Cell Phones Don’t Cause Cancer
Anything’s possible, but the evidence we have so far says there’s no reason to fear cancer from cell phones. Stories on cancer risk from phones endlessly crop up on the Internet with sirens and alarm bells and the debate never seems to be settled one way or the other. If it does turn out to be more truth than clickbait we’ll all need to pay attention, but we’re not there yet.
The current incarnation of the cancer story came up last week in a story on Microwave News leaking preliminary results from a rat study by the National Toxicology Program:
The cell phone cancer controversy will never be the same again.
The U.S. National Toxicology Program (NTP) is expected to issue a public announcement that cell phone radiation presents a cancer risk for humans. The move comes soon after its recently completed study showed statistically significant increases in cancer among rats that had been exposed to GSM or CDMA signals for two-years.
The operative sentence is the first one, because the story is claiming a major breakthrough in the connection between cell phones and cancer that some researchers have been hoping to make for a very long time. NTP studies are respected, so a finding of a significant causal connection in one of its studies would be very, very important.
The NTP study was commissioned by Chris Portier, now retired, and designed by Ron Melnick, also now retired, apparently to shed some light on the classification of cell phones by IARC (International Agency for Research on Cancer, one of the advisors to the World Health Organization) as possible carcinogens. More about that later.
The “game changer” metaphor played in a big role in the first stories based on the Microwave News leak. Mother Jones, the crunchy lefty web site that promotes organic farming and denounces GMOs, was quick on the draw with quotes from Portier:
The findings should be a wake-up call for the scientific establishment, according to Portier, who is now a contributing scientist at the Environmental Defense Fund. “I think this is a game changer,” he said. “We seriously have to look at this issue again in considerable detail.”
Post-publication, Mother Jones toned down the alarmism with quotes from scientists skeptical of the Microwave News story:
Potentially confounding the results, the rats exposed to radiation on average lived longer than those that weren’t. Some outside reviewers argued that the study’s authors should have given more weight to that caveat. Reviewers were also puzzled that the unexposed control rats didn’t exhibit the usual number of brain tumors. “I am unable to accept the authors’ conclusions,” wrote Michael Lauer, the deputy director of the National Institute of Health’s office of extramural research.
So do cell phones cause cancer or do they make us live longer? Hmmm…the leak seems to say yes to both. This is complicated because cancer is primarily a disease of old age, so the longer we live the more cancers we get regardless of all the causal factors.
An uncorrected Wall Street Journal article also sounded the “game changer” alarm with a quote from Melnick:
“Where people were saying there’s no risk, I think this ends that kind of statement,” said Ron Melnick, who ran the NTP project until retiring in 2009 and recently reviewed the study’s results.
The press coverage forced NTP to publish preliminary findings and to pledge to publish full findings by sometime late next year. The NTP prelim includes comments from selected reviewers, which falls a bit short of the blind peer-review we expect from scientific papers. One reviewer is the Dr. Lauer quoted by Mother Jones, and he says (pages 37-38):
Summary: I am unable to accept the authors’ conclusions:
a) We need to know all other findings of these experiments (mice, other tumor types) given the risk of false positive findings and reporting bias. It would be helpful to have a copy of the authors’ statistical code.
b) We need to know whether randomization was employed to assign dams to specific groups (control and intervention).
c) We need to know whether randomization was employed to determine which pups from each litter were chosen for continued participation in the experiment.
d) We need to know whether there was a formal power/sample size calculation performed prior to initiation of the experiment. If not, why not? If yes, we need to see the details. In particular, we need to know whether the authors followed the recommendations of the FDA guidance document (in particular Table 13).
e) I suspect that this experiment is substantially underpowered and that the few positive results found reflect false positive findings. The higher survival with RFR, along with the prior epidemiological literature, leaves me even more skeptical of the authors’ claims.
So maybe it’s not all that.
Reviewer Diana Copeland Haines, DVM raises concerns about the exposure level, which was considerably higher than the level humans would experience from cell phones in real-world conditions (page 34):
There may be also several caveats relating to “under the conditions of these studies”, including how well the conditions recapitulate actual human exposure: whole body exposure from in utero to old age; 18.5 hours/day (10 min on/10 min off, for total of 9hr actual exposure); and dose. I’m not a physicist, so have to presume experts analyzed and accepted concept of the reverberation chamber, including “doses” as being relevant to human exposure.
Reviewer Maxwell P. Lee, Ph.D., Laboratory of Cancer Biology and Genetics, NCI, had issues with the study design (page 53):
Increased incidence of heart schwannomas in male rats exposed to GSM-or CDMA-modulated RFR is statistically significant by the chi-square trend test. The evidence is better for CDMA exposure than GSM exposure. I think additional experiments are needed to assess if the incidence of brain gliomas in male rats exposed to GSM- or CDMA-modulated RFR is significantly higher than the control group or not.
