Improving the therapeutic ratio of external beam irradiation for carcinoma of the prostate.

From 1975 to 1983, 240 patients with carcinoma of the prostate, Stages A2 to C, were treated with whole pelvic radiation followed by a 2-week rest and then a reduced field of radiation. The reduced prostatic field was evaluated for adequacy of tumor coverage by CT scan or ultrasound. The local regional control rate was 94%, with a 5-year actuarial survival for all stages of 72%. Severe complications occurred in 3% of patients and moderate complications in 13%. Two major factors that were identified as contributing to the risk of complications included previous or subsequent surgical intervention. Our technique of external beam radiotherapy resulted in a favorable therapeutic ratio, that is, excellent local-regional control with minimal morbidity.