AB066. Sensitivity of initial biopsy or transurethral resection of bladder tumor(s) for detecting histological variants on radical cystectomy

OBJECTIVE: To investigate the efficacy of initial biopsy or transurethral resection of bladder tumor for detecting histological variants on radical cystectomy and to assess the prognostic significance of variant histology on urothelial carcinoma outcomes after radical cystectomy. METHODS: Clinical and histopathological characteristics of 147 patients with variant histology who underwent radical cystectomy for urothelial carcinoma between 2006 and 2012 were assessed. Sensitivity was calculated as the proportion of radical cystectomy specimens with a particular variant that also presented the variant in the biopsy or transurethral resection specimen. The Kaplan-Meier method and multivariate Cox proportional hazard regression analysis were used to estimate cancer-specific survival. RESULTS: Of the 147 patients, 116 (79%) were diagnosed with a single variant histology, and 31 (21%) had multiple patterns. Squamous differentiation (31%) was the most common single variant histology, followed by glandular differentiation (28%). Except for small cell variant (100%), the sensitivity of biopsy and transurethral resection was most effective for the diagnosis of squamous differentiation, 19% vs. 40% respectively, followed by glandular differentiation, 11% vs. 21% respectively. A total of 6% and 49% patients could be variant-free partially due to biopsy or complete resection(s) respectively. Presence of variant differentiation in urothelial carcinoma at cystectomy was significantly associated with inferior survival both in univariate analysis (P=0.005) and multivariate analysis (HR 4.48, 95% CI: 1.03–19.53). CONCLUSIONS: Overall sensitivity of biopsy or transurethral resection to detect variant differentiation on cystectomy is relatively low. Patients with variant differentiation on cystectomy specimens have inferior survival.