Elective postoperative radiotherapy for locally advanced colorectal cancer. A preliminary report.

Preoperative radiotherapy in colorectal carcinoma invalidates surgical staging and delays performing the surgical resection. Postoperative radiotherapy does neither. From October 1972, to December 1975, 40 patients at high risk for local recurrence (B2 and C) received postoperative radiotherapy. Lesions that were located in the rectum, rectosigmoid and low sigmoid colon were given 4600 rads in four and a half weeks through an inverted T-shaped field which encompassed the pelvic and paraortic nodes. Patients with tumors located above mid-sigmoid were treated to the entire abdominal cavity by the moving strip technique. Of 19 patients with rectal and rectosigmoid lesions, 14 (74%) are alive without evidence of disease. Two had local recurrence in the treated area. Of 21 patients with lesions above the mid-sigmoid, four have failed locally, while 11 (52%) are alive without evidence of disease. One of these 40 patients died to radiation enteritis. Although the follow up period is short, the results suggest that a moderate dose of radiation may prevent local recurrence in patients with locally advanced colorectal cancer.