Breast cancer among Alaska Native women potentially exposed to environmental organochlorine chemicals

Abstract

Objectives. To determine if an increased rate of breast cancer in Alaska Native women is related to their consumption of a subsistence diet that may contain p,p'-dichlorodiphenylethylene (DDE) and polychlorinated biphenyls (PCBs). Study Design. A retrospective case control design. Methods. We analyzed banked serum collected between 1981 and 1987 from 126 Alaska Native women, including 63 case women who subsequently developed breast cancer and 63 age-matched control women who remained cancer-free. Serum was analyzed for DDT, DDE, 13 other chlorinated pesticides, and 28 PCB congeners. Results. The geometric mean for p,p'-DDE levels among case women was 8.67 ppb (95% Confidence Interval 7.48, 10.04); among control women, the geometric mean was 7.36 ppb (6.53, 8.30). The geometric mean for total PCB levels among case women was 4.55 ppb (3.61, 5.74) and for control women, the geometric mean was 6.10 ppb (4.73, 7.86). Cancer status and total PCB levels varied across ethnicity (i.e., Eskimo, Aleut, and Indian) but DDE levels were uniform among these ethnic groups. Using conditional logistic regression analysis to adjust for potential confounders (e.g., ethnicity, family history of breast cancer, parity), we found an odds ratio of 1.43 (0.46, 4.47) for the highest tertile of DDE exposure and 0.42 (0.07, 2.38) for the highest tertile of total PCB exposure. Conclusions. Although the results are limited by small sample size and restricted risk factor information, our findings of higher DDE levels, but lower PCB levels among women with breast cancer are consistent with previous research. Our results confirm exposure to organochlorines among Alaska Native women but do not identify these exposures as a significant risk factor for breast cancer.

Abundance and distribution of polychlorinated biphenyls (PCBs) in breast tissue

“…Numerous studies encompassing thousands of women have failed to detect an association between PCB levels in serum and breast cancer risk (Gammon et al, 2002;Rubin et al, 2006;Ruder et al, 2014). In this study, we observed the highest levels of PCB congeners in breast tissue from Groups II and III, which have been associated with breast cancer potential in vitro, but we detected no associations between total PCB levels, functional groupings, or individual congeners and clinical and pathological characteristics in women with breast disease.…”

Systematic Review and Meta-analysis of Cyclodiene Insecticides and Breast Cancer

“…The meta-analysis of oxychlordane was based on 5 studies comparing odds ratios (23,25,(30)(31)(32) and 9 studies comparing means (23,25,27,29,(31)(32)(33)(34)(35). No significant pooled association was detected in either analysis.…”

Impact of Environmental Contaminants on Breast Cancer / Wpływ Zanieczyszczenia Środowiska Na Raka Piersi

“…However, epidemiologic studies concerning exposure to PCB and breast cancer risk have been controversial. Several earlier studies suggested a positive association [38][39][40][41][42][43][44], other studies showed no increased breast cancer risk [45][46][47][48][49][50]. More recent data suggested that the CYP1A1 m2 polymorphisms might add an increased risk to the etiology of breast cancer in women with environmental exposure to PCBs [51].…”