Metastasis-Free Survival in Patients with Biochemical Recurrence After Robot-Assisted Radical Prostatectomy: A Multicenter, Retrospective Cohort Study in Japan (MSUG94 Group).

Robot-assisted radical prostatectomy (RARP) is the definitive surgical treatment for localized prostate cancer (PCa). Some patients with post-RARP biological recurrence (BCR) eventually develop distant metastases and subsequent PCa-related mortality. The objective of this study was to clarify the predictive factors for the risk of metastatic disease after BCR in patients with PCa who underwent RARP. This multicenter retrospective cohort study was conducted in nine Japanese institutions and enrolled 491 men with BCR, detected between 2011 and 2024. During the median 59-month follow-up period, 44 patients (9.0%) had radiological confirmation of distant metastasis. Patients with developed metastases after BCR exhibited higher biopsy Gleason grade and pathological T stage, increased lymphovascular invasion (LVI) in the surgical specimen, and a shorter interval from RARP to BCR. In univariate analysis, LVI and a time to BCR after RARP of ≤14.9 months were significant predictors of distant metastasis. In the multivariate analysis, LVI constituted a significant independent predictor of distant metastasis (p = 0.011). The 3-year metastasis-free survival (MFS) rates were 85.5% and 94.1% in patients with and without LVI, respectively. The MFS was significantly prolonged in patients with negative LVI compared to those with positive LVI (p = 0.007). In Japanese males with BCR after RARP, LVI was identified as an independent predictor of metastatic progression.