Correlation of polypoid lesions in the distal colorectum and proximal colon in asymptomatic screening subjects.

OBJECTIVE: Knowledge of a possible correlation between distal polyps found at screening sigmoidoscopy and proximal colonic lesions is important for deciding whether to perform total colonoscopy or not. PATIENTS: A prospective analysis of 2439 consecutive patients with colorectal polyps. Of these, 304 were asymptomatic subjects who underwent complete colonoscopy for screening and were found to have adenomatous or hyperplastic polyps in the distal colorectum.
RESULTS: Ten (15%) out of 65 patients with distal hyperplastic polyps only and 86 (36%) out of 239 with distal adenomatous polyps were found to have adenomatous polyps in the proximal colon as well (P < 0.001). The frequency of synchronous proximal adenomas in patients with small (< or = 5 mm) or large distal adenomas (> 5 mm) was comparable (37% and 35%, respectively). However, patients with small distal adenomas had significantly smaller proximal adenomas (P = 0.004) containing less villous component (P = 0.017) than those with large distal adenomas. Neither the patient's age nor the presence of multiple distal adenomas increased the prevalence of proximal adenomas.
CONCLUSION: Hyperplastic polyps found on rectosigmoidoscopy do not indicate a need for a complete colorectal examination, as 15% of patients with distal hyperplastic polyps will have proximal adenomatous polyps, a figure that is comparable with that of asymptomatic patients having no distal polyps, either hyperplastic or adenomatous. When only small distal adenomas are found at screening sigmoidoscopy in asymptomatic persons the decision to do a total colonoscopy should be based on individual considerations, as in such cases only small polyps are to be expected in the proximal colon.