High dose rate transurethral brachytherapy as a boost dose for localized adenocarcinoma of the prostate

From September 1989 to February 1993, 11 patients with localized adenocarcinoma of the prostate were treated with pelvic external-beam radiation therapy followed by high dose rate (HDR) transurethral brachytherapy as a boost dose. External-beam radiation therapy was administered through opposed pelvic fields using a 60Co teletherapy unit to a tumor dose of 46-50 Gy in 23-25 fractions and followed by three fractions of transurethral brachytherapy, delivered using a 60Co HDR remote afterloading equipment. The treatment time was calculated using the prostatic capsule as the reference point. The dose calculated to be delivered to the capsule was 5 Gy/fraction, making a total of 15 Gy. The follow-up period ranged from 11 to 65 months, with a median follow-up time of 30 months. Local control was achieved in all patients. The prostate-specific antigen levels were normalized within 3 months of radiotherapy in 9 patients and within 3-6 months in the remaining 2. Transurethral brachytherapy appears to be a simple and feasible form of brachytherapy. Preliminary local control and radiotherapy-related morbidity rates are comparable to those of other forms of brachytherapy. Further follow-up is required for assessment of long-term local control and delayed radiotherapy-related morbidity.