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 adeno carcinoma of the prostate were treated with pelvic external-beam radia tion therapy followed by high dose rate (HDR) transurethral brachyther apy as a boost dose. External-beam radiation therapy was administered through opposed pelvic fields using a Co-60 teletherapy unit to a tumo r dose of 46-50 Gy in 23-25 fractions and followed by three fractions of transurethral brachytherapy, delivered using a Co-60 HDR remote aft erloading equipment. The treatment time was calculated using the prost atic capsule as the reference point. The dose calculated to be deliver ed to the capsule was 5 Gy/fraction, making a total of 15 Cy. The foll ow-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 prosta te-specific antigen levels were normalized within 3 months of radiothe rapy in 9 patients and within 3-6 months in the remaining 2. Transuret hral brachytherapy appears to be a simple and feasible form of brachyt herapy. Preliminary local control and radiotherapy-related morbidity r ates are comparable to those of other forms of brachytherapy. Further follow-up is required for assessment of long-term local control and de layed radiotherapy-related morbidity.