Regional Discrepancy in Biochemical Recurrence-Free Survival After Robot-Assisted Radical Prostatectomy: A Comparative Study Using Propensity Score Matching in Japan and the United States From 2012 to 2018

Purpose: To compare biochemical recurrence (BCR) rates after robot-assisted radical prostatectomy (RARP) between Japan (JPN) and the United States. Methods: Consecutive patients with prostate cancer (PCa) who underwent RARP at 9 institutions in JPN and the University of Rochester Medical Center in the United States between 2012 and 2018 were included in this retrospective study. Patients with clinically metastatic PCa or pT4 disease and those who received neoadjuvant and/or adjuvant treatments before BCR were excluded. BCR-free survival (BCRFS) was compared between the JPN and US cohorts through 1:1 propensity score matching. Results: A total of 1557 and 1605 patients were identified in the JPN and US cohorts, respectively. The JPN and US cohorts showed significant differences in follow-up duration, age at operation, preoperative prostate-specific antigen values, pathological Grade Group, pathological T and N stages, and surgical margin status; however, BCRFS was comparable between the 2 cohorts ( P = .142). After propensity score matching (n = 731 in each cohort), BCRFS was significantly worse in the US cohort than in the JPN cohort ( P = .003), and the 5-year BCRFS was 84.5% and 90.4% in the US and JPN cohorts, respectively. Moreover, after propensity score matching (n = 683 in each cohort), BCRFS in Caucasian/White patients in the US cohort was significantly worse than that in Asian patients in the JPN cohort ( P = .002). Conclusions: Our study indicated that regional and/or racial discrepancy might exist in post-RARP prognosis between JPN and US cohorts.