Cigarette smoking and risk of histological subtypes of epithelial ovarian cancer in the EPIC cohort study

Abstract

IJCNew data regarding a positive association between smoking and risk of epithelial ovarian cancer (EOC), especially the mucinous tumor type, has started to emerge. The purpose of this study was to examine the association between different measures of smoking exposures and subtypes of EOC in a large cohort of women from 10 European countries. The European Prospective Investigation into Cancer and Nutrition (EPIC) cohort is a multicenter prospective study initiated in 1992. The questionnaires included data about dietary, lifestyle, and health factors. Information about cigarette smoking was collected from individuals in all participating countries. We used Cox proportional hazard regression models to estimate hazard ratio (HR) of EOC overall and serous, mucinous, and endometroid histological subtypes, with 95% confidence intervals (CIs) associated with different measures of smoking exposures adjusting for confounding variables. Altogether 836 incident EOC cases were identified among 326,831 women. The tumors were classified as 400 serous, 83 mucinous, 80 endometroid, 35 clear cell, and 238 unspecified. Compared with never smokers, current smokers had a significantly increased risk for mucinous tumors [HR 5 1.85 (95% CI 1.08-3.16)] and those smoking more than 10 cigarettes per day had a doubling in risk [HR 5 2.25(95% CI 1.26-4.03)] as did those who had smoked less than 15 pack-years of cigarettes [HR 5 2.18 (95% CI 1.07-4.43)]. The results from the EPIC study add further evidence that smoking increases risk of mucinous ovarian cancer and support the notion that the effect of smoking varies according to histological subtype.Ovarian cancer is the fifth most common cancer among women in Europe with an estimated number of 67,000 (4.5%) new cases, and the sixth most common cause of cancer death with an estimated number of 42,000 (5.5 %) deaths in 2008.1 Except for the well-established protection by parity and oral contraceptive use, relatively little is known about other factors that may influence the risk of developing the disease. 2,3 In 2004, the Monograph on ''Tobacco smoke and involuntary smoking'' from the International Agency for Research on Cancer (IARC) reported that there was insufficient evidence to draw conclusions regarding the possible effect of smoking on ovarian cancer risk. 4 However, new data regarding a positive association between smoking and risk of epithelial ovarian cancer (EOC), especially with the mucinous tumor type, have started to emerge. A systematic review from 2006, 5 including a meta-analysis on the association of smoking and ovarian cancer, with data from one cohort study 6 and 18 case-control studies, showed a significant twofold increased risk of mucinous tumors among current compared with never smokers. Since then, three 7-9 cohort and two case control 10,11 studies have examined the relationship between smoking and histological subtypes of EOC, all supporting the notion that the histologic subtypes of EOC may represent different entities. In the most recent summary statement from I...

Recent Concepts of Ovarian Carcinogenesis: Type I and Type II

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Association between the rs11614913 variant of miRNA-196a-2 and the risk of epithelial ovarian cancer

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Clinical and Emergent Biomarkers and Their Relationship to the Prognosis of Ovarian Cancer

“…In addition, patient age at menarche, use of oral contraceptives, parity, education level, and smoking status were also explored. All these clinical variables were chosen because previous studies had suggested prognostic relevance [4–6]. Of note, the majority of patients received cancer therapy in keeping with established guidelines with debulking surgery followed by 18 weeks of platinum-based chemotherapy.…”