The association between variant urothelial histologies, pathological stage and disease specific survival in patients with bladder cancer

Objective: We aimed to compare the oncological outcomes of patients with variant urothelial histologies (VH) with pure urothelial histology (PUH) in bladder cancer (BC) patients. Material and methods: This study includes 223 patients who underwent radical cystectomies (RCs) between September 2006 and July 2016 with complete follow-up data A retrospective screening was performed to identify the patients with PUH and VH. The primary outcomes of interest were pathological stage of disease at RC and disease-specific survival (DSS). For comparison of categorical variables, Fisher’s exact test and Pearson chi- square and for continuous variables Wilcoxon rank-sum and Mann-Whitney U tests were used. Kaplan-Meier (KM) method was used for survival analysis and log-rank test was used for comparison of survival rates. Predictors of survival were detected with mulitivariable Cox-proportional hazards model including the variables such as gender, age, existence of VH, lymph node dissection (LND) type and pathological stage of the disease. Results: A moderate-degree correlation was detected between VH and pathological stages of RC (r=0.45, p<0.001). In PUH group, 39 (25.8%) of 151 patients died after a median follow-up of 20 (0-107) months; whereas 37 (51.4%) of 72 patients with VH died after a median follow-up of 16.5 (0-104) months (p<0.001). In terms of pathological stage, the number of patients with PUH and VH were at stages pT0-2 (n=100; 66.2% vs. n=19; 26.4%), pT3-4 (n=35; 23.2% vs. 38; 52.8%, and in 16 (10.6%) and 15 (20.8%) patients with LN positivity, respectively (p<0.001). KM survival analysis revealed a significantly decreased DSS in patients with VH compared to PUH (p<0.001). Meanwhile, pathological disease stage and existence of VH were found to be associated with decreased DSS in the multivariate model. Conclusion: The present study revealed that VH is associated with advanced pathological tumor stage at RC and decreased DSS compared to patients with PUH in patients with BC.