The Invisibility of Appendiceal and Colorectal NETs – do the math


Do the math not the myth

In addition to my mountain of evidence against the so-called rarity of Neuroendocrine Neoplasms, a new study from US indicates that many NETs are hidden among colorectal cancer cases in cancer registries. The study reported extraordinary figures of NET cases found when analysing the data.
For years, doctors have been warning about the increasing incidence of colorectal cancer amongst younger people. For that reason, the American Cancer Society recommended people to start screening at a younger age (45 years instead of 50 years) in 2018. This would affect 22 million Americans who now are recommended screening. Colorectal covers the large intestine including the sigmoid colon and rectal cases.   You can read this article from the National Institute of Health covering the issue in US.  I’m fairly certain this is a known issue in many other countries.  In fact the article from NIH stated that “Similar trends have also been documented in Canada, New Zealand, Australia, and some parts of Europe and Asia. In most of these places, the number of cases in younger adults started trending upward around 1995“.  The other interesting statement in the NIH article is that “when the incidence of a disease changes by generation, that suggests the culprit is something in the environment, rather than something biological” – although the authors did accept that there may be a set of unique risk factors for colorectal cancer in younger adults that researchers haven’t yet identified. 
The study covered the SEER database from 2000-2016 and includes 119,624 patients with colorectal cancer to assess early-onset incidence rates (IRs) and changes in incident rates over time, stratified by histologic subtype, primarily adenocarcinoma and (annoyingly), the study mentions “carcinoid tumors” as another subtype. These figures do not cover the small intestine (small bowel).
The results of the study indicated that the steepest changes in adenocarcinoma 3-year average annual IRs were:
– for rectal-only cases in persons aged 20 to 29 years (+39% [0.33 to 0.46 per 100 000]; P < 0.050) and 30 to 39 years (+39% [1.92 to 2.66 per 100 000]; P < 0.050)
– colon-only cases in those aged 30 to 39 years (+20% [3.30 to 3.97 per 100 000]; P < 0.050).
In persons aged 40 to 49 years, 3-year average annual IRs increased in both colon-only (+13% [12.21 to 13.85 per 100 000]; P < 0.050) and rectal-only (+16% [7.50 to 8.72 per 100 000]; P < 0.050) subsites.
NETs (the study called them “Carcinoid tumors”) were common, representing approximately 4% to 20% of all colorectal and 8% to 34% of all rectal cancer cases, depending on age group and calendar year. Colon-only NETs were rare. Colorectal NET IRs increased more steeply than adenocarcinoma in all age groups, thus affecting the contribution of NETs to overall cancer cases over time. These changes were driven by rectal subsites and were most pronounced in persons aged 50 to 54 years, in whom rectal NETs increased by 159% (2.36 to 6.10 per 100 000) between 2000 to 2002 and 2014 to 2016, compared with 10% for adenocarcinoma (18.07 to 19.84 per 100 000), ultimately accounting for 22.6% of all rectal cancer cases. One of the suggestions in the study is that the risk of early onset colorectal cancer is less than first thought due to the inclusion of a signification ratio of NET cases. The authors clearly forgot that all NETs have malignant potential.
It will probably never be known if any of these cases of NETs identified in this SEER study were included in the Neuroendocrine Neoplasms SEER study of 2012, the controversy over that data remains today (mainly that it was understated, despite the large rises found).

Do the math, not the myth.

Another addition to the Invisible NET Patient Population read more here

Source documents – please note the full study is paid article so only working from abstracts.

A comprehensive review of early-onset colorectal SEER data is the first to specifically assess adeno | EurekAlert! Science News

Original Research 15 December 2020

If this wasn’t enough, another study covering the same subject (referencing the above study) expands the issue to include appendiceal NETs and therefore Colon NETs. I realise the latter’s numbers are small but the appendiceal NET figures are already substantial. 

Comparison of trends in early-onset colorectal cancer in North America and Europe. More evidence that the true incidence rates for Neuroendocrine Cance are being hidden by not recognising anatomical/histological subtypes.  For example, in the abstract below, a second study categorised the appendix as part of the colon and did not distinguish between histological subtypes.

Read the abstract by clicking here


I am not a doctor or any form of medical professional, practitioner or counsellor. None of the information on my website, or linked to my website(s), or conveyed by me on any social media or presentation, should be interpreted as medical advice given or advised by me.  Neither should any post or comment made by a follower or member of my private group be assumed to be medical advice, even if that person is a healthcare professional as they are not members of the private group or followers of my sites in any official capacity.  Please also note that mention of a clinical service, trial/study or therapy does not constitute an endorsement of that service, trial/study or therapy by Ronny Allan, the information is provided for education and awareness purposes and/or related to Ronny Allan’s own patient experience. This element of the disclaimer includes any complementary medicine, non-prescription over the counter drugs and supplements such as vitamins and minerals.

Subscribe to my newsletter

Thanks for reading.


I’m also active on Facebook. Like my page for even more news. Help me build up my new site here – click here and ‘Like’

Sign up for my newsletters – Click Here


My Diagnosis and Treatment History

Follow me on twitter

Check out my online presentations

Check out my WEGO Health Awards

Like my new awareness page – click here or on the photo.  (Like rather than follow please!)

Check out my Glossary of Terms – click here

patients included

Please Share this post for Neuroendocrine Cancer awareness and to help another patient


RonnyAllan.NET – Summary of November 2022

In November 2022, I was very active on my blog site as it was World Neuroendocrine Cancer Day on 10th Nov (although every day is

Read More »

In the news – new Neuroendocrine Tumour PET Fluorine-18 based ‘tracer’

This should be of interest, particularly to Canadians. (Not to be confused with 18F-FDG which is a different scan). For people waiting for imaging tests

Read More »

Incurable isn’t terminal

Opinion Words are important I was diagnosed with stage IV cancer in 2010.  OK, it wasn’t a really aggressive type but it had caused a

Read More »

The Inspirational Wilko Johnson: 12 July 1947 – 21 November 2022

Wilko playing at his last show. Oct 2022 in London. Aged 75. RIP Wilko Johnson – Neuroendocrine Cancer I have been following Wilko’s cancer story

Read More »

Neuroendocrine Neoplasms (NEN) – genetic related syndromes

Definitions – the differences between Hereditary vs Familial vs Genetic Disorders I wanted to start with these definitions because people may unintentionally use these three

Read More »

Neuroendocrine Cancer: Those who know, know!

Over the years of my advocating, I’ve tried to explain Neuroendocrine Cancer to many people outside the community.  Some ‘get it’ but many don’t.  Most

Read More »

Ask More, Assume Less

This is a great catchphrase from Neuroendocrine Cancer UK. It is partly based on the realisation that Neuroendocrine Cancer is no longer rare.  OK, that

Read More »

Piss off Cancer, it’s been 12 years since my “big surgery”

I’m still here I was 54 years and 9 months old at diagnosis on 26th July 2010.  For the first few months, I had no

Read More »

Neuroendocrine Cancer: 10 questions your dietitian will ask

Background to Diet and Nutrition  This is clearly an important topic for many patients.  In my group, it is the 12th most common topic out

Read More »

I love comments - feel free!

%d bloggers like this: