MARCH 1998 VOLUME 19 NUMBER 3


INTERVIEW

 
Living Downstream
An interview with Sandra Steingraber
 

Ecologist, poet and cancer survivor, Sandra Steingraber, Ph.D. is an internationally recognized expert on the environmental links to cancer. She is the author of Post-Diagnosis, a volume of poetry, and co-author of a work on ecology and human rights in Africa, The Spoils of Famine. She has taught biology and held visiting fellowships at several universities, and was recently appointed to serve on President Clinton's National Action Plan on Breast Cancer. She was named Ms. Magazine's 1997 Woman of the Year, and is the author of 1997's highly acclaimed Living Downstream: An Ecologist Looks at Cancer and the Environment.

Multinational Monitor: What made you decide to write Living Downstream?
Sandra Steingraber:
I was searching around for a book like this and couldn't find it. The closest to it is a book that Dr. Samuel Epstein wrote in the mid-1970s, The Politics of Cancer. And even that wasn't exactly what I was looking for. I was looking for a close examination of all of the lines of evidence linking cancer and the environment. I wanted to look at all of the evidence and ask, "How strong is all of the evidence? Where are the data gaps? Do we have enough information now to act on what we already know?" Instead, the kind of commentary I got back from cancer researchers was, "The evidence is preliminary, it is a possibility, but nobody really knows." With these answers, I became more and more frustrated. We didn't know and we couldn't act because nobody had pulled all the data together in one place so we could sit back and just look at it. When I realized that there was no such book out there, I decided to write it myself.

MM: And what did you find?
Steingraber:
The evidence we have is very strong. The environment is playing a significant role in our current burden of cancer. There is no one study that I could hold up and say, "Here is the absolute proof of a profound link between rising rates of toxics and rising rates of cancer." But there are many studies from various disciplines that make the point. There are studies of wildlife showing that wildlife get cancer in very contaminated areas of the United States. There are studies from the cancer registries showing rising rates of cancer in all age groups -- childhood cancers, testicular cancers. We can't explain these cancers by the aging of the population. We can't explain the cancers' increase by better detection methods. I looked at the molecular biological data, which provides the smoking gun evidence. Molecular biologists have gotten better at determining which carcinogens cause which cancers. You can actually go into somebody's cells and determine which carcinogen the person has been exposed to.

MM: They can look at the cancer cells of a human being and determine which carcinogen caused the cancer?
Steingraber:
Not for every chemical and not for every cancer, but certainly for some. When you combine this evidence with the molecular animal data and with the data from cancer registries, you end up with a strong link between these toxics and the increase in cancer.

We'll never have what my detractors might call absolute proof. First, absolute proof in science in very rare. Second, it would require controlled human studies. That is, having two populations and exposing one human group to known amounts of certain chemicals and then watching the results. We will never do that. So, we will always have to infer from humans that have been inadvertently exposed to unknown amounts of chemicals for unknown amounts of time, from lab animal studies, from wildlife studies and from cells growing in a petri dish. We will have to do the best we can and use our judgment.

I argue in Living Downstream that more and better data should never be a substitute for good judgment. At some point, there is enough information to act in a precautionary manner to protect human health.

MM: You have cancer, is that right?
Steingraber:
Yes. I had bladder cancer.

MM: How old were you when you learned of this?
Steingraber:
I was 20. I'm now 38.

MM: How are you doing?
Steingraber:
I never know how to answer that. I've had good news over the years, I've had bad news over the years. Bladder cancer, like so many other cancers, is the kind of cancer that can come back years or even decades later. I have never declared myself cured. On the other hand, I don't live my life waiting for the other shoe to drop. Like so many cancer patients, I feel it is not only behind me, but perhaps in front of me. I see it all around me, in good friends who have had recurrences years later.

MM: Do you believe the environment caused your cancer?
Steingraber:
As a biologist, I can't answer that. There is no way you can look at one individual and assign a cause. We know that cancer is a multicausal disease. I've had a microscope since I was nine years old. I've been a biologist for a long time. When I learned that I had this unusual cancer, I went to the biological literature to find out who gets this cancer and what we know about its causes.

