The Invisible NET Patient Population 

The Invisible NET Patinet Population



I found some of the quotes from the recent NET SEER Database study (Dasari et al) very interesting.  The National Cancer Institute’s Surveillance, Epidemiology, and End Results (SEER) Program is a comprehensive source of population-based information initiated in 1973 that is updated annually. Although the study is US-based, it represents the largest study of Neuroendocrine Tumors (NETs) ever recorded and is therefore a good guide to what might be found beyond USA. In fact, other national declarations of incidence and prevalence of NETs seem to bear these statistics out, i.e incidence rates of 7-8/100,000 …… almost 7 times the rate recorded in the 1970s. If you want to understand the factors behind this massive increase, I covered this extensively in my post “Neuroendocrine Tumors – not as rare as you think“.  In this article, I looked at USA and beyond. Those who are regular readers of my articles will already know I’ve been ‘banging on’ about this for a few years. Other organisations and individuals (including NET specialists) are now indicating these tumors are not rare, some vindication for my aforementioned ‘banging on’.  This is now a serious disease with some serious statistics behind it and we need a new way of doing things.

 There are two further quotes which I’d like to focus on in this article:

1. From the NET SEER Database study published 2017:

…… many cases of NETs may not have been reported to cancer registries unless considered malignant…… it is likely that we have underestimated their true incidence and prevalence” – i.e. the slide here:

SEER 2012 Underestimated

2. From Dana Farber (Kulke, Chan):

“Estimated more than 200,000 undiagnosed cases in the US” – this slide here:


…. But what do these quotes actually mean?  Here’s my take:

Underestimating the true incidence and prevalence of NETs

I studied the latest SEER NET study, formally titled “Trends in the Incidence, Prevalence, and Survival Outcomes in Patients With Neuroendocrine Tumors in the United States” (authored by Arvind Dasari, MD, MS; Chan Shen, PhD; Daniel Halperin, MD; et al). From this document, I can see the authors were aware of the well-known faults in cancer registries worldwide and the effect this has on the true incidence and prevalence of Neuroendocrine Cancer.  These issues, which are a worldwide problem, include the incorrect registration of Neuroendocrine Cancer as other types based on the anatomical location of the primary tumor.  At this point, you may wish to check out my post “The Human Anatomy of Neuroendocrine Cancer” which provides some real life examples of the confusion between primary Neuroendocrine location and other cancers. That said, things are definitely improving because the latest SEER data shows a marked increase in the incidence of High Grade Neuroendocrine Carcinomas (NEC), an area where this issue is prevalent. A similar increase in NEC was also illustrated in the UK’s figures from Public Health England (PHE) in 2016 (click here) indicating that cancer registries are getting better and not before time, although it has to be said this only came about due to a major intervention by NET Patient Foundation and others. Through this work, it’s becoming clear that the incidence of all NETs in UK is around 8 to 9 per 100.000 (rare threshold <=5).

But there’s another issue impacting whether a diagnosis is actually entered on a cancer registry or not.  Unfortunately, there are members of the medical community who still see well differentiated NETs as benign tumors, ‘not a proper cancer’ and still use ancient terminology ………  ‘Carcinoid’.  The WHO 2010 classification for NETs was based on the concept that all NETs have malignant potential. Here’s a quote from the UKINETS Guidelines in 2011 (Ramage, Caplin, Meyer, Grossman, et al).

Tumours should be classified according to the WHO 2010 classification (Bosman FT, Carneiro F, Hruban RH, et al. WHO Classification of Tumours of the Digestive System. Lyon: IARC, 2010). This classification is fundamentally different from the WHO 2000 classification scheme, as it no longer combines stage related information with the two-tiered system of well and poorly differentiated NETs. The WHO 2010 classification is based on the concept that all NETs have malignant potential, and has therefore abandoned the division into benign and malignant NETs and tumours of uncertain malignant potential.

The guidance in WHO 2017 for Endocrine Organs reinforces this statement.

The undiagnosed NET patient population

From above, you can see why the incidence (and therefore the prevalence) of our disease has almost definitely been underestimated.  However, that’s not the end of my story……..

A number of statements are clear about Neuroendocrine Tumors:

  • Low/Intermediate grade well differentiated tumors are known to have been growing slowly over a number of years before discovery or accurate diagnosis occurs,
  • They can be difficult to diagnose,
  • They are not that well-known amongst the general medical population,
  • Many people are initially misdiagnosed with another condition, with some this will result in late presentation with metastatic disease.
  • Many NETs are found during autopsies.

