Background Acromegaly seems to be associated with an increased prevalence of colonic adenomas, although factors affecting their development and recurrence of the latter are not fully known.

Patients and Methods Seventy-nine patients with active acromegaly were prospectively followed for 5 yr. Two hundred and eighty healthy subjects served as controls. Colonoscopy and assessment of acromegaly activity were performed at 1-year intervals. Acromegaly was defined as controlled if serum IGF-1 levels were within the normal age-adjusted range.

Results Colonic adenomas were found in 26 of 79 acromegalic patients (32.9%) and in 60 of 280 controls (21.4%) at baseline(P = 0.035, adjusted for age and sex, odd ratio 1.82, 95% CI, 1.02-3.25). Seven patients had hyperplastic polyps; the remaining 46 acromegalic patients had no detectable lesions at the baseline and did not develop adenomas during the study period. Of the 26 patients with colonic adenomas at baseline, 16 (61.5%) had at least one recurrence of colonic adenomas (P < 0.0001 vs. patients without colonic lesions at baseline) and multiple recurrences were more frequent in patients with uncontrolled acromegaly (66.7% vs. 17.6% in patients with controlled acromegaly, P = 0.028).

Conclusions The first colonoscopy helps to identify acromegalic patients at high risk of developing colonic adenomas. If colonic adenomas are not present initially, it is unlikely that they develop thereafter, independently of metabolic control of acromegaly. Conversely, new lesions are frequent (and often multiple) in patients who already have colonic adenomas at baseline, particularly if acromegalic disease is poorly controlled by treatment.