Sex differences in bladder cancer outcomes among smokers with advanced bladder cancer

To study the effect of smoking on bladder cancer presentation and outcome in a large cystectomy population.

A database including 546 patients from the University Health Network (Toronto, Canada) and Turku University Hospital (Turku, Finland) was studied. In addition to the association of smoking with clinicopathological parameters, the effect of smoking on survival was analyzed. Categorical data were analyzed by the chi-squared test and numerical data were analyzed by Student's t-test. The Kaplan-Meier method, log-rank test and a proportional hazards model were used to estimate the effect of smoking on survival.

In total, 352 patients (64%) were smokers and 194 (36%) were non-smokers. Smokers had more frequently advanced tumours and nodal metastasis. The 10-year disease-specific survival (DSS) was 52% vs 66% for smokers and non-smokers, respectively (P = 0.039). Smokers also had significantly worse overall survival (10-year overall survival 37% vs 62%; P = 0.015). Smoking affected significant DSS among men (P = 0.012), although no effect was observed among women. In a univariate model smoking was associated with a hazard ratio (HR) of 1.4 (95% confidence interval, CI, 1.0-1.9) for bladder cancer specific mortality and 1.4 (95% CI, 1.1-1.8) for overall mortality. In a multivariate model, smoking did not impact on DSS (HR, 1.1; 95% CI, 0.8-1.6; P = 0.41). In addition to advanced stage and nodal metastasis, female sex was an independent risk factor for DSS (HR, 1.6; 95% CI, 1.1-2.3; P = 0.007).

Smokers appear to have worse outcomes after radical cystectomy for bladder cancer; however, it does not appear to be an independent prognostic factor for survival. Smoking affected survival only among men. Women had poorer survival but smoking was not a contributing factor to this.