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

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.

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.

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 < 0.01) and African American (11% vs. 5%; P < 0.01). Patients with SCC presented at a higher stage than UC with muscle-invasive bladder cancer (MIBC) present at diagnosis in 70% vs. 19%. On multivariate analysis, SCC independently predicted poorer prognosis (hazard-ratio [HR] 1.79, P < 0.01) when controlling for patient characteristics and treatment modality. Unlike UC, there was no benefit with the use of NAC over radical cystectomy alone (HR 0.93, P = 0.69) for patients with SCC.

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.

Urologic oncology. 2019 Jan 28 [Epub ahead of print]

Justin T Matulay, Solomon L Woldu, Amy Lim, Vikram M Narayan, Gen Li, Ashish M Kamat, Christopher B Anderson

Department of Urology, Division of Surgery, University of Texas MD Anderson Cancer Center, Houston, TX. Electronic address: ., Department of Urology, University of Texas Southwestern Medical Center, Dallas, TX., Department of Urology, Division of Surgery, University of Texas MD Anderson Cancer Center, Houston, TX., Department of Biostatistics, Columbia University Medical Center, New York, NY., Department of Urology, Columbia University Medical Center, New York, NY.