Low-dose abiraterone acetate for the treatment of prostate cancer: An observational cohort study.

[OBJECTIVE] To compare radiographic progression-free survival in metastatic prostate cancer patients treated with low-dose abiraterone versus standard-dose abiraterone acetate (Abi-SD), and to evaluate prostate-specific antigen progression-free survival.

[METHODS] Retrospective cohort study of patients with metastatic prostate cancer, castration-sensitive or castration-resistant, treated with low or standard-dose abiraterone. All patients were followed until radiographic or prostate-specific antigen progression. Cox proportional hazards regression was used to assess radiographic progression-free survival and prostate-specific antigen progression-free survival according to abiraterone dose (low vs. standard-dose). The model was adjusted for Charlson Comorbidity Index, castration resistance status, disease volume based on CHAARTED criteria, and presence of de novo metastases.

[RESULTS] A total of 144 patients with metastatic prostate cancer were included in the study, with 28.4% (n = 41) receiving low-dose abiraterone. The median age was 79 years (IQR: 75-85) in the low-dose group and 75 years (IQR: 70-81) in the standard-dose group. For radiographic progression-free survival, the crude hazard ratio for the low-dose group compared with the standard-dose group was 0.49 (95% CI: 0.23-1.07). After adjusting for clinical variables, the adjusted hazard ratio was 0.65 (95% CI: 0.29-1.45). For prostate-specific antigen progression-free survival, the crude hazard ratio was 0.48 (95% CI: 0.24-0.90), and the adjusted hazard ratio was 0.58 (95% CI: 0.29-1.14).

[CONCLUSION] This study provides evidence supporting the use of low-dose abiraterone in patients with metastatic prostate cancer, showing survival and progression outcomes comparable to those of the standard-dose. This approach may improve access to treatment; however, larger studies are needed to validate these findings.