A Novel ADT Strategy Without Conventional Anti-Androgen Pretreatment: An Observational Study of Abiraterone Combined With Castration Therapy

Purpose Prostate cancer(PCa) ranks among the most common malignancies in men, with ~ 30% of Chinese patients with advanced disease at diagnosis. LHRH agonist-based castration is the the cornerstone of ADT, but may induce transient "flare-up effect" at initiation, which increases the risk of disease progression and adverse events. We aims to evaluate the dynamic changes in serum testosterone with synchronous abiraterone and LHRH agonists, instead of anti-androgen, providing evidence for initial ADT strategies. Patients and Methods: This single-center observational cohort enrolled 35 patients with locally advanced or metastatic PCa. All patients received goserelin(10.8mg) plus abiraterone acetate(1000mg daily) and prednisone(5mg twice daily). The primary endpoint was the proportion of patients achieving castration-level serum testosterone(< 0.5ng/mL) at predefined timepoints(days 1, 2, 3, 7, 14, 28). Secondary endpoints included PSA changes at day 28, hepatic function, and adverse events. Results By Day 28, all patients(100%) achieved castration-level testosterone. Except for 2 patients(5.7%) showing mild testosterone elevation on Day 1, 94.3% patients exhibited immediate testosterone decline(6.2%–96.6% from baseline). The proportions of patients reaching castration levels on Day 2, 3, 7, 14 and 28 were 74.3%(26/35), 94.2%(33/35), 97.1%(34/35), 100%(35/35), and 100%(35/35), respectively. No grade 3–5 adverse events were observed. Most common treatment-related adverse events were grade 1–2 flushing(20%), facial edema(2.9%), and grade 2 hepatic dysfunction(2.9%). All patients demonstrated PSA decline at day 28, with a median reduction of 95.4%(IQR: 90.2%–98.9%). Conclusion Abiraterone plus LHRH agonist rapidly suppresses testosterone, and may obviate the need for traditional anti-androgen pretreatment. This strategy demonstrates streamlines initial treatment workflows, warranting further validation in multi-center trials.