DIAGNOSTIC FAILURE IN COLONOSCOPIES FOR MALIGNANT DISEASE

Background: While colonoscopy has become established as more accurate than double contrast barium enema for detecting colonic polyps and can cers, as well as offering the opportunity for therapy, there are occas ional instances where colonoscopy is misleading. The present study is to determine what problems occur, with a view to finding a solution. M ethods: The records of the Colorectal Project at the Princess Alexandr a Hospital indicate retrospectively that 346 patients have been correc tly diagnosed with cancer of the colon and rectum by colonoscopy in th e 5 years up to October 1996. During the same time eight patients (2.3 %) were recorded at the same hospital as being misdiagnosed by colonos copy, the lesion being either missed completely or misplaced. Results: In five of these patients there was failure to recognize that the who le colon had not been examined endoscopically, thereby missing a more proximal lesion. In two patients the lesion was missed although the en tire colon was examined. In one patient the lesion was discovered but inaccurately sited. Six of these mistakes would have been obviated by the routine use of fluoroscopy to confirm the totality of the colonosc opy and to site any lesions found. The other two cases occurred becaus e of failure to remember that colonic examination during withdrawal sh ould be performed meticulously back as far as the anal canal. Failure to diagnose a colon cancer on the initial colonoscopy led to an averag e delay of 6 months for definitive care. Conclusions: It is recommende d that fluoroscopy be used routinely during colonoscopy to site accura tely any lesions found, and to confirm the completeness of insertion i f reliable landmarks, including terminal ileum, are not clearly identi fied.