Association between cigar or pipe smoking and cancer risk in men: A pooled analysis of five cohort studies

Introduction: Use of non-cigarette tobacco products such as cigars and pipe has been increasing, even though these products entail exposure to similar carcinogens to those in cigarettes. More research is needed to explore the risk of these products to guide cancer prevention efforts. Methods: To measure the association between cigars and/or pipe smoking, and cancer incidence in men, we performed meta-analyses of data from five prospective cohorts. Cox regression was used to evaluate the association between different aspects of cigars and pipe smoking and risk of each smoking-related cancer (head and neck, esophagus, lung, stomach, liver, pancreas, kidney, and bladder) for each study. Adjusted HRs were combined using random-effects models. Results: Cigars and/or pipe smokers were at increased risk for head and neck [HR, 1.51; 95% confidence interval (CI), 1.22–1.87], lung (HR, 2.04; 95% CI, 1.68–2.47), and liver cancers (HR, 1.56; 95% CI, 1.08–2.26). Ever-smokers of cigars and/or pipe had an increased risk of developing a smoking-related cancer when compared with never smokers of any tobacco product (overall HR, 1.07; 95% CI, 1.03–1.12). The risk for smoking-related cancers was also increased in mixed smokers who smoked cigars or pipe as well as cigarettes, even when they were smoking predominantly pipe or cigars. Discussion: This pooled analysis highlights the increased risk for smoking-related cancers, particularly for lung and head and neck cancers in exclusive and predominant smokers (former and current) of cigars and pipe. Tobacco prevention efforts should include these products in addition to cigarettes. ©2017 AACR