Treatment of colonic polyps--practical considerations

Abstract

The adenomatous colonic polyp, a neoplastic lesion, is the precursor of most if not all carcinomas of the colon and rectum. Confirmatory evidence is derived from epidemiological, histological and clinical data demonstrating a close parallelism between adenomas and cancer of the colon. Based on current knowledge, all colonic polyps should be removed to prevent the development of colonic cancer. However, since the risk of malignancy within an adenoma is related to its size, histology and the degree of dysplasia, practical considerations dictate that all polyps 1 cm in diameter or larger should be removed upon their detection by barium enema or colonoscopy since such adenomas are the ones most likely to contain malignancy. The endoscopic removal of colon polyps can be efficiently and safely accomplished when established principles of colonoscopy and electrosurgery are followed. This technique requires the proper equipment, a skilled endoscopy assistant, and an experienced endoscopist with the ability to adeptly perform colonoscopy, an understanding of the basic concepts of electrocautery and knowledge of the various structural configurations of colonic polyps. Colonoscopic polypectomy will avoid the need for surgical resection in most instances. Management of the malignant colonic polyp remains controversial. The patient with a sessile or pseudo-pedunculated polyp containing invasive cancer should undergo colonic resection. Surgery is not necessary for the majority of patients whose pedunculated adenomas contain invasive cancer, unless the malignancy is poorly differentiated, the cancer invades lymphatics or vascular channels, or tumour is seen at or near the resection margin. Surveillance colonoscopy after endoscopic polypectomy should be performed in most instances within one year to look for recurrent tumour, missed polyps or a metachronous adenoma. Subsequently, colonoscopy should be performed every two years in patients with multiple index polyps, and every three years after removal of a single index adenoma.