The living undiagnosed. It’s worth pointing out that one of the conclusions made by the recent SEER NET study is that the increase in incidence and prevalence can be attributed to a number of factors including earlier diagnosis.  This is of course excellent news.  Also worth noting that another conclusion of the study is that we are all living longer, reflecting improvements in therapies.  This is also great news and is a factor in increased prevalence figures. However, it seems obvious that there are hundreds of thousands of people out there still be diagnosed who have tumors silently growing inside them and who are in a loop of referrals between primary and secondary care awaiting a proper diagnosis. See the Dana Farber slide above.  Please help these people by sharing this article (you never know who it will reach – Diagnosing the Undiagnosed.

The dead undiagnosed? The true incidence of NETs may be much 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 (based on the known incidence rate at the time, this is 8 per 100,000).
  • 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.
  • A Hong Kong study indicated that 1% of all autopsies discovered an ‘Islet Cell’ tumour (i.e. a Pancreatic NET or pNET).
  • In one series, (excuse the outdated terminology…….) ‘carcinoid’ tumors were found in 1.22% of 16,294 autopsies in Malmö, Sweden, 90% of which were incidental findings.

It’s possible that many of these people showed no NET symptoms during their life but …… it’s equally possible that many of these people had NET symptoms but just put up with it and/or had been diagnosed with something else, and then died without a correct diagnosis.  There is no evidence that any investigation follow ups were done so this possibility remains.

The potential for even more undiagnosed. To add to the underdiagnoses of NETs issue, 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. D.  This was a pan-cancer piece of research which indicated that Neuroendocrine disease may be more prevalent than anyone has ever thought.  There’s a summary article here which I suggest you read fully.  The rather explosive extract is as follows:

We expected that about 1 percent of

Are you undiagnosed but suspect NETs?

Check out my advice by clicking here.


I suspect there’s an invisible patient population for many conditions but the slow-growing and relatively quiet nature of Neuroendocrine Cancer means there could be a significant undiagnosed burden walking around, looking for a diagnosis, putting up with symptoms and being treated for other conditions. I see people on forums looking for clues, social media can sometimes be helpful here. That said, I do get the feeling some do not have NETs, regardless of the symptoms they associate with the disease, but I guess many of them will go on to be formally diagnosed with something. I’m contacted by many ‘undiagnosed’ people on my own blog and supporting Facebook sites (mostly privately) and I can tell you that’s a tough gig.  I only hope I’ve given them some useful ideas about where to look or what to ask/suggest.

I feel earlier diagnosis reported in the SEER study is partly due to increased awareness, particularly in the medical world. I would also suggest that it has improved in the general population due to the explosion of social media information dissemination. It’s also accurate to say that improvements in diagnostic capabilities is also playing its part in pushing up incidence rates, just as improved therapies have pushed up prevalence rates, something emphasised by Dasari (et al) in the most recent study.  Things are improving but there is so much more to do.

The issues caused by inefficient registries together with ‘the undiagnosed’, combine to suggest there is a large invisible NET patient population out there ……. we just need to find them!  

Thanks to NET Patient Foundation for featuring this article here.

NET Patient Foundation logo

Neuroendocrine Cancer: To cut or not to cut?


OPINION – nothing in here should be taken as advice from the author. 

On paper, surgery remains the only potentially ‘curative‘ option for Neuroendocrine Tumours (NETs) but there are stage, grade and anatomical constraints to that opinion. Many people get ‘twitchy’ about any inference of the ‘C word’ (cure) but our most eminent NET specialists use the term frequently including in the major treatment guidelines.

I use the word ‘curative’ with some reservations because for many who are diagnosed at an advanced stage, surgery will not cure but will debulk or cytoreduce as much tumour as possible in order to palliate symptoms and improve quality of life.  This is a big deal because NETs is one of a small number of cancers where debulking surgery can often provide a survival advantage for metastatic cases.  One of the reasons it’s a big deal is because with more aggressive cancers at an advanced stage, surgery just might not be offered. It follows that surgery is most likely adding to the fairly decent NETs survival statistics, including for those with metastatic disease at diagnosis.  More on this below.

