Background/aims: Colonoscopy is presently recommended for patients with any benign neoplasm found on sigmoidoscopy. The purpose of this study was to determine whether characteristics of adenomas on flexible sigmoidoscopy predict advanced lesions on baseline colonoscopy.
Methods: A total of 226 asymptomatic and symptomatic patients with adenomas noted on flexible sigmoidoscopy at a large, multispecialty medical group were prospectively studied. The histology, size, and number of benign polyps on flexible sigmoidoscopy were compared with those on subsequent colonoscopy. Advanced lesions were defined as adenomas > 1 cm in diameter or with villous or severe dysplasia histology. Univariate comparisons were assessed using the chi 2 test and multivariate analysis with stepwise logistic regression.
Results: There was a 24% prevalence of new adenomas found on colonoscopy. Six percent of the patients had advanced lesions on colonoscopy, and none had cancer. Multivariate analysis indicated that findings on flexible sigmoidoscopy predict (P < 0.01) those on colonoscopy. Patients with advanced lesions on sigmoidoscopy had a > 10% prevalence of an advanced lesion on colonoscopy. Patients with small (< or = 1 cm) tubular adenoma(s) on sigmoidoscopy had a < 1% occurrence of an advanced synchronous lesion.
Conclusions: The histology and size of benign neoplasms found on flexible sigmoidoscopy predict findings on baseline colonoscopy.