Environment and Breast Cancer: Science Review

Evidence From Humans
Print this page
Serum organochlorines and breast cancer risk in Japanese women: a case-control study
Itoh, H., Iwasaki, M., Hanaoka, T., Kasuga, Y., Yokoyama, S., Onuma, H., Nishimura, H., Kusama, R., Tsugane, S. Cancer Causes Control. 2009. 20:5, 567-80.
Topic area
Environmental pollutant - Organochlorine Pesticides DDT DDE PCBs
Study design
Hospital based case-control
Funding agency
Health and Labour Sciences Research Grant
Study Participants
Menopausal Status
The menopausal status of women included in this study is listed here.
Analyses stratified by menopausal status
Number of Controls
Controls: 403
Participant selection: Inclusion and exclusion criteria
Criteria used to select participants in the study.
Cases were women aged 20-74 years with newly diagnosed invasive breast cancer, recruited from 4 area hospitals. Hospital-based controls (medical checkup examinees), without cancer diagnosis, were matched 1:1 by age (+/- 3 years) and residential area.
Exposure Investigated
Exposures investigated
Lipid-standardized serum measures from blood samples were collected after enrollment and measured for sum of 41 PCB congeners, DDT, DDE, nonachlor, HCB, oxychlordane, and mirex. Blood was drawn between 2001 and 2005, prior to surgery for cases. Status of
Exposure assessment comment
Able to detect organochlorines in 100% of serum samples (with low limit of detection) including o,p'-DDT and p,p'-DDT, which is uncommon for studies in the USA.
Breast cancer outcome investigated
Primary incident breast cancer
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.
Total lipid concentration, BMI, menopausal status, age at menopause, smoking status, fish consumption, vegetable consumption, family history of breast cancer, age at first childbirth, parity, age at menarche, breast cancer screening history, breastfeeding
Genetic characterization included
If the study analyzed relationships between environmental factors and inherited genetic variations, this field will be marked “Yes.” “No”, if not.
Strength of associations reported
Fourth quartile vs. first quartile (ng/g):
o,p'-DDT: OR=0.67 (95% CI 0.30-1.52)
p,p'-DDT: OR=0.58 (95% CI 0.27-1.25)
p,p'-DDE: OR=1.02 (95% CI 0.46-2.26)
trans-Nonachlor: OR=0.49 (95% CI 0.22-1.06)
cis-Nonachlor: OR=0.41 (95% CI 0.19-0.91)
HCB: OR=0.95 (95% CI 0.43-2.11)
mirex: OR=0.40 (95% CI 0.19-0.84)
β-HCH: OR=1.04 (95% CI 0.43-2.52)
total PCBs: OR 0.33 (95% CI 0.14 to 0.78)

The relative risk of breast cancer decreased significantly for individuals with increasing levels of mirex (p-trend=0.02) and total PCBs (p-trend=0.0008) exposure.

No evidence for effect modification by tumor subtype except for mirex, which appeared to have the strongest negative association with ER+/PRtumors.
Results Comments
The authors state that organochlorines are highly correlated with each other, and may also be correlated with unmeasured substances, so observations may not represent a direct effect of organochlorines.
Author address
Epidemiology and Prevention Division, Research Center for Cancer Prevention and Screening, National Cancer Center, 5-1-1 Tsukiji, Chuo-ku, Tokyo 104-0045, Japan.