Long-term biochemical and survival outcome of 921 patients treated with I-125 permanent prostate brachytherapy

Abstract

Purpose: To assess long-term biochemical and survival outcome after permanent prostate brachytherapy (BT).

Methods and materials: Data on 921 patients, treated with permanent interstitial BT monotherapy between 1989 and 2004 for <or=T2c Nx/0 Mx/0 prostate cancer were evaluated. All patients were treated with I-125 seeds (prescription dose 144 Gy). Eighty-five patients with a gland volume >or=50cc received 6 months of antiandrogen therapy before treatment. Patients were classified into risk groups with 232 defined as low-, 369 intermediate-, and 320 high-risk disease. The median follow-up was 69 months (range, 4-186 months); mean age was 67 years.

Results: Average 5- and 10-year biochemical no evidence of disease (bNED) rates were 79% and 57%. Average 10-year bNED rates by risk group were 88% for low-risk, 61% for intermediate-risk, and 30% for high-risk disease. The average 10-year overall and disease-specific survival rates were 59% and 82%. Ten-year overall and disease-specific survival rates by risk group were, respectively, 68% and 96% for low-risk, and 64% 87% for intermediate-risk, and 49% and 69% for high-risk disease. In multivariate Cox regression analysis, both risk group and treatment era were independent predictors of bNED and survival.

Conclusions: These data on long-term survival continue to support the use of I-125 monotherapy for prostate cancer in low-risk patients and, in particular, demonstrate its efficacy in intermediate-risk patients.