That’s a fairly simplistic explanation on behalf of surgery. However, as we all know, nothing in Neuroendocrine Cancer is simple.  There are always a number of factors involved and every decision can in some way be on an individual basis.  There are guidelines for treatment of most types of NETs but ……. they are just that – guidelines.  NET Centres and NET Specialists are encouraged to use these guidelines, for example, a European Centre of Excellence has ENETS Guidelines.  There is a North American equivalent set published by NANETS and NCCN have a decent complementary set.  The UK and Ireland guys (UKINETS) also published a set although many UK centres are ENETS accredited.

Whether to cut or not to cut (or watch and wait then cut if necessary) and the sequencing of treatments is a really difficult issue for NET specialists.  I quite liked watching these two video clips and they cover this issue quite nicely including some interesting abdominal challenges in surgery from known NET Specialists – these short video sessions are highly recommended:

a.  Risk Stratification and Management of NETs – click here

b.  Surgical Considerations for NETs – click here

Surgery can sometimes be a tough call (……to cut or not to cut?)

It is an area where I have some sympathy for physicians and surgeons who sometimes have tough decisions to make. Surgery is risky, particularly where people are presenting in a weak condition, perhaps with very advanced disease, secondary illness and comorbidities.  I also suspect age is a factor (I was surprised to find myself considered ‘young’ at 55).  Physicians and surgeons need to weigh up these risks and the  consequences of the surgery against a ‘watch and wait’ or alternative non-surgical approach.  This would normally be discussed via a ‘Tumor Board’ or Multi-Disciplinary Team (MDT) meeting. However, and although imaging helps, the situation is not really 100% clear until the surgeon ‘gets inside’.  Remember, all physicians and surgeons are bound by the ‘Hippocratic oath’ of “Do no harm“.  Sometimes with NETs, it’s a tough call not only before they go inside but whilst they’re inside.

Surgery should be a carefully considered treatment (…..think before cutting?)

I read many stories from many different parts of the world and I also hear them from people who contact me privately on a daily basis.  Some of them are perplexed why they are not receiving surgery and some are not entirely happy with the surgery they received. Many are perplexed by different advice from different doctors.  I find it very difficult to respond to many. My most frequent answer is “ask your doctor” but I’m normally pretty helpful with the sorts of questions to ask.

One thing which tends to surprise people is speed – or lack of it!  With lower grade NETs, the extent of the tumour (stage), its metastases, histological grade and secretory profile should be determined as far as possible before planning treatment. I like to remind people that in 2010, it took from 26 July to 9 Nov before my body saw a scalpel. With Grade 1/2 well differentiated NETs, you can often get away with that gap.  Sometimes when you are diagnosed with NET, it’s a case of ‘hurry up and wait’.

Back to the guidelines, of course most people will probably fit reasonably well into the relevant guidelines flow chart.  A very generic example here (not for active use please, your area may have an alternative based on availability of treatments etc):

Very generic treatment algorithm UKINETS – Ramage JK, Ahmed A, Ardill J, et al. Guidelines for the management of gastroenteropancreatic neuroendocrine tumours (NETs) Gut 2012;61:6-32.  For example purposes only please.

Timing of Surgery (……to cut now, to cut later?)

Following on from the scenario above, timing of surgery can be another factor in a ‘watch and wait’ situation. I guess this might be something in the back of the minds of more cautious doctors when faced with a rather indolent and very slow growing Neuroendocrine Tumour. For some this can be a sensible thing – ‘kicking butt’ in a surgical context is sometimes the wrong approach. The worry is that if they are not a NET specialist, they may not fully understand the vagaries of neuroendocrine tumor behaviour (i.e. they all have malignant potential – WHO 2010/2017). We’ve all heard the stories of people being told it’s not cancer, right? Please note my article Benign vs Malignant.  However, you may be interested in this post from someone who is one of the most experienced NET surgeons on the planet.  Dr Eric Liu talks quite candidly about the ‘timing’ of surgery suggesting a ‘watch and wait’ approach in certain scenarios.

Of course cutting now might actually be a pre-emptive measure. For example, if physicians can see a growth which is critically placed close to an important structure such as a blood vessel or the bile duct or bowel. Even if the disease cannot be cured, removing the tumour may prevent problems in the future by removing disease from key areas before the vital structure has been damaged or blocked. For example, my surgeon conducted a high risk operation on some desmoplasia (serotonin fibrosis) which had encircled my aorta and cava almost occluding the latter. There’s an excellent surgery pamphlet from NET Patient Foundation and I strongly recommend a read as it’s an experienced surgeon’s approach to surgery with NETs (actually written by my own surgeon Mr Neil Pearce!).  Click here to read it.

