Patient characteristics, treatment patterns, and survival outcomes in patients with castration-resistant prostate cancer: results from the J-CaP registry.

BACKGROUND

The optimal treatment sequence of approved therapies for castration-resistant prostate cancer (PC) is unclear. This study assessed real-world patient characteristics, treatment patterns, and effectiveness in patients with castration-resistant PC in Japan.

METHODS

Using data from the Japan Study Group of Prostate Cancer registry (2016-2018), this retrospective study included patients with ≥1 record of: primary androgen-deprivation therapy for hormone-sensitive PC and clinical progression to castration-resistant PC during primary androgen-deprivation therapy. The primary outcomes were patient characteristics, treatment patterns, and treatment duration. Other outcomes were overall survival (OS), cancer-specific survival (CSS), time to disease progression, and time to second disease progression.

RESULTS

A total of 600 patients were included. The mean age was 75.3 (SD: 7.9) years at PC diagnosis. The median prostate-specific antigen level was 135.5 (IQR: 37.3-542.2) ng/mL. The most common first-line castration-resistant PC treatments were enzalutamide (30%), docetaxel (20%), abiraterone (18%), flutamide (12%), and bicalutamide (8.7%). The most common second-line treatments were enzalutamide (28.5%), abiraterone (21.9%), and docetaxel (16.6%). The median treatment duration for enzalutamide, docetaxel, abiraterone, and flutamide was 254.0, 176.0, 197.0, and 111.5 days, respectively. Across all treatments, the median OS, CSS, time to disease progression, and second disease progression was 1028.0, 1239.0, 616.0, and 887.0 days, respectively.

CONCLUSION

Androgen receptor signaling inhibitors and docetaxel were the most common first- and second-line castration-resistant PC treatments. Enzalutamide was the preferred androgen receptor signaling inhibitor with the longest treatment duration.