Hormonal Therapy or External-Beam Radiation With Brachytherapy and the Risk of Death From Prostate Cancer in Men With Intermediate Risk Prostate Cancer

Abstract

PurposeTo determine whether external-beam radiotherapy (EBRT) improves disease control compared with supplemental androgen suppression therapy (AST) in men with intermediate-risk prostate cancer who are being treated with brachytherapy. Patients and MethodsA total of 807 men with intermediate-risk prostate cancer (T2bNXM0, Gleason ≤7, prostate-specific antigen [PSA] <20 ng/mL; or cT1c-T2bNXM0, Gleason 7) were consecutively treated with either AST and brachytherapy or EBRT and brachytherapy, between 1997 and 2007, and were followed up until September 21, 2007. A Fine and Gray competing risks multivariable regression model was used to assess whether AST or radiotherapy dose escalation reduced the risk of prostate-cancer–specific mortality (PCSM) when adjusting for age, PSA, Gleason score, and tumor category. ResultsTreatment with brachytherapy and with EBRT was associated with a significant increase in the risk of PCSM compared with brachytherapy and AST (adjusted hazard ratio [HR] 4.027 [95% CI, 1.168-13.89]; P = .027) after adjusting for age and prostate cancer prognostic factors. A Gleason score of 4+3 and increasing PSA were associated with worse PCSM (adjusted HR 8.882 [95% CI, 1.095-72.04]; P = .041; and adjusted HR 8.029 [95% CI, 2.38-28.8]; P = .0014, respectively). ConclusionSupplemental AST use compared with EBRT is associated with a lower risk of PCSM in men with intermediate-risk PC undergoing brachytherapy. Prospective validation in a randomized controlled trial is needed.