This study aims to evaluate the deep response of Apalutamide in high-risk metastatic castration-sensitive prostate cancer (mCSPC), with a particular focus on the PSA response during the first 6 months of treatment.

A retrospective study was conducted on patients with mCSPC who underwent Apalutamide therapy at Kaohsiung Chang Gung Memorial Hospital from 2022.12.01 to 2024.09.30. Baseline PSA levels (iPSA) were obtained before the start of treatment, and follow-up PSA measurements were taken monthly up to 6 months. PSA reduction percentages were calculated, and the rates of achieving PSA90 and PSA99 were assessed. Descriptive statistics were applied to summarize patient data, and the proportion of patients reaching these PSA milestones was reported.

A total of 93 patients were included in the analysis. The average age was 73 years old, with iPSA > 50 ng/mL (ranging from 13.32 to 819.63) in most patients (72/93, 77.5%). Median PSA was 82.75. At the 1-month interval, 78.4% of patients achieved PSA90, with 39.2% reaching PSA99. By the 3-month interval, 94.7% of patients achieved PSA90, and 77.9% reached PSA99. At 6 months, 95.1% of patients achieved PSA90, and 85.2% achieved PSA99. Most patients experienced significant PSA reductions, emphasizing the early effectiveness of Apalutamide therapy.

This study shows that Apalutamide therapy results in substantial PSA reductions in patients with mCSPC, with a significant percentage reaching PSA90 and PSA99 levels within the first 6 months. These results reinforce the effectiveness of Apalutamide as a treatment strategy for enhancing clinical outcomes in prostate cancer.