One NET centre in USA has published very detailed surgical statistics indicating that surgical cytoreduction in NET patients has low morbidity and mortality rates and results in prolonged survival.  Their conclusion went on to say “We believe that surgical cytoreduction should play a major role in the care of patients with NETs”.  You can read the extract from this document by clicking here.  Authors: Woltering et al.

Was Steve Jobs a smart guy who made a stupid decision when it came to his health? It might seem so, from the broad outlines of what he did in 2003 when a CT scan and other tests found a cancerous tumour in his pancreas. Doctors urged him to have an operation to remove the tumour, but Mr. Jobs put it off and instead tried a vegan diet, juices, herbs, acupuncture and other alternative remedies. Nine months later, the Neuroendocrine Tumour had grown. Only then did he agree to surgery, during which his doctors found the cancer had spread to his liver. The rest is summarised in my article Steve Jobs.


This is a difficult subject and no one size fits all. Treatment for NETs can be very individual including surgery.  I guess you need to be comfortable with your team. I was lucky, in that I lived close to a NET Centre.  I was referred to their surgical team once my staging and grading were complete and I was stabilised on somatostatin analogues (carcinoid syndrome under control).  I realise it’s difficult for many but I always say to people who make contact, it’s best if you can be seen by a NET centre or an experienced NET specialist – at least be guided by one if not possible or practical.  Personally, I think the surgeon’s experience in dealing with NETs is really important.  But even experienced NET centres/specialists have to make tough calls.

You may benefit from my 10 Questions article which also has links to NET Specialists.

Thanks for reading


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Neuroendocrine Cancer – not as rare as you think


Although initially considered rare tumours up until 10 years ago, the most recent data indicates the incidence of NETs 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, NETs represent the second most common gastrointestinal malignancy after colorectal cancer. Consequently, many experts are now claiming NETs 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 incident rate is 9/100,000. Contrast this against the US incident rate as at 2012 of 7/100,000 for all NETs.  The rare threshold in Europe is 5/100,000 and below.

And on 7th January 2019, an internationally known NET Specialist described NETs as very common.

strosberg not rare
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 in USA”. 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 in USA …….” 

SEER study 2004 – NETs

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]
extrapolation europe

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]

simron singh nets not rare

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.

That means a new NET diagnosis every 2 hours. You can see a summary of the report   NEW:  Public Health England release new incidence data for Neuroendocrine Cancer

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 this data is now 5 years old (3 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”.

not rare yao netrf

incidence 2012 jama
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 –

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 math
hendifar not rare
Dr Hendifar has done the math
not rare yao netrf
Dr Yao has done the math

simron singh nets not rare
Dr Singh has done the math

strosberg not rare
Dr Strosberg has done the math

The Invisible NET Patient Population

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.  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. D.  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:

We expected that about 1 percent of

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:

SEER 2012 Underestimated
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.

Eric Liu Not Rare

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)

“… 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)

You may also wish to check out my article “The Invisible NET Patient Population” where this is explored further.

Carcinoid vs Neuroendocrine


CARCINOID misnomer etc

There’s a constant debate regarding the validity of the term ‘Carcinoid‘.  I’ve posted about this a few times and as far as I know, the debate has been raging for some years.

You may have noticed that ‘Carcinoid’ is often used as a standalone word and tends not to be suffixed with the word ‘Cancer’ or ‘Tumour’ – unlike Bowel Cancer, Breast Cancer, Prostrate Cancer, Lung Cancer, Brain Tumour, etc.  Nobody goes around saying “Breast” or “Bowel” do they?  But they happily say “Carcinoid”.  Unfortunately, the term ‘Carcinoid’ has become entrenched in both pathology and clinical literature over the past 100 years. The main problem with the word Carcinoid is that it means different things to different people. Some use the term almost exclusively to designate serotonin-producing tumours that arise from the enterochromaffin cells that can result in carcinoid syndrome i.e. most commonly in the appendix, small intestine, stomach, lung, rectum and uncommonly in other places. Some use it to (incorrectly) refer to all Neuroendocrine Tumours. The most worrying connotation of the use of the word ‘Carcinoid’ is the belief that they all have benign clinical and biological behaviour.  That is dangerous thinking and has the potential to kill people.  Fortunately, NET specialists are starting to move away from using the word – check out the quote below:
carcinoid falling out of favor

Siegfried Oberndorfer
Siegfried Oberndorfer

The Origins

The following history of ‘Carcinoid’ is well documented: Siegfried Oberndorfer (1876-1944) became the first to adequately characterise the nature of Carcinoid tumours and refer to them as “benign carcinomas.” During his tenure at the Pathological Institute of the University of Munich, Oberndorfer noted in 1907 that the lesions were distinct clinical entities and named them “karzinoide” (“carcinoma-like“), emphasizing in particular their benign features. However, In 1929 he amended his classification to include the possibility that these small tumours could be malignant and also metastasise. (Author’s note – a name change would have been handy at this point).

