The impact of squamous histology on survival in patients with muscle-invasive bladder cancer

Abstract Background Bladder cancer is the ninth most common noncutaneous malignancy worldwide, though a fraction (2%–5%) are diagnosed as squamous cell carcinoma (SCC) in the Western world. Current understanding is based on small, single-institution studies and SEER-database reviews with conflicting results. We used the National Cancer Database to explore clinical characteristics and outcomes from a large cohort of invasive bladder SCC. Methods We queried the National Cancer Database for diagnoses of urothelial carcinoma (UC) or SCC using International Classification of Disease-O-3 morphologic codes from cases reported between 2004 and 2015. Primary outcome was overall survival in cT2-4N0M0 bladder cancer. Statistical analysis performed using chi-squared test, Kaplan-Meier survival, binomial logistic regression, and Cox proportional hazards. Results The final cohort included 394,979 bladder cancer patients, of which 4,783 (1.2%) were classified as SCC histology. In comparison to UC, patients with SCC were more likely female (49% vs. 24%; P P P P  = 0.69) for patients with SCC. Conclusions Invasive SCC of the bladder carries a worse prognosis as compared to UC histology, both overall and on a stage-for-stage basis. As opposed to UC, we did not observe a survival benefit for NAC among SCC patients treated with cystectomy.