Adjuvant radiation therapy in colorectal carcinoma

A series of sixty-five patients with adenocarcinoma of the rectum and rectosigmoid is reviewed. Thirty-two patients had surgery alone, fourteen patients underwent postoperative radiation therapy, and nineteen patients underwent preoperative radiation therapy. A moderate dose program of 4,000 to 4,500 r was used. The postoperative treatment group had a higher incidence of stage C lesions and a higher recurrence rate, but there were no statistically significant differences in survival. Postoperative radiation therapy in patients with stage C lesions did not prolong life and is of little benefit. The preoperative treatment group tolerated the radiation very well, and there were no major complications. Eight patients underwent anterior resections in irradiated fields. Two minor anastomotic leaks subsequently healed spontaneously. There were no pelvic recurrences in the preoperative treatment group, and the incidence of lymph node metastases was 26% as opposed to 41% in controls. We conclude that preoperative moderate dose radiation is not associated with increased risk of morbidity or mortality. It may be useful in reducing the incidence of lymph node metastases and pelvic recurrence. The effect on survival is not determined in this study.