Cigarette smoking and risk of epithelial ovarian cancer (Australia)

Objectives: We studied the association between cigarette smoking and ovaria n cancer in a population-based case-control study. Methods: A total of 794 women with histologically confirmed epithelial ovar ian cancer who were aged 18-79 years and resident in one of three Australia n states were interviewed, together with 855 controls aged 18-79 years sele cted at random from the electoral roll from the same states. Information wa s obtained about cigarette smoking and other factors including age, parity, oral contraceptive use, and reproductive factors. We estimated the relativ e risk of ovarian cancer associated with cigarette smoking, accounting for histologic type, using multivariable logistic regression to adjust for conf ounding factors. Results: Women who had ever smoked cigarettes were more likely to develop o varian cancer than women who had never smoked (adjusted odds ratio (OR) = 1 .5; 95% confidence interval (CI) = 1.2-1.9). Risk was greater for ovarian c ancers of borderline malignancy (OR = 2.4; 95% CI = 1.4-4.1) than for invas ive tumors (OR = 1.7; 95% CI = 1.2-2.4) and the histologic subtype most str ongly associated overall was the mucinous subtype among both current smoker s (OR = 3.2; 95% CI = 1.8-5.7) and past smokers (OR = 2.3; 95% CI = 1.3-3.9 ). Conclusions: These data extend recent findings and suggest that cigarette s moking is a risk factor for ovarian cancer, especially mucinous and borderl ine mucinous types. From a public health viewpoint, this is one of the few reports of a potentially avoidable risk factor for ovarian cancer.