A randomized, controlled trial to assess a novel colorectal cancer screening strategy: The conversion strategy - A comparison of sequential sigmoidoscopy and colonoscopy with immediate conversion from sigmoidoscopy to colonoscopy in patients with an abnormal screening sigmoidoscopy

OBJECTIVE: Our study was a randomized, controlled trial to assess a novel s trategy that provides comprehensive colorectal cancer screening in a single visit versus traditional sigmoidoscopy and, where appropriate, colonoscopy on a subsequent day. METHODS: Consecutive patients referred for screening were randomized to con trol. or so-called "conversion" groups. Patients in the control group were prepared for sigmoidoscopy with oral phospho-soda. Those with an abnormal s igmoidoscopy were scheduled for colonoscopy on a future day after oral poly ethylene glycol preparation. In the conversion group, patients were prepare d with oral phosphosoda. Patients with a polyp >5 mm or multiple diminutive polyps were converted from sigmoidoscopy to colonoscopy, allowing comprehe nsive screening in a single visit; Clinical outcomes were assessed by postp rocedure physician and patient questionnaires. RESULTS: Two hundred thirty-five patients were randomized (control = 121, c onversion = 114). In the control group, 28% had an indication for colonosco py. Three of 33 (9%) with an abnormal sigmoidoscopy did not return for colo noscopy. At colonoscopy, 27% had a proximal adenoma. In the conversion grou p, 28% had an abnormal sigmoidoscopy and underwent conversion to colonoscop y. Forty-one percent undergoing colonoscopy in the conversion group had a p roximal adenoma. Physicians reported no differences in preparation or proce dure difficulty, whereas patients reported no differences in the level of c omfort or overall satisfaction between groups. When queried regarding prefe rences for future screening, 96% chose the conversion strategy. CONCLUSIONS: The conversion strategy led to similar outcomes compared to tr aditional screening while improving compliance with colonoscopy in patients with an abnormal sigmoidoscopy. (C) 2000 by Am. Cell. of Gastroenterology.