Preoperative radiotherapy for colorectal cancer

In a prospective randomized trial, 700 patients with a confirmed histologic diagnosis of adenocarcinoma of the rectum or rectosigmoid were randomized to receive radiotherapy prior to operation (2000 to 2500 rads in 2 wk) or surgery alone. 5 yr observed survival in 453 patients on whom 'curative' resection was possible was 48.5% in the X ray treated group compared with 38.8% in controls, while in the 305 having low lying lesions requiring abdominoperineal resection, survival in the treated group was 46.9% compared with 34.3% in controls. Although suggestive of a treatment benefit, neither figure is considered statistically significant. Histologically positive lymph nodes were found in 41.2% of the control group and in only 27.8% of the patients receiving radiotherapy. Review of all patients who died during the study shows a consistently lower death rate from cancer in the radiotherapy group. Although this study suggests a treatment benefit from preoperative radiotherapy, further studies now in progress are necessary to determine the optimal dose regimen.