3 ms·

If you screen more people for the disease, and do it better, such that you reduce the incidences and fatalities in the 50+ cohort, that improvement logically im

If you screen more people for the disease, and do it better, such that you reduce the incidences and fatalities in the 50+ cohort, that improvement logically implies that you must be catching incidences in the under 50 cohort. So it's going to skew the numbers. Incidences that would have been tallied in the 50+ cohort, are now counted in the under 50. E.g. a 45-year-old with a latent colorectal cancer who would previously not have been diagnosed early, but only late when they developed symtpoms, by which time they hit 50, would have counted as an incidence or a likely fatality, among the 50+ data. But if that same individual had been caught at 45, they would have counted as an incidence against int he under-50 cohort. Earlier, better and more available screening alone will shift the data this way.

greygoo222 8mo ago
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.
- kazinator 8mo ago
  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.
- pfannkuchen 8mo ago
  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 8mo ago
    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 8mo ago
    C'mon, I already said that, that was half of my comment!
    - pfannkuchen 8mo ago
      Sorry for the drive by! Thanks for being thorough in your analysis!
- timr 8mo ago
  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.
NedF 8mo ago
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greygoo222 8mo ago

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.

kazinator 8mo ago
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.
pfannkuchen 8mo ago
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 8mo ago
  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 8mo ago
  C'mon, I already said that, that was half of my comment!
  - pfannkuchen 8mo ago
    Sorry for the drive by! Thanks for being thorough in your analysis!
timr 8mo ago
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.

NedF 8mo ago

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