"No Link Between Cell Phone Use and Brain Cancer" - Article

A number of the world's nations now have more cell phones (also referred to as mobile phones or cellular
phones) than they have fixed or land phones. Numbers are increasing fast, all over the world, and there has
been growing concern about the risk of developing brain cancer from radiofrequency signals given off by
handheld cellular phones.
Cell phones are low-power radio devices. They transmit and receive electromagnetic radiation at
frequencies of about 1000 MHz, just above the ultrahigh-frequency (UHF) television portion and just
below the microwave part of the electromagnetic spectrum. These three frequency ranges are within the
radio-frequency zone of that spectrum.
Cell phones operate at a lower power (less than 1 watt) than police or other emergency-communication
devices. Cordless telephones, which have a base unit that is wired to a conventional telephone service,
operate at a lower frequency and power than cellular telephones; they cannot be classified as a type of cell
phone.
In spite of the low power, there have been a number of claims that cell phones cause cancer, but these
appear to fit the standard logical fallacy known as post hoc, ergo propter hoc, Latin for "it happened after
this event, so it was caused by this event". So how do we assess this properly?
There are a number of solutions. We can look at the incidence of suspect cancers in users and non-users
of cell phones, but then we find a problem: the financially well-off are more likely to own a cell phone, and
it may be that some other factor is causing any observed difference. We can try to assess the exposures
people get, and see if that ties in with cancer frequencies.
The exposure users get to radio-frequency radiation from a cellular telephone depends on the power of
the signal the device transmits. Weak signals from the base station cause the cellular telephone to increase
the power of the signal it sends back. For this reason, the power level increases with the distance of the
telephone from the base station and when the connection between the base station and the cellular
telephone is obstructed by buildings, hills, and other barriers, more distant users might be expected to have
more cancers, if the radiation does have any causal effect.
With the world's first lawsuit for damages being launched in the US in December 2000, what are the risks
for the more than 86 million American cellular phone users reported in 1999 - or for the telephone
companies? While the behavior of US courts can never be predicted, any finding for the plaintiff would
seem remote, given the scientific evidence available.
A case-control study of 891 people who regularly used a cellular phone appeared in the December 20
issue of the Journal of the American Medical Association. This showed no statistical association between
the amount of cell phone usage and the likelihood of developing brain cancer.
Joshua Muscat from the Division of Epidemiology of the American Health Foundation and the study's first
author commented in these terms: "The recent phenomenon of widespread use of cellular phones had been
a suspected risk factor for the development of brain cancer and needed to be clarified by a study. The data
showed no correlation between the use of cell phones and the development of brain cancer. In addition,
there was no association between the amount of cell phone usage and brain cancer."
In a retrospective, case-control study, 469 men and women diagnosed with primary brain cancer and 422
people without brain cancer were interviewed between 1994 and 1998 using a structured questionairre.
They were asked which type of cell phone (manufacturer) they used, the usage per month in minutes and
hours, the year of first use, and the number of years of usage. In addition, an estimated monthly phone bill
was ascertained. The patients, aged 18 to 80, were scrupulously matched to the control group by age, sex,
race, years of education, and occupation.
There was a slight increase in usage for cancer patients over the control group, but this was not
statistically significant. The median monthly use was 2.5 hours for cases with cancer and 2.2 hours for the
control. The mean duration of use was 2.8 years for brain cancer patients and 2.7 years for the controls.
What was significant was the location of the tumors. Mark Malkin, a neuro-oncologist at Memorial
Sloan-Kettering Cancer Center and study co-author explained one of the study's key findings: "Because 85
per cent of people in the study reported extending the antenna during calls, we might have expected to find
a disproportionate cluster of tumors behind the eye and the ear on the side the cell phone was used since
radiation emission is highest at the antenna. In fact we found no link between cell phone usage and
temporal lobe tumors, nor was there any association between handedness and tumor location."
Of course, nobody is prepared to rule out any risk entirely, and so we get the following cautious
statement: "Based on all available data including studies by other groups, the researchers believe that
extended use of cellular phones does not appear to cause brain cancer. However, further research is
indicated as this study covers people who have mostly used analog cellular phones for a relatively short
period of time (two to three years). As people continue to use cell phones for extended durations, the
long-term health effects, if any, need to be monitored."
The New England Journal of Medicine for January 11 reports a case-control study of intracranial tumors
of the nervous system conducted between 1994 and 1998 which indicates no sign of any risk. The
researchers enrolled 782 patients through hospitals in Phoenix, Boston and Pittsburgh; 489 had
histologically confirmed glioma, 197 had meningioma, and 96 had acoustic neuroma. The 799 controls
were patients admitted to the same hospitals as the patients with brain tumors for a variety of nonmalignant
conditions.
They found that there was no evidence that the risks were higher among persons who used cellular
telephones for 60 or more minutes per day, or regularly for five or more years, and significantly, tumors did
not occur disproportionately often on the side of head on which the telephone was typically used.
Once again, though, the researchers are cautious: "These data do not support the hypothesis that the
recent use of hand-held cellular telephones causes brain tumors, but they are not sufficient to evaluate the
risks among long-term, heavy users and for potentially long induction periods."
An editorial in the same issue of the New England Journal of Medicine notes that the energy emitted by
cellular telephones produces minimal local heating in the brain (about 0.1°C), and that this small
temperature increase is suspected by some of being at the base of the problem. Electromagnetic radiation at
certain radio frequencies has been reported to cause sleep disturbances, headaches, and
electroencephalographic changes, says the editorial, pointing to the opinions held by some " . . . scientists,
especially in Russia . . . that even microwave radiation that is too weak to cause detectable heating might
still pose a risk."
The concern about the possibility of cell phone-generated cancers, says the New England Journal of
Medicine, arises from anecdotal reports that frequent users of cellular telephones have happened to die
from brain tumors. And that, probably, is the key issue: two major studies have failed to find a link,
suggesting that the risk, if it exists, is weak, though the editorial observes that more, larger-scale studies are
probably needed.
"This study allays fears raised by alarmist reports that the use of cellular telephones causes brain tumors.
Of course, we do not have the final word on this question, and the results of future investigations may
modify our perspective. Nevertheless, we believe that it is highly unlikely that the use of cellular telephones
substantially increases the risk of brain tumors. The lack of empirical evidence of the carcinogenicity of radiation at the radio frequencies used by cellular telephones and the absence of a theoretical basis for
nonthermal effects at these frequencies suggest that cellular telephones do not pose a risk of cancer."
So should we always ignore the doom-sayers? No, says the editorial, because when the real or presumed
risk involves communicable agents, such as the prions that cause BSE (mad cow disease), no precaution,
however extreme, can be considered excessive, and we have to cover all the possibilities. On the other
hand, say the editorial writers, when noncommunicable agents, such as radio-frequency energy stand
accused, slightly different rules should apply. "[T]he lack of a theoretical foundation and the absence of
empirical evidence of a substantial increase in risk legitimize cautious inaction, unless and until a small
excess risk is firmly documented," they conclude.
All of which must be bad news for lawyers, the makers of hands-free kits for cell phones, and the
inventors of new low-power and directional antennas for cell phones. On the other hand, the ruckus that
continues to be raised may inspire the telephone suppliers to add more towers to their systems, to lower the
output, just in case. With luck, the line "you seem to be breaking up" may become a thing of the past.