Background and Objectives: This study's objective was to examine patients treated with robot-assisted radical prostatectomy (RARP) for intermediate-risk prostate cancer (IR-PCa), and to identify preoperative risk factors for biochemical recurrence (BCR) in these patients in Japan. Materials and Methods: We conducted a retrospective multicenter cohort study of patients with PCa who underwent RARP at 10 institutions in Japan. A total of 3195 patients were enrolled in this study. We focused on patients with IR-PCa who underwent RARP. We obtained data on pre- and postoperative covariates from the enrolled patients. Biochemical recurrence-free survival was the primary endpoint of this study. We also identified useful preoperative predictive factors for BCR in patients with IR-PCa after RARP. Results: A total of 1144 patients with IR-PCa were enrolled in this study. The median follow-up period was 23.7 months. At the end of the follow-up period, 94 (8.2%) patients developed BCR. The 2 and 3 year biochemical recurrence-free survival (BRFS) rates were 92.2% and 90.2%, respectively. Using the Kaplan-Meier method, Gleason grade (GG) 3 was significantly associated with poor BRFS compared with ≤GG 2. In multivariate analysis, GG 3 was a significant predictive factor for BCR in patients with IR-PCa. Conclusions: The results of the study indicated a significant relationship between GG 3 and post-RARP BCR in patients with IR-PCa.
Keywords: Gleason grade; biochemical recurrence; intermediate-risk prostate cancer; multicenter cohort study; robot-assisted radical prostatectomy.