2008–2009 Annual Report President’s Cancer Panel

REDUCING ENVIRONMENTAL CANCER RISK

What We Can Do Now

Executive Summary

Despite overall decreases in incidence and mortality, cancer continues to shatter and steal the lives of Americans. Approximately 41 percent of Americans will be diagnosed with cancer at some point in their lives, and about 21 percent will die from cancer. The incidence of some cancers, including some most common among children, is increasing for unexplained reasons.

Public and governmental awareness of environmental influences on cancer risk and other health issues has increased substantially in recent years as scientific and health care communities, policymakers, and individuals strive to understand and ameliorate the causes and toll of human disease.

Between September 2008 and January 2009, the President’s Cancer Panel (the Panel) convened four meetings to assess the state of environmental cancer research, policy, and programs addressing known and potential effects of environmental exposures on cancer. The Panel received testimony from 45 invited experts from academia, government, industry, the environmental and cancer advocacy communities, and the public. This report summarizes the Panel’s findings and conclusions based on the testimony received and additional information gathering.

Research on environmental causes of cancer has been limited by low priority and inadequate funding. Current toxicity testing relies heavily on animal studies that utilize doses substantially higher than those likely to be encountered by humans. These data—and the exposure limits extrapolated from them— fail to take into account harmful effects that may occur only at very low doses.

The prevailing regulatory approach in the United States is reactionary rather than precautionary. That is, instead of taking preventive action when uncertainty exists about the potential harm a chemical or other environmental contaminant may cause, a hazard must be incontrovertibly demonstrated before action to ameliorate it is initiated.

Only a few hundred of the more than 80,000 chemicals in use in the United States have been tested for safety. U.S. regulation of environmental contaminants is rendered ineffective by five major problems: (1) inadequate funding and insufficient staffing, (2) fragmented and overlapping authorities coupled with uneven and decentralized enforcement, (3) excessive regulatory complexity, (4) weak laws and regulations, and (5) undue industry influence.

People from disadvantaged populations are more likely to be employed in occupations with higher levels of exposure (e.g., mining, construction, manufacturing, agriculture, certain service sector occupations) and to live in more highly contaminated communities. The reality of this unequal burden is not just a health issue, but an issue of environmental justice. While all Americans now carry many foreign chemicals in their bodies, women often have higher levels of many toxic and hormone-disrupting substances than do men. Some of these chemicals have been found in maternal blood, placental tissue, and breast milk samples from pregnant women and mothers who recently gave birth. Thus, chemical contaminants are being passed on to the next generation, both prenatally and during breastfeeding. Some chemicals indirectly increase cancer risk by contributing to immune and endocrine dysfunction that can influence the effect of carcinogens. Children of all ages are considerably more vulnerable than adults to increased cancer risk and other adverse effects from virtually all harmful environmental exposures.

Many of these contaminants— even substances banned more than 30 years ago—remain ubiquitous in the environment because they break down very slowly, if at all. Other industrial chemicals or processes have hazardous by-products or metabolites. Numerous chemicals used in manufacturing remain in or on the product as residues, while others are integral components of the products themselves.

The entire U.S. population is exposed on a daily basis to numerous agricultural chemicals, some of which also are used in residential and commercial landscaping. Many of these chemicals have known or suspected carcinogenic or endocrine disrupting properties. Pesticides (insecticides, herbicides, and fungicides) approved for use by the U.S. Environmental Protection Agency (EPA) contain nearly 900 active ingredients, many of which are toxic. Farmers and their families, including migrant workers, are at highest risk from agricultural exposures.

Conveniences of modern life—automobile and airplane travel, dry cleaning, potable tap water, electricity, and cellular communications, to name a few—have made daily life easier for virtually all Americans. Some of these conveniences, however, have come at a considerable price to the environment and human health, and the true health impact of others is unconfirmed. Disinfection of public water supplies has dramatically reduced the incidence of waterborne illnesses and related mortality in the United States, but research indicates that long-term exposure to disinfection by-products such as trihalomethanes may increase cancer risk.

The use of cell phones and other wireless technology is of great concern, particularly since these devices are being used regularly by ever larger and younger segments of the population. At this time, there is no evidence to support a link between cell phone use and cancer. However, the research on cancer and other disease risk among long-term and heavy users of contemporary wireless devices is extremely limited. Similarly, current and potential harms from extremely low frequency radiation are unclear and require further study. In addition, ultraviolet radiation from excess sun exposure and tanning devices has been proven to substantially increase skin cancer risk.

In the past two decades, improved imaging technologies, nuclear medicine examinations, and new pharmaceutical interventions have made possible significant strides in our ability to diagnose and treat human disease, including cancer. Computed tomography (CT) and nuclear medicine tests alone now contribute 36 percent of the total radiation exposure and 75 percent of the medical radiation exposure of the U.S. population.

In addition, pharmaceuticals have become a considerable source of environmental contamination. Drugs of all types enter the water supply when they are excreted or improperly disposed of; the health impact of long-term exposure to varying mixtures of these compounds is unknown.