It turns out that bladder cancer is the classic environmental cancer. The evidence on bladder cancer and its relationship to environmental contaminants is stronger than most diseases. Exposure to contaminants in tap water is a pattern I found over and over again in human studies that looked at whole populations.

That gave me grounds years later to go back to my hometown -- Pekin, Illinois -- and become a kind of environmental detective there. Pekin is just downstream from Peoria.

MM: You mentioned that molecular biologists now can go and look at a person's cancer and determine what carcinogen caused it. Did they do that for you?
Steingraber:
No. You can't walk into a doctor's office and ask for these tests. They are part of research protocols. Between doctor and patient, the issue of causality is almost never discussed.

Why is there this lack of curiosity on the part of the medical community about the causes of cancer? Part of the answer to that is simply that doctors don't need to know the cause of the disease in order to treat it. You can have your tumor successfully treated by a whole variety of methods without the doctor knowing anything about what might have triggered it. On the other hand, I do believe the medical community has a responsibility to get curious about these things and ask these questions. If they don't, they may be returning their patients to a very toxic environment where they may be exposed to some of the very same carcinogens that caused the cancers in the first place -- whether it's a workplace or home environment.

MM: What are your suspicions as to the causes of your cancer?
Steingraber:
The first half of Living Downstream is my best attempt as a biologist to outline all the lines of evidence linking cancer to the environment. The second half of the book, which is interwoven in and out of the first science-based part of the book, is my own story about growing up in Pekin, my cancer and the cancer in my family. My family is an adopted family, so we don't share chromosomes in common, but we do share an environment. It also tells the story of my return to my hometown and my use of the right-to-know laws that give us access to information about what toxic emissions industry is putting into our environment, air, water and soil. I also filed some Freedom of Information Act requests and uncovered the presence of dry cleaning fluids in my hometown drinking water wells.

Dry cleaning fluids are chemicals with suspected links to bladder cancer. Do I think that's what caused my cancer? I don't know. It is like asking which straw broke the camel's back. We know that you need about eight to 10 mutations to a single cell before that cell is placed definitively on the pathway to tumor formation. One of the straws in that heap on your back might be from the environment, another might be from genes that you inherited, another might be from a lifestyle choice like smoking.

But it seems to me that no matter how large or small the burden is from the environment, it is a human rights issue. Unlike lifestyle choices, those are risks that we have not consented to. Unlike hereditary contributing factors, we can do many things about toxics in the environment. There is nothing we can do about our ancestors. Cancer genes play a role in maybe 5 to at most 10 percent of all cancers. That 5 or 10 percent of the puzzle we can do nothing about.

All of that logically argues for looking at the environment as a place to begin a meaningful program of cancer prevention.

MM: How do we know that cancer genes only cause 10 percent of the problem?
Steingraber:
My citations for this are from the cancer geneticists who are doing the research. When they isolate and identify one of these cancer genes, the most famous being the breast cancer gene (BRCA-1), there is a way that they can trace the gene back in certain families. They can look at how the pattern of inheritance flows through families. And then they can do some random testing to see what percent of the general population might carry this gene. In the case of BRCA-1, maybe 2 to 5 percent of breast cancers might be attributable to that cancer gene. There are other genes that seem to play a role in things like colon cancer. When you add it all together, it appears that at most 10 percent of all cancers are attributable to cancer genes.

MM: Does that mean that 90 percent of cancers are caused by lifestyle and toxics in the environment?
Steingraber:
Yes, but distinguishing between the two is where the real argument begins.

We know for a fact that 90 to 95 percent of those of us who contract cancer are born with a perfectly healthy set of genes to which something bad happens during our lifetimes. Any one cancer might be caused both by mutations from lifestyle and by mutations from the environment. And you cannot always untwist these two variables from each other -- they are not independent of each other.

