How accurate are self-reports of smoking exposure among bladder cancer patients?

A recent study suggests the need for biochemical verification with cotinine or additional questions about other sources of nicotine to accurately identify nonmuscle invasive bladder cancer (NMIBC) patients who have smoking-related exposures.

Cigarette smoking is associated with the development of NMIBC, and continued exposure following diagnosis may increase the likelihood of adverse clinical outcomes, according to the authors.

This cross-sectional analysis compared self-reported vs biochemically verified nicotine exposure to determine the accuracy of self-report among those recently diagnosed with NMIBC. A total of 517 NMIBC 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 were included in the analysis.

The authors used cotinine, the primary metabolite of nicotine, as an objective biomarker of recent nicotine exposure.

The prevalence of high, low, and no cotinine exposure was 13 percent, 54 percent, and 33 percent, respectively. Of the patients, 38 (7.3 percent) reported being a current smoker, while 65 (13 percent) had cotinine levels consistent with active smoking exposure. Twenty-seven of these 65 patients denied smoking, leading to a sensitivity of self-reported current smoking of 58 percent.

Sensitivity rose to 82 percent after considering other sources of nicotine exposure such as e-cigarettes, cigars, nicotine replacement therapy, and living with a smoker. Almost all patients with low cotinine denied any smoking-related exposure.

“Accurate classification of active and passive smoking exposure is essential to allow clinicians to advise cessation and help researchers estimate the association between postdiagnosis smoking-related exposure and NMIBC recurrence risk,” the authors said.