Men aged 65 and older in the US enrolled in Medicare with castrate resistant prostate cancer identified after January 1, 2006.
The study cohort included men who meet all of the following inclusion criteria:
• Enrolled in both Medicare Parts A and B for at least 1 year before the cohort entry date (minimum lookback period for comorbidities and treatments)
• Primary site code of prostate cancer (International Classification of Diseases for Oncology, Third Edition [ICD-O-3] 1 topography code C61.9) in SEER data
• Surgical castration or androgen deprivation therapy after prostate cancer diagnosis; androgen deprivation therapy will be indicated by the use of any of the following drugs: abarelix, bicalutamide, buserelin, cyproterone, degarelix, diethylstilbestrol, estramustine, flutamide, gonadorelin, goserelin, histrelin, leuprolide,
medroxyprogesterone, megestrol, nafarelin, nilutamide, polyestradiol, triptorelin
• Evidence that prostate cancer was resistant to surgical castration or androgen deprivation therapy (“castration-resistant prostate cancer”), as indicated by starting one of the following second-line systemic therapies (cohort entry date): abiraterone, cabazitaxel, docetaxel, enzalutamide, mitoxantrone, or sipuleucel-T
• Cohort entry date 01 January 2006 or later
• Age 65 years or older on the cohort entry date