Prostate-specific antigen failure and risk of death within comorbidity subgroups among men with unfavorable-risk prostate cancer treated in a randomized trial

Abstract

Purpose: Physicians sometimes make management recommendations on the basis of early results from randomized controlled trials (RCTs) relating to reduced prostate-specific antigen (PSA) failure, yet whether this early end point is associated with all-cause mortality (ACM), particularly in men with competing risks, is unknown. Using a validated metric in men treated within the context of an RCT, we aimed to determine whether PSA failure is associated with the risk of ACM stratified by comorbidity score. Patients and Methods: Between 1995 and 2001, 206 men with localized (T1b to 2b) intermediate- and high-risk prostate cancer (PC) were randomly assigned to receive radiation therapy or radiation therapy and 6 months of ADT. Cox regression analyses were performed to evaluate whether PSA failure modeled as a time-dependent covariate was associated with an increased risk of ACM among men with Adult Comorbidity Evaluation-27-defined no or minimal versus moderate-to-severe comorbidity adjusting for age, PC prognostic factors, and treatment. Results: After a median follow-up of 16.62 years, 156 men (76%) died, 29 of whom (19%) died as a result of PC. PSA failure was associated with an increased ACM risk among men with no or minimal (adjusted hazard ratio, 1.59; 95% CI, 1.03 to 2.46; P=. 04), but not moderate or severe comorbidity (adjusted hazard ratio, 1.75; 95% CI, 0.76 to 3.99; P =. 19). Conclusion: Recommending treatment on the basis of reduced PSA failure observed from early results of RCTs is unlikely to prolong survival in men with moderate-to-severe comorbidity but may prolong survival in men with no or minimal comorbidity, providing evidence to support discussing the early results with these men.