Treatment Patterns, Clinical Outcomes, Health Care Resource Utilization and Costs in Older Patients With Metastatic Castration-Resistant Prostate Cancer in the United States: An Analysis of SEER-Medicare Data

Background: Prostate cancer (PC) is more likely to develop in men >= 65 years old than in those <65 years old. This study aimed to generate real-world evidence on treatment patterns, clinical outcomes, health care resource utilization (HCRU), and costs among older patients with metastatic castration-resistant PC (mCRPC). Materials and Methods: A claims algorithm based on treatments expected for mCRPC was used to identify men >= 65 years old with mCRPC in the SEER-Medicare data between 2007 and 2019. The index date was defined as the date of the start of first-line therapy (1L). Treatment patterns and all-cause and PC-specific HCRU and costs were measured in the 12 months preindex period and the postindex follow-up period. Time to next treatment or death (TNTD) and overall survival (OS) were assessed in the follow-up period. Results: A total of 4758 patients met the eligibility cr iteria and received 1L treatment. Among these 1L patients, 57.4% subsequently received second-line (2L) treatment; among patients receiving 2L treatment, 49.3% subsequently received third-line (3L) treatment. Abiraterone, enzalutamide, and docetaxel were most common regimens in 1L (41.9%, 22.0%, 22.0%, respectively), 2L (33.3%, 32.7%, 13.6%, respectively), and 3L (17.9%, 25.1%, 22.3%, respectively). On average, patients had 1.2 inpatient admissions, 1.1 emergency room visits, and 27.6 outpatient visits per year during follow-up. The mean total all-cause and PC-related costs during the follow-up period were $111,060 and $99,540 per-patient-per-year, respectively. Median TNTD was 9.3, 6.5, and 5.7 months for 1L, 2L, and 3L, respectively. Median OS from the start of 1L treatment for mCRPC was 21.5 months. Discussion: Among older patients with mCRPC, high attrition from 1L to subsequent lines of therapy was observed. Median TNTD was <1 year and median OS was <2 years. These results highlight a need to introduce more effective mCRPC therapies in 1L to improve clinical outcomes for older patients.