CBCRP Leads the Way in California and the Nation

Catherine Thomsen, M.P.H.
Special Research Initiatives Project Lead

California has a long history of leading the nation, socially and politically. When California breast cancer activists joined forces with scientists, healthcare professionals, and state legislators to win passage of the legislation that created our unique Program, they created breakthroughs not only in state funding for breast cancer research but also in including those affected by the disease in the process of setting funding priorities, carrying out research, and disseminating the results.

A priority of the CBCRP’s architects was and is to advance the riskier and potentially most promising areas of study. They felt that research into the role of the environment in breast cancer was so critical that they incorporated a mandate for the CBCRP to investigate it into our legislation. This was revolutionary in 1993 and remains a vital question in breast cancer research today. Yet, despite years of research, the role of the environment in breast cancer is still controversial.

Is the Environment Important to Breast Cancer?
From the 1940s to the 2000s, breast cancer incidence increased in the United States and elsewhere. The rise cannot be explained by better and more widespread screening or changes in known risk factors. During this time, an increasing number of new chemicals were developed and used, from plastics and cleaners to flame retardants and solvents. Studies of immigrants, twins, workers, and geographic patterns of breast cancer incidence around the world suggest that environmental factors play an important role in breast cancer.1

Many researchers have attempted to explain the changes in breast cancer rates and differences between populations; however, most studies have focused on a few behaviors, such as smoking and alcohol, and ignored the wide range of potential environmental risk factors. More recently, the focus has narrowed even further on breast cancer genetics; yet we know that some environmental exposures interact with genes.

While we have new technology and knowledge to address these complex questions, obstacles still exist because we are not exposed to one thing at a time, but in mixtures that vary over the course of our lives. We don’t have adequate databases or frameworks to get the answers. Sometimes we are lucky. One researcher, Dr. Barbara Cohn, had the resources to find a very significant link between DDT and breast cancer—but only among those exposed to the banned pesticide during adolescence, when breasts are developing.2 Infants and teens may react to contaminants differently, and we can’t measure that when they are adults already facing a breast cancer diagnosis.

Disparities Add to the Complexity
The environment also plays a critical role in understanding breast cancer disparities. Where a person lives, works, plays, and prays is related to their culture and social group(s). People with low incomes are less likely to live in safe neighborhoods with sidewalks and more likely to live near traffic, thus breathing more polluted air. Immigrant women’s risk of breast cancer increases after coming to California, but is it from the change in diet or exposure to pesticides, solvents, or other toxins from their work here? Social factors and location appear to play a role in breast cancer. Breast cancer and other health outcomes are worse among people who have experienced racial discrimination. Breast cancer rates are lower in rural areas than in cities; is this because they get more Vitamin D from the sun or experience less stress?3

African American women have a higher death rate from breast cancer (34.7 per 100,000), than white women (25.9 per 100,000), even though white women have higher rates of getting the disease. Possible reasons for poorer outcomes include differences in treatment and access to medical care. Genes could explain why young African American women get breast cancer more often and have less chance of surviving—but there are no “African American genes,” just patterns that are more common among one ethnic group than another. Genes may play a role, but they are not the whole story, and they may interact with our environment.

CBCRP Funding Cutting Edge Research
The CBCRP is leading several initiatives that will focus on solutions to the roles of the environment and disparities. Three initiatives have been funded and are starting:

Chemicals Policy and Breast Cancer: John Balmes, M.D., Director of the Northern California Center for Occupational and Environmental Health (COEH) was funded to conduct research and lead a work group to consider the biological pathways through which chemicals contribute to breast cancer and identify the best currently available chemical safety tests. Dr. Balmes will work with Dr. Meg Schwarzman of COEH and Dr. Sarah Jansen of the National Resources Defense Council to ensure that breast cancer etiology is not forgotten in our state’s innovative chemicals policy. The California Green Chemistry program “to reduce or eliminate hazardous chemicals in our products and the environment” was advanced when AB 1879 and SB 509 were signed into law on September 29.3 The CBCRP and our grantees want to make sure that breast cancer is considered as these policies are developed.

Demographic Questions for California Breast Cancer Research: Scarlet Lin Gomez, Ph.D., of the Northern California Cancer Center was funded to lead an expert panel to research and develop a standard set of demographic measures for research into racial, ethnic, socioeconomic and other differences in breast cancer. Dr. Gomez will lead the group to create and test a core set of survey questions in various languages. More regular, common data elements and standard analysis methods will allow researchers to pool their data and better predict health behaviors and outcomes among diverse populations. Understanding the differences may point us to the cause.

Understanding Racial and Ethnic Differences in Stage-Specific Breast Cancer Survival: With CBCRP funding, researchers are collaborating to determine if they can pool data from existing California studies to provide a better understanding of why people from different racial and ethnic groups, who are diagnosed with breast cancer at the same stage, have different survival outcomes. The following researchers and studies have been funded to determine whether data can be combined and important questions answered:

Until more research is done on individual chemicals and on the real-life mixtures of environmental contaminants at different points in our lives, we won’t know if and how much the environment is contributing to breast cancer or other diseases. The best reason for studying the role of the environment in breast cancer is that we can prevent many exposures. Changing policies and behaviors to reduce exposures to contaminants may offer our best hope for reducing the burden of breast cancer. The CBCRP’s Special Research Initiatives are pursuing unique opportunities to identify and address breast cancer risk factors from the social and physical environments in more comprehensive and interdisciplinary ways to make a real difference in understanding and eventually preventing breast cancer.

1 Maximizing the Impact of the California Breast Cancer Research Program: Studying Environmental Influences and Breast Cancer Robert Millikan, Ph.D. (2006) (http://www.cbcrp.org/publications/papers/millikan/index.php)

2 DDT and breast cancer in young women: new data on the significance of age at exposure. Environmental Health Perspectives (2007) 115(10):1406-14

3 Identifying Gaps in Breast Cancer Research (http://www.cbcrp.org/sri/reports/index.php)

4 “Governor Schwarzenegger Signs Groundbreaking Legislation Implementing First-inthe- Nation Green Chemistry Program” press release (http://gov.ca.gov/index.php?/pressrelease/10666/)