Adjuvant radiation therapy for rectal cancer.

Since 1976, 104 patients with rectal cancer have been treated with a new approach of combined pre- and postoperative radiation. All patients were given 500 rad preoperative irradiation on the day of or the day before surgery. Surgery in the majority of patients was an abdominal perineal resection. The disease was then staged pathologically according to Astler-Coller's modification of Duke's staging. Patients with early stage cancer (Stages A and B1) were followed with no further therapy. Patients with poor prognostic characteristics (Stages B2, C1, C2) were given postoperative pelvic irradiation (4500 rad in 5 weeks). Twenty-nine patients were found to have Stage A or B1 cancer and were followed with no further therapy. Of these 29 patients, 1 patient developed recurrence and one has died of metastatic disease. The excellent survival of patients with early tumors indicates that minimizing the role of adjuvant therapy in this group has not been detrimental to their survival. Fifteen were found to have liver metastases at laparotomy and had just a colostomy and palliative therapy. Sixty patients had Stage B2 and C disease. Thirty-one received postoperative irradiation as per protocol. Twenty-nine patients did not receive postoperative irradiation for a variety of reasons. Follow-up ranges from 1 to 7 years in these patients. Of the 29 patients with Stage B2 and C disease who should have but did not receive postoperative radiation, 10 patients (34%) have developed a recurrence in the pelvis, and 5 other patients (17%) have developed metastatic disease. Of 31 patients who received postoperative irradiation, only 2 patients (6%) developed a local recurrence and 4 patients (13%) have developed distant metastases. Survival at 3 years was 80% for patients receiving the combined treatment, as compared to 42% for those not receiving the postoperative part of the treatment protocol.