Environment and Breast Cancer: Science Review

Evidence From Humans
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Increased risk of relapse after breast cancer with exposure to organochlorine pollutants
Charlier, C. J., Dejardin, M. T. Bull Environ Contam Toxicol. 2007. 78:1, 1-4.
Topic area
Environmental pollutant - Organochlorine pesticides DDT
Study design
Funding agency
Not reported
Study Participants
Number of Cases
14 with relapse
Menopausal Status
The menopausal status of women included in this study is listed here.
No analyses by menopausal status
Number in Cohort
Cohort: 125 cases
Participant selection: Inclusion and exclusion criteria
Criteria used to select participants in the study.
Study subjects were women with breast cancer who underwent surgery followed by chemotherapy or hormonal therapy, recruited immediately prior to starting radiotherapy treatment. Those who had received previous irradiation treatment were not eligible.
Comment about participation selection
It is unclear how the participants were recruited into the study, and there is no indication of how "relapse" is defined with respect to time of diagnosis or treatment. This research group has presented work on a larger hospital-based case-control study; this appears to be a follow-up study of the case population.
Exposure Investigated
Exposures investigated
Serum DDT, p,p-'DDE and HCB from fasting samples collected prior to starting radiation treatment.
Exposure assessment comment
Of the 125 participants, 31 (24.8%) had undetectable levels of pesticide residue. Additionally, only one subject had detectable levels of DDT, whereas 76% had detectable levels of p,p'-DDE in their blood serum. A strength of this study is that exposure was evaluated prior to the outcome (relapse). Exposure measure may or may not correctly rank the exposures relevant to disease. A limited list of organochlorines was evaluated.
Breast cancer outcome investigated
Recurrence or progression
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.
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
Total pesticide concentration (ppb) was significantly higher in relapsing patients than in nonrelapsing patients (p<0.005). The difference remained significant after adjusting for age (p=0.037).

sum HCB + p,p'-DDE (ng/mL):
All cases: mean 4.05, SD 4.95
Relapsing case: mean 7.76, SD 6.15
Not relapsing case: mean 3.64, SD 4.66
ER+ tumors: mean 3.92, SD 5.03
Results Comments
The study authors assessed correlation between pesticide concentrations and BMI and chemotherapy because weight loss in breast cancer treatment might lead to increased circulating pesticide concentrations. No significant correlations were found; however, it is unclear from this is analysis whether change in BMI over the course of treatment affects pesticide concentrations. For the 14 relapsing patients, time to relapse was not reported.
Author address
Clinical Toxicology Laboratory, Liege University Hospital, Tour II+5, CHU Sart-Tilman, B4000 Liege, Belgium. C.Charlier@chu.ulg.ac.be