100 years later

NANETS, UKINETS and ENETS seem to defer to the WHO classification nomenclature and it is here another term is introduced – Neuroendocrine Neoplasms (NENs).  NANETs state that “all of the entities under discussion are neoplastic, and neoplasm is therefore a more accurate term than tumor, which means only a mass“.  These organisations tend to use the term Neoplasm as a catch-all for all Neuroendocrine disease and then the term ‘tumor’ and ‘carcinoma’ applies to well and poorly differentiated respectively.  It’s worth noting that since 2010, the WHO classification is based on the concept that all NETs have malignant potential, and has therefore abandoned the division into benign and malignant NETs and tumours of uncertain malignant potential. Neuroendocrine Carcinoma is malignant by defintion. All of this has been reinforced in the 2017 publication. The term ‘Carcinoid’ is conspicuously missing from these texts.

To put it simply – the term ‘carcinoid’ is no longer credible

Due to its historical meaning, Carcinoid does not adequately convey the potential for malignant behaviour that accompanies many of these neoplasms as described above.  The term Carcinoid decodes to ‘Carcinoma like’.  Contextually “Carcinoid Cancer” decodes to “carcinoma like cancer” which is, of course, totally misleading and its use simply perpetuates the claim by some that it is ‘not a proper cancer’.  If we only needed one reason to ditch the word ‘Carcinoid’, this would be it.

carcinoid is inadequate oberg quote 2016

I mentioned confusion above and this has led to a hybrid effect of naming the condition.  For example, there is a tendency by some (including medical establishments and patient organisations) to use the term ‘Carcinoid’ and ‘Neuroendocrine Tumors’ interchangeably which is patently incorrect. Neither is it helpful that many patients and organisations continue to refer to this disease as “Carcinoid Neuroendocrine Tumor”, “Neuroendocrine Carcinoid Tumor”, “Neuroendocrine Carcinoid Cancer”, “Carcinoid/Neuroendocrine”, “CNET”; and many other variations along these lines. Many seemingly credible organisations will say “Carcinoid and Neuroendocrine Tumors” not realising it’s a contradiction in terms. Continued use of the term in any phrase or standalone context is not doing our case for recognition any good – it’s bad enough that some seem to cling to outdated and invalid diagnostic clichés and icons from the 1980s.  All of it needs to go.

carcinoid npf quote

I know I’m not alone in this thinking given the decrease of its use in the NET world, including NET Specialists (see lead graphic) and NET Specialist organisations (some have changed their names).  There’s an interesting article written by a NET specialist where the term ‘carcinoid’ is described as “unfortunate”, “misleading”, “outmoded”, “archaic”, “confusing” and “misnomer”. Exactly!  In the recent SEER NET study, a NET specialist reaffirmed this thinking by stating that “the belief these tumors did not metastasize, did not reach any great size, and appeared harmless, has since been proven false”.  Continued use of the term ‘Carcinoid’ has the potential to regress this thinking.  We must not let this happen.

referring to carcinoid

So what terms should we be using?

People and organisations will be out of date with modern Neuroendocrine Neoplasms nomenclature and some will still want to continue with their own nomenclature (….. and because of the confusion, some will fall into both categories not realising they’re out of date).  Here’s a classic example of the problem we face – the American Cancer Society(ACS) does not even list Neuroendocrine Tumor as a cancer type.  Instead you can find “Gastrointestinal Carcinoid Tumors” and “Lung Carcinoid Tumor”. You’ll find Pancreatic NETs inside Pancreatic Cancer.  Americans should harangue the ACS to get this right. I could go on with many similar observations on seemingly respectable sites. I intentionally used a US example as this country appears to be way behind in the changes to NET nomenclature, pretty surprising as they tend to be at the forefront of many other aspects in the world of NETs.

