[kashunstva]

> And conversely, maybe if you're not willing or able to get a colonoscopy when invited, you're more likely to ignore symptoms until it's too late.

Yes. This is the argument against relying on the secondary analysis in this study. Although the invited and standard care groups were randomized such that differences in putative confounders were adjusted for, the rejection of the intervention itself may have reintroduced systematic differences that reduce the reliability of the hypothesis that intention to screen for colon cancer reduces mortality. Possibly those who accepted screening colonoscopy are more attentive to other health and lifestyle practices that reduce colon cancer mortality.