Colorectal adenomas are well-known to be precancerous lesions that develop into colorectal cancers on the basis of the adenoma-carcinoma sequence. The effects of screening for colorectal adenomas and removing precancerous lesions on the prevention of colorectal cancer have been established. Because of the high recurrence rates of colorectal adenomas in patients who have undergone polypectomy, the potential chemopreventive agents that may reduce the risk of colorectal adenoma recurrence need to be investigated.~Metformin is a widely used diabetes medicine. In recent years, anticancer activity of metformin has been explored. The aim of this study is to investigate the effect of metformin on the recurrence of colorectal adenomas by conducting a randomized, placebo-controlled, prospective clinical.
Most of the sporadic colorectal cancer (CRC )develop from colorectal adenoma (CRA), patients with CRA have a high risk of recurrence and development of metachronous CRA or CRC after removal, therefore, the investigators conducted this clinical trial to explore the chemoprevetion effect of metformin for CRA recurrence after removal.