Cigarette smoking and the risk of mucinous and nonmucinous epithelial ovarian cancer

Background. The association between cigarette smoking and ovarian cancer may vary according to the histologic type of tumor. Methods. We examined cigarette smoking as a risk factor for both mucinous and nonmucinous tumors in a population-based case-control study comparing 767 incident cases of epithelial ovarian cancer with 1,367 community controls frequency matched to cases by age and race. Results. Smoking was associated with mucinous tumours (odds ratio [OR] = 1.9; 95% confidence interval [CI] - 1.3-2.9) but not with nonmucinous tumors (OR = 1.1; CI = 0.9-1.3). Furthermore, the odds ratios for smokers with mucinous tumors increased with increasing pack-years of smoking (OR = 1.0, 1.9 and 2.7 for <5, 5-24, and >24+ pack-years, respectively P for trend = 0.01). Conclusions. Cigrette smoking appears to be a risk factor for mucinous but not for nonmucinous tumours.