Objective: to evaluate predictors and the prognostic impact of favorable vs. unfavorable tumor upgrading among low-risk prostate cancer (LR PCa) patients treated with robot-assisted radical prostatectomy (RARP). Methods: From January 2013 to October 2020, LR PCa patients treated with RARP at our institution were identified. Unfavorable tumor upgrading was defined as the presence of an International Society of Urological Pathology (ISUP) grade group at final pathology > 2. Disease relapse was coded as biochemical recurrence and/or local recurrence and/or presence of distant metastases. Regression analyses tested the association between clinical and pathological features and the risk of unfavorable tumor upgrading and disease relapse. Results: Of the 237 total LR PCa patients, 60 (25.3%) harbored unfavorable tumor upgrading. Disease relapse occurred in 20 (8.4%) patients. Unfavorable upgrading represented an independent predictor of disease relapse, even after adjustment for other clinical and pathological variables. Conversely, favorable tumor upgrading did not show any statistically significant association with PCa relapse. Unfavorable tumor upgrading was associated with tumors being larger (OR: 1.03; p = 0.031), tumors extending beyond the gland (OR: 8.54, p < 0.001), age (OR: 1.07, p = 0.009), and PSA density (PSAD) ≥ 0.15 ng/mL/cc (OR: 1.07, p = 0.009). Conclusions: LR PCa patients with unfavorable upgrading at final pathology were more likely to be older, to have PSAD ≥ 0.15 ng/mL/cc, and to experience disease relapse. Unfavorable tumor upgrading is an issue to consider when counseling these patients to avoid delayed treatments, which may impair cancer-specific survival.
Keywords: ISUP 1 prostate cancer; adverse pathology; prostate cancer progression; tumor upgrading.