they are at risk of developing NETs and their doctors should know the most common locations for primary tumours associated with each gene. So a declared or suspected hereditary syndrome is useful in finding primary tumours if they exist and are proving difficult to find.

Biopsies. “Tissue is the issue”. Pathology can very often give really strong clues as to the type of NET and therefore the likely location of a primary tumour, for example additional tests such as immunostains. Many biopsies will come from secondary cancer (metastases), mostly the liver.  Despite all the potential diagnostic routes above, the place the cancer started is sometimes still not found and this may lead to atypical diagnostic/treatment plans and in certain cases this might even include exploratory biopsies via surgery (invasive/minimally invasive), perhaps combined with opportunistic tumour removal if found during the procedure.

Staging. Simple staging can be given if locations of metastases are known. For example in the case of Liver metastases, the stage is automatically Stage 4. However, the full staging definition relies on knowing distant metastases, loco-regional metastases and the full Tumour/Node/Metastases (TNM) definition (size, spread, etc) cannot be fully complete without a primary. Read more here.

Cancers of Unknown Primary

Cancer is always named for the place where it started, called the primary site. Sometimes doctors can’t tell where a cancer may have started. When cancer is found in one or more places where it seems to have spread, but the site where it started is not known, it is called a cancer of unknown primary (CUP) or an occult primary cancer.

When you look at the ratio of all cancers, the figure for cancers of unknown primary (CUP) is quite startling. Depending on where you look the figure is around 2-10%. That doesn’t seem a lot but when you consider the amount of people diagnosed with cancer, the total figure must be staggering. Interestingly, Cancer Research UK say that 60% of CUP cases are in the over 75s. In another interesting Swedish study, doctors claimed that the rates of metastatic cases were higher with certain NETs than they were in their anatomical counterparts, reinforcing the dangerous and sneaky nature of NETs.

Despite quite advanced scanning and diagnostic testing currently in place, and the extensive knowledge of NET specialists, there can still be reasons for not being able to find the primary tumour:

  • The primary is just too small to be seen and is growing quite slow. Very small cancers might not cause symptoms or be seen on scans. This is a particularly relevant point with NETs.
  • The primary could be hidden in tissue in between different organs causing confusion about the actual primary location.
  • The body’s immune system killed the primary cancer. It’s also possible (but not common) that any secondary cancer (i.e. metastases) is still growing.
  • The tumour has become loose from its primary location and exited the body, e.g. from a wall of the bowel and excreted out in the stool.
  • The primary cancer was removed during surgery for another condition and doctors didn’t know cancer had formed. For example, a uterus with cancer may be removed during a hysterectomy to treat a serious infection.

Summary

I hope this is useful for many NET patients, particularly those who are looking for a diagnosis or looking for a primary tumour.

Neuroendocrine Cancer – at times, it can really be like looking for a needle in a haystack.

Thanks for reading

Ronny

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Weight – the NET Effect

Weight – The NET Effect

Firstly, let me say that I have no intention of advising you how to lose or gain weight!  Rather, I’d like to discuss what factors might be involved and why people with NETs might lose or gain weight either at diagnosis or after treatment.  Clearly I can talk freely about my own experience and associated weight issues. If nothing else, it might help some in thinking about what is causing their own weight issues.

I wrote a patient story for an organisation over 3 years ago and it started with the words  “Did you mean to lose weight”.  Those were actually the words a nurse said to me after I nonchalantly told her I thought I’d lost some weight (….about half a stone).  I answered the question with “no” and this response triggered a sequence of events that led to all the stories in all the posts in this blog (i.e. my diagnosis).

I annoyingly can’t remember at which point I started to lose the weight but I was initially reported to have Iron Deficiency Anemia due to a low hemoglobin result and my subsequent iron test (Serum Ferritin) was also low and out of normal range.  This, combined with the weight loss, the GP was spot on by referring me to a clinic.  The sequence of events during the referral led to a diagnosis of metastatic NETs (Small Intestine Primary). If I had been a betting man, I would have put money on my GP thinking “Colorectal Cancer”.  So my adage “If your doctors don’t suspect something, they won’t detect anything” applies.

I can also tell you that I weigh myself most days at the same time using the same scales. Weight loss or gain needs to be recorded.  Clearly 2 or 3 pounds is nothing to worry about, I found you could put on or lose that amount in a day, depending on time of weighing and food intake. I’m looking for downwards or upwards trends of 7lbs or more (3kg).

