The role of early PSA response after abiraterone treatment for metastatic castration resistant prostate cancer: A retrospective cohort study

Purpose: 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 in Taiwan. Materials and methods: This retrospective cohort study analyzed mCRPC patients who underwent abiraterone treatment from January 2005 to December 2019. Patients were further divided into prechemotherapy (prechemo) and postchemotherapy (postchemo) groups, with 114 and 181 patients, respectively. The treatment involved 1000 mg of abiraterone daily and 5 mg of prednisolone twice daily, with regular monitoring of PSA levels and tumor assessments. Results: This study enrolled 295 mCRPC patients undergoing abiraterone treatment, with a median follow-up of 54.7 months. The OS for the prechemo group was 13.4 months, while for the postchemo group was 25 months. A 90% PSA response within 3 months was a strong indicator of improved OS. In the prechemo group, 14% achieved PSA90, which was associated with improved survival outcomes. In the postchemo group, 44% reached PSA90, also correlating with better survival and fewer bone lesions. Conclusion: This study highlights the predictive value of a 90% decline in PSA levels within the initial 3 months of treatment for oncological outcomes in patients with mCRPC receiving abiraterone in chemotherapy-naive patients and those who had previously received chemotherapy.