Effects of preoperative radiotherapy on rectal cancer. Preliminary report on combining radiation with intratumor injections of peplomycin and bromodeoxyuridine. Between 1976 and 1983, 61 patients with advanced rectal cancer underwent Miles' operation at the authors' institution. All lesions were located 10 cm or less from the anal verge. Of these patients, 25 were treated by surgery alone and 36 were given preoperative radiotherapy. The total dose was 42.6 Gy, (30.6 Gy [1.8 Gy/fr x 5/week]) delivered to the entire pelvis plus an additional 12 Gy (3.0 Gy/fr x 4/week) delivered to the primary tumor. Of 36 patients, 21 were administered intratumor injections of peplomycin and bromodeoxyuridine at the time of boost radiation and 15 were treated without intratumor injections. During the follow-up period (3 to 9 years), in the groups of patients who underwent radiation, there was only one local failure (2.8 percent). In contrast, in the group of patients treated by surgery alone, eight local failures occurred (32 percent). The intratumor injection significantly enhanced the effect of radiation on tumor regression. The incidence of positive lymph nodes was higher in patients in the surgery alone group than it was in the groups treated with radiation. There was no difference in the rate of distant metastasis among the three treatment groups. The five-year survival rate for the radiation with intratumor injection group, radiation alone group, and surgery alone group, was 77.8, 69.2, and 56.0 percent, respectively. No severe complication was experienced. 