Shifting paradigms in the estimation of survival for castration-resistant prostate cancer : A tertiary academic center experience

OBJECTIVES: Castration-resistant prostate cancer (CRPC) has retained a guarded prognosis, with historical survival estimates of 18 to 24 months. However, the landscape of available therapy has changed, and the emphasis has altered from supportive to active treatment. Few large series from real-world populations exist in the contemporary era with fully mature survival data to confirm the indication based on clinical trials that patients with CRPC are surviving far longer than the historical estimates. We aim to review a large patient cohort with CRPC and provide mature survival data. METHODS AND MATERIALS: Using the electronic histopathology database at Queen Elizabeth Hospital, Birmingham, UK, all prostate-specific antigentest results between April 2006 and September 2007 were extracted, and patients satisfying the American Society for Radiation Oncology (ASTRO) definition of hormone failure were identified. Electronic records were reviewed and variables were collected, including survival, treatment, biochemistry, histopathology, and demographics. Probability of survival, and of developing metastasis or CRPC, was determined using the Kaplan-Meier method. Patients were stratified into 3 groups, namely, D0--no metastasis at diagnosis but later appearance, D1--no metastasis at diagnosis or at last follow-up, and D2--metastasis at diagnosis. RESULTS: From 8,062 patient-prostate-specific antigen episodes, we identified 447 patients meeting the criteria. A notes review revealed 147 patients with CRPC. Median overall survival (OS) from diagnosis was 84.7 months (95% CI: 73-89), and 129 deaths had occurred (88%). Median OS from diagnosis for D0, D1, and D2 patients was 100.4, 180.1, and 58.9 months, respectively (P< 0.0001), and median OS from CRPC was 40 months (95% CI: 31-58), 82.9 (95% CI: 72-94; P = 0.0125), and 38.7 months (95% CI: 33-46), respectively. One-quarter of patients survived 6 years after development of CRPC. Metastasis is the key prognostic event. CONCLUSIONS: Some current international guidelines quote ≤19 months as a survival figure for patients with metastatic CRPC. In our study, median survival is more than double this. We have shown survival more than previously reported figures and believe that these data benefit clinicians and patients in understanding prognosis and treatment choices. Importantly, our patients were diagnosed before the current wave of novel therapeutics for CRPC, so survival for men diagnosed today may be more than our findings