Accuracy of Self-reported Smoking Exposure Among Bladder Cancer Patients Undergoing Surveillance at a Tertiary Referral Center

Abstract

Background Smoking is a risk factor for developing bladder cancer (BCa). Even though continued exposure after diagnosis may adversely affect prognosis, patients may be reluctant to disclose to their physicians that they are currently smoking, leading to inaccurate reporting of exposure and missed opportunities to deliver smoking-cessation advice and treatment in the context of cancer care. Objective We examined the extent of misclassification of recent smoking exposure among patients undergoing BCa surveillance. Design, setting, and participants A consecutive sample of 145 patients with a self-reported smoking history and prior initial diagnosis of BCa was recruited from a tertiary referral urology clinic. Outcome measurements and statistical analysis Patients were asked if they had smoked a cigarette or used nicotine replacement therapy (NRT) within the past week and whether they lived with a smoker. At the same visit, we collected urine under a biospecimen protocol. We used urinary cotinine, the primary metabolite of nicotine, as an objective biomarker of recent smoking exposure. Nine patients whose urine could not be interpreted for cotinine were excluded. We calculated the smoking status misreporting rate by comparing biochemically verified smoking status (≥31.5 ng/ml vs <31.5 ng/ml) against self-reported current smoking status (yes vs no) while considering recent NRT use. Results and limitations Overall, 11% (15 of 136) of patients had cotinine values consistent with current smoking. Of these 15 patients, 7 reported being former smokers, resulting in a 47% misclassification rate. However, three of the seven patients who denied smoking in the past week were currently using NRT. Excluding NRT users, the misclassification rate was 33%. Conclusions Future studies investigating the impact of postdiagnosis nicotine exposure on BCa outcomes should use biochemical verification combined with self-reported smoking exposure to classify patients accurately. Patient summary Bladder cancer patients may misreport smoking exposure, thereby missing opportunities for smoking cessation.

Association of Biochemically Verified Post-Diagnosis Smoking and Nonmuscle-Invasive Bladder Cancer Recurrence Risk

“…We previously demonstrated that accurate classification of smoking exposure is enhanced when cotinine values are considered. 16,23 Despite biochemically verifying smoking at multiple times during followup, we did not find that post-diagnosis smoking exposure influenced NMIBC recurrence risk in our patient cohort. We do not believe our findings minimize the important role that smoking cessation can play in bladder cancer risk, treatment and survivorship.…”

Electronic Cigarette Use among Survivors of Smoking-Related Cancers in the United States

“…Indeed, studies suggest that cancer survivors often underreport their cancer history in surveys (18)(19)(20)(21)(22). Similarly, patients with cancer and survivors may misreport their e-cigarette use and smoking status (23,24). However, we have no reason to believe that underreporting of cancer diagnosis or current smoking status would significantly alter our study prevalence estimates given the similar rates of e-cigarette use in those with self-reported cancer history in our study relative to the general population (3,12).…”

The association between smoking cessation before and after diagnosis and non-muscle-invasive bladder cancer recurrence: a prospective cohort study

“…The large proportion (about 1 in 3) of former smokers pre-diagnosis who reported to have started smoking again post-diagnosis is implausible and is probably observed due to misclassification of either the questionnaire at baseline or during follow-up. A high misclassification rate (47%) when comparing self-reported data on smoking behavior to cotinine values in blood was also shown in another sample of bladder cancer patients undergoing surveillance [ 43 ]. Preferably, future studies should consider more reliable ways of verifying smoking exposure through biochemical analysis.…”