In other words, he checked the numbers and didn’t find significant evidence of brain tumors (gliomas) over the false-positive level dictated by the control group size, but he did find a suspicious connection between heart tumors (schwannomas) in the male rates exposed to CDMA. (Note: the study attempted to simulate 2G phones using GSM or CDMA, but not 3G or 4G.) Lee also found some errors in the study’s math, not surprising since it’s not done yet.
Similarly, other reviewers from NCI accepted the connection between heart lesions in male rats and RF energy as potentially significant, but not much else.
The most thorough review of the NTP study and the reporting on it comes from David Gorski’s Science-Based Medicine blog. I’ve been reading Gorski for ten years or more, so I’m inclined to trust him because I’ve never seen him proved wrong even though he’s been attacked for his examination of subjects such as evolution, the HIV/AIDS connection, and just about everything else anti-science crusaders don’t like. If your interest in this is really deep, you’ll be well-advised to read his entire post. Here’ the key paragraph:
I become even more skeptical by taking a Bayesian approach to the analysis and considering the very low prior probability of a positive result based on what we know about biology coupled with the multiple outcomes examined. Taking these issues into account, I agree with Lauer that the results reported are almost certainly due to chance and are not indicative of a real biological effect. There are just so many red flags in the study that should have told journalists that there’s a lot less there than meets the eye. I could tell this, and I’m not even a statistician.
The New York Times, to its credit, didn’t jump on the clickbait train and published a reasonable story instead, Questions and Answers on the New Study Linking Cellphones and Cancer in Rats:
Do cellphones cause cancer? Most health authorities do not think so, but a new federal study could reignite the controversy over this issue.
The preliminary study, released Friday, found that radiation from cellphones appears to have increased the risks that male rats developed tumors in their brains and hearts. But there are many caveats and some experts are debunking the study…
Many studies have been conducted, including some very large ones like the Million Women Study in Britain, and a Danish study of more than 350,000 cellphone users. There also were studies examining the effects of these radio waves in animals and cells growing in petri dishes. The results are reassuring. There is no convincing evidence of any link between cellphone use and cancer or any other disease.
Also, the incidence of brain cancer in the United States has remained steady since 1992, despite the stark increase in cellphone use.
In fact, the brain cancer rate was a little higher in 1992 than it is today, despite the rapid adoption of smart phones.
So what about Chris Portier? He commissioned the NTP study before leaving government service, but he’s still very much a player in science policy. Portier was a science consultant to a recent IARC panel on the carcinogenicity of the weed-killer glyphosate (active ingredient in Monsanto’s Roundup.) Eyebrows were raised about Portier’s involvement because he’s not a credentialed toxicologist and has a colorful history, as documented in the Risk-Monger blog from Europe:
The media have seemed to overlook the presence of an environmental activist at the centre of an anti-pesticide decision from an international scientific body. Perhaps it is just too easy to use the IARC study to bash Monsanto than to do some research and objective analysis.
Mr Portier is an activist for the Environmental Defense Fund (EDF), an American campaign organisation that has long been campaigning to deny farmers the means to protect their crops. EDF was founded on anti-pesticides campaigns and claims credit for banning DDT in the 1960s (and the millions of victims of malaria that ban has caused).
Portier himself is no wallflower on the Monsanto hate-scene, listing, among his achievements, research on the health effects in Vietnam from the use of Agent Orange. He recently wrote an article condemning Elsevier for retracting the controversial Séralini activist science article on Roundup and GM maize. Having Portier as the technical specialist involved in the working group deciding the carcinogenic fate of a main chemical in Roundup is like leaving a rat in charge of the cheese factory.
I think this says that some people are inclined to see cancer everywhere. IARC reports to WHO, and WHO essentially vacated Portier’s IARC report when it recently declared Roundup is not a likely carcinogen in a report co-authored with the UN’s Food and Agriculture Organisation. As the Guardian reports:
Glyphosate, the key ingredient in Monsanto’s Roundup weedkiller brand, has been given a clean bill of health by the UN’s joint meeting on pesticides residues (JMPR), two days before a crunch EU vote on whether to relicense it.
The co-analysis by the UN’s Food and Agriculture Organisation (FAO) and World Health Organisation found that the chemical was “unlikely to pose a carcinogenic risk to humans from exposure through the diet”.
This finding flatly contradicts an assessment by the WHO’s cancer agency last year that the herbicide solution was “probably carcinogenic to humans”.
So here’s a prediction: Just as the WHO and UN FAO contradicted Portier’s assertion (shared aggressively with the press) that glyphosate causes cancer, the NTP will take a closer look at the experimental design, control group, statistics, and exposure level in the cell phone research and say it needs to do a further study. In the meantime, enjoy your phone because it’s more likely to save your life than to take it away.