A lesson in sigmoidoscopy.

"watershed effect," finding 10 to 15 years ofproblems all in 2 years due to an enhanced technology, or the common effect of increased findings that happens with many new screening or casefinding programs. In any event, as a direct result of screening sigmoidoscopies, three patients have had their cancers diagnosed at an earlier time than would have otherwise happened. Most importantly, four to six of my patients will never have to face the diagnosis of colorectal cancer because their villous and tubular adenomas have been removed! Of the first 253 patients to whom I offered an FFS examination, three either refused the offer or failed to show for their appointments, giving a compliance rate of 98.8%. I offer these data to encourage other family physicians to add FFS to their diagnostic skills and to demonstrate that the research ofSelby et al,3 Newcomb et al, and Atkin et al6 can translate into real benefits for our patients. Your suggestion of waiting 15 years for the results of a study involving 120 000 patients sentences thousands of Canadians to face preventable colorectal cancer (2/3 or 3/4 of 15 000 cases per year times 15 years). While we are waiting for the results of such a prospective study, we practising physicians will have to make do with casecontrol studies '4 to guide us in our decision of whether to screen for colorectal cancer or not. I make the plea for more widespread use of FFS as a screening tool. And, yes, I did notice that the sigmoidoscope shown on the cover of the September 1993 issue is about to be used upside down or is being held backward in the wrong hand. Perhaps it is being handed to a physician by an assistant or the negative was turned inside out. Gregory P Cully, MD Calgay References