MP47-05: TIMELY CYSTECTOMY IS CRITICAL FOR VARIANT HISTOLOGY OF UROTHELIAL BLADDER CANCER

TIMELY CYSTECTOMY IS CRITICAL FOR VARIANT HISTOLOGY OF UROTHELIAL BLADDER CANCER

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INTRODUCTION

For muscle-invasive bladder cancer (MIBC), the gold standard treatment is radical cystectomy (RC). The timing of cystectomy on oncologic outcomes is poorly characterized for variant histology (VH) of urothelial carcinoma. Our objective was to compare clinical characteristics and analyze the impact of a delay in RC for pure urothelial carcinoma (PUC) and VH MIBC.

METHODS

Using our IRB approved, prospectively maintained bladder cancer database and excluding patients who received neoadjuvant chemotherapy or intravesical therapy, we identified 358 patients with non-metastatic muscle invasive urothelial carcinoma (cT2-T4N0M0) who underwent radical cystectomy between 2003 and 2014. The effect of time from first diagnosis of muscle invasive cancer to RC was analyzed as a continuous variable and dichotomized at 4, 8, and 12 weeks. Histology at RC determined by dedicated genitourinary pathologists was categorized as PUC (n=292) or VH (n=71). Univariate and multivariable Cox proportional hazards models were used to analyze the impact of time to RC on overall survival (OS).

RESULTS

VH types included squamous (n=27), glandular (n=8), micropapillary (n=6), sarcomatoid (n=5), clear cell (n=4), neuroendocrine (n=3), nested (n=1), spindle (n=1), inverted papilloma (n=1), and mixed variants (n=15). VH was more likely to present with extravesical disease (16.9% vs 7.5%, p