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

Objectives: Cigarette 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 materials: A 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.

Results: The 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,<10y before diagnosis, vs. current smoker at diagnosis) did not significantly affect the risk of recurrence (Ptrend = 0.31) and progression (Ptrend = 0.19).

Conclusions: Based on our study, smoking status, smoking intensity, or cessation at any time before diagnosis does not seem to alter the risks of recurrence and progression among patients with NMIBC. Patients' smoking history is not useful for the guidance of clinical management decisions. Patients should nevertheless be advised to quit considering the known beneficial effects on other non-NMIBC-related end points such as cardiovascular disease and second primary cancers.