Real-world management of metastatic castration-resistant prostate cancer (mCRPC): A national multicenter cohort study.

252 Background: The management of patients with mCRPC has evolved since the introduction of androgen-receptor axis targeted agents (ARATs). The Genitourinary Research Consortium (GURC) initiated a prospective, phase 4, multicentre, non-interventional, longitudinal cohort study of Canadian men with advanced prostate cancer to determine real-world treatment patterns and outcomes. Methods: 25 sites across Canada participated in this study including patients managed by urologists, medical- and radiation-oncologists between 2018 to 2021. Baseline patient characteristics and mCRPC treatment patterns are reported here. Treatment patterns reviewed included time to second-line treatment use and time to progression or death. Results: 136 mCRPC patients were enrolled. Median age was 73 years (range 66 to 80) with 54 (40%) having a Gleason score of >8 at diagnosis. Median PSA at enrollment was 8.9 (2.4 to 25.1) ng/ml. At study entry, 90/132 (66%) patients with mCSPC and 42/132 (31%) patients nmCRPC had progressed to develop mCRPC. One hundred and twenty-one (89%) of patients in this cohort received first-line treatment for mCRPC, the most common was abiraterone acetate + prednisone in 67 (49%) and enzalutamide in 41 (30%), followed by docetaxel in 6 (4.4%), and Radium-223 in 5 (3.7%) patients. During the 25-month median follow-up period (range 6-28), 59 (49%) of the patients receiving first line mCRPC therapy had documented disease progression or death. At the time of last recorded follow-up, 37 (28%) patients who progressed received a second-line therapy for mCRPC. Median time to progression in this cohort was 21 months (95% CI: 15.2 - NE), with ARAT-to-ARAT being the most common sequencing pattern observed in 15 (39%) patients, followed by ARAT to chemotherapy in 14 (37%). Conclusions: In this real-world analysis of mCRPC patients, ARAT therapy was the preferred approach for first-line treatment intensification in over 108 (80%) patients. Despite evidence of poor response rates, ARAT-to-ARAT was the most common sequencing for second line therapy, followed by ARAT-to-chemotherapy treatment. Further analysis and follow-up will help define optimal mCRPC management, in real world setting.