Rigotti, Nancy A.

Abstract BACKGROUND: Previous work has demonstrated that smokers have higher white blood cell counts than nonsmokers, but the effect of biochemically-confirmed smoking cessation on peripheral leukocyte counts has not been demonstrated in a large prospective study. METHODS: Subjects were healthy smokers enrolled in a trial of sustained-release bupropion for relapse prevention after smoking cessation. White blood cell (WBC) counts and absolute neutrophil counts (ANC) were measured at baseline, week 7 and week 52. Smoking status was assessed at weeks 7 and 52 by self-report and biochemically confirmed with expired air carbon monoxide levels. Multivariate analyses compared changes in WBC count and ANC between smokers who did and did not stop smoking, adjusting for treatment group, age, sex, and body mass index. RESULTS: Of 784 smokers enrolled, 461 had biochemically-confirmed tobacco abstinence after 7 weeks of bupropion; 429 were randomly assigned to receive continued bupropion or placebo until week 52. At baseline, the mean WBC count was 8.4 x 109/L (SD ±2.3) and the mean ANC was 5.3 x 109/L (SD ±1.9). The baseline WBC count and ANC were higher in smokers with greater tobacco exposure, measured by daily cigarette consumption and serum cotinine level. Between baseline and week 7, there was a significantly larger decrease in WBC count in continuously abstinent subjects compared with continuing smokers (adjusted p =.031). At 52 weeks, biochemically-confirmed continuously abstinent subjects, as compared with continuing smokers, had a greater decline from baseline in WBC count (1.2 x 109/L versus 0.1 x 109/L, p<0.001) and ANC (0.1 x 109/L versus 0.2 x 109/L, p<0.001). CONCLUSION: The WBC count and ANC of healthy smokers increase with increasing tobacco exposure. Biochemically-confirmed tobacco abstinence leads to a rapid and sustained decrease in WBC count and ANC, possibly reflecting a decrease in an underlying state of tobacco-induced inflammation.

Abstract There is strong evidence that cigarette smoking causes adverse outcomes in people with cancer. However, more research is needed regarding those effects and the effects of alternative tobacco products and of secondhand smoke, the effects of cessation (before diagnosis, during treatment, or during survivorship), the biologic mechanisms, and optimal strategies for tobacco dependence treatment in oncology. Fundamentally, tobacco is an important source of variation in clinical treatment trials. Nevertheless, tobacco use assessment has not been uniform in clinical trials. Progress has been impeded by a lack of consensus regarding tobacco use assessment suitable for cancer patients. The NCI-AACR Cancer Patient Tobacco Use Assessment Task Force identified priority research areas and developed recommendations for assessment items and timing of assessment in cancer research. A cognitive interview study was conducted with 30 cancer patients at the NIH Clinical Center to evaluate and improve the measurement items. The resulting Cancer Patient Tobacco Use Questionnaire (C-TUQ) includes “Core” items for minimal assessment of tobacco use at initial and follow-up time points, and an “Extension” set. Domains include the following: cigarette and other tobacco use status, intensity, and past use; use relative to cancer diagnosis and treatment; cessation approaches and history; and secondhand smoke exposure. The Task Force recommends that assessment occur at study entry and, at a minimum, at the end of protocol therapy in clinical trials. Broad adoption of the recommended measures and timing protocol, and pursuit of the recommended research priorities, will help us to achieve a clearer understanding of the significance of tobacco use and cessation for cancer patients. Clin Cancer Res; 22(8); 1907–13. ©2016 AACR.