Introduction

Knowledge of comparative oncological outcomes of histological variants after radical cystectomy (RC) for muscle-invasive bladder cancer (MIBC) relies on small case series. Our aim was to compare the effect of squamous cell, adenocarcinoma, and neuroendocrine carcinoma vs. pure urothelial carcinoma of the bladder (UCB) on overall survival (OS) and pathological tumor, lymph node, and surgical margin status after RC.

Methods

Using the National Cancer Data Base, we retrospectively examined patients undergoing RC for MIBC between 2003-2011. Our cohort was stratified according to pure histology: squamous cell, adenocarcinoma, neuroendocrine, and UCB. Inverse probability weighting (IPW)-adjusted and facility-clustered Cox and logistic regressions were used to assess the impact of histological variants vs. UCB on OS and histopathological outcomes.

Results

Overall, 475 (4.4%), 224 (2.1%), 155 (1.4%), and 10,033 (92.2%) patients underwent RC for MIBC with pure squamous cell, adenocarcinoma, neuroendocrine carcinoma, and UCB, respectively. In IPW-adjusted analyses, squamous cell (HR=1.26; 95%CI=[1.07-1.49]; P=0.006) and neuroendocrine (HR=1.53; 95%CI=[1.21-1.95]; P<0.001) were associated with worse OS relative to UCB (Figure 1). Squamous cell (OR=1.58; 95%CI=[1.23-2.04]; P<0.001), adenocarcinoma (OR=1.49; 95%CI=[1.04-2.14]; P=0.030), and neuroendocrine carcinoma (OR=2.37; 95%CI=[1.58-3.55]; P<0.001) at diagnosis were associated with greater odds of ≥pT3 disease. Squamous and neuroendocrine variants were associated with decreased (OR=0.66; 95%CI=[0.48-0.91]; P=0.012) and increased (OR=1.58; 95%CI=[1.06-2.37]; P=0.026) odds of pN+ disease, respectively, while adenocarcinoma was associated with greater odds of positive margins (OR=2.14; 95%CI=[1.39-3.30]; P=0.001).

Conclusions

Pure squamous cell and neuroendocrine carcinoma is associated with worse OS relative to UCB, whereas no difference was found between adenocarcinoma and UCB. All histological variants were associated with higher pT stage at surgery compared to UCB.

Funding

None