Cancer and the Environment
This report from the President's Cancer Panel will not come as a big surprise to anyone. We all suspect that a myriad of environment factors play a role in the development of some cancers. This is a very difficult puzzle as it is impossible to tease out single possible factors or agents. How do you study the impact of, for example, chemicals used on lawns when everyone was also exposed to second hand smoke and additives in food and beverages and toxins in the air and who knows what else? It has always made sense to me, in my totally non-medical brain, that some cancers are caused by a perfect storm of a particular environmental agent and a particular genetic vulnerability in the individual. That is, in order to figure this out, we would have to not only isolate the possible carcinogen but also identify the genetic vulnerability or flaw in an individual. That is a big project.
Here is a summary from MedPage:
Cancer Panel Says Environment May Contribute to Cancer Risk
By Emily P. Walker, Washington Correspondent, MedPage Today
May 06, 2010
WASHINGTON -- Environmental carcinogens are responsible for a far greater number of cancer than previously believed; thus eradicating these environmental threats should be a priority for President Obama, according to the report of a presidential advisory panel.
"The Panel was particularly concerned to find that the true burden of environmentally induced cancer has been grossly underestimated," wrote the authors of the report "Reducing Environmental Cancer Risk: What We Can Do Now."
"The panel urges you most strongly to use the power of your office to remove the carcinogens and other toxins from our food, water, and air that needlessly increase healthcare costs, cripple our Nation's productivity, and devastate American lives," the report's authors wrote in a letter to President Obama.
The President's Cancer Panel was established by the National Cancer Act of 1971, when then President Richard Nixon declared war on cancer. The panel is required to submit an annual report to the president describing the status of the "war" and identifying both progress and barriers to continued advances. The singling out of environmental causes for cancer in this year's report is considered a major -- and some said welcome -- departure from previous reports, according to a number of cancer specialists contacted by ABC News and MedPage Today.
"For the past 30 years . . . there has been a systematic effort to minimize the importance of environmental factors in carcinogenesis," said Philip Landrigan, MD, MSc, director of the Children's Environmental Health Center at Mount Sinai School of Medicine in New York City. "There has been disproportionate emphasis on lifestyle factors and insufficient attention paid to discovering and controlling environmental exposures," he said. "This report marks a sea change."
Jennifer Lowry, MD, a medical toxicologist at Children's Mercy Hospitals and Clinics in Kansas City, Mo., said the report finally lends a "voice that could be heard that the environment does play an important role in the health of all people of every age."
The report is actually a synthesis of testimony from more than two dozen experts in cancer, chemicals, and environmental toxins. Based on that testimony and research compiled over the last two years, LaSalle D. Leffall, Jr., MD, of Howard University and Vivian Smith, PhD, professor emerita at the University of Texas M.D. Anderson Cancer Center, who co-authored the report, concluded that the government has failed to prevent
unnecessary exposures to carcinogens. The challenge for the Obama administration, they wrote, is to intensify research efforts into environmental toxins.
"With the growing body of evidence linking environmental exposures to cancer, the public is becoming increasingly aware of the unacceptable burden of cancer resulting from environmental and occupational exposures that could have been prevented through appropriate national action," Leffall and Smith wrote in the letter to the president.
Among the potential exposures cited in the report were pesticides, fertilizers, pharmaceutical by-products that enter the water supply, household chemicals, and tanning beds. Emissions from cars, trucks, and planes add to the toxic mix, the authors wrote. But the authors said there was no evidence connecting the use of cell phones to increased risk of cancer.
While Americans are exposed to thousands of chemicals each year, only several hundred of those chemicals have been safety tested, Leffall and Smith said.
The study of environmental factors and their effect on cancer has been given short shrift compared with studying lifestyle factors and genetic and molecular causes of cancer, the authors claimed. But paging through the lengthy report, it was difficult to find solid science to back that strong statement. "At this time, we do not know how much environmental exposures influence cancer risk and related immune and endocrine dysfunction," Leffall and Smith wrote.
In an interview, Leffall said he hoped the report, if nothing else, would raise awareness that chemicals and other environmental toxins may be causing cancer and that more studies are needed. "We think, based on what we know, when you look at all the data, it just appears to us that there are areas where it's been greatly under-reported," Leffall said. "We don't know 100%, but that's why we believe we need to do more research."
The National Toxicology Program, part of the Department of Health and Human Services, does list some chemicals such as benzene and formaldehyde and some substances such as tobacco to be carcinogenic, but environmental factors such air pollutants and naturally-occurring chemicals are less well understood. Public awareness about some compounds, such as bisphenol A (BPA), has increased in the past year as a handful of studies and reports linked the ubiquitous chemical -- widely used in plastics such as baby bottles and other drink containers -- to metabolic disorders and heart disease and male sexual dysfunction.
Also, the FDA recently announced it would review safety data on another common chemical,triclosan, which is used in antibacterial soaps and washes, toothpastes, and cosmetics, after lab tests on animals were concerning.
In the report, Leffall and Smith recommended that physicians routinely ask about their current workplace and living environment as a routine part of collecting patient history.
They also recommended:
Conducting a thorough assessment of workplace exposures and cancer risks
Creating a more coordinated and transparent system for enforcing environmental health standards
Increasing funding for federal research into occupational and environmental epidemiologic cancer research The Environmental Protection Agency should lower its current maximum standard for radon exposure, and the public should be better informed about the risks of radon
Providing better care to military personnel who were exposed to nuclear fallout
Radiation exposure has long been recognized as a cancer risk, but this latest report from the President's Cancer Panel claims that patients and healthcare professionals are not completely aware of radiation exposure from imaging techniques such as computed tomography (CT) scans -- a radiation exposure that might be increasing with the use of whole body scans and virtual colonoscopy.
And while the report issued a call for increased emphasis on dialing down the radiation exposure with CT, the government may actually be out in front on this issue -- the FDA recently proposed new safety requirements for manufacturers of CT scanners and fluoroscopic devices. Those new requirements are designed to reduce unnecessary radiation from medical imaging.
This article was developed in collaboration with ABC News.