Real-world outcomes in second-line treatment of metastatic castration-resistant prostate cancer (mCRPC): The Prostate Cancer Registry.

212Background: The Prostate Cancer Registry is the first prospective, international observational study in mCRPC documenting characteristics and management in routine clinical practice, independent of treatment used. The study began in June 2013 enrolling > 3000 mCRPC patients (pts) followed for ≤ 3 years. Methods: Source-verified data were collected from men with documented mCRPC initiating a new mCRPC treatment or in surveillance. A history of disease progression despite surgical or chemical ADT was confirmed in all pts. This interim analysis reports baseline characteristics, treatments and outcomes in pts with no prior mCRPC treatment. To evaluate comparative effectiveness between treatments, propensity scoring (PS) methods were used to reduce effects of confounding. Results: Of 1906 evaluable pts with ≥ 12-month follow-up, the most commonly initiated first-line mCPRC treatments (n ≥ 50) were abiraterone acetate + prednisone (AA, n = 472), enzalutamide (ENZ, n = 98) or docetaxel (DOC, n = 382). Baselin...