Overall survival of black and white men with metastatic castrate-resistant prostate cancer: A retrospective analysis across 20 years in the largest healthcare trust in the United Kingdom.

Abstract

35 Background: Prostate cancer in Black (B) men has been associated with poorer outcomes than their White (W) counterparts. However, this perception has been derived from studies conducted predominantly in the localized prostate cancer setting, were based on data derived from clinical trials and usually conducted solely within the United States. Methods: We reviewed the outcomes of cases with metastatic castration resistant prostate cancer (mCRPC) treated at St Bartholomew’s Hospital – the UK's largest Healthcare Trust - between 1997-2016. Statistical analyses were conducted using Intercooled Stata 8.2 (State College, TX, USA). Results: We identified 425 cases of mCRPC in the 20 year period. A substantial minority of our patients, 103 (24%) were Black (B), and the remainder White (W). Characteristics were matched in age (73 years in both groups), proportion enrolled in clinical trials (33% in both groups) and median PSA (65.6,B vs 78,W, p=0.86), with a larger proportion of Black patients with a ECOG Performance Status ≥ 2 (19%,B vs 9%,W). In the total cohort analysis, the median Overall Survival (OS) was 25.5 months (B) vs 21.8 months (W), (Hazard Ratio, HR=0.81,p=0.08). For the subpopulation who received chemotherapy at some point of their treatment (n=306), survival was comparable in both groups (median OS 23.8 months, B vs 22.8 months, W, HR=0.97,p=0.82). Interestingly, there was a trend to prolonged survival in the Black population in those who only received hormone therapy (n=106) throughout their treatment course; 39.7 months (B) vs 17.1 months (W), HR=0.54, p=0.019. In a multivariate analysis for prognostic factors for survival from mCRPC therapy considering ethnicity (HR 0.81 p=0.08), time from diagnosis to castrate resistance (HR 1.02, p=0.136), presence of bone metastases at CRPC diagnosis (HR 1.89,p=0.001) – only bone metastases were significant. Conclusions: In the first set of real-world data in a study conducted outside the US, we demonstrate that Black patients do not do worse than White patients with mCRPC. The study suggests that there is a greater margin of benefit of hormone-based therapy in the Black subpopulation.