Personally, I think the acceptance of a common worldwide nomenclature should come from the World Health Organisation (WHO) classification for Neuroendocrine Neoplasms.  They are divided into a number of chapters including ‘Endocrine Organs’, Digestive System, Lung Tumours….. and no doubt some others.  Frustrating, but medical people tend to look at things in anatomical terms. Nonetheless, the agreed classification nomenclature for the whole group of Neuroendocrine Neoplasms can be found with some research and access to clinical publications.  The correct nomenclature should then be flowed down in regional groupings, e.g. ENETS representing Europe, NANETS representing North America, etc.  As I understand it, ENETS and UKINETS are already essentially aligned with WHO and NANETS appears to be. From these organisations, the use of the correct terminology should then rub off on patients, patient advocate organisations and general cancer sites.  However, the biggest challenge will be with hospitals/medical centres, cancer registries and insurance companies whose medical record processing is run using reference data (think drop down selections and database structures).  Easier said than done but ‘change’ always has to start somewhere.  Technically it has started (albeit late) as the big NET medical organisations are already starting to reduce the use of outmoded words such as ‘carcinoid’.

I once argued that the term ‘carcinoid’ needed to be retained as it represented a histopathological grouping of a particular type of NET comprising mostly appendiceal, stomach (gastric), rectal, small intestine and lung NETs.  However, reading through the ENETS 2016 guidance in conjunction with the most up to date WHO classification publications, I’ve changed my mind after noticing they no longer use the word ‘Carcinoid’ in relation to a tumor type.  Rather, they use the latest WHO terms above and then use the anatomy to distinguish the different types of NET (like we already do for Pancreatic NET or pNET).

Perhaps patients can lead the way here ………

Rather than say:

‘Carcinoid’ or ‘Carcinoid Tumor’….. why not say Neuroendocrine Tumor or NET (adding your primary location if required – see below);

‘Carcinoid Cancer; ….. why not say Neuroendocrine Cancer;

‘Lung Carcinoid’ ….. why not say Lung NET (adding typical or atypical if required);

‘Small intestine Carcinoid’, why not say Small Intestine NET (or ‘SiNET which is becoming popular); p.s. I’m not a fan of ‘small bowel’ due to the potential for confusion with the widely used term ‘bowel cancer’);

‘Gastric Carcinoid’, why not say Gastric NET (adding your type if required);

‘Rectal Carcinoid’, why not say Rectal NET;

‘Appendiceal Carcinoid’, why not say Appendiceal NET;

…. and so on.  And you can add your stage and grade/differentiation for a richer picture.

You can listen to a very well known NET Specialist say something similar in this video here.

Worth noting that even ENETS and NANETS cannot agree on tumor type terminology – the latter uses Small Bowel NETs (SBNETs) whereas ENETS uses Small Intestine NENs (SiNENs). I did say it’s easier said than done.

As I said above, the term ‘Carcinoid’ has become entrenched in both pathology and clinical literature over the past 100 years so it will still appear in many texts and need to be searchable online to support medical and advocacy business.  However, these are technical issues and I don’t therefore believe people need to use the terms to make them searchable online.  I tag all my posts with ‘Carcinoid’ even if I don’t mention the word in my text.  I have started only using the term for context when it is required and am currently reviewing all of my posts to ensure that is still the case.

Hang on…what about Carcinoid Syndrome

When someone wants to know which syndrome you have, you can’t just state (say) “small intestine syndrome” or “midgut syndrome”.  ‘NET Syndrome’ doesn’t work either as there are several NET syndromes.  This has led to the situation where people try to drop the word ‘carcinoid’ and just say “the syndrome” which is even more confusing! I accept this one is a difficult challenge but I don’t believe it’s insurmountable, just needs some willpower and agreement.  I could come up with other terms in about 5 minutes.

What about Carcinoid Heart Disease

Personally I don’t see why this cannot be renamed to ‘Neuroendocrine Heart Disease’ or its technical name – ‘Hedinger syndrome’.

What about Carcinoid Crisis

World renowned NET specialists already make statements that these issues can apply to all types of NET; and it’s well-known that a similar crisis situation already applies to other types e.g. Pheochromocytomas.  I cannot see why something along the lines of ‘Neuroendocrine Crisis’ or ‘NET Crisis’ would not be acceptable.


We as patients are unlikely to be able to force changes on the medical and insurance communities but we can be a ‘force for change’ by setting the example of using a correct and more apt terminology to describe our disease.


Thanks for listening


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