Do the math not the myth
An 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.
Original Research 15 December 2020
Thanks for reading.