6971 Association of duration of the test with yield and miss rate of polyps at screening sigmoidoscopy.

Abstract

AIMS To study the association of the duration of the test with the polyps yield and the miss rate for polyps of sigmoidoscopy (FS) among patients undergoing FS screening for coloretal cancer (CRC). METHODS We compared the polyps yield of FS and colonoscopy (TC) among subjects referred for TC in Turin in the context of the SCORE trial of FS screening for CRC, conducted as parallel study to the UK trial (coordinator:W Atkin). Endoscopists were instructed to excise all small (=5 mm) polyps detected at FS and to record the duration of the test, as well as shape, size and location of all polyps detected. Patients detected with polyps >5 mm, CRC, high-risk polyps=5 mm (villous component, severe dysplasia), >2 adenomas were referred for TC.TCs were performed within 1 month from FS in the same Endoscopy Unit. Only subjects with complete FS (instrument passed beyond the sigmoid-descending colon junction, under adequate bowel preparation) were included in this analysis.Patients with distal CRC were excluded. RESULTS Out of 3540 FSs performed in Turin, 2888 (81.6%) were completed. Complete information for the analysis is available for 2225 tests (duration of the procedure was not recorded in 557 and polyp size in 6 cases). FS was completed within 5 minutes in 64.6% of the cases, between 6 and 10 minutes in 29.6% and it required >10 minutes in 5.7% of the patients. Polyps yield was 11%, 27.3%, and 45.9% (p-trend-: 10 minutes respectively. The observed increase in the detection rate was associated with an increase in the proportion of polyps=5 mm: 56.7%, 68.1% and 88.5% for tests completed within 5, 10 and >10 minutes respectively (p-trend- : 10 minutes respectively. CONCLUSIONS Only a small proportion of the screening FS lasted more than 10 minutes.A positive association was observed between polyps yield and duration of the test, mainly attributable to a trend toward a higher detection rate for small polyps. The time devoted to the excision of small polyps might explain the longer duration of the tests in these cases. Accuracy of the screening FS was apparently not reduced if the test was completed within 5 minutes.