OBJECTIVES: I. Determine the acute and late grade 3-5 genitourinary (GU) and gastrointestinal (GI) toxic effects of external beam radiotherapy followed by permanent source brachytherapy using interstitial iodine I 125 seeds in patients with intermediate risk, clinically localized adenocarcinoma of the prostate. II. Determine the freedom from prostate specific antigen (PSA) failure, overall survival, disease specific survival, and local and/or distant clinical relapse rates in patients treated with this regimen.
OUTLINE: This is a multicenter study. Patients undergo external beam radiotherapy (EBRT) to the pelvis 5 days a week for 5 weeks. Permanent source brachytherapy comprised of ultrasound-guided implantation of iodine I 125 seeds into the prostate is performed 2-6 weeks after completion of EBRT. Patients are followed at 1, 3, 6, 9, and 12 months, then every 6 months for 2 years, and then annually thereafter.
PROJECTED ACCRUAL: A total of 110 patients will be accrued for this study within 1 year.