Objective: In cancer patients, cigarette smoking causes poorer response to treatment, treatment toxicity, increased risk of recurrence, higher surgical complication rates, and poorer overall survival. As such a significant determinant of patient prognosis, accurate classification of current smoking status is important. Self-reported smoking status may lead to misclassification if patients conceal their true status. The purpose of this study was to assess the validity of self-reported tobacco use during the previous 48 hours in head and neck cancer patients on the day of surgery.
Study design: Cross-sectional.
Setting: Two academic medical centers in the southeastern United States.
Subjects and methods: On the day of surgery, 108 head and neck cancer patients completed a survey asking about tobacco use during the past 48 hours and had semi-quantitative levels of urinary cotinine measured to biochemically validate self-reported recent smoking.
Results: Self-reported smoking yielded a sensitivity of 60.9% (95% CI, 45.4%-74.9%) and a specificity of 98.4% (95% CI, 91.3%-100.0%). The sensitivity increased to 76.1% (95% CI, 61.2%-87.4%) when allowing for the possibility that exposure to secondhand smoke or use of nicotine-containing products could have caused a positive cotinine test.
Conclusion: In this patient population, self-reported recent smoking yielded a high (39%) proportion of false-negatives, and even 24% remained false-negatives after allowing for other sources of nicotine exposure. This magnitude of underreporting combined with the importance of tobacco use to patient prognosis supports the need for routinely biochemically verifying recent tobacco use in self-reported nonsmokers within the clinical setting.
Keywords: cancer patients; cigarette smoking; cotinine; measurement of smoking status; research methods; validity.
© American Academy of Otolaryngology—Head and Neck Surgery Foundation 2015.