COLORECTAL CANCER SCREENING

COLORECTAL CANCER SCREENING SIR: Your recent article on routine screening for colorectal neoplasm (Journal, June 13) raises important issues which are not dealt with adequately. The detected cancer incidence of 0.29%, which is by implication attributed to the screening procedure, includes patients with known bleeding and those in whom the disease had already spread beyond the bowel wall. In fact, a potentially curable lesion confined to the bowel wall was detected in only 0.13% of patients. In another 0.71 % of patients polyps were detected. These patients are at higher risk than usual of developing bowel carcinoma but is their detection and regular follow-up going to outweigh their associated anxiety and the risks of follow-up? Nineth-three normal people had full gastroenterological examinations in order to detect 6 potentially curable carcinomas. There were also 84 people whose doubtfully positive initial screening test had to be repeated. There is no mention of the anxiety, irradiation, time loss and cost to these people. This needs to be balanced against the advantage of detecting cancer early in six others. There is no mention of the possibility of false negative results in the majority of patients whose screening test was normal. At least some of these patients may have had a carcinoma present and at best will have gained a temporary false sense of security; at worst the diagnosis will have been delayed. Finally there are no grounds for the unconvincing statement that "the over-all cost of effectiveness of the programme would seem to be very great indeed". This would be questionable if only the direct costs to which the authors refer are counted. If the indirect costs to which I refer are also included, the cost effectiveness of the programme may well be unsatisfactory.