Percutaneous transperineal placement of gold 198 seeds for treatment of carcinoma of the prostate.

Thirty-one patients have been treated for carcinoma of the prostate with 198Au seeds placed transperineally using transrectal ultrasonic guidance. Twenty patients have been followed postoperatively for periods ranging from 3 to 31 months, with an average follow-up time of 12 months. Cumulative dose of radiation to the prostate calculated by dosimetry was either 9,000 rads or 15,000 rads. Serial transrectal ultrasound examinations performed on these patients showed a decrease in prostate size in all patients within 6 months of treatment, with a statistically significant decrease observed between the third and sixth months. No significant difference in amount or rate of tumor regression was noted when tumor stage and grade were correlated to volume decrease after treatment. Patients who received the larger doses of radiation (15,000 rads) showed a significantly greater rate of decline in prostatic volume than those who received 9,000 rads. Seven patients underwent prostate biopsy between 12 and 18 months after treatment; six biopsies showed residual tumor. Complications after treatment included urinary retention because of prostatic edema (three), radiation urethritis (three), and rectal ulceration (one). Transperineal placement of 198Au is well tolerated and offers an alternative to external beam radiation for treatment of carcinoma of the prostate.