Why did I lose weight?

The drop from 12st to 11st was clearly something to do with the anemia symptom (the NETs). But after diagnosis, I had major surgery about 10 weeks later.  When I left the hospital after my 19 day stay, I was a whole stone lighter (14 lbs or 6.3 kg).  I guess 3 feet of intestine, the cecum, an ascending colon, a bit of a transverse colon together with an army of lymph nodes and other abdominal ‘gubbins’ actually weighs a few pounds.

However, add the gradual introduction of foods to alleviate pressure on the ‘new plumbing’, and this is also going to have an effect on weight.  I remember my Oncologist after the surgery saying to use full fat milk – the context is lost in memory but I guess he was trying to help me put weight back on.  I also vividly remember many of my clothes not fitting me after this surgery. In fact, since 2010, I’ve actually dropped 2 trouser sizes and one shirt/jumper size.  I did spend a lot of time in the toilet over the coming months, so I guess that also had an impact!  However, what I wasn’t aware of was the side effect of my surgery.  I started to put on some weight in time for my next big surgery – a liver resection.  The average adult liver weighs 1.5 kg so I lost another 1 kg in one day based on a 66% liver resection.

However, what was also going on was something that took me a while to figure out – malabsorption and vitamin/mineral deficiency. My new ‘plumbing’ wasn’t really as efficient as my old one, so the malabsorption. issues caused by a lack of terminal ileum was slowly starting to have an effect. The commencement of Lanreotide in Dec 2010 added to this complication. That knowledge led me to understand some of the more esoteric nutritional issues that can have a big effect on NET patients and actually lead to a host of side effects that might be confused with one of the several NET syndromes.  What it also confirmed to me was that I could still eat foods I enjoy without worrying too much about the effect on my remnant tumours or the threat of a recurrence of my carcinoid syndrome, something I was experiencing prior to and after diagnosis.

Armed with the ‘consequences of NETs’ knowledge, I did eventually adjust my diet and my weight has now ‘flat-lined’ at around 10 st 7 lbs (give or take 1 or 2 lbs fluctuation).  Amazingly, the same weight I was when I left hospital after major surgery, looking thin and gaunt and not very well at all!  The difference to day is that I have adapted to my new weight and look fit and healthy.

I actually lost another half a stone (7 lbs or 3.5 kg) in 2014 whilst training for an 84 mile charity walk – many commented that I looked thin and gaunt despite being extremely fit from all the training. Perspectives.  It took several months to put the weight back on but at least I knew what had caused the loss and then subsequent gain.

I don’t have any appetite issues although I try to avoid big meals due to a shorter gut, so I snack more.  With the exception of the 4 months of intense training for the 84 mile hike, I cannot seem to lose or gain weight.  As my current weight is bang in the middle of the BMI green zone (healthy), I’m content.

Why do NET patients lose weight?

That’s a tricky one but any authoritative resource will confirm fairly obvious things such as (but not limited to) loss of appetite and side effects of cancer treatments.  NETs can be complex so I resorted to researching the ISI Book on NETs, a favourite resource of mine.  I wanted to check out any specific mentions of weight and NETs whether at diagnosis or beyond. Here’s some of the things I found out:

Carcinoid Syndrome.  Weight loss is listed but not as high a percentage as I thought – although it tends to be tied into those affected most with diarrhea.

Gastrinoma/Zollinger-Ellison Syndrome.  Up to half of these patients will have weight loss at diagnosis.

Glucagonoma.  90% will have weight loss.

Pheochromocytoma.   Weight loss is usual.

Somatostatinoma.  Weight loss in one-third of pancreatic cases and one-fifth in intestinal cases.

VIPoma.  Weight loss is usual.

MEN Syndromes.  One of the presentational symptoms can be weight loss.

Secondary Effects of NETs.

Many NETs can result in diabetes (particularly certain pNETs) and as somatostatin analogues can inhibit insulin, it could push those at borderline levels into formal diabetic levels (including any type of NET using long term somatostatin analogues).  In people with diabetes, insufficient insulin prevents the body from getting glucose from the blood into the body’s cells to use as energy. When this occurs, the body starts burning fat and muscle for energy, causing a reduction in overall body weight. 

Hypothyroidism is another potential issue. 

