Defying the Unfavorable Risk: The Efficacy of LDR Brachytherapy Monotherapy in Gleason 7 Prostate Cancer: A 16-Year Single-Center Retrospective Study

Background: Prostate cancer patients with intermediate disease risk [Gleason score (GS)7] can be divided into two groups: GS = 7(3 + 4) (ISUP 2) (favorable disease risk) and GS = 7(4 + 3) (ISUP 3) (unfavorable disease risk). Low-dose-rate brachytherapy (LDR-BT) is an effective treatment for low- and intermediate-disease-risk patients. Objectives: The main goal of this study was to evaluate the effectiveness of LDR-BT monotherapy in prostate cancer patients classified as ISUP 3 when compared with ISUP 2 patients. Methods: This was a retrospective study that evaluated prostate cancer patients classified as ISUP 2 and ISUP 3 followed up at the Center for the Treatment of Urological Diseases, Portugal, who underwent LDR-BT. Overall survival (OS), biochemical recurrence-free survival (BRFS), bone metastasis and complications post-LDR-BT treatment were evaluated. Results: A total of 602 patients classified with GS = 7 (481/602 ISUP 2 and 121/602 ISUP 3) treated with LDR-BT were recruited. High OS rates and a reduced frequency of complications were described in both groups of patients. ISUP 3 patients had a lower BRFS rate, a higher risk of biochemical recurrence, and developed more bone metastasis in a shorter period when compared with ISUP 2 patients. No significant differences were detected in prostate-cancer-specific mortality between groups. Conclusions: LDR-BT monotherapy is a safe and effective treatment for prostate cancer patients with favorable and unfavorable intermediate disease risk, with similar OS rates and reduced complications.