Abstract
OBJECTIVE: Recently, hormonal therapy using abiraterone acetate, a second-generation androgen receptor axis-targeted agent, was reported to improve overall survival and progression-free survival in men with LATITUDE-high-risk metastatic castration-sensitive prostate cancer. This observational multicenter study aimed to assess the efficacy of upfront abiraterone acetate in Japanese patients with LATITUDE-high-risk metastatic castration-sensitive prostate cancer. METHODS: The present study included 112 Japanese patients with LATITUDE-high-risk metastatic castration-sensitive prostate cancer who received upfront abiraterone acetate at four institutions belonging to the Tokai Urologic Oncology Research Seminar group, between January 2018 and September 2020. Progression-free survival and overall survival were assessed, and Cox regression analyses were carried out to evaluate the prognostic significance of upfront abiraterone acetate for progression-free survival. RESULTS: Within a median follow-up period of 13 months, the progression-free survival and overall survival rates were 76.8% and 89.3%, respectively. Both univariate and multivariable Cox regression analyses showed that the presence of Gleason pattern 5, performance status and hemoglobin were independent predictors of progression-free survival. The patients were subsequently divided into three groups as follows: group 1, 17 patients negative for these three independent progression-free survival predictors; group 2, 49 patients with one positive independent progression-free survival predictor; and group 3, 45 patients with two or three independent progression-free survival predictors. Progression-free survival was significantly different among these three groups (P < 0.001). CONCLUSION: Upfront abiraterone acetate might provide satisfactory outcomes for Japanese patients with LATITUDE-high-risk metastatic castration-sensitive prostate cancer. Gleason pattern 5, performance status and hemoglobin are potential predictors of progression-free survival in Japanese patients with LATITUDE-high-risk metastatic castration-sensitive prostate cancer who received upfront abiraterone acetate.