Environment and Breast Cancer: Science Review

Evidence From Humans
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Organochlorines and breast cancer risk by receptor status, tumor size, and grade (Canada)
Woolcott, C. G., Aronson, K. J., Hanna, W. M., SenGupta, S. K., McCready, D. R., Sterns, E. E., Miller, A. B. Cancer Causes and Control. 2001. 12:5, 395-404.
Topic area
Environmental pollutant - organochlorine, pesticide, PCB, DDT
Study design
Hospital-based case-control
Funding agency
Other: Canadian Breast Cancer Research Initiative,
Study Participants
Menopausal Status
The menopausal status of women included in this study is listed here.
Pre menopausal
Post menopausal
Number of Controls
Controls: 213
Participant selection: Inclusion and exclusion criteria
Criteria used to select participants in the study.
Women under age 80 with no previous cancer or breast implant who had a diagnostic breast biopsy. Controls frequency-matched by 5-year age and study site
Comment about participation selection
Controls who present for breast biopsy do not represent a normal population.
Exposure Investigated
Exposures investigated
14 PCB congeners, 10 pesticides, including p,p'-DDT, p,p'-DDE, cis-nonachlor, trans-nonachlor, oxychlordane, HCB, Mirex, beta-HCH. Concentration in lipid categorized into tertiles from breast adipose tissue.
Exposure assessment comment
Exposure measure may or may correctly rank the exposures relevant to disease. Exposure measure is years after the chemicals were banned and is subject to effects of time since exposure, parity and lactation, recent diet, weight loss.
Statistical Analysis
Breast cancer outcome investigated
Primary breast cancer: ER positive and ER negative, progesterone receptor status, tumor size, tumor grade
Ethnic groups with separate analysis
If this study provided a separate analysis by ethnic or racial group, the groups are listed here.
Confounders considered
Other breast cancer risk factors, such as family history, age at first birth, and hormone replacement therapy use, that were taken into account in the study.
Age, city, menopausal status, parity, lactation duration, age last breast-fed, ethnicity, family history, body mass index, fat intake, alcohol intake, current smoking, cumulative smoking.
Genetic characterization included
If the study analyzed relationships between environmental factors and inherited genetic variations, this field will be marked “Yes.” “No”, if not.
Description of major analysis
Polytomous logistic regression. Analysis of variance.
Strength of associations reported
Cases, OR (95% CI)
DDE, highest compared with lowest tertile. ER-negative tumors: 27 cases, OR = 2.4 (1.0-5.4); ER-positive tumors: 52 cases OR = 1.1 (0.6-1.9)
Total PCBs, highest compared with lowest tertile: ER-negative tumors: 23 cases, OR = 1.5 (0.7-3.3); ER-positive tumors: 54 cases OR = 1.3 (0.7-2.3)
Elevated, mostly statistically unstable, odds ratios for PCB 180 and total PCBs for PR-negative tumors and, to a lesser extent, PR-positive tumors.
Odds ratios are mostly below or near one for compounds tested other than PCBs and DDE (Table 3).
Results Comments
"Concentrations of organochlorines were almost always higher in cases with tumors of poorer prognosis (ER-negative, PR-negative, Size 2 cm and great, grade III). "The PCBs that were found to be higher in ER-negative cases were those that are dioxin-like and potentially antiestrogenic." Consistent with Demers finding of OCs associated with tumors that were more agressive (higher stage and size at diagnosis) and with poor survival. Authors argue that measurement in breast adipose rather than blood is more relevant to target site. Another advantage is better detection, resulting in fewer samples below detection limit. Study size may be too small. Results for some individual PCBs differ from Holford et al. PCB 180 is positively associated with breast cancer in both studies (with PR- and PR+ tumors in this study). Holford et al. argues against analyzing risk for total PCBs.
Author address
Department of Community Health and Epidemiology, Queen's University, Kingston, Ontario, Canada.