SHORT-TERM FREEDOM FROM DISEASE PROGRESSION AFTER I-125 PROSTATE IMPLANTATION

Purpose: To evaluate short-term clinical and chemical disease progression following computed tomography (CT)-based transperineal I-125 prostate implantation. Methods and Materials: Sixty-two patients with clinical Stage T1 or T2 prostatic carcinoma had outpatient, CT-based transperineal I-125 prostate implantation and have been followed for 6-55 months (median: 19 months). Fifty-six patients had an elevated prostate specific antigen (PSA) before implantation (> 4.0 ng/mL). Twenty patients had well-differentiated tumors, 39 were moderately differentiated, 2 were poorly differentiated, and 1 was indeterminate. A total of 32-73 mCi I-125 was implanted (median: 47 mCi). The prescribed minimum prostatic dose was 140-160 Gy, and the actual matched peripheral dose ranged from 109-258 Gy (median: 160 Gy). Lymph node dissection or postimplantation prostatic biopsies were not routinely performed. Results: Of 54 patients with an elevated PSA prior to implantation and no prior hormonal treatment, 96% returned to normal within 24 months of treatment. In 85% of patients, the PSA fell below 2.0 ng/mL and in 74% of patients, the PSA value fell to below 1.0 ng/mL. Seven patients had disease progression, one of whom has an isolated, rising PSA. The actuarial rate of chemical (rising PSA) or clinical failure at 3 years following implantation was 17%. Of 38 patients who were sexually potent prior to implantation, 81% remained potent at 3 years. Five patients developed radiation-induced rectal ulcerations, 11-22 months following implantation. Three patients required a transurethral resection of the prostate for postimplant urinary symptoms. Conclusions: The short-term clinical and chemical freedom-from-progression rates following I-125 implantation are comparable to that achieved with prostatectomy, with high preservation of sexual potency and moderate morbidity.