Elective postoperative radiotherapy after incomplete resection of colorectal cancer.

It is known that patients with incompletely resected epithelial cancers are at high risk of local recurrence. A prospective study to determine whether elective postoperative radiotherapy can decrease the incidence of local recurrence and thus improve survival of those patients with an incompletely resected tumor was made of 125 irradiated patients with locally advanced colorectal cancer (B2, C1, C2) 78 patients had rectosigmoid tumors and 47 had colonic cancers. Complete resection (R0) was performed in 94 patients (75 per cent). Thirteen (10 per cent) had microscopic (R1) and 18 (14 per cent) had gross residual disease (R2). Local control and survival (average follow-up, 38 months) of patients with microscopic residual cancer (RI) were 84 per cent (11/13) and 77 per cent (10/13) respectively. These results were identical to those obtained in patients without residual disease (R0). Patients with gross residual disease (R2) had a local control of 50 per cent (9/18) and a survival of 39 per cent (7/18). Radiation complication occurred in seven of 125 patients (6 per cent). One patient died, of radiation enteritis. One patient required a nephrostomy. The remaining five patients were treated conservatively. Elective postoperative radiotherapy given to patients who had incomplete resection of a colorectal cancer prevented local recurrence in the majority and may have increased survival.