Risk group stratification in patients undergoing permanent (125)I prostate brachytherapy as monotherapy.
Academic Article
Overview
abstract
PURPOSE: Patients undergoing prostate brachytherapy (PB) as monotherapy are often selected on the basis of favorable pretreatment factors. However, intermediate and high-risk prostate cancer patients are commonly offered PB as monotherapy without the addition of external beam radiotherapy (EBRT) or hormonal therapy. This series reports the outcome of patients undergoing PB as monotherapy who were stratified into low, intermediate, and high-risk groups with extended follow-up. METHODS AND MATERIALS: A total of 102 patients with clinically localized prostate cancer underwent PB alone as monotherapy. EBRT or hormonal therapy was not part of their initial treatment. Prostate-specific antigen (PSA) relapse-free survival (PRFS) was determined in accordance with the American Society for Therapeutic Radiology and Oncology consensus statement. Patients were stratified as at favorable risk (Stage T1-2a, pretreatment PSA < or =10.0 ng/mL, and Gleason score < or =6), intermediate risk (one prognostic indicator with a higher value), or unfavorable risk (> or =2 indicators with higher values). The median follow-up period for patients in this series was 7 years (range 2.1-9.7). The median age at treatment was 71 years (range 54-80), and the median prescribed dose of (125)I was 145 Gy. RESULTS: Forty patients experienced a biochemical relapse at a median of 1.9 years (range 0.4-4.2). The 5-year actuarial PRFS rate for patients with favorable, intermediate, and unfavorable risk was 85%, 63%, and 24%, respectively (p <0.0001). All but 1 patient had the relapse within the first 5 years of treatment. When stratifying patients on the basis of their pretreatment PSA level, the 5-year PRFS rate for men with a PSA < or =10 ng/mL vs. >10 ng/mL was 78% vs. 35%, respectively (p = 0.0005). Furthermore, the 5-year PRFS rate for men with a Gleason score of < or =6 vs. > or =7 was 74% vs. 33%, respectively (p = 0.0001). No difference was found between Stage T1-T2a and Stage T2b or higher (64% vs. 54%, respectively; p = 0.353). CONCLUSION: On the basis of risk stratification, PB as monotherapy produces comparable PRFS to EBRT and surgery at 7 years of follow-up. PB as monotherapy is particularly ineffective in patients with unfavorable risk factors, and additional therapy is warranted.
