The primary goal of radical radiation therapy in men with localized prostate carcinoma is cure and a secondary but important goal is to achieve cure without treatment related sequelae, such as loss of continence, rectal injury, loss of potency and the need for castration. A literature review of 2,611 men undergoing irradiation for all stages of localized prostatic carcinoma documented a 0.2% incidence of treatment related mortality, 1.9% severe complications, 0.9% incontinence and 33 to 60% maintenance of full potency 5 or more years after treatment. A separate analysis was made of 331 patients with only early tumors (stages T1 and T2) treated with conventional external beam radiation therapy to doses of 63 to 74 Gy. from 2 individual centers (Massachusetts General Hospital and M.D. Anderson Hospital) and 1 multi-institutional group (Radiation Therapy Oncology Group). Median followup was 6.1 years; however, in 2 series followup ranged to 14 years. This analysis revealed frequencies of treatment associated sequelae of 0% for mortality, 0% severe complications, 0.4% urinary incontinence, 5.4% genitourinary structures (1.2% persisting), 5.1% hematuria (0.9% persisting) and 5.4% rectal bleeding (0.6% persisting). This composite analysis of men undergoing irradiation for stages T1 and T2 tumors with conventional fractionation and doses indicates that acute morbidity is minor and usually transient, severe injury is rare, most late gastrointestinal and genitourinary symptoms of radiation injury are neither permanent nor debilitating, and few symptoms of radiation injury develop beyond 5 years from treatment. These data, combined with the low progression rates (using prostate specific antigen criteria) following irradiation of men with early tumors, further substantiate the primary role of radical radiotherapy in the treatment of surgical risk adversive patients.