High-intermediate prostate cancer treated with low-dose-rate brachytherapy with or without androgen deprivation therapy

Abstract

Purpose: To describe outcomes of men with unfavorable (high-tier) intermediate risk prostate cancer (H-IR) treated with low-dose-rate (LDR) brachytherapy, with or without 6 months of androgen deprivation therapy (ADT).

Methods and materials: Patients with H-IR prostate cancer, treated before 2012 with LDR brachytherapy without external radiation are included. Baseline tumor characteristics are described. Outcomes between groups receiving ADT are measured by Phoenix (nadir +2 ng/mL), and threshold 0.4 ng/mL biochemical relapse definitions (bNEDs), as well as clinical end points. Standard descriptive and actuarial statistics are used.

Results: Two hundred sixty men were eligible, 139 (53%) did not receive ADT and 121 (47%) did. Median follow-up was 5 years. Men treated with ADT had higher T stage and percent positive cores but lower pathologic grade group. bNED rates with and without ADT at 5 years are 86% and 85% (p = 0.52) with the Phoenix definition, and 83% and 78% (p = 0.13) with the threshold definition. Local recurrence or metastasis were rare in both groups (<5%, p = not significant). Death from prostate cancer only occurred in 4 patients, 2 in each group. Overall survival was 85% in those treated with ADT and 93% without at 8 years, p = 0.15.

Conclusions: The addition of 6 months of ADT to LDR brachytherapy for H-IR prostate cancer does not improve 5 year prostate specific antigen control, and we no longer routinely recommended it.

Keywords: Androgen deprivation therapy; Biochemical control; Brachytherapy; Intermediate risk; Low-dose-rate; Prostate cancer.