IS COLONOSCOPY NEEDED FOR THE NONADVANCED ADENOMA FOUND ON SIGMOIDOSCOPY

Background & Aims: The need for colonoscopy when small tubular adenoma s with low-grade dysplasia are found on sigmoidoscopy is uncertain. Th e aim of this study was to examine the prevalence and characteristics of proximal adenomas in patients with distal adenomas, Methods: We stu died 981 subjects with distal adenomas found on the index colonoscopy before randomization in the Polyp Prevention Trial. Results: Four hund red sixty patients (46.9%) had greater than or equal to 1 distal adeno ma that was pathologically advanced (villous component, high-grade dys plasia, or greater than or equal to 1 cm); 21.5% (211 of 981) had any proximal adenoma; and 4.3% (42 of 981) (95% confidence interval [CI], 3.0-5.5) had an advanced proximal adenoma. A greater percentage of pat ients with an advanced distal adenoma (5.9%) (95% CI, 3.7-8.0) had an advanced proximal adenoma compared with those with a nonadvanced dista l adenoma (2.9%) (95% CI, 1.4-4.3) (OR, 2.1; 95% CI, 1.1-4.3; P = 0.03 ). Not performing a colonoscopy in patients with a nonadvanced distal adenoma would have missed 36% (15 of 42) of the advanced proximal aden omas, Conclusions: Patients with an advanced distal adenoma are twice as likely to have an advanced proximal adenoma as patients with a nona dvanced distal adenoma. However, eschewing a colonoscopy in patients w ith a nonadvanced distal adenoma would result in not detecting a sizea ble percentage of the prevalent advanced proximal adenomas. These data support performance of a colonoscopy in patients with a nonadvanced d istal adenoma, Confirmation of these results in asymptomatic subjects undergoing screening sigmoidoscopy is advisable.