Purpose: Cigarette smoking is a risk factor for developing nonmuscle invasive bladder cancer, and continued smoking exposure after diagnosis may increase the likelihood of adverse clinical outcomes. We compare self-reported vs biochemically verified nicotine exposure to determine the accuracy of self-report among recently diagnosed nonmuscle invasive bladder cancer patients.
Materials and methods: This cross-sectional analysis consisted of 517 nonmuscle invasive bladder cancer patients who contributed a urine or saliva specimen the same day as self-reporting their smoking, use of e-cigarettes, nicotine replacement therapy and whether they lived with a smoker. Cotinine, the primary metabolite of nicotine, was used as an objective biomarker of recent nicotine exposure.
Results: The prevalence of high, low and no cotinine exposure was 13%, 54% and 33%, respectively. Overall, 7.3% of patients (38/517) reported being a current cigarette smoker, while 13% (65/517) had cotinine levels consistent with active smoking exposure. Of these 65 patients 27 denied current smoking, resulting in a sensitivity of self-reported current smoking of 58%. After considering other sources of nicotine exposure such as e-cigarettes, cigars, nicotine replacement therapy and living with a smoker, the sensitivity was higher, at 82%. Nearly all patients with low cotinine denied any smoking-related exposure.
Conclusions: Our findings suggest either biochemical verification with cotinine or additional questions about other sources of nicotine are needed to accurately identify nonmuscle invasive bladder cancer patients who have smoking-related exposures. Accurate classification of active and passive smoking exposure is essential to allow clinicians to advise cessation and help researchers estimate the association between post-diagnosis smoking-related exposure and nonmuscle invasive bladder cancer recurrence risk.
Keywords: cotinine; smoking; urinary bladder neoplasms.