[greygoo222]

This mostly can't explain the fact that mortality is also rising in under 50s. It is true mortality is rising less than incident, and that a small proportion instances of mortality could be deaths related to reasonable risks taken on from treatment side effects (to make up numbers, it makes sense to take a 5% chance of dying from treatment this year over a 80% chance of dying from cancer in 5 years), but this is probably not the whole effect. Something is causing more CRC in people under 50.

[timr]

Go look at the graphs again. The “split by age” graph shows an increase in diagnosis of ~60%, but an increase in mortality of only ~10%. That’s not a small difference, and we aren’t that good at curing colon cancer.

GP’s hypothesis is one of the leading explanations for this trend, but of course gets rejected by advocates for colonoscopy. Taking into account error bars on these numbers (which author doesn’t show, because they are inconvenient to the argument being made), it seems at least somewhat likely that the explanation for the rise in younger cases is due to increased screening, with the “increased” mortality either being statistical noise, or misattribution of deaths that also would have occurred in earlier periods.

[pfannkuchen]

Does treatment ever speed up death? Given that chemo is super hard on the body I imagine it could? That might just account for your use of “mostly”, though.

[greedo]

It would depend on the treatment. In my case I had neoadjuvant radiation followed by chemo, then surgery, capped off with more chemo to kill any cancer cells that might have tried to make a dash for it. I would assume that while the radiation treatment elevated my risk for future cancers, the greater risk was my 10 hour surgical procedure.

[greygoo222]

C'mon, I already said that, that was half of my comment!

[kazinator]

No, it can't explain that; but the rise is very small. On the per 100,000 mortality graphs divided into the age cohorts, the under fifty mortality is almost a flat line. There is something there, but it doesn't seem like a huge alarm.