Abstract 4469: Clinical outcomes among patients treated with abiraterone acetate for advanced prostate cancer with pre-existing cardiovascular conditions

Abstract

Abstract Background: Advanced prostate cancer patients with pre-existing cardiovascular diseases (CVD) are often excluded from clinical trials of abiraterone acetate (AA). Therefore, the clinical outcomes of these patients are uncertain. This study was undertaken to examine their outcomes - changes in the rate of hospitalization and short-term mortality after AA initiation by pre-existing CVD conditions. Methods: This population-based study identified PCa patients from the linked Surveillance, Epidemiology and End Result (SEER)-Medicare files diagnosed between 1/1/1991 and 12/31/2013 and treated with AA in 2011-2014. The primary endpoints were 6-month overall mortality and changes in hospitalization rates following AA initiation. Major pre-existing conditions are listed in the Table 1. The changes in hospitalization rate were measured by the incidence rate ratios (IRR), post treatment rate divided by pre-treatment rate. Results: Among 2,845 patients treated with AA (median age 75 years), 1,924 (67.6%) of these patients had at least one pre-existing CVD condition. Compared to pre-treatment period, the hospitalization incidence post-AA increased by 58% to 88%. The crude risk of 6-month overall mortality was between 21.4% to 25.6%. Table 1:Risk of Hospital Visits and 6-month Overall Mortality among AA Patients by Pre-Existing CVD condition.Pre-existing CVD conditionNo. hospitalizations per 6-months prior to AAIRR for hospitalizations (95% CI)Crude 6-month post AA MortalityAcute Myocardial Infraction0.651.88 (1.48-2.40)25.6%Atrial Fibrillation0.561.58 (1.36-1.83)24.4%Congestive Heart Failure0.591.72 (1.54-1.92)23.4%Stroke0.521.67 (1.40-2.01)22.1%Ischemic Heart Disease0.471.78 (1.63-1.95)21.4%No CVD0.251.87 (1.59-2.20)15.8% Conclusion: All patients experienced significant increase in hospitalization after initiation of AA. Our study highlights the importance of carefully monitoring patients after prescribing AA. Citation Format: Grace Lu-Yao, Nikita Nikita, Scott Keith, Krupa Gandhi, Timothy R. Rebbeck, Jennifer Cullen, Ginah Nightingale, Mark Mann, Andrew Chapman. Clinical outcomes among patients treated with abiraterone acetate for advanced prostate cancer with pre-existing cardiovascular conditions [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 4469.