Sept. 12, 2002 -- Older-model analog phones -- predecessors of today's digital phones -- may be cancer-promoters, a new study shows.
It's stirred the debate once again. Public health officials point to several large studies showing that cell phones of any vintage are benign ear ornaments. Yet others in the industry say the current study from Sweden warrants more research.
The researchers looked at 1,617 patients with brain tumors and compared them with a similar-sized group of people without tumors. Those who used a type of analog phone found in Sweden -- Nordic Mobile telephones -- were 30% more likely to have brain tumors, reports oncologist Lennart Hardell, MD. His study appears in the August issue of the European Journal of Cancer Prevention.
The tumors were typically on the side of the head that the phone touched, says Hardell. Those who used the phones longer than 10 years were 80% more likely to develop tumors.
There's plenty of evidence to the contrary, says John Boice, PhD, scientific director of the International Epidemiology Institute in Rockville, Md. He reviewed the study for WebMD.
A number of studies in the U.S., some by the National Cancer Institute (NCI) and American Health Foundation, dealt only with analog phones and found "absolutely no association with brain tumors," tells WebMD.
The Swedish study is "poorly designed," he says, since it only involves people who survived their brain cancer -- thereby leaving out half the patient population. And it relies on answers from questionnaires, which are typically unreliable.
Also, the study shows a link only with a type of small, benign tumor called acoustic neuroma, says Boice, who is also professor of medicine at Vanderbilt University in Nashville, Tenn. "It's not 'brain cancer,'" he tells WebMD.
Boice published his own study of digital cell phones last year. That study looked at nearly half a million cellular telephone subscribers in Denmark. "We found no association with tumors," he tells WebMD.
Studies published by the NCI in The New England Journal of Medicine and The Journal of the American Medical Association were "very large, well conducted, sound studies," says Boice. "Patients came into the hospital diagnosed with brain tumors and were interviewed regarding their use of cellular telephones" -- a more reliable data-gathering method. The findings: "no association with brain cancer."
In the last month, a study from Australia looked at mice genetically engineered to be prone to developing a type of cancer called lymphoma. In that study, published in the journal Radiation, mice were exposed up to two years to microwave radio frequencies similar to those from a cellular phone. "They were not able find genetic damage," says Boice. "But this study, like the earlier studies, needs to be replicated. You haven't shown anything until you can replicate it."
That's the problem with studies that have found links with brain cancer -- researchers haven't been able to replicate the findings, he says.
Not everyone is convinced that cell phones are benign.
"Clearly, there is something to [the Swedish study], says Louis Slesin, editor of Microwave News. "What I find intriguing is that some of the risks go up with number of years of use. That tells you there is something to look at. After 10 years, the risk goes up from 30% to 80%, and that is certainly significant."
Slesin admits that cell phone radio waves are too weak to cause DNA damage. "No one argues that. But what is being suggested -- which is as important -- is that it modulates the repair of DNA as well as the break. It can cause breaks and it can hinder repairs. It's not black and white. It's not that simple."
"I don't want to discount the need for research. It's something we should be evaluating," Boice says. "There is a public concern, and we're going to look at it as carefully as possible. This is not the end. But when you take the totality of scientific evidence today, it's such that cellular telephones are not the cause of cancer."
"You can't look at one study and draw any conclusions," says Jo-Ann Basile, spokeswoman for the Cellular Telecommunications Industry Association. "Public health officials look at all the science when they make their assessments. And the judgment of public health agencies and scientific bodies around the world -- as they look at science to date -- is that there are no adverse health effects from cell phones."