A new book, "Misconceptions About the Causes of Cancer," released by The Fraser Institute and written by leading scientists at the University of California at Berkeley, examines the scientific evidence from studies in humans; animal cancer tests; exposures to naturally occurring and synthetic chemicals; and methods used to evaluate and regulate cancer risks.
The authors highlight what they perceive to be nine misconceptions about pollution, pesticides, and the causes and prevalence of cancer, and show that:
- Cancer rates are not soaring in either Canada or the United States.
- Synthetic chemicals at levels found in the environment have not been shown to be an important cause of cancer.
- Reducing pesticide residues is not an effective way to prevent cancer.
- Potential cancer hazards are not primarily the result of human exposures to synthetic chemicals.
- The toxicology of the synthetic chemicals is not different from that of natural chemicals that make up 99.99 percent of chemical exposure.
- High dose animal cancer tests do not provide enough information to assess human cancer risks at the usual levels of exposure.
- Pesticides and other synthetic chemicals at levels found in the environment are not likely to be significant in disrupting human hormones.
- The current regulatory policy of low, hypothetical risks is not effective in advancing public health.
The authors observed that overall cancer death rates in Canada (excluding lung cancer due to smoking) have declined 17 percent in women and 5 percent in men since 1971. If lung cancer is included, current cancer mortality rates are similar to those in 1972. In the United States, the decline is similar: overall cancer death rates (excluding lung cancer) have declined 19 percent since 1950.
For some cancers, mortality rates have begun to decline due in part to early detection, treatment and improved survival. This is clearly the case with breast cancer in women. The types of cancer where death rates have increased are often linked to specific lifestyle choices such as smoking, sun-exposure and dietary habits.
Because cancer is due, in part, to normal aging and increases exponentially with age, the proportion of cancer caused by normal metabolic processes will increase with an aging population regardless of exposures to normal levels of synthetic industrial chemicals in the environment.
"The ever-longer life expectancies, and ever-healthier lives enjoyed by people in developed countries is evidence that technological development and economic freedom are wellsprings of health and safety. Yet the constant drumbeat of alarmism about risk blurs people's understanding; denies them the ability to make lifestyle choices that would best reduce their personal risk; and leads them to support poor allocation of scarce public health resources," commented Ken Green, chief scientist and director of the Risk and Environment Policy Centre at The Fraser Institute says,
The authors point out that policy based on what they call a "distorted understanding" of risk "squanders the limited resources that any society can devote to securing safety and environmental quality for its citizens." If the public assimilates misinformation about the causes of cancer, their inclination will be to support public policy that is itself distorted, investing scarce resources poorly by focusing on small, uncertain, risks rather than focusing on larger, more certain risks.
"The prevention of cancer will come from knowledge obtained from biomedical research, better education of the public, and lifestyle changes made by individuals. A re-examination of priorities in both research investment and regulatory focus regarding cancer prevention, both public and private, seems called for," conclude the authors, who include:
- Lois Swirsky Gold, director of the Carcinogenic Potency Project and a senior scientist at the University of California, Berkeley and Lawrence Berkeley National Laboratory.
- Thomas B. Slone, a scientist on the Carcinogenic Potency Project at the University of California, Berkeley, and Lawrence Berkeley National Laboratory for 17 years.
- Neela B. Manley, a scientist on the Carcinogenic Potency Project at the University of California, Berkeley, and Lawrence Berkeley National Laboratory for 13 years.
- Bruce N. Ames, a professor of Biochemistry and Molecular Biology at the University of California, Berkeley, and a senior scientist at Children's Hospital Oakland Research Institute.
Established in 1974, The Fraser Institute is an independent public policy organization based in Vancouver, with offices in Calgary and Toronto.
The book can be viewed as a PDF at www.fraserinstitute.ca.