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

Abstract

Introduction: 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. Methods: Between September 1994 and November 2007, 207 patients at Sir Charles 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. Results: Median follow-up was 7.8 years. 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. Conclusion: 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.