Abstract A126: Characteristics of menstruation and pregnancy and the risk of lung cancer in women

Abstract

Abstract A126 Differences between men and women in the descriptive epidemiology of lung cancer suggest that hormonal factors may influence lung carcinogenesis in women. Few epidemiological studies have been conducted on hormone-related variables and lung cancer risk and the findings have not been consistent. We investigated the association between characteristics of menstruation and pregnancy in relation to lung cancer risk in a population-based case-control study carried out in Montreal, Canada. Between January 1996 and December 1997, newly diagnosed lung cancer cases were identified and recruited from 18 Montreal-area hospitals that together diagnose 98% of cases that occur among Montreal residents. Population controls from Montreal were identified from the provincial electoral lists and were randomly selected, stratified to the expected age and sex distribution of cases. The participation rate was 81.7% among cases and 69.4% among controls. Among cases, interviews were conducted an average of 12.1 months after diagnosis. For each variable, odds ratios (OR) and 95% confidence intervals (CI) were estimated using unconditional logistic regression modeling. Each hormone-related variable was modeled separately. Associations were also examined according to age at diagnosis and level of smoking and by lung cancer histology. All statistical tests were two-sided. Among 422 women with lung cancer and 577 controls, we observed that most characteristics of menstruation and pregnancy were not associated with the risk of lung cancer. However, an increased lung cancer risk was observed for women who had had surgical menopause with bilateral oophorectomy compared to women who had had a natural menopause (OR=1.95, 95% CI: 1.29-3.17). These results did not vary by age at diagnosis or level of smoking, and they were similar for different histological types. Our results suggest that hormonal factors, related to surgical menopause and/or ovary removal, may play a role in the risk of lung cancer. Further studies are needed to confirm these findings, and to assess the possible contribution of hormone replacement therapy. Citation Information: Cancer Prev Res 2008;1(7 Suppl):A126.