It must be emphasised that there will always be exceptions and the above will not apply to every single patient with one of the above.

Suggested reading for putting weight back after surgery

An excellent reference document produced by Royal Free Hospital, authored by Tara Whyand and distributed via the NET Patient Foundation – hints and tips for different types of NET by anatomy:  click here

What about weight gain?

You always associate weight loss with cancer patients but there are some types of NETs and associated syndromes which might actually cause weight gain.  Here’s what I found from ISI and other sources (as mentioned):

Cushing’s Syndrome.  Centripetal weight gain is mentioned.  (Centripetal – tends to the centre of the body).  I also noted that Cushing’s Syndrome tends to be much more prevalent in females. Cushing’s syndrome comprises the signs and symptoms caused by excessive amounts of the hormone cortisol (hypercortisolism) or by an overdosage of drugs known as glucocorticoids.

Insulinoma. Weight gain occurs in around 40% of cases, because patients may eat frequently to avoid symptoms.  However, according to an Insulinoma support group site, I did note that after treatment (some stability), things can improve.

Again, it must be emphasised that there will always be exceptions and the above will not apply to every single patient with one of the above.  As in weight loss scenarios, the Secondary Effects of NETs can have an effect.  Hypothyroidism is another potential issue and weight gain is a listed symptom.  I just been diagnosed with hypothyroidism this year but I was not gaining weight!  

The NETs Jigsaw

Like anything in NETs, things can get complex.  So it is entirely possible that weight loss or weight gain is directly caused by NETs, can be caused by side effects/secondary effects of treatment, and it’s also possible that it could be something unrelated to NETs (Dr Liu “Even NET patients get regular illnesses“).  I guess some people might have a good idea of the reason for theirs – my initial weight loss was without doubt caused by the cancer and the post diagnostic issues caused by the consequences of the cancer.

Summary

I guess that weight loss or weight gain can be a worry. I also suspect that people might be happy to lose or gain weight if they were under/over weight before diagnosis (every cloud etc).  However, if you are progressively losing weight, I encourage you to seek advice soonest or ask to see a dietician (preferably one who understands NETs).

Edit:  I changed my blood thinner in May 2017 and lost 2kg (4 pounds) after 6 months.

Edit: I started Creon at the beginning of 2018 (read about this here) and almost immediately put on 2kg (4 pounds) to offset the 2kg loss from 6 months prior.  However, no real change after 3 months of Creon (March 2018).

Edit: I was recently diagnosed with Hypothyroidism, one of the symptoms can be weight gain.  Clearly that has not applied to me.  Hyperthyroidism is the opposite condition where weight loss is a symptom.

Edit: Due to a bad chest infection in June 2018 and due to the consequences of the effects of that illness and most likely the treatments undergone, I have dropped three quarters of a stone (~10lbs).  My lightest weight for over 30 years.   To me that is a significant loss of weight in such a short space of time. Currently trying to put it back on again – I need the weight!

Edit: 4 Sep 2018. After the 10lbs (~4.5kg) loss following the chest infection, people who see me regularly have noticed the visible difference. I’m still struggling to get back beyond 10st after 2 months. I’m monitoring this really closely.

Edit: 28 Nov 2018. I’m back at 10st after increasing my dosage of Creon.

Edit: 10 Jan 2019.  I’m back at 10st 3lbs, my approximate weight before the chest infection.  It’s taken 7 months and the recent acceleration coincides with Creon dose increase.

Edit 7th Feb 2019.  Changed from Creon to Nutrizym.

Edit: 17 Mar 2019.  It appears my trouser waist size is back to 32″.  Is the use of Pancreatic Enzymes making me eat more, or getting more nutrients through, or making me eat food which makes me put on weight?

For those wishing to see the output from an online discussion with Tara Whyand on the subject of ‘Weight’ issues for NET patients – please see this link inside my closed Facebook group.

weight online chat
Click the Link to see the online event output

Thanks for reading

Ronny

I’m also active on Facebook. Like my page for even more news. I’m also building up this site here: Ronny Allan

Disclaimer

My Diagnosis and Treatment History

Most Popular Posts

Sign up for my twitter newsletter

Read my Cure Magazine contributions

Remember ….. in the war on Neuroendocrine Cancer, let’s not forget to win the battle for better quality of life!

patients included

Please Share this post