The New York Times has an interesting article on the current conventional wisdom within the scientific communityt on pollution's relative role (or lack thereof) in U.S. cancer rates. Contrary to some claims, there is little evidence that pollution and exposure to toxic chemicals are significant contributors to cancer rates.
pinning cancer on trace levels of poisons in the environment or even in the workplace is turning out to be a vexing task. There has been recent progress in addressing the issue, but the answers that many people believe must be out there remain elusive.In 1993 the National Institute of Environmental Health Sciences and the Environmental Protection Agency began a major study of chemical exposures and cancer rates of 55,000 farmers and their spouses in Iowa and North Carolina. Farmers are a good group to study because they are regularly exposed to pesticides. Thus far, the study has yet to find any "definitive" connections, just what one researcher calls "interesting leads." Overall, cancer data show no evidence of a "cancer epidemic" brought about by industrial pollution.
"It's an area where there's certainly been a lot of heat and not a lot of light for some time," said Robert Hoover, director of the epidemiology and biostatistics program at the National Cancer Institute. For the most part, Dr. Hoover said, "we are down to speculations based on some data but without having the information we need."
Rates of cancer have been steadily dropping for 50 years, if tobacco-related cancers are taken out of the equation, said Prof. Richard Peto, an epidemiologist and a biostatistician at Oxford University.The story does contain some contrary views -- but not from scientists. Rather, various activists and cancer survivors are quoted on their beliefs about the causes of cancer.
What appear as increases in cancers of the breast and prostate, Dr. Peto added, are in fact artifacts of increased screening. When healthy people are screened, the tests find not only cancers that would be deadly if untreated, but also a certain percentage of tumors that would never cause problems if let alone.
His analysis of cancer statistics leads Dr. Peto to this firm conclusion: "Pollution is not a major determinant of U.S. cancer rates."