Real-world analyses of mortality risk after androgen deprivation therapy initiation in Black vs. White patients with prostate cancer.

Abstract

84 Background: 2 studies found significantly longer overall survival in Black vs. White patients with metastatic castration-resistant prostate cancer (PCa): a 2019 meta-analysis of 9 phase III trials and a 2020 registry study. Our real-world data study compared all-cause mortality risk for Black vs. White PCa patients. Compared to the prior studies, our study encompasses a broader scope and is not exclusive to men with castration-resistant PCa. Methods: Data were collected from the Decision Resources Group Real World Evidence repository, which links medical and prescription claims, and US Electronic Healthcare Records. The analysis set included PCa patients who received ≥1 androgen deprivation therapy (ADT) injection between 1991-2020. Cox regression was used to compare all-cause mortality rates between White and Black patients. Multivariable regression model accounted for the following variables: baseline metastasis, BMI, oncology vs. urology setting, antagonist vs. agonist, personal major adverse cardiovascular event (MACE) history, tobacco history, baseline PSA (>4 vs. ≤4 ng/mL), race (White vs. Black), statin use, increasing age per year, ethnicity (non-Hispanic vs. Hispanic), increasing ADT exposure per year, diabetes, hypertension, and family MACE history. Results: 44,439 patients were included for the all-patient analyses. 34,762 patients were included in the Black vs White analyses: 5,817 and 28,945 were Black and White, respectively. Overall, mortality risk was 2.6% and 17% at 1 and 4 years after ADT initiation, respectively. Mortality risk after ADT initiation was 1.6% and 2.6% at 1 year and 11.7% and 18.1% at 4 years for Black and White patients, respectively. Both unadjusted (HR=1.66, 95% CI 1.53-1.80, p<0.05) and adjusted (HR=1.24, 95% CI 1.01-1.52, p<0.05) mortality risks were higher for White vs. Black patients. Conclusions: All-cause mortality incidence was higher in White vs. Black patients. Adding to the body of evidence, our research also reveals that Black race is associated with a protective effect on survival for all-cause mortality in men undergoing ADT. Potential hypotheses for higher mortality in White vs. Black patients include survival bias to MACE (i.e., Black patients may have died from PCa before having MACE), survival bias to be diagnosed with PCa (i.e., Black patients may have higher rate of CV death and kidney failure prior to PCa diagnosis), and protective effects of higher BMI in Black patients against cancer cachexia. The large size (~45,000 patients from a database with >300 million patients), long follow-up (10 years for some patients), recent clinical experience (99% from 2010-2020), and diversity of the dataset give weight to the results being an accurate representation of current clinical experience. Future studies should confirm our findings that White PCa patients have higher mortality risk and investigate the above hypotheses.