AB107. Impact of variant differentiation on survival of patients with urothelial carcinoma of the bladder treated with radical

OBJECTIVE: To determine the impact of variant histologic differentiation of patients with urothelial carcinoma of the bladder on survival after radical cystectomy. METHODS: Between 2006 and 2012, 418 consecutive patients who underwent radical cystectomy with lymphadenectomy for urothelial carcinoma of the bladder were included. The patients were divided into three groups based on pathological results: group A included 262 patients with pure urothelial carcinoma, group B included 103 patients with squamous and/or glandular differentiation and group C comprised 53 patients with non-squamous and/or glandular differentiation. The Kaplan-Meier method was used to estimate cancer-specific and overall survivals. Multivariate Cox proportional hazard regression analysis was used to evaluate the association of histological differentiation with cancer-specific and overall mortality. RESULTS: Of the 418 patients, 108 were diagnosed with a single variant histology, and 58 had multiple patterns. Squamous differentiation (n=48; 11.5%) was the most common single variant histology, followed by glandular (n=40; 9.6%) and sarcomatoid (n=13; 3.1%). Compared to group A, group B and C were more likely to have advanced tumor stage (pT4 in group B vs. group C vs. group A: 29, 14, 24; 28.2% vs. 26.4% vs. 9.2%), lymph node metastases (35, 13, 31; 34.0% vs. 24.5% vs. 11.8%) and lymphovascular invasion (45, 22, 49; 43.7% vs. 41.5% vs. 18.7%) (P values <0.017). In univariable analyses, group B and group C were at significantly higher risk for cancer specific mortality and overall mortality than patients with pure UCB (P values <0.01). In multivariable analyses, group C had significantly prognostic influence on cancer-specific mortality (HR 2.49, 95% CI: 1.32-4.67, P<0.01) and overall mortality (HR 2.21, 95% CI: 1.31-3.73, P<0.01). CONCLUSIONS: Variant differentiation was independently associated with adverse outcomes for patients with urothelial carcinoma of the bladder after radical cystectomy.