Ten-year outcomes using low dose rate brachytherapy for localised prostate cancer: An update to the first Australian experience.

Abstract

To report long-term prostate-specific antigen (PSA) and toxicity outcomes for patients with localised prostate cancer treated with Iodine-125 permanent implantation at a single Australian centre. Between September 1994 and November 2007, 207 patients at SirCharles Gairdner Hospital with localised prostate cancer were consecutively treated with Iodine-125 permanent interstitial implantation. Post-therapy assessment was performed three times a month and included clinical review and biochemical (PSA) evaluation. PSA progression was evaluated using the Phoenix (nadir + 2.0) definition. Treatment-related morbidity was assessed using the Common Terminology Criteria for Adverse Events (CTCAE) version 3.0 guidelines. The rate of biochemical failure was calculated by Kaplan-Meier plots. Univariate and multivariate analyses were performed to evaluate outcomes by pre-treatment clinical prognostic factors and radiation dosimetry. Median follow-up was 7.8years. The 10-year biochemical disease-free survival (bDFS) for the entire cohort was 89%. Ten-year bDFS estimates by pre-treatment risk group were 96% for low-risk, 83% for intermediate-risk and 50% for high-risk disease. On multivariate analysis, pre-treatment PSA was an independent predictor of bDFS. D90 dose did not show a statistically significant effect on bDFS. The peak incidences of late grade 3 or higher urinary and rectal toxicities were 10.7% and 1.1% respectively. Excellent long-term biochemical control was demonstrated with Iodine-125 permanent interstitial implantation in appropriately selected patients with prostate cancer. The results of our single centre experience are comparable with those of other single institutions.