PhotoCredit:istockThe latest study supposedly linking cell-phone radiation to cancer was meant to serve the public good. But its effect on the public has been bad. The $25 million government-funded experiment produced confusion and scary headlines, but little in the way of useful information -- beyond perhaps an indication of where the science publicity machine is broken.
This wasn't necessarily a case of bad science. The researchers, from the National Toxicology Program, subjected one group of rats to high doses of radiation of a frequency similar to that emitted by cell phones. Following accepted protocol, they compared the radiation-exposed rats to a control group. The pathologists looking for cancer didn't know which animals came from which group.
But last week, the scientists released partial, unpublished results in a rush, suggesting some public health urgency. They claimed to have identified a link between the radiation and a type of brain cancer called a glioma as well as a non-malignant growth called a schwannoma. Adding fuel to their health scare, they offered up sound bites such as "breakthrough" and "game changer."
Only after the first round of scary headlines did critics get a chance to explain why the result was statistically weak, riddled with unanswered questions and somewhat implausible.
It's not clear why scientists are carrying out these studies in the first place. There's no compelling theoretical or empirical reason to suspect that cell-phone use has anything to do with cancer. Otis Brawley, chief medical officer for the American Cancer Society, said investigations of possible links are done because people are interested in the question. That interest, he said goes back to 1990, when Republican political strategist Lee Atwater was diagnosed with a deadly brain tumor at the age of 39. He was dead the next year.
At the time, Brawley said, some people noted that Atwater had been an early adopter of cell phones, though the reality is that brain cancer occasionally strikes all kinds of people with no apparent risk factors. Adding to the shock over Atwater's fate was confusion about the term radiation, which scientists use to describe everything from radio waves to what comes out of a light bulb to the deadly emanations from the Chernobyl nuclear power plant. X-rays and gamma rays do cause cancer by damaging DNA, and ultraviolet light can damage DNA in skin, but lower-energy radiation such as microwaves and radio waves would have to cause cancer some other way.
Brawley said dozens of studies have been done to test the safety of cell phones. The bulk of evidence to date suggests they are safe to use except for their role in car, bike and pedestrian accidents. Despite the explosion of cell-phone use over the last decades, the overall rate of brain cancer has remained flat, he said.
There's some disagreement over whether it's even physically or biologically possible for cell-phone radiation to cause cancer. Chris Adami, a professor of physics and microbiology at Michigan State University, said it's remotely possible that cell-phone radiation could have some biological effect by heating fat and protein molecules, just as a microwave oven uses low-frequency waves to cook food. But there's no known mechanism by which heating would lead to cancer in rats or people, he said, so the researchers should have set a very high bar of evidence before they announced a threat to public health.
Rats tend to get cancer without any help from scientists, he said, so if cell-phone radiation caused these types of cancer, what they'd expect to see is the normal number of cases in the control group and an excess in the one subject to the radiation.
Instead, they got no cases of either cancer in the controls and the normal number of gliomas and schwannomas in the exposed group. The researchers couldn't explain this nor could they explain the curious fact that the control mice died younger than the exposed ones. "If there is an effect you don't understand, then you don't understand the whole system," Adami said.
The study was done by toxicologists. Had it been done by cancer researchers, they would have looked for signs that the radiation was having some relevant biological influence. If there's any effect, it would be on material that surrounds the DNA and influences which genes are activated. There are ways to detect such so-called epigenetic changes, Adami said, but the authors of this study didn't appear to employ them. He said pressure to produce sexy or scary results can motivate scientists to hype marginal findings. He also blames the media for the tendency to assume that every second counts in disseminating health news even when it's of dubious accuracy.
Brawley, of the American Cancer Society, was the one who introduced the term "game changer" to the description of the study. He said that if the claims are backed up, it would be the first time that this kind of low-energy radiation was shown to have any effect on cancer. However, he said, that's a big if, and even in that case it would not necessarily mean that cell phones cause cancer in people.
He suggested that people who are worried can use an earpiece. "But I'm talking to you on a cell phone," he said. "And it's pressed against my ear."