Small Cell Carcinoma Of The Bladder (Sccb): Clinical, Histopathologic, And Genomic Predictors Of Clinical Outcomes.

294Background: SCCB is a rare, aggressive subtype of bladder cancer. We reviewed our center’s experience in SCCB management and investigated potential markers of clinical outcomes. Methods: SCCB cases were identified and re-reviewed for confirmation by detailed histologic evaluation. A subset of SCCB was sequenced with MSK-IMPACT ( u003e 279 genes) (Cheng et al J Mol Diagn 2015). Clinical stage, treatment response and proportion of neuroendocrine component (%NE) were correlated with progression-free (PFS) and overall survival (OS), calculated from the time of cystectomy. Distribution of somatic alterations (alts) was compared between responders ( ≤ ypT1pN0) and nonresponders. Results: Between 1985 and 2015, 214 SCCB patients (pts) were identified. Median age was 68 years (range: 38 – 94) and 78% were male. Of 199 pts with sufficient data, 147 (74%) were nonmetastatic (M0) and 52 pts (26%) had metastatic disease (M1). 14 pts did not receive SCCB-directed therapies. Of M0 pts, 108 underwent cystectomy: 71 recei...