Background/Aim: Oncological outcomes for metastatic castration-sensitive prostate cancer (mCSPC) have improved with upfront androgen receptor signaling inhibitor (ARSI) doublet therapy. However, the prognostic value of prostate-specific antigen (PSA) kinetics in real-world settings remains unclear. This study aimed to evaluate the clinical significance of PSA kinetics in patients with high-risk mCSPC. Patients and Methods: We retrospectively analyzed 352 patients with high-risk mCSPC from the ULTRA-J database who received upfront ARSI doublet therapy between 2018 and 2023. PSA kinetics, including PSA nadir, PSA response rate, and time to PSA nadir (TTN), were assessed. Associations with castration-resistant prostate cancer-free survival (CRPC-FS) and overall survival (OS) were evaluated using Kaplan–Meier analysis and Cox proportional hazards models. Results: A PSA nadir ≤0.02 ng/ml and PSA response rate ≥99% were significantly associated with prolonged CRPC-FS and OS (p0.02 ng/ml, PSA response rate Conclusion: PSA kinetics are strong independent prognostic factors in patients with high-risk mCSPC treated with upfront ARSI doublet therapy. These readily available biomarkers may help identify patients who require treatment intensification or closer monitoring in clinical practice.
YAMAMOTO et al. (Wed,) studied this question.