Evaluating clinical and pathologic predictors for pathologic lymph node positivity (pN+) in patients with clinical T1-4N0M0 bladder cancer undergoing cystectomy.

877 Background: Occult pathological lymph node involvement at radical cystectomy (RC) in patients with clinical (cN0) bladder cancer (BC) remains a diagnostic and therapeutic challenge. We sought to evaluate clinical and pathological predictors of lymph node positivity (pN+) and its correlation with outcomes in patients with cT1-4N0M0 BC at RC. Methods: The study included patients with cT1-4N0M0 BC undergoing RC and pelvic lymph node dissection between 2004 and 2020. Patients were grouped as pN+ vs. pN0 at surgery. Baseline characteristics like age at surgery, sex, ethnicity, body mass index, concomitant carcinoma in situ (CIS) on TURBT, and lymphovascular invasion (LVI) were summarized using descriptive statistics. We performed logistic, univariable, and multivariable Cox regression models to identify independent predictors for pN+ at surgery. Kaplan Meier analysis and multivariable Cox proportional hazards model were used to analyze recurrence-free survival (RFS) and overall survival (OS). Results: 440 patients with T1-4N0M0 bladder cancer undergoing RC were evaluated, of which 359 (81.6%) were pN0 and 74 (16.8%) were pN+. Seven patients (1.6%) had incomplete information and were not included in the final analysis. Most patients were male (79.8%), White (87.7%), and had a median age of 71 years at surgery. Most patients had T2 (54.5%) disease, followed by T1 (24.8%) and T3 (5.7%) disease. On multivariable analysis, LVI [HR 3.02 (95% CI 1.21-7.54); p = 0.018] and positive surgical margins [HR 15.38 (95% CI 4.69-50.41); p < 0.001] at RC were independent predictors for lymph node positivity at surgery. Interestingly, pN+ was not significantly associated with concomitant CIS, preoperative hydronephrosis, and preoperative renal function on multivariable analysis. pN+ demonstrated significantly worse RFS [HR 7.48 (95% CI 4.89-11.42); p < 0.001] and OS (HR 7.86 (95% CI 5.20-11.89); p < 0.001]. Preoperative hydronephrosis [HR 1.76 (95% CI 1.16-2.69); p = 0.008] was an independent predictor for RFS. Preoperative hydronephrosis [HR 1.60 (95% CI 1.19-2.15); p = 0.002] and positive surgical margins [HR 2.31 (95% CI 1.26-4.25); p = 0.007] were independent predictors for OS. Conclusions: LVI and positive surgical margins were significant predictors for pN+ at surgery in patients with cT1-4N0M0 BC. These features could inform perioperative therapy considerations and bladder preservation approaches in cN0 BC.