Organochlorines and endometrial cancer risk

There is concern that persistent environmental pollutants such as dichlorod iphenyltrichloroethane (DDT) and polychlorinated biphenyls (PCBs) increase breast cancer risk, at least partially through estrogenic effects. Because the endometrium is more sensitive to estrogenic stimulation than the breast , such a carcinogenic effect should be more pronounced in the endometrium t han the breast. In a population-based case-control study in Sweden, we meas ured serum concentrations of 10 chlorinated pesticides and 10 PCB congeners in 154 endometrial cancer cases and 205 population controls. Information o n potential confounders was obtained by mailed questionnaires. We used logi stic regression to calculate odds ratios (ORs) as measures of relative risk . We performed analyses for lipid-adjusted concentrations of each individua l substance and after grouping substances according to putative hormonal ef fects. We found no significant associations of increasing levels of pestici de or PCB exposure with endometrial cancer risk. The multivariate OR was 1. 0 (95% confidence interval, 0.6-2.0; P for trend, 0.78) for the highest com pared with the lowest quartile of dichlorodiphenyldichloroethylene (DDE), t he predominant dichlorodiphenyltrichloroethane metabolite. Corresponding OR s were 1.0 for hexachlorobenzene, 0.9 for beta-hexachlorocyclohexane, 1.4 f or oxychlordane, and 1.2 for trans-nonachlor. Analyses of substances groupe d by putative hormonal effect also showed no associations with endometrial cancer risk. For all estrogenic compounds, the OR for the highest compared with the lowest quartile was 1.1 (95% confidence interval, 0.6-2.2; P for t rend, 0.90). Our data do not support the hypothesis that the organochlorine exposure studied increases the risk for endometrial cancer.