Consider high-fat diet, which has been implicated as a classic lifestyle risk factor in several big-ticket malignancies. Why is high-fat diet associated with several cancers? Of all the foodstuffs, animal fat is the substance in our diet that is the most heavily contaminated with dioxins as well as very persistent pesticides that bioaccumulate as you move up the food chain. The fatty portion of the meat, milk or eggs is what is carrying the huge load.

So, on the one hand, fat is a lifestyle choice, but on the other hand, it is also a vehicle for carrying fat-soluble carcinogens into our bodies.

If we weaned U.S. agriculture from its dependency on pesticides and stopped incinerating plastic waste, which is a major source of dioxin production, we could get these chemicals out of animal fat and people could choose to eat what they want to eat. Perhaps a high-fat diet would not carry such a cancer risk.

MM: How geographically concentrated is cancer in the United States?
Steingraber:
It depends on what cancer you are looking at. I spend one chapter looking at cancer maps. For cancers like bladder, colon and breast cancer, on a map, you would light up in red an area from Maine down to Washington, D.C. and then you would also light up in red the area all along the Great Lakes Basin. Those of course are the two areas of the United States that are the most heavily industrialized.

But there are other cancers that show very different patterns. One of them is non-Hodgkins lymphoma. It is one of the more swiftly rising cancers right now. It has tripled in incidence rate over the past 50 years. It has no known lifestyle risk factors. It has no known hereditary risk factors. And it is rising the fastest. It is the cancer that killed Jackie Kennedy Onassis, so it is getting more attention now.

If you looked at the mortality map of non- Hodgkins lymphoma, you would light up in red the central part of the United States -- the Midwest and Great Plains area. That is the part of the country where we use pesticides in agriculture most intensively. That correlation does not necessarily indicate cause, but it certainly does give us grounds for further inquiry.

When you look more closely at the possibility that pesticides are playing a role in non-Hodgkins lymphoma, you find some interesting studies. For example, dogs whose owners regularly use certain kinds of weed killers have twice the rate of canine non-Hodgkins lymphoma than dogs whose owners don't use these lawn chemicals. If you look by occupation at who gets non-Hodgkins, you find that farmers, golf course supervisors and Vietnam Vets exposed to Agent Orange have higher rates of non-Hodgkins than folks in the general population. Those are all occupations that have exposure to pesticides.

In the molecular biological literature, there are studies by Dr. Vincent Garry at the University of Minnesota about what kinds of mutations pesticide exposure causes. He looked at a population of pesticide applicators and found they had a very unusual mutation in one of the middle chromosomes. The chromosome actually breaks off, flips upside down and reattaches itself. It is called a chromosome inversion. The only other population besides pesticide applicators where he has seen that kind of mutation in high frequency are non-Hodgkin lymphoma patients.

All of the evidence -- the occupational literature, the cancer maps, the cancer registry data, animal studies, and studies from inside humans themselves -- is pointing to certain pesticides playing some kind of role in the increase of certain cancers.

MM: But the idea that genes cause cancer is grabbing more of the media spotlight.
Steingraber:
It has been. But I believe we are in the middle of a sea change. When you read the media reports on the inheritance of cancer genes, you eventually come to a paragraph explaining that this applies only to a tiny minority of cancers. Certainly, the identification of heritable cancer genes does not offer hope for prevention. Other than the remote possibility of gene therapy, the most that the discovery of these so-called cancer genes offers us is the possibility for marketing and commodifying a test that would allow you to know whether you carry one of the genes that would make you susceptible. That has raised the question of what value is that knowledge if there is nothing you can do about it. The promise and excitement of that has waned a bit, as it should.

Now we have two powerful databases: the Toxic Release Inventory [which includes extensive information data on industry pollution emissions] and the cancer registries, which measure the incidence of cancer in every county of every state. Together, they give us the ability to ask questions and get some answers as to whether or not there are relationships between toxic emissions and cancer rates. So, we are seeing a shift in focus in the medical research community. Perhaps the media will be the last to come on board. But I've seen a shift in reporting in the last year or two, with more emphasis on the environment.

