Plasma levels of dichlorodiphenyldichloroethene (DDE) and dichlorodiphenyltrichloroethane (DDT) and survival following breast cancer in the Carolina Breast Cancer Study.

ABSTRACT: OBJECTIVES:To examine plasma levels of dichlorodiphenyldichloroethene (DDE) and dichlorodiphenyltrichloroethane (DDT) in association with survival among women with breast cancer who participated in a population-based case-control study. METHODS:Participants included 456 white and 292 black women from the Carolina Breast Cancer Study Phase I who were diagnosed with primary invasive breast cancer from 1993 to 1996, and who had available DDE/DDT and lipid measurements from blood samples obtained on average 4.1?months after diagnosis. Using the National Death Index, we identified 392 deaths (210 from breast cancer) over a median follow-up of 20.6?years. We used Cox regression to estimate covariate-adjusted hazard ratios (HRs) and 95% confidence intervals (CIs) for all-cause and breast cancer-specific 5-year mortality, and 20-year mortality conditional on 5-year survival, for lipid-standardized DDE and DDT levels. Associations stratified by race and estrogen receptor (ER) status were also examined. RESULTS:The highest versus lowest DDE tertile and the highest vs non-detectable DDT quantile were associated with HRs of 1.95 (95% CI?=?1.31-2.92) and 1.64 (95% CI?=?1.10-2.44), respectively, for 20-year conditional all-cause mortality. DDE levels above versus below the median were associated with a HR of 1.69 (95% CI?=?1.06-2.68) for 20-year conditional breast cancer-specific mortality among women overall, and HRs were 2.36 (95% CI?=?1.03-5.42) among black women and 1.57 (95% CI?=?0.86-2.89) among white women (PInteraction?=?0.42), and 3.24 (95% CI?=?1.38-7.58) among women with ER- tumors and 1.29 (95% CI?=?0.73-2.28) among women with ER+ tumors (PInteraction?=?0.03). CONCLUSION:Exposure to DDE/DDT may adversely impact overall and breast cancer-specific survival. DDE exposure may contribute to the racial disparities in breast cancer survival.

SUBMITTER: Parada H 

PROVIDER: S-EPMC6448589 | biostudies-literature | 2019 Apr

REPOSITORIES: biostudies-literature