Surgical management of malignant colorectal polyps.

The anatomic landmarks of the depth of invasion for pedunculated lesions (Haggitt level) and the Sm system for the sessile lesions give excellent objective information in the management of malignant colorectal polyps. Malignant polyps with low risk of lymph node metastasis include pedunculated lesions with invasion into Haggitt levels 1, 2, and 3. Level 4 pedunculated lesions and sessile lesions in which the invasion is into Sm1 or Sm2 level also have low risk if there are no adverse factors. These lesions can be treated by a complete local excision. Lesions that have high risk of lymph node metastasis are those with invasion into the lower third of the submucosa (Sm3), lesions that contain lymphovascular invasion, and lesions sited in the lower third of the rectum. These lesions require an oncologic colorectal resection. For lesions in the distal third of the rectum, a per anal full-thickness excision followed by an adjuvant chemoradiation may be an alternative. The box below summarizes malignant colorectal polyps requiring oncologic bowel resections: