Relation between smoking and skin cancer.

PURPOSE Tobacco smoking is a risk factor for several cancers. The risk of cutaneous malignancies related to smoking, however, is relatively unknown. We investigated the possible association between smoking and skin cancer. PATIENTS AND METHODS A hospital-based case-control study was performed that included 161 patients with squamous cell carcinoma, 301 with nodular basal cell carcinoma, 153 with superficial multifocal basal cell carcinoma, 125 with malignant melanoma, and 386 controls. Information on smoking history was collected in personal interviews. Relative risks were estimated using exposure odds ratios from cross-tabulation and logistic regression. RESULTS An association between smoking and squamous cell carcinoma of the skin was found (relative risk, 2.3; 95% confidence interval, 1.5 to 3.6; P: = .0001), with a higher risk for current smokers (relative risk, 3.3; 95% confidence interval, 1.9 to 5.5) than for former smokers (relative risk, 1.9; 95% confidence interval, 1.2 to 3.0). After adjustment for age, sex, and sun exposure, the relative risk of squamous cell carcinoma was 2.0 (95% confidence interval, 1.2 to 3.2; P: = .008). There was a dose-response relationship with number of cigarettes and pipes smoked. No significant association was found between smoking and nodular basal cell carcinoma, superficial multifocal basal cell carcinoma, or malignant melanoma. CONCLUSION Tobacco smoking is an independent risk factor for cutaneous squamous cell carcinoma.