Pathologic and Prognostic Outcomes of Very Low- and Low-Risk Prostate Cancer According to the National Comprehensive Cancer Network Guidelines in Japanese Patients with Radical Prostatectomy

Background: The purpose of this study was to validate the treatment strategy for a cohort of Japanese patients with very low-risk (VLR) and low-risk (LR) prostate cancer according to the National Comprehensive Cancer Network (NCCN) guidelines. Methods: We studied 751 patients with T13N0M0 prostate cancer treated with radical prostatectomy at our institution between 2000 and 2012. Patients with neoadjuvant treatments were excluded. We retrospectively reviewed the clinical and pathological outcomes for patients with VLR or LR prostate cancers that were classified by NCCN guidelines. Results: We identified 45 patients with VLR and 137 with LR prostate cancer. Non-biochemical recurrence rate at 5-year for 45 patients with VLR was 86.9% and 81.2% for 137 patients with LR (p = 0.56). However, none of the 19 patients >65 years old with VLR progressed, while 19% of 26 patients ≤65 years old with VLR cancer, 14% of patients >65 years old with LR cancer, and 17% of patients ≤65 years old with LR cancer progressed during the follow-up period (p = 0.04, p = 0.04 and p = 0.05, respectively). In analyses of prostatectomy specimens, both VLR and LR had similarly favorable outcomes, but patients >65 years old with VLR had the smallest tumors, with a mean of 5 mm in diameter. Conclusions: Our results support the treatment strategy of the NCCN that patients with VLR cancer and age >65 years old are good candidates for active surveillance, and that other treatment options—including active surveillance and aggressive treatments—can be applied to the remaining patients with VLR or LR cancers. Corresponding author.