Researchers downplay cellphone-cancer link
Cellphones could possibly be linked to cancer, according to a report from the World Health Organization’s (WHO) that was released last week. Yet researchers at the H. Lee Moffitt Cancer Center and the USF College of Medicine say cellphones should not be abandoned quite yet.
Radiofrequency electromagnetic fields, which cell phones emit, were classified as “possibly carcinogenic” to humans after 31 scientists from 14 countries attended WHO’s series of May International Agency for Research and Cancer (IARC) meetings in Lyon, France. According to their report the group’s chairman, Jonathan Samet of the University of Southern California said, “The conclusion means that there could be some risk, and therefore we need to keep a close watch for a link between cellphones and cancer.”
Cellphones join chloroform, DDT, coffee, lead, diesel fuel and gasoline in the IARC’s list of 266 possible carcinogens, yet Edward Pan, a neuro-oncologist at H. Lee Moffitt Cancer Center and Research Institute, said he has not seen enough evidence to suggest a correlation between cancer and cellular phone usage.
“(Of) the studies that have been coming out, nothing has been so definitive to cause us to modify what we are doing or modify us to change how we (use cellphones),” Pan said. “If you do prove a link you have to be able to define what is the threshold, how much exposure from electromagnetic radiation is necessary to cause (cancer).”
Pan, who said he will continue to use a cellphone regularly, said such a study would require subjects to be monitored accurately over a period of years, rather than rely on the subjects to recall how often they use their cellphones like in the WHO study. He said he doubts limited exposure to cellphone radiation would be risk for glioma, a rare malignant type of brain tumor, as the study suggests.
“It would be very hard to convince me if a person uses a cellphone one hour a week, which is very low, that they’re going to be at risk of developing glioma. I would find that very, very hard to believe,” he said. “If we’re talking heavy cellphone usage, people are on it for, I don’t know, six hours a day every single day. Or, we’re talking about young children using it constantly, then OK, if someday they show some sort of correlation, maybe that’s more believable. It is not only if there is a link or not, but how much do you need to talk to get that risk (for cancer). It will be years before we get the answers to that.”
According to the Cellular Telecommunications Industry Association, the estimated number of wireless subscriptions in the U.S. is 302.9 million. An estimated 27.23 percent of Floridians 18 or older live in wireless-only households, according to estimates published in April by the Centers for Disease Control and Prevention. Comparatively, an estimated 10.9 percent of Floridians live in landline-only households.
The IARC group involved in the classification discussed and evaluated existing peer-reviewed scientific literature to arrive at their conclusion, according to the report. One such study the IARC used showed a 40 percent increase of risk for gliomas in subjects who use their cellphones at least 30 minutes per day over a 10-year period. According to the Moffitt website, glioma account for 60 percent of primary brain tumors and 17,000 patients in the U.S. are affected by primary brain tumors each year.
Chuanhai Cao, an assistant professor in USF’s College of Medicine, said he finds himself on the opposite end of the cellphone debate. While the WHO has classified cellphones as a possible carcinogen, Cao’s research into mice bred to develop Alzheimer’s shows a reduction or reversal of Alzheimer’s symptoms after exposure to radiofrequency fields emitted by cell phones.
Cao said the scientific community is oversaturated with “junk” studies.
“People like to play the game, particularly in the science field,” he said. “Science and nature, all this hype is weekly-based, every week they publish one issue. How much really is useful? They discover that stuff, they report that, but maybe a few years later people won’t even know that about that and it becomes junk.”
The IARC admitted that their evidence was limited among users of wireless telephones for glioma and acoustic neuroma. It is inadequate to draw conclusions for other types of cancers. In the report, IARC director Christopher Wild said it is important their findings be followed by additional research.
“Given the potential consequences for public health of this classification and findings,” Wild said in the IARC report, “it is important that additional research be conducted into the long-term, heavy use of mobile phones. Pending the availability of such information, it is important to take pragmatic measures to reduce exposure such as hands-free devices or texting.”
In the meantime, Pan said cellphone users can play it safe if they like.
“I would say if people want to use more Bluetooth or use more speakerphone, that’s fine, nothing wrong with that,” he said. “If they want to limit the usage for children, just in case one day in the future there is such a link, fine, nothing wrong with that either.”