MM: What were the reviews like for Living Downstream?
Steingraber:
Other than the New England Journal of Medicine, they have all been very positive. I was very gratified. The Chicago Tribune, Washington Post, Portland Oregonian and others -- they all gave it great reviews. I was disappointed that the New York Times did not review the book.

MM: Who reviewed the book for the New England Journal of Medicine?
Steingraber:
Dr. Jerry Berke. His review ran on November 20, 1997.

MM: What did he say?
Steingraber:
It was a scathing review. It accused me of emotionalism, bias and exaggeration. He said I was speaking as a victim. He launched a broadside against environmentalists in general. He talked about the work product of environmentalists being controversy. He said environmentalists scare people in order to raise money for their organizations.

MM: What was your response to the review?
Steingraber:
Sometime in November, I was in Austin, Texas, and heard that the New England Journal had reviewed my book and it was not favorable. Somebody read it to me over the phone and I felt terribly sad and depressed. But I thought there was nothing I could do except shrug it off and go on. I flew from Austin to Vermont. I was giving a lecture at the University of Vermont hospital when someone asked me my response to the New England Journal Review. And I assumed they meant the content of the review. And they asked if I knew about the controversy that had been generated by the review. They told me that in fact the reviewer was a senior official at the W. R. Grace chemical company. I remember just stopping in my tracks and my mouth just fell open for a moment. I think of the New England Journal as a cut above the other journals.

MM: Berke signed his name to the review with a home address and didn't reveal that he was with Grace.
Steingraber:
Right. That is very unusual in the New England Journal. You usually provide an institutional affiliation. In fact, he is director of toxicology at W. R. Grace. [see "Behind the Lines," Multinational Monitor, January/February 1998]

MM: What are the implications of focusing on prevention of environmental causes of cancer? Does it mean shutting down the petrochemical industry?
Steingraber:
It means moving toward non-toxic alternatives for chemical carcinogens. At the end of the book, I stake out a philosophical argument about the use of chemical carcinogens and our dependence on them in our economy. I make comparisons with slavery. At one point our economy was dependent on slave labor, and at some point, we had to abolish the institution completely -- not reform it, not regulate it, but simply abolish it.

MM: So, are you saying abolish the petrochemical industry?
Steingraber:
No. We need to eliminate chemicals that have been linked to cancer and immediately move to find non-toxic substitutes.

MM: What would be an example?
Steingraber:
The dry cleaning industry. I feel particularly passionate about this one, since I grew up drinking dry cleaning fluids myself. I feel as if I have an intimate relationship with this particular solvent -- perchloroethylene (perc).

Perc is classified as a probable human carcinogen. Eighty percent of the production of perc in the United States is used for dry cleaning clothes. Perc is found in drinking water of communities around the country, it is in the bodies of fresh water fish, it is in ambient air. We are contaminating the world with a chemical that has been strongly linked to human cancer in order to clean our clothes.

I spend most of my time in Boston, where we have a wet cleaner, which relies on soap and water to wash wools and silks. But they have re-engineered washing machines that have computerized controls to control humidity and agitation. It's not like you or I throwing our clothes in the washing machine. And all of my clothes come back looking great. And I know that no one is going to get cancer from cleaning my clothes.

MM: Are you convinced that we can determine which synthetic chemicals are carcinogenic and which are not?
Steingraber:
Sure. Science is a powerful tool. There are many chemicals on the market now that have never been tested. That overwhelms us. We should reverse the burden of proof. Industry must be required to demonstrate to us that the chemicals are safe before they are allowed onto the market. Now, the public has to prove that we are being harmed by the chemical.

MM: We don't know what impact reversing the burden of proof will have on the petrochemical industry. Does it eliminate all plastics? Does it shut down the industry?
Steingraber:
We can't continue in the direction we are going. It is essentially premeditated murder. We don't know who the victims are, but we know that when you release certain chemicals into the environment, a certain number of people are going to get cancer and die because of that. That is just wrong. When we decided to eliminate slavery, we didn't know the implications to society and to the economy.