The Invisible NET patient population

I found some of the quotes from the recent NET SEER Database study 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.  The NET study is 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). Although the study is US-based, it did represent the largest study of Neuroendocrine Tumors (NETs) ever recorded. Other national declarations of incidence and prevalence of NETs seem to bear these statistics out.

I covered the increasing incidence and prevalence extensively in my post “Neuroendocrine Tumors – not as rare as you think“.  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’.

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

2. From Dana Farber (Kulke, Chan):

“Estimated more than 200,000 undiagnosed cases in the US”

But what do these quotes actually mean?  Here’s my take!

Underestimating the true incidence and prevalence of NETs

When I studied the latest SEER NET data, I saw 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 (e.g. a Neuroendocrine Tumor of the Pancreas is recorded as Pancreatic Cancer).  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 in UK due to a major intervention by NET Patient Foundation and others).

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 some of them are still living in last centuries ‘Carcinoid World’.  You can occasionally be excused for being out of date but being 7 years (plus) out of date is unacceptable.  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 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.

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.  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.

For example, in USA, a respected NET specialist stated that the autopsy find for ‘carcinoid’ is 4 times the recorded diagnosis rate. In Australia, one study claimed that 0.05% of all autopsies found a Pheochromocytoma or Paraganglioma.  What is missing from these statements is whether the previously undiscovered tumors had been causing symptoms and the person either lived with them or had been misdiagnosed for something else during their lifetime.

Given the factors above, it’s also clear that many more diagnoses are on the way – as confirmed in the insightful (and brave) statement in the slide below.  It’s also worth pointing out that the latest SEER NETs reported that the increase in incidence is due to earlier diagnosis, so in many ways we are finding some of the ‘invisible’ NET patient population.  What this also says is that the figure of 200,000 was perhaps much higher 10 or 20 years ago.

Summary

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.

Clearly more awareness is required to catch more people earlier and from the latest SEER NET study, it appears this is starting to work.  I feel earlier diagnosis is partly due to increased awareness, particularly in the medical world. I would also suggest it has improved in the general population due to the explosion of social media information dissemination. It’s also accurate to suggest that improvements in diagnostic capabilities are also playing their part in pushing up incidence rates, just as improved therapies have pushed up prevalence rates, something emphasised by Dasari (et al) in the recent SEER Data study.

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

Thanks for reading

Ronny

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