Surgical resection is indicated as the initial treatment for this patient who has stage I rectal cancer, which is defined as a tumor that invades into, but not fully through, the rectal wall, with no evidence of lymph node metastases (T2N0M0, stage I). The procedure for a tumor of the mid rectum, such as that in this patient, is a low anterior resection using the technique of total mesorectal excision to accomplish an en-bloc removal of the rectum with a fully intact mesorectum. The mesorectum is the fatty sheath that surrounds the rectum and contains the locoregional lymph nodes. Careful pathologic examination of the primary tumor and lymph nodes is necessary to confirm the disease stage. If pathology findings indicate that the tumor is a higher T stage than expected (T3 or T4) or if any of the locoregional lymph nodes in the mesorectum are found to contain cancer (N1 or N2), postoperative chemoradiation and chemotherapy would be indicated. However, if the final pathology report confirms stage I rectal cancer, the probability of cure with surgery alone is high, and no additional treatment is indicated.

Neither chemotherapy, radiation therapy, nor combined chemotherapy plus radiation has been demonstrated to improve outcomes in patients with stage I rectal cancer, and all of them would expose these patients to unnecessary risk and toxicity.