Our murky understanding of cancer and chemicals (part 1)
Host: Rebecca Williams
Show date: 03/05/2012
According to the latest numbers from the National Cancer Institute, roughly 41 percent of us will be diagnosed with some type of cancer in our lifetimes.
But “cancer” is not just one type of disease.
There are more than 100 different kinds with different personalities and causes. And the causes are not all that well understood.
This week, we’re taking a closer look at cancer and environmental pollutants.
It’s a subject researchers are trying to learn more about, but the picture of how the chemicals in our everyday lives interact with our bodies’ cells is far from clear.
What it's like to hear the word "cancer"
Six years ago, Corinna Borden woke up in the middle of the night with a shooting pain under her right rib cage. It was the kind of pain that made her want to crawl out of her skin.
Months went by and the pain got worse. Doctors were stumped.
She was taking two Vicodin pills every four hours for relief. The medical tests continued, and they eventually found the problem.
Hodgkin’s lymphoma – cancer.
She was 29 years old when she got the news.
“I basically shut down,” said Borden. “Like I was totally blown apart and terrified, and I couldn’t think of anything but that I was going to die and that this was really unfair. And then there was a small part of me that was happy that the pain was not totally in my head, and hadn’t been… And then [I was] angry that nobody had found it. So there was a lot going on. There’s that great line with Paul Simon, ‘when you lose love, it’s like everyone can see into your heart.’ It’s the same feeling, you've just been stripped…. every boundary you have is just laid open. It’s a really emotionally horrible feeling. ”
Doctors reassured Borden that Hodgkin’s lymphoma is treatable, and a week later, she started chemotherapy.
But after months of treatment, it didn’t work. Her scans still showed a spot where cancer might be lurking.
“To be honest my anger with the western establishment of not having the chemotherapy help me was also coupled with the anger [that] I’ve been poisoned by whatever that’s been going on… I mean I have no idea what it is I’ve been actually eating, or drinking, or every cosmetic, they don’t have list all of the ingredients or the 'natural flavors' - that is an umbrella that can mean anything,” said Borden.
How could this have happened?
It’s a common question after being diagnosed. People ask, “How could this have happened to me - or to my sister, my uncle, my mom, my neighbor?”
There are many factors that can lead to cancer. There are the genes we have inherited. There are viruses. There are naturally occurring things like sun exposure, arsenic in water, and radon.
All these factors can interplay with our genes and cause the cells in our body to grow out of control.
And then there are the man-made chemicals in our lives. How these impact cancer can be tough to figure out.
The National Toxicology Program of the U.S. Department of Health and Human Services publishes a list of substances that could cause cancer “to which a significant number of persons residing in the United States are exposed.”
The list is published every two years, and the most recent edition lists 240 substances that can lead to cancer.
- 54 of these substances are listed as “known to be human carcinogens,”
- and 186 substances are listed as “reasonably anticipated to be human carcinogens.”
The President's Cancer Panel calls for more action
Each year a panel of scientists appointed by the President takes stock of the nation’s strategy to fight cancer.
In 2010, a panel appointed by former President George W. Bush issued a report that said quote - “the true burden of environmentally induced cancer has been grossly underestimated.”
Chair of the President’s Cancer Panel Dr. LeSalle Leffall said that only a fraction of the 80,000 chemicals in use today are tested for safety.
“The health effects of many of these chemicals have not been studied or they’ve been understudied and the chemicals really remain unregulated,” said Leffall.
Leffall said the panel recommended more research and more action.
“We think that the government needs to take action to eliminate carcinogens from our workplaces, our schools, and our homes, and that action needs to start now,” said Leffall.
The President’s Cancer Panel report, “Reducing Environmental Cancer Risk,” talked about reducing exposure to things such as toxic substances in drinking water, pesticides, medical x-rays, car exhaust, and plastic food containers.
It was criticized by the American Cancer Society. They say only about 6% of cancer deaths are caused by occupational exposure and environmental pollutants.
From the ACS’ report “Cancer Facts & Figures 2012”:
Exposure to carcinogenic agents in occupational, community, and other settings is thought to account for a relatively small percentage of cancer deaths – about 4% from occupational exposures and 2% from environmental pollutants (man-made and naturally occurring).
They said the President’s Cancer Panel report put too much emphasis on these potential environmental risks to the detriment of other known risks – bigger risks – things like smoking, diet, and lack of exercise.
How can we know?
Dr. Richard Clapp is an environmental epidemiologist at Boston University.
He said the 6% number is outdated.
“This is a thirty-year old estimate. I think it was wrong 30 years ago and it’s wrong now. I don’t know what the real percentage is. I don’t think anyone knows what the real percentage is because things interact,” said Clapp.
He said right now, we simply don’t know enough.
“It’s not like environmental or occupational exposures cause 70% or 80%, we don’t know that,” said Clapp. “Anyone that claims they know that is making it up. There’s no way to prove that. But we do know that there are people getting exposed to stuff that causes cancer; why would we want to have that continue?”
Clapp says if there’s a chemical that looks like it might be linked to cancer, it’s wise to get rid of it.
He points to the falling rates of lung cancer as evidence of how we should approach the problem.
“It’s good news that lung cancer, especially in males, has begun to come down, and probably is beginning to come down in females. So that’s a story that needs repeating… We don’t exactly know the mechanism, we don’t know exactly what happens to an individual cell, from even whether it’s benzo[a]pyrene in the cigarette smoke, or something else in it, there’s lots of carcinogens in cigarette smoke. So we don’t know the exact details of how that works. But we know if we prevent that exposure it’s going to have a benefit for people’s health.”
Moving from a "reactionary principle" to a "precautionary principle"
Clapp said the U.S. should move toward the European model of chemical regulation. The REACH program (Registration, Evaluation, Authorization, and Restriction of Chemical substances) was adopted in Europe in 2007. It “places greater responsibility on industry to manage the risks from chemicals and to provide safety information on the substances.”
A similar, precautionary approach to chemical regulation has been introduced in the U.S. Congress.
The Safe Chemicals Act (S.847) was introduced by Senator Frank R. Lautenberg (D-NJ), and hearings on the bill were held last November.
And the National Institute for Occupational Safety and Health (NIOSH) is working on a new carcinogens policy expected later this year that could move toward a more precautionary approach to chemical regulation in the workplace.
Making changes, but trying not to be consumed by them
Corinna Borden doesn’t know what caused her cancer, but she has changed her life.
Soon after her diagnosis, she got rid of the chemicals in her house, she began filtering her tap water, and she changed what she eats.
But she tries not to be consumed by these choices. She say she still has to live.
“I’ve been in a position where I didn’t want to get out of bed, because I was so afraid of dying,” said Borden. “And that’s not how we should live. Life is precious and beautiful and I really feel that you need to go out and experience it. And going out and being a little closer to the edge is… what choice do we have?”
It’s been almost six years since Borden first heard the word cancer, and she doesn’t know yet if her cancer is in remission. (Borden keeps a blog about her experiences and life lessons, and she's also written a book, "I Dreamt of Sausage.")
For those who get the disease these days – fewer are dying from it because of advances in treatment and screening.
But researchers continue to work on one of the biggest puzzles – what makes our cells turn cancerous in the first place?
Tomorrow, as part of our week-long series on cancer and the environment, Sarah Alvarez will take us to White Lake, Michigan. Some families there are trying to figure out where cancer in their community might come from.