Impact of Age at Diagnosis on Outcomes in Men with Castrate-Resistant Prostate Cancer (CRPC)

Background: The association between age and outcomes in men with castrate resistant prostate cancer (CRPC) is not well understood. Objective: We aimed to evaluate CRPC patients to determine if their age at initial diagnosis impacted their cancer specific outcomes. Design, Setting, and Participants: A retrospective chart review was conducted on 333 consecutive CRPC patients treated at the Princess Margaret Hospital (PMH) between 1995 and 2005. Patients were divided into 4 age categories, (A) <55, (B) 55-64, (C) 65-74 (reference), and (D) ≥ 75 years (yrs). Outcome Measurements and Statistical Analysis: Primary endpoints included impact of age at diagnosis on overall survival (OS) and on prostate cancer specific survival. Secondary endpoints were time from diagnosis to development of CRPC, time from CRPC to death, and time from diagnosis to bone metastases. Results and Limitations: The median OS from diagnosis to death was: Group A 5.5 yrs (95% CI 3.0-7.5); Group B 6.7 yrs (95% CI 5.9-8.4); Group C 7.8 yrs (95% CI 6.6-9.3); and Group D 4.3 years (95% CI 2.9-5.0). The hazard ratio (HR) for death in Group D was 2.58 (95% CI 1.58-4.21, p=0.0002); and in Group A was 1.49 (95% CI 0.90-2.46, p=0.13). The duration of hormone sensitivity in Group D was less and predictive of OS, as was Gleason Score ≥8 and Stage 4 disease at diagnosis. Conclusions: Age at initial diagnosis appears to impact on outcome of patients who subsequently develop CRPC with a bimodal distribution of risk, with the shortest survivals in the ≥75 and <55 groups.