Biochemical outcome for hormone-naı̈ve intermediate-risk prostate cancer managed with permanent interstitial brachytherapy and supplemental external beam radiation

Purpose: To report the 6-year biochemical disease-free outcome for hormone-naı̈ve patients with intermediate-risk disease (Gleason score ≥7, prostate-specific antigen (PSA) ≥10 ng/ml, or clinical stage ≥T2b [1997 American Joint Committee on Cancer]) undergoing brachytherapy with supplemental external beam radiation (XRT). Methods and Materials: Seventy-seven consecutive hormone-naı̈ve intermediate-risk prostate cancer patients received supplemental XRT followed by a brachytherapy boost. No patient underwent pathologic lymph node staging. The median patient age was 69 years and the median follow-up was 52 months. Biochemical disease-free survival was defined by the American Society of Therapeutic Radiology and Oncology consensus definition. Clinical and treatment parameters evaluated included patient age, clinical stage, Gleason score, pretreatment PSA, and isotope. Results: The 6-year actuarial biochemical no-evidence-of-disease survival rate was 97.4%. None of the evaluated clinical or treatment parameters, except for a Gleason score ≥8, predicted for failure. The mean and median posttreatment PSA was 0.08 ± 0.19 ng/ml and <0.1 ng/ml, respectively. When stratified by isotope, the mean posttreatment PSA was not significantly different (0.07 ± 0.11 ng/ml for 103Pd vs. 0.14 ± 0.32 ng/ml for 125I; p = 0.397). Conclusions: Hormone-naı̈ve intermediate-risk prostate cancer patients undergoing brachytherapy with supplemental XRT have a high probability of 6-year biochemical disease-free survival. None of the evaluated clinical or treatment parameters, except Gleason score ≥8, predicted for treatment failure.