The military is a major source of toxic occupational and environmental exposures that can increase cancer risk. Some of these sites and the areas surrounding them became heavily contaminated due to improper storage and disposal of known or suspected carcinogens including solvents, machining oils, metalworking fluids, and metals. In some cases, these contaminants have spread far beyond their points of origin because they have been transported by wind currents or have leached into drinking water supplies. Hundreds of thousands of military personnel and civilians in the United States received significant radiation doses as a result of their participation in nuclear weapons testing and supporting occupations and industries, including nuclear fuel and weapons production, and uranium mining, milling, and ore transport. These populations include the families of military and civilian workers, and people—known as “downwinders”—living or working in communities surrounding or downstream from testing and related activities, and in vi 2008–2009 Annual Report, President's Cancer Panel relatively distant areas to which nuclear fallout or other radioactive material spread. Federal responses to the plight of affected individuals have been unsatisfactory.

Most environmental hazards with the potential to raise cancer risk are the product of human activity, but some environmental carcinogens come from natural sources. For example, radon gas, which forms naturally from the breakdown of uranium mineral deposits, is the second leading cause of lung cancer in the United States and the leading cause of lung cancer among people who have never smoked.

Reducing Environmental Cancer Risk: A Call to Action The burgeoning number and complexity of known or suspected environmental carcinogens compel us to act to protect public health, even though we may lack irrefutable proof of harm. Action is possible at several levels: conducting scientific research to enhance our understanding and by extension, our ability to prevent and respond to environmental carcinogens; enforcing existing policies and regulations that protect workers and the public; implementing policy and regulatory changes that support public health and reduce the burden of cancer; and taking personal action.

The Panel concludes that:

• We Need to Determine the Full Extent of Environmental Influences on Cancer. Environmental contamination varies greatly by type and magnitude across the nation, and the lifetime effects of exposure to combinations of chemicals and other agents are largely unstudied. Similarly, the cancer impact of exposures during key “windows of vulnerability” such as the prenatal period, early life, and puberty are not well understood.

• The Nation Needs a Comprehensive, Cohesive Policy Agenda Regarding Environmental Contaminants and Protection of Human Health. It is more effective to prevent disease than to treat it, but cancer prevention efforts have focused narrowly on smoking, other lifestyle behaviors, and chemopreventive interventions. Scientific evidence on individual and multiple environmental exposure effects on disease initiation and outcomes, and consequent health system and societal costs, are not being adequately integrated into national policy decisions and strategies for disease prevention, health care access, and health system reform.

• Children Are at Special Risk for Cancer Due to Environmental Contaminants and Should Be Protected. Opportunities for eliminating or minimizing cancer-causing and cancer-promoting environmental exposures must be acted upon to protect all Americans, but especially children. . There is a critical lack of knowledge and appreciation of environmental threats to children’s health and a severe shortage of researchers and clinicians trained in children’s environmental health.

• Continued Epidemiologic and Other Environmental Cancer Research Is Needed. Available evidence on the level of potential harm and increased cancer risk from many environmental exposures is insufficient or equivocal. The Panel is particularly concerned that the impact, mechanisms of action, and potential interactions of some known and suspected carcinogens are poorly defined.

• An Environmental Health Paradigm for Long-Latency Disease Is Needed.
• Existing Regulations for Environmental Contaminants Need to Be Enforced and Updated; Stronger Regulation Is Needed. Regulations for workplace environments are focused more on safety than on health.

• Radiation Exposure from Medical Sources Is Underappreciated. The use of radiation-emitting medical tests is growing rapidly. Efforts are needed to eliminate unnecessary testing and improve both equipment capability and operator skill to ensure that radiation doses are as low as reasonably achievable without sacrificing image or test data quality.

• Medical Professionals Need to Consider Occupational and Environmental Factors When Diagnosing Patient Illness. Moreover, gathering this information would contribute substantially to the body of knowledge on environmental cancer risk.

• Workers, Other Populations with Known Exposures(e.g., agricultural and chemical workers and their families, radiation-exposed groups such as uranium mine workers, nuclear industry workers, nuclear test site workers and “downwinders,” residents of cancer “hot spots” or other contaminated areas), and the General Public Require Full Disclosure of Knowledge about Environmental Cancer Risks.

• The Military Needs to Aggressively Address the Toxic Environmental Exposures It Has Caused. Overall, the military has not responded adequately to health problems associated with its operations absent substantial pressure from those affected, advocacy groups, or the media. Of special concern, the U.S. has not met its obligation to provide for ongoing health needs of the people of the Republic of the Marshall Islands resulting from radiation exposures they received during U.S. nuclear weapons testing in the Pacific from 1946– 1958.

• Safer Alternatives to Many Currently Used Chemicals Are Urgently Needed. Many chemists require additional training to understand environmental hazards and reformulate products. Importantly, “green chemistry” alternative products themselves require longitudinal study to ensure that they do not pose unexpected health hazards.

The Panel believes that just as there are many opportunities for harmful environmental exposures, ample opportunities also exist to intervene in, ameliorate, and prevent environmental health hazards. Governments, industry, the academic and medical communities, and individuals all have untapped power to protect the health of current and future generations of Americans and reduce the national burden of cancer.