Serum factors associated with precancerous colonic lesions in acromegaly

Background: Insulin, 25-hydroxy vitamin D3 [25(OH)D3] and folate have been differently associated with a risk of colonic neoplasms in the general population. Acromegalic patients have an increased risk of colorectal tumors and an association between fasting insulin concentrations and colonic lesions has been reported. However, it is unknown whether insulin, 25(OH)D3, folate, and homocysteine interact to determine the risk of colonic tumors in acromegaly. Aim: To investigate whether serum insulin, 25(OH)D3, folate, and homocysteine concentrations were associated with precancerous colonic lesions in acromegalic patients. Material and methods: A cohort of 146 consecutive acromegalic patients was evaluated for colonoscopy findings and fasting insulin, 25(OH)D3, folate, and homocysteine levels. A preliminary study was conducted in 9 naive acromegalic patients to evaluate the effect of somatostatin analogues (SSA) on serum levels of those factors. Results: Insulin reduced during SSA whereas the other factors did not change. In the cohort study, colonic lesions (14 adenomas; 32 hyperplastic polyps) were detected in 46 patients. Fasting insulin, 25(OH)D3, folate, and homocysteine levels did not differ in patients with or without colonic adenomas. High folate levels were associated with a lower risk of developing precancerous colonic lesions at the multivariate analysis, when corrected by age, gender, disease activity and SSA therapy. Conclusions: Serum insulin, 25(OH)D3 and homocysteine serum concentrations do not seem to influence the development of precancerous colonic lesions in acromegalic patients, while higher folate levels may be associated with a lower risk of colonic lesions.