Overall cancer rates and deaths have declined in the United States. Nevertheless, about 41 percent of all Americans still will be diagnosed with cancer during their lifetime, and about 21 percent will die from it, according to the National Cancer Institute’s SEER Cancer Statistics Review. In 2009 alone, about 1.5 million new cases were diagnosed.
For the past 30 years, federal agencies and institutes have estimated that environmental pollutants cause about 2 percent of all cancers and that occupational exposures may cause 4 percent.
Patients who have a chest CT scan receive a dose of radiation in the same range as survivors of the Hiroshima atomic bomb attacks who were less than half a mile from ground zero. The panel called those estimates ”woefully out of date.” The panel criticized regulators for using them to set environmental regulations and lambasted the chemical industry for using them “to justify its claims that specific products pose little or no cancer risk.”
But Thun of the American Cancer Society said that conclusion “does not represent scientific consensus. Rather, it reflects one side of a scientific debate that has continued for almost 30 years.” [Editor’s Note: added May 7, 2010]
The report does not try to estimate environmentally induced cancers but said the old estimates, dating back to 1981, fail to take into account many newer discoveries about people’s vulnerability to chemicals. Many chemicals interact with each other, intensifying the effect, and some people have a genetic makeup or early life exposure that makes them susceptible to environmental contaminants.
“It is not known exactly what percentage of all cancers either are initiated or promoted by an environmental trigger,” the panel said in its report. “Some exposures to an environmental hazard occur as a single acute episode, but most often, individual or multiple harmful exposures take place over a period of weeks, months, year, or a lifetime.”
Boston University’s Clapp was one of the experts who spoke to the panel in 2008. ”We know enough now to act in ways that we have not done…Act on what we know,” he told them.
“There are lots of places where we can move forward here. Lots of things we can act on now,” such as military base cleanups and reducing use of CT scans, Clapp said in an interview.
Dr. Ted Schettler, director of the Science and Environmental Health Network, called the report an “integrated and comprehensive critique.” He was glad that the panel underscored that regulatory agencies should reduce exposures even when absolute proof of harm was unavailable.
Scientists are divided on whether there is a link between cell phones and cancer.
Also, “they recognized that exposures happen in mixtures, not in isolation” and that children are most vulnerable.
“Some people are disproportionately exposed and disproportionately vulnerable,” said Schettler, whose group was founded by environmental groups to urge the use of science to address public health issues related to the environment.
Schettler said it “took courage” for the panel to warn physicians about the cancer risk posed by CT scans, particularly for young children.
“It’s almost become routine for kids with abdominal pain to get a CT scan” to check for appendicitis, he said. Although the scans may lead to fewer unnecessary surgeries, doctors should consider the high doses of radiation. “I’m very glad this panel took that on,” Schettler said.
Another sensitive issue raised in the report was the risk of brain cancer from cell phones. Scientists are divided on whether there is a link.
Until more research is conducted, the panel recommended that people reduce their usage by making fewer and shorter calls, using hands-free devices so that the phone is not against the head and refraining from keeping a phone on a belt or in a pocket.
Even if cell phones raise the risk of cancer slightly, so many people are exposed that “it could be a large public health burden,” Schettler said.
The panel listed a variety of carcinogenic compounds that many people routinely encounter. Included are benzene and other petroleum-based pollutants in vehicle exhaust, arsenic in water supplies, chromium from plating companies, formaldehyde in kitchen cabinets and other plywood, bisphenol A in plastics and canned foods, tetrachloroethylene at dry cleaners, PCBs in fish and other foods and various pesticides.