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Breast Cancer and the Environment: A Life Course Approach - Report Release from an IOM Committee

Presented by Irva Hertz-Picciotto, PhD, MPH and Robert Hiatt, MD, PhD on behalf of the Institute of Medicine.


On December 7, 20011, the Institute of Medicine released a report entitled Breast Cancer and the Environment: A Life Course Approach. The report, which was commissioned by Susan G. Komen for the Cure®, analyzes scientific findings regarding breast cancer and the environment.

With more than 230,000 new cases of breast cancer expected to be diagnosed in the United States in 2011, many wonder about the role that environmental exposures may be playing.

Komen for the Cure® asked the Institute of Medicine (IOM) to review the current evidence on breast cancer and the environment, consider gene-environment interactions, review the research challenges, explore evidence-based actions that women might take to reduce their risk, and recommend directions for future research. Overall, the IOM finds that major advances have been made in understanding breast cancer and its risk factors, but more needs to be learned about its causes and how to prevent it. The report urges a life-course approach to studying breast cancer because new information suggests that women and girls might be more susceptible to some risk factors during certain life stages.

The committee defined “environment” broadly, and reviewed evidence on a range of factors women encounter in their daily lives.

Of the environmental factors reviewed, those with the most consistent evidence of a link with increased breast cancer risk:

  • Exposure to ionizing radiation, especially at a young age
  • Use of combination estrogen-progestin hormone therapy
  • Being overweight or obese after menopause

Factors associated with a decreased breast cancer risk include:

  • Physical activity and exercise

There was some data to now suggest that cigarette smoking may increase the risk of breast cancer as well as other cancers and non-malignant diseases.

And the good news is that the IOM found no link to the use of hair-dye to breast cancer.

The IOM concludes that women may have some opportunities to reduce their risk of breast cancer through personal actions, such as:

  • Avoiding unnecessary medical radiation throughout life
  • Avoiding use of estrogen progestin hormone therapy
  • Avoiding smoking
  • Limiting alcohol consumption
  • Increasing physical activity, and
  • For postmenopausal breast cancer, minimizing weight gain.

In addition to applying a life-course approach to studies of breast cancer, research recommendations in the report include developing improved tools for epidemiologic research and testing of chemicals and other substances, developing effective preventive interventions, developing better approaches to modeling breast cancer risks, and improving communication about breast cancer risks.


Susan G. Komen for the CureŽ Statement on Institute of Medicine Report on Environmental Links to Breast Cancer

Susan G. Komen for the Cure President Elizabeth Thompson issued the following statement last week regarding the Institute of Medicine (IOM) report "Breast Cancer and the Environment, a Life Course Approach," regarding environmental links to the disease. The report was released December 7 at the San Antonio Breast Cancer Symposium.

"Understanding the role that environmental factors play in the development of breast cancer is hugely complex and the IOM has done a good job laying out the challenges. We intend to use these findings to guide our decisions about research to fund, so that women and their families have the best science to guide them in making important lifestyle choices. We believe our efforts going forward will be made even more effective through the guidance provided by this study.

"As the IOM makes clear, significantly more research is needed to gain a full understanding of what substances can be definitively linked to breast cancer.

"In our ongoing commitment to uncovering the causes of breast cancer, we are issuing a challenge to other agencies working in the environmental area to join with Susan G. Komen to create a fund to begin work on these very important initiatives."

To view Komen’s current research programs visit

The IOM full report can be viewed at

Breast Cancer and the Environment: A Life Course Approach - Report Release from an IOM Committee


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