Sociodemographic and survival disparities for histologic variants of bladder cancer

To investigate the impact of perioperative factors on overall survival among patients with histologic variants of bladder cancer treated with radical cystectomy.

The National Cancer Data Base was utilized to identify patients diagnosed with muscle-invasive bladder cancer (cT2-4, N0, M0) from 2004-2013. Variant histology bladder cancers (non-mucinous adenocarcinoma, mucinous/signet ring adenocarcinoma, micropapillary urothelial carcinoma, small cell carcinoma, and squamous cell carcinoma) were compared to urothelial carcinoma with respect to overall survival. Adjusted hazard ratios (aHR) and 95% confidence intervals (95% CI) were calculated from a multivariable Cox regression model to examine factors affecting overall survival, T upstaging, N upstaging, and positive surgical margins. Median survival was calculated using Kaplan-Meier analysis.

A total of 5,856 patients were included in this study. Significant predictors of worse overall survival included: African-American ancestry (aHR = 1.24, 95%CI: 1.03-1.48, p = 0.021), age (1.03, 1.02-1.03, p < 0.001), comorbidity (1.30, 1.20-1.40, p < 0.001), cT3 stage (1.41, 1.26-1.57, p < 0.001), and cT4 stage (1.59, 1.38-1.84, p < 0.001). Small cell carcinoma (2.10, 1.44-3.06, p < 0.001) and non-mucinous adenocarcinoma (1.59, 1.15-2.20, p = 0.005) were significant predictors of worse overall survival compared to urothelial carcinoma. Small cell carcinoma had the worst 5 year overall survival (15.5%, 95% CI: 5.2%-30.9%) compared to urothelial carcinoma (48.7%, 95% CI: 47.2%-50.2%). Micropapillary urothelial carcinoma was a significant predictor of increased progression to node positivity and positive margin status after radical cystectomy compared to urothelial carcinoma (6.01, 3.11-11.63, p < 0.001; 4.38, 2.05-9.38; p < 0.001).

Among bladder cancer patients with equal treatment and staging, small cell carcinoma and non-mucinous adenocarcinoma variant histologies were predictive of worse overall survival compared to urothelial carcinoma. Patient demographics such as African-American ancestry and age were also predictive of worse overall survival among variant histology bladder cancer and urothelial carcinoma.