Smoking and the Risk of Nonmelanoma Skin Cancer Systematic Review and Meta-analysis

Objective: To perform a systematic review and meta-analysis to collate evidence of the effects of smoking on the risk of nonmelanoma skin cancer. Data Sources: We searched 4 electronic databases (from inception to October 2010) and scanned the reference lists of the publications retrieved to identify eligible comparative epidemiologic studies. Study Selection: Titles, abstracts, and full text were assessed independently by 2 authors against prespecified inclusion/exclusion criteria. Data Extraction: Data were extracted and quality was assessed independently by 2 authors using the Newcastle-Ottawa Scale. Data Synthesis: Meta-analysis was performed using random-effects models. Results are presented as odds ratios (ORs) with 95% CIs. Heterogeneity was assessed using I-2. Twenty-five studies were included. Smoking was significantly associated with cutaneous squamous cell carcinoma (OR, 1.52; 95% CI, 1.15-2.01; I-2=64%; 6 studies). Smoking was not significantly associated with basal cell carcinoma (OR, 0.95; 95% CI, 0.82-1.09; I-2=59%; 14 studies) or nonmelanoma skin cancer (OR, 0.62; 95% CI, 0.21-1.79; I-2=34%; 2 studies). Conclusion: This study clearly demonstrates that smoking increases the risk of cutaneous squamous cell carcinoma; however, smoking does not appear to modify the risk of basal cell carcinoma.