Purpose: We estimated the risk of prostate cancer (PC) -specific mortality (PCSM) after brachytherapy alone or in conjunction with androgen suppression therapy (AST), external-beam radiation therapy (EBRT), or both in men with high-risk PC.
Patients and methods: The study cohort comprised 1,342 men with a prostate-specific antigen level more than 20 ng/mL and clinical T3 or 4 and/or Gleason score 8 to 10 disease. Competing risks multivariable regression was performed to estimate the risk of PCSM in men treated with brachytherapy alone or with supplemental AST, EBRT, or both, adjusting for age, year of treatment, and known PC prognostic factors.
Results: Despite higher baseline probabilities of PCSM after a median follow-up of 5.1 years, there was a significant reduction in the risk of PCSM (adjusted hazard ratio [AHR], 0.32; 95% CI, 0.14 to 0.73; P = .006) in men treated with brachytherapy and both AST and EBRT as compared with neither. When compared with brachytherapy alone, a significant decrease in the risk of PCSM was not observed in men treated with either supplemental AST (AHR, 0.63; 95% CI, 0.27 to 1.47; P = .28) or EBRT (AHR, 0.57; 95% CI, 0.21 to 1.52; P = .26). There was a near-significant reduction (AHR, 0.53; 95% CI, 0.27 to 1.07; P = .079) in the risk of PCSM in men treated with tri- as compared with bimodality therapy.
Conclusion: Supplemental AST and EBRT but not either supplement compared with brachytherapy alone was associated with a decreased risk of PCSM in men with high-risk PC.