Regional Discrepancy in the Incidence of Intraductal Carcinoma of the Prostate in Radical Prostatectomy Specimens

摘要

Purpose: To compare the regional discrepancies in the incidence of intraductal carcinoma of the prostate (IDCP) in robot-assisted radical prostatectomy (RARP) specimens between Japan (JP) and the United States. Materials and Methods: A total of 730 consecutive patients with prostate cancer (PCa) in JP who underwent RARP at Mie University (n = 392) and Aichi Medical University (n = 338) from 2015 to 2021 as well as 720 consecutive patients with PCa in the United States who underwent RARP at the University of Rochester Medical Center from 2010 to 2011 were enrolled in this retrospective study. Patients with clinically metastatic PCa (cM1) and those who received neoadjuvant and/or adjuvant therapies before biochemical recurrence were excluded. One-to-one propensity score matching (PSM) was also performed. Results: Although the incidence of IDCP was comparable between the entire JP (24.5%) and US (24.7%) cohorts, PSM analysis in the matched cohorts showed a significantly higher proportion of IDCP positivity in the US cohort (22.9%) than in the JP cohort (16.8%). In addition, in the entire cohorts, the rates of IDCP in GG2-3 or GG4-5 cases were significantly higher in the US cohort (26.8% or 65.9%, respectively) than in the JP cohort (19.0% or 46.8%, respectively). Moreover, the percentages of IDCP-positive cases with GG2-3 or GG4-5 PCa were significantly higher in White patients in the US cohort (64.9% or 27.2%, respectively) than in Asians in the JP cohort (46.8% or 18.9%, respectively). Conclusions: Our study demonstrated regional discrepancies in the incidence of IDCP in RARP specimens between JP and US patients.