Colonoscopy is regarded as the most effective screening modality for the detection of early colon carcinoma. It enables a visualized surveillance of the entire colon as well as biopsy or removal of grossly abnormal lesions. Synchronous or metachronous carcinoma can also be excluded during this procedure.

It is generally accepted that the majority of colorectal cancer tracks an adenoma-carcinoma sequence. An adenoma smaller than 1 cm has an approximately 1% risk of malignancy. Conversely, polyps larger than 2 cm have a 35% to 50% incidence of associated carcinoma. The histologic presentation of adenomatous polyps consists of tubular, tubulovillous, and villous. The malignant potential augments with increased villous glandular formation. The malignant potential also correlates with histologic degree of dysplasia. Polyps with severe dysplasia have about a 50% incidence of malignancy. Other adverse risk factors of malignant polyps are
lymphovascular invasion, poorly differentiated or mucinous adenocarcinoma, tumor budding, a flat or depressed lesion, and depth of tumor invasion into the lower third of the submucosal level, although these characteristics may be difficult to determine.

Sessile polyps have a reportedly higher incidence of lymph node metastasis than pedunculated polyps, ranging from 12% to 25%. Therefore, sessile polyps often require more aggressive surgical treatment for curability than pedunculated polyps.