THE BLOG
01/26/2012 03:27 pm ET | Updated Mar 27, 2012

Environment

The woman walked up to me, the bandana covering where her hair used to be, a brave smile on her face. She had just completed her initial treatments for a breast cancer diagnosis that came as a complete surprise. She was an otherwise healthy woman in her 40s who exercised, watched what she ate, and had no history of breast cancer in her family. The lump she discovered seemed to come from nowhere. "Why this diagnosis for someone like me?" she asked me. "I can't help but think that I've done something wrong. How could I have avoided this?"

I always feel a pang when women blame themselves for a disease whose origins we don't fully understand. There's some sense that if we had exercised more or eaten more organic food -- even been nicer people in our youth -- this might not have happened to us. That's hardly the case.

How breast cancer starts is still one of the most vexing questions facing science today. Unlike viruses or bacteria, which can be identified and isolated, cancer begins when otherwise normal cells suddenly "click on" in some people and begin a deadly trek through the body. How do these cells go from friend to foe, and how does an otherwise vigilant immune system allow them to grow and spread to bones and organs far away?

There are many theories, but none seems to fit into a neat mold. Certainly, there are genetic links to breast cancer that make vigilance necessary for the daughters and sons of cancer patients, or descendants of ethnic groups with higher numbers of genetic mutations linked to breast cancer (e.g., the BRCA1 and 2 mutations more prevalent in Ashkenazi Jews). We know that some racial groups, African American women, for example, are diagnosed with aggressive forms of breast cancer at higher rates than Caucasians, which is why we fund and urge more research into disparities in breast cancer.

We also know that people may be able to reduce their risk of breast cancer by maintaining a healthy weight, being active, and avoiding excessive alcohol use and perhaps even smoking. As established as even these factors are, they are by no means conclusive, and certainly don't explain the 88-year-old chain smoker who never develops cancer, or the 40-year-old non-drinking vegan marathon runner, with no family history, who is diagnosed with breast cancer out of the blue.

An area that requires infinitely more study is the role of environmental agents in breast cancer, that is, food additives, cosmetics, pollution or chemicals that we come in contact with every day. Some believe that these external agents must be responsible for what seems to be a growing incidence of cancers worldwide -- I've seen at least one publication suggest that 90 percent of all breast cancers today are environmentally-based.

As seductive as that argument might be, I'm reminded that cancer was first written about by Egyptian doctors on papyrus several thousand years ago. And that people died of cancer long before the industrial age, at a time when I'm very sure everyone was eating organic.

Nevertheless, there is merit to the notion that substances we're exposed to may have links to cancer. Certainly, high levels of radiation and some industrial chemicals are linked rather conclusively to cancer clusters that have occurred in the past. We suspect that other substances that we eat, breathe or apply to our skin through personal care products may play a role as well. The question is: Which ones? And how?

Like everything else in cancer, there are no clear-cut answers, at least not yet, despite the forests of paper used to print study after study on specific substances that might or might not play a role. Some of these are conclusive. Most are not. This is why we went looking for answers at Susan G. Komen for the Cure, through a study that we requested and funded through the respected Institute of Medicine (IOM), considered the most authoritative voice in medical science today.

Some, including us, were hoping that this study might play out like the final scene in a murder mystery, with the IOM conclusively pointing the finger at a whole host of suspect substances, so that we could rule them in or out. That hope may have been naïve, given the thousands of environmental substances we are exposed to, at various times and at various levels in our lives, and their complex role in cancer development, if any.

To its credit, IOM did not play Hercule Poirot. Rather than riding a tide of ungrounded theories, the IOM's team of environmental scientists, public health experts, advocates and clinical practitioners spent almost two years reviewing reams of evidence and concluded that, with a few exceptions, answers to environmental issues in breast cancer will require more than throwing darts at a hodgepodge of conflicting studies. The answers require long-term, large-scale and well-designed studies that cover years of a woman's development, starting in childhood or infancy (and maybe even before) through old age.

Why? Because the most common form of testing these substances -- exposing lab rats or test tube cells to large doses of a substance -- tells us that large doses of a substance might cause cancer in rats and cells in test tubes. They don't tell us the impacts of those agents on cancer development in human beings. They also don't take into account the effect of exposures over time: Some substances may have no impact on a 40-year-old or 60-year-old, but a profound impact when a girl is exposed during puberty, when her breasts are developing.

Some environmental studies that get wide publicity rely on the memories of people after they become ill. These are generally considered unreliable -- at that point, it's generally held, people are looking for answers to their illness (like my friend in the bandana) and are likely, understandably, to answer questions in a way that fits their theories.

Of course, testing these substances on humans is unethical.

This means that as eager as we are to get to the answers of the origins of cancer, we agree with the IOM that most answers just don't exist today, and hard work over time is required. We at Susan G. Komen for the Cure are prepared to do that work with the blueprint laid out by IOM. We are challenging all funding organizations -- non-profits, governmental and corporate -- to join us, and to begin the long, but ultimately most fruitful, range of large-scale studies that follow large populations over long periods of time, and give us the definitive answers we must have to understand the role of environmental factors in breast cancer.

Our great hope is that many others will join us.

As we seek to move the science in the right direction, some would suggest that, until we have these answers, all environmental agents are suspects and should be banned or warned against with vigor. We think that, instead, women should have the information they need to make informed decisions for themselves and their families -- information that is readily available on our website and those of the National Cancer Institute and other well-regarded cancer institutions.

We do not agree that women are served by a steady stream of warnings based on suspect scientific evidence. Better science is needed, and all of us in the cancer community should be prepared to put our money where those answers lie.

For more by Ambassador Nancy G. Brinker, click here.

For more on breast cancer, click here.

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