Does ADT benefit unfavourable intermediate risk prostate cancer patients treated with brachytherapy boost and external beam radiotherapy? A propensity-score matched analysis.

To investigate the role of androgen deprivation therapy (ADT) in unfavorable intermediate risk (UIR) prostate cancer patients treated with high-dose rate (HDR) brachytherapy (BT) boost.

Data from 326 consecutive NCCN UIR prostate cancer patients treated in a single institution from 2009 to 2016 with 15 Gy HDR-BT boost plus 37. 5 Gy external beam radiotherapy (EBRT) in 15 fractions to prostate and proximal seminal vesicles were retrospectively collected. Baseline information was collected and patients receiving vs. not receiving ADT were matched using a propensity-score model. Primary endpoint was biochemical-failure-free survival (BFFS). Kaplan-Meier estimates and stratified log-rank tests (adjusting for matched design) were used to compare BFFS, castration-resistance (CRFS) and metastasis free survival (MFS) outcomes between both groups.

A total of 326 patients were included in the analysis of which 52 ADT patients were matched to 104 non-ADT patients in a 1:2 ratio. Median follow-up was 3.4 years and 5.5 years for ADT and non-ADT respectively. No significant baseline differences were observed. ADT was used for a median total time of 6 months (interquartile range [IQR]: 4-6) and delivered a median time of 2.7 months (IQR: 1.7-4.3) prior to HDR-BT. BFFS was significantly improved in the ADT group (stratified log-rank: p= 0.043) with 3-year and 6-year BFFS of 98% and 90% for the ADT group and 92% and 82% for the non-ADT group, respectively. No significant differences were detected for CRFS or MFS.

Short-term ADT increased BFFS in UIR prostate cancer patients treated with HDR-BT boost plus EBRT.

Radiotherapy and oncology : journal of the European Society for Therapeutic Radiology and Oncology. 2020 Jun 30 [Epub ahead of print]

Lucas C Mendez, Kevin Martell, Andrew Warner, Chia-Lin Tseng, Hans Chung, Andrew Loblaw, George B Rodrigues, Gerard Morton

Division of Radiation Oncology, London Health Sciences Centre, London, Ontario, Canada., Department of Oncology, University of Calgary, Calgary, Alberta, Canada., Department of Radiation Oncology, Sunnybrook Health Sciences Centre, Toronto, Ontario, Canada., Department of Radiation Oncology, Sunnybrook Health Sciences Centre, Toronto, Ontario, Canada. Electronic address: .