The effect of smoking and timing of smoking cessation on clinical outcome in non–muscle-invasive bladder cancer

AbstractObjectivesCigarette smoking is the most important risk factor for urinary bladder cancer. The prognostic effect of cigarette smoking on disease recurrence and progression in patients with non–muscle-invasive bladder cancer (NMIBC), however, is still unclear. We evaluated the effect of smoking status and intensity, and timing of smoking cessation, on NMIBC prognosis.Methods and materialsA population-based series of patients diagnosed with NMIBC from 1995 until 2010 was identified through the Netherlands Cancer Registry. Self-reported smoking history was obtained by a postal lifestyle questionnaire at study inclusion. Detailed clinical data concerning diagnosis, treatment, and disease course were collected retrospectively through a medical file survey. The association of smoking variables with recurrence- and progression-free survival of 963 patients with primary NMIBC was studied using cumulative incidence curves and competing risk regression analyses.ResultsThe study population comprised 181 never smokers (18.8%), 490 former smokers (50.9%), and 292 current smokers (30.3%) at the time of diagnosis. No statistically significant difference or trend in risk of recurrence (Ptrend = 0.47) or progression (Ptrend = 0.23) across the 3 smoking status categories was found. Moreover, no dose-response association was observed across categories of smoking quantity, duration, or cumulative exposure in relation to NMIBC prognosis. The timing of smoking cessation (i.e., ceased smoking≥10y before diagnosis,