The problem with this news feature is that it assumes a-priori that screening for colorectal cancer is effective, without good evidence. Screenings result in f

The problem with this news feature is that it assumes a-priori that screening for colorectal cancer is effective, without good evidence. Screenings result in false positives and in complications. One has to show rigorously that screening has net benefits. I thought we have learned our lesson from the PSA fiasco. Their main criticism of the study is this: > If the compliance rate had been 100%, the researchers’ analysis showed, the test would have reduced cancer risk by 31% — from 1.22% to 0.84% — and it would have reduced the risk of death from colorectal cancer by 50% — from 0.3% to 0.15%. But the study did no such thing. There's no way for the study to do such a thing. What they describe is the comparing the results on the SELF SELECTED group of those who decided to go and get screened. This is no longer a randomized controlled trial. We have no idea why those who decided to get screened did so, it might be that they had some symptoms, it might be that they had family members that got cancer, and so on. That introduces the biases that plague all other observational studies.