The Role of Early PSA Response After Abiraterone Treatment for Metastatic Castration Resistant Prostate Cancer

Abstract Background Novel hormone agents (NHAs), such as Abiraterone, offer an alternative treatment for metastatic castration-resistant prostate cancer (mCRPC) but often result in secondary resistance. Among prostate cancer biomarkers, prostate-specific antigen (PSA) is the most researched and correlates with survival outcomes. This study aims to assess the initial PSA response to Abiraterone in mCRPC patients and its impact on survival, using data from the Chang Gung Research Database across four tertiary referral centers in Taiwan. Methods This retrospective cohort study analyzed mCRPC patients who underwent abiraterone treatment from Chang Gung Research Database including the data of four major medical centers in Taiwan. The treatment involved 1000 mg of abiraterone daily and 5 mg of prednisolone twice daily over 90-day cycles, with regular monitoring of PSA levels and tumor assessments. Results This study examined 295 mCRPC patients undergoing abiraterone treatment, with a median follow-up of 54.7 months. Patients were divided into pre-chemotherapy (pre-chemo) and post-chemotherapy (post-chemo) groups, with median overall survival (OS) of 13.4 months and 25 months, respectively. Patients were further classified into PSA90 and non-PSA90 groups based on a 90% decrease in PSA levels. In the pre-chemo group, 14% achieved PSA90, which was associated with improved survival outcomes. In the post-chemo group, 44% reached PSA90, also correlating with better survival, fewer bone lesions, and less high-risk patients. Conclusions This study highlights the predictive value of a 90% decline in PSA levels within the initial three months of treatment for oncological outcomes in patients with mCRPC receiving abiraterone in chemotherapy-naïve patients and those who had previously received chemotherapy.