BREAST CANCER: A SECOND LOOK AT ENVIRO FACTORS
Air Date: Week of July 25, 1997
Some women’s health groups are looking more closely at the environment in relation to breast cancer. At the recent World Congress on Breast Cancer in Canada, many speakers said the role that chemicals and other toxins play may be greater than what mainstream science is willing to admit. Among them is Dr. Julia Brody, the head of the Silent Spring Institute in Newton, Massachusetts, a state-funded organization that’s conducting a major study of environmental pollutants, and the possible link to breast cancer. Dr. Brody speaks with guest host Laura Knoy.
KNOY: This is Living on Earth. I'm Laura Knoy, sitting in for Steve Curwood. In recent years, Americans have been bombarded with information about breast cancer, and ways to reduce their risk of getting it. Don't smoke, don't drink too much, eat a low-fat diet, exercise, and so on. Scores of articles have also discussed the role that heredity plays, and whether childbirth later in life makes a difference. But the vast majority of breast cancer victims have none of these risk factors. So some women's health groups are looking more closely at the environment. At the recent World Congress on Breast Cancer in Canada, many speakers said the role that chemicals and other toxins play may be greater than what mainstream science is willing to admit. Among them is Dr. Julia Brody. She's head of the Silent Spring Institute in Newton, Massachusetts, an organization that's conducting a major study of environmental pollutants and the possible link to breast cancer.
BRODY: There are a couple of different types of evidence that I think are like a neon sign that says the environment is a place we should look. When women live in one region and then move to another, their breast cancer rates change and so do their daughters' and their granddaughters'. So if women move from Asia, for example, which has lower breast cancer rates, to California, which has some of the highest rates in the world, their breast cancer rates change until their daughters' and granddaughters' breast cancer rates come very close to women from California originally. The other thing that makes me think there may be environmental causes of breast cancer has to do with recent findings about endocrine disruptors. Those are pollutants that are synthetic chemicals but can act like estrogen. We know that many of the established risk factors for breast cancer are related to exposure to estrogen or to other hormonal factors. For example, the age when a woman gets her first period, the age at menopause, the number of kids she has and how old she was when her first kid was born. Now, as we learn more about how synthetic chemicals can act like estrogen, it makes a lot of sense to give priority to finding out whether these synthetic chemicals also increase breast cancer risk.
KNOY: Your organization has studied breast cancer on Cape Cod, Massachusetts, where the incidence of breast cancer is more than 20% higher than the rest of the state. What do you think is going on there?
BRODY: We're looking at pesticides. Pesticides have been used very widely on the Cape to control gypsy moth and mosquitoes, and also on cranberry bogs and golf courses. And earlier research suggests that pesticides may be related to breast cancer risks. Some studies have found higher levels of DDT in blood of women with breast cancer than without. But some studies haven't found this association, so it's still a question that we need to pursue. The second thing we're looking at is pollution from wastewater. Since endocrine disruptors are in a lot of commercial products, detergents, and plastics, they go down the drain into the septic system if you're on Cape Cod. And then there's a potential for them to move out through the sandy soil on the Cape into the aquifer that's the source of drinking water.
KNOY: You mentioned wastewater and also pesticides. What other types of pollution are we talking about that may possibly be linked to breast cancer? And the reason I ask is I think some people may think that it has to be extreme. You know, you have to live next to a toxic waste site, or you have to work in a really horrible factory with all sorts of chemicals around you. But the evidence that your organization and others seem to be finding is that it can be ordinary stuff that we would all come in contact with.
BRODY: Well, we haven't really made the link to humans yet, but we do see a lot of indicators from wildlife. The Environmental Protection Agency recently released a report about endocrine disruptors that summarizes effects on wildlife, and we are seeing effects on wildlife reproduction at very low levels of contamination.
KNOY: This link between breast cancer and pollution has been discussed and studied for many years, and study is still ongoing. But some scientists say it's just very, very hard to prove. Do you agree?
BRODY: That is so true. It is a very hard area of research. One thing that's making it harder now is that we're learning things that suggest that it may make a difference when in a woman's life she's exposed to pollutants. The breast develops differently at different parts of life, and it's beginning to look like exposures prenatally may be particularly important, and maybe exposures during adolescence. So we face a tremendous challenge in trying to go back in history to find out what kinds of pollutants may have been in the environment some time in the past.
KNOY: Well, should the state or Federal government take any action based on the concerns that you and others have about breast cancer and pollution?
BRODY: Yes, I think we are ready to act in some ways, even though we don't know yet everything we want to about breast cancer and the environment. First important step is to change the tests we use to identify cancer-causing chemicals. Right now they aren't very sensitive to endocrine effects. They also don't pick up effects early in a test animal's life, and we know that that could be important for breast cancer.
KNOY: Well, I'd like to thank you very much for joining us.
BRODY: Thank you. It was a pleasure to be here.
KNOY: Dr. Julia Brody heads the Silent Spring Institute in Newton, Massachusetts. Her group is conducting a major study of the possible link between breast cancer and environmental pollutants.
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