Surgical management of early colorectal cancer.

An early colorectal carcinoma is TNM stage T1NxMx. Most early carcinomas of the colon and rectum can be treated by adequate local excision, such as colonoscopic polypectomy and per-anal excision. If there are adverse risk factors, especially poorly differentiated carcinoma, lymphovascular invasion, or incomplete excision, a radical resection is indicated if there is no contraindication. In the case of a low rectal carcinoma, adjuvant chemoradiation should be considered. Recently a new classification has been developed: sm1 is invasion to the upper one-third of the submucosa, sm2 is invasion to the middle one-third, and sm3 is invasion to the lower one-third. Lesions of sm1 and sm2 have a low risk of local recurrence and lymph node metastasis; local excision is adequate. The sm3 lesions and sm2 flat and depressed types have a high risk of local recurrence and lymph node metastasis; further treatment is indicated.