The opposing views expressed by Sidney Winawer and Ann Zauber1 and Kenneth Marshall2 on colorectal cancer screening stem from a common problem in screening programs, namely that “screening for cancer has always been highly controversial, partly because the procedure is for seemingly healthy people, for whom the benefit should be clear cut. Evidence of this benefit is, however, for the group as a whole. At the individual level, prediction of who will benefit and who will suffer more harm than good is impossible. The balance between favourable and unfavourable effects is delicate.”3
Technical details such as annual versus biennial and unhydrated versus hydrated aside, population-based studies have shown that fecal occult blood testing is efficacious.4,5,6 Although there are no published cost-effectiveness studies of colorectal cancer screening in Canada, it is unlikely that Canadian findings would differ from those in other countries, where studies have consistently shown support for testing.7,8,9,10 Most articles suggest that colorectal cancer screening is acceptable to the medical community. But are we, the medical community, the ones who should ultimately decide?
The acceptability of screening to targeted individuals is poorly understood.11 People will probably participate in population-based screening programs because participation is recommended, rather than from a true understanding of the risks and benefits. A 39% reduction in cause-specific colorectal cancer mortality for people who comply with screening guidelines, as quoted by Winawer and Zauber, makes screening a seemingly easy sell. Marshall, however, points out that in the context of the larger picture of overall mortality, colorectal cancer screening has little impact. What information should be presented to the person offered screening?
Before a decision is made about population-based colorectal cancer screening, more should be learned about its acceptability to the target population. An attempt should be made to fully inform a representative sample of this community of the risks and benefits of colorectal cancer screening from both a population and individual perspective and then survey their attitudes. This information can then be used to shape policy. Let the people decide.