Cellphones and Cancer
What
do brain surgeons know about cellphone safety that the rest of us don’t?
Experts Revive Debate Over Cellphones and Cancer
By TARA PARKER-POPE
Published: June 3, 2008
What do brain surgeons know about cellphone safety that
the rest of us don’t?
Last week, three prominent neurosurgeons told the CNN
interviewer Larry King that they
did not hold cellphones next to their ears. “I think the
safe practice,” said Dr. Keith Black, a surgeon at Cedars-Sinai Medical
Center in Los Angeles, “is to use an earpiece so you keep the microwave
antenna away from your brain.”
Dr. Vini Khurana, an associate professor of
neurosurgery at the Australian National University who is an outspoken
critic of cellphones, said: “I use it on the speaker-phone mode. I do not
hold it to my ear.” And CNN’s chief medical correspondent, Dr. Sanjay Gupta,
a neurosurgeon at Emory University Hospital, said that like Dr. Black he
used an earpiece.
Along with Senator Edward M. Kennedy’s recent diagnosis
of a glioma, a type of tumor that critics have long associated with
cellphone use, the doctors’ remarks have helped reignite a long-simmering
debate about
cellphones and cancer.
That supposed link has been largely dismissed by many
experts, including the American Cancer Society. The theory that cellphones
cause brain tumors “defies credulity,” said Dr. Eugene Flamm, chairman of
neurosurgery at Montefiore Medical Center.
According to the Food and Drug Administration, three
large epidemiology studies since 2000 have shown no harmful effects. CTIA —
the Wireless Association, the leading industry trade group, said in a
statement, “The overwhelming majority of studies that have been published in
scientific journals around the globe show that wireless phones do not pose a
health risk.”
The F.D.A. notes, however, that the average period of
phone use in the studies it cites was about three years, so the research
doesn’t answer questions about long-term exposures. Critics say many studies
are flawed for that reason, and also because they do not distinguish between
casual and heavy use.
Cellphones emit non-ionizing radiation, waves of energy
that are too weak to break chemical bonds or to set off the DNA damage known
to cause cancer. There is no known biological mechanism to explain how
non-ionizing radiation might lead to cancer.
But researchers who have raised concerns say that just
because science can’t explain the mechanism doesn’t mean one doesn’t exist.
Concerns have focused on the heat generated by cellphones and the fact that
the radio frequencies are absorbed mostly by the head and neck. In recent
studies that suggest a risk, the tumors tend to occur on the same side of
the head where the patient typically holds the phone.
Like most research on the subject, the studies are
observational, showing only an association between cellphone use and cancer,
not a causal relationship. The most important of these studies is called
Interphone, a vast research effort in 13 countries, including Canada, Israel
and several in Europe.
Some of the research suggests a link between cellphone
use and three types of tumors: glioma; cancer of the parotid, a salivary
gland near the ear; and acoustic neuroma, a tumor that essentially occurs
where the ear meets the brain. All these cancers are rare, so even if
cellphone use does increase risk, the risk is still very low.
Last year, The American Journal of Epidemiology
published data from Israel finding a 58 percent higher risk of parotid gland
tumors among heavy cellphone users. Also last year, a Swedish analysis of 16
studies in the journal Occupational and Environmental Medicine showed a
doubling of risk for acoustic neuroma and glioma after 10 years of heavy
cellphone use.
“What we’re seeing is suggestions in epidemiological
studies that have looked at people using phones for 10 or more years,” says
Louis Slesin, editor of Microwave News, an industry publication that tracks
the research. “There are some very disconcerting findings that suggest a
problem, although it’s much too early to reach a conclusive view.”
Some doctors say the real concern is not older
cellphone users, who began using phones as adults, but children who are
beginning to use phones today and face a lifetime of exposure.
“More and more kids are using cellphones,” said Dr.
Paul J. Rosch, clinical professor of medicine and psychiatry at New York
Medical College. “They may be much more affected. Their brains are growing
rapidly, and their skulls are thinner.”
For people who are concerned about any possible risk, a
simple solution is to use
a headset. Of course, that option isn’t always
convenient, and some critics have raised worries about wireless devices like
the Bluetooth that essentially place a transmitter in the ear.
The fear is that even if the individual risk of using a
cellphone is low, with three billion users worldwide, even a minuscule risk
would translate into a major public health concern.
“We cannot say with any certainty that cellphones are
either safe or not safe,” Dr. Black said on CNN. “My concern is that with
the widespread use of cellphones, the worst scenario would be that we get
the definitive study 10 years from now, and we find out there is a
correlation.”