The purpose of this study is to learn about the safety of TALZENNA in patients with BRCA mutation-positive metastatic castration-resistant prostate cancer. BRCA mutation positive means any changes to the BRCA gene. Metastasis means the cancer that has spread to other parts of the body. Castration-resistant prostate cancer means the prostate cancer that keeps growing even when the amount of male sex hormone in the body is reduced to very low levels. Prostate is a male sex organ. The study is seeking for participants: * with BRCA mutation-positive metastatic castration-resistant prostate cancer * who have not used this study medicine before. All patients in this study will receive TALZENNA according to the prescriptions. Patients will be followed up to 52 weeks (12 months) from the day of start of treatment start (Day 1). However, in cases where treatment has been completed or stopped less than 52 weeks (12 months) after the start of giving study medicine, the participants will be checked until completion (discontinuation) of treatment.