Surveillance strategies in patients after polypectomy

Colorectal cancer (CRC) is a major cause of cancer death in the Western world. It develops slowly over several years from premalignant lesions (most prominently adenomatous polyps) to invasive cancer. The molecular basis of CRC pathogenesis has been well characterized. The most effective method to prevent CRC is endoscopic polypectomy. However, adenomatous polyps are known to recur at significant rates. The aim of surveillance programs after polypectomy is to further reduce the incidence of CRC in individuals where precancerous lesions have been identified and treated. However, the medical risks and the costs of repeated examinations must be kept as low as possible. Therefore, the identification of patient subgroups with a particular low cancer risk who may be followed-up less frequently seems important. There is recent evidence that other colorectal lesions, namely flat and depressed type adenomas (F&D adenoma) and possibly some hyperplastic polyps and serrated adenomas may also carry a malignant potential which could influence our screening, treatment and surveillance strategies for the colorectum in the future. General surveillance guidelines regarding these entities have not been issued to date. This article will first discuss the biology, natural history, present surveillance recommendations and future issues for sporadic adenomatous polyps. Then, recent literature on F&D type adenomas, hyperplastic polyps and serrated adenomas will be reviewed with respect to their malignant potential and the potential necessity for treatment and surveillance of these lesions.