In recent days study assuring and claiming to prove that mobile phones cannot cause brain cancer has been making headlines around the world. The study in question is by Frank de Vocht, Igor Burstyn, and John W Cherrie, entitled “Time Trends (1998-2007) in Brain Cancer Incidence Rates in Relation to Mobile Phone Use in England” and was published on-line (28 JAN 2011, DOI: 10.1002/bem.20648) in the journal Bioelectromagnetics.
In the abstract and the conclusions the authors state that:
in abstract –
“…The observed increase in the rate of cancers in the temporal lobe, if caused by mobile phone use, would constitute <1 additional case per 100,000 people in that period. These data do not indicate a pressing need to implement a precautionary principle by means of population-wide interventions to reduce RF exposure from mobile phones…”
in conclusions –
“…We cannot exclude the possibility that there are persons who are susceptible or some rare brain cancers are associated with RF from mobile phones…” and “…However, we interpret the present data as not indicating a pressing need to implement a precautionary principle to reduce exposure to RF from mobile phones by means of population-wide interventions…”.
Indeed, as also I have previously written in this science blog(
), when assuming that the numbers presented in the INTERPHONE study are correct, the potential increase of the individual risk of having brain cancer due to RF exposures is low but, I stressed, that the consequences for the society might be much greater. Of course there are numerous complaints about the reliability of INTERPHONE’s conclusions, but my calculations were hypothetical, assuming that the numbers might be correct.
Here, the increase of 1 case of brain cancer/100000 shown in the de Vocht et al. study can indeed be considered as low risk for individual user. However, for the society it might be not exactly so. If we consider de Vocht et al. numbers as correct and we take into account total number of mobile phone users that is ca. 4,5 billon then this 1/100000 risk of new brain cancer cases translates into 45000 new brain cancer cases globally. It can be considered as much, especially when we add the societal consequences as not only the costs of treatment of cases but also loss of productivity of the whole affected families as well as costs that can not be measured with money.
The American Cancer Society’s most recent estimates for brain and spinal cord tumors in the United States are for 2010 (
- About 22,020 malignant tumors of the brain or spinal cord (11,980 in males and 10,040 in females) will be diagnosed. These numbers would likely be much higher if benign tumors were also included.
- About 13,140 people (7,420 males and 5,720 females) will die from these tumors.
- Both adults and children are included in these statistics.
These numbers is possible to compare with the 45000 of new cases globally (or 3000 new cases in USA only; estimate based on 300 millon users) that will appear according to de Vocht et al. These are large numbers. Also, the new cancer cases will not be distributed evenly around the world and the treatment received by “the cases” will also differ. Though, I would not go as far as some, calling that the “epidemic” is close…
Many of these potential cases might be prevented by simple measures of precaution, even if not calling for precautionary principle, against which de Vocht et al. are advising. We do not know what the causes of the brain cancer are and we do not know what is the latency period that is often referred as “tens of years”. In such context, the period of time analyzed in the study is insufficient to claim that the RF will not have effect. May be yes or may be not, but the data used for the conclusions in de Vocht et al study are insufficient to support their claim. At that time, and before that period where from the data were collected, much fewer users used for much shorter time cell phones. It means that much fewer were heavily exposed and for a long time (over 10 years) and much, much, fewer would then have potential chance to develop cancer. So, because of the latency period the study has no sufficient chance to detect effect, if such effect exists. Therefore, it seems like the conclusions of the study are unfortunately not supported by the data.
In their conclusions, calling for no-precautions, de Vocht et al. go further then the considered as “conservative” in its opinions American Cancer Society. (
) (bold emphasis by DL):
Cell phone use: This has been the subject of a great deal of debate in recent years. Cell phones give off (emit) radiofrequency (RF) radiation, a form of energy on the electromagnetic spectrum between FM radio waves and those used in microwave ovens, radar, and satellite stations. Cell phones do not emit ionizing radiation, the type that damages DNA and is known to have the ability to cause cancer. Still, there have been concerns that the phones, whose antennae are built-in and therefore are placed close to head when in use, might somehow raise the risk of brain tumors.
Some early population-based studies suggested a possible increased risk with cell phone use, but most of the larger studies done to date have not found an increased risk of brain tumors, either overall or among specific types of tumors. Still, there are very few studies of long-term use (10 years or more), and cell phones haven’t been around long enough to determine the possible risks of lifetime use. The same is true of any possible higher risks in children, who are increasingly using these phones. Cell phone technology also continues to change, and it’s not clear how this might affect any risk.
Studies are under way to help assess these risks, but it will likely be many years before firm conclusions can be made. In the meantime, for people concerned about the possible risks there are ways to lower exposure, such as using an earpiece to move the phone itself away from the head when in use.”.
It means that the ACS, correctly, leaves the “door open”. We do not know yet enough, phones were not long enough around to make final claims. And this is the correct science based approach.
At the same time de Vocht et al. state (or rather speculate) in the text of the article that:
“…the lack of a plausible biological mechanism by which RF exposure could be genotoxic suggests that if an association exists, RF exposure is more likely to have a promotion or progression effect on tumor growth and an average latency time of 5–10 years is therefore more plausible…”.
Why so? If the tumors are induced by other factors than RF then, the RF exposure would, according to de Vocht et al., only speed up their appearance but would not increase their frequency… It means that the cases will appear earlier but not in higher numbers.
Furthermore, yet again, the lack of mechanism to explain phenomenon is considered by de Vocht et al. as good cause to dismiss possibility of the potential existence of the phenomenon. It is not scientifically valid approach. Let us remember that we do not know causes and mechanisms of many phenomena but they exist, among them the brain cancer… Finally, it is the “shortened” latency period by the authors that is used as the argument to support the correctness of their findings. But is this assumption of 5-10 years latency time correct? The basis for such claim is that the RF does not cause genotoxic effects. Yes, it can not break DNA directly because of too low energy. But could it affect DNA integrity via other mechanisms, like free radicals or reactive oxygen species? May be but still nobody knows for sure. However, outright dismissing this possibility at this stage of the knowledge is incorrect because it is not yet supported by the scientific data.
Finally, it is somewhat surprising that statements about no need for any precaution passed through peer review. However, we have to remember that the peer-review is not a perfect tool to gauge the quality of the paper. It can be influenced by the editors ahead of time – reviews can and often depend on the views of reviewers on the matter in question.
And let us remember that also WHO and ICNIRP advise precaution, not to mention many national organizations…
The overstatements by the scientists that are not supported by the data is one of the reasons why this research area has credibility problems. If journalist writes something and over blows some issues then we, scientists, can not do much about it. That is called freedom of the press. But if we, scientists, ourselves over blow our conclusions and they are not supported by the scientific evidence then it is our “fault” that alarmist headlines (either claiming that imminent epidemic of brain cancer approaches or claiming that there is no risk at all) appear in news media. As a consequence the general public and decision makers alike are at least confused and stop paying attention…
The problem of interaction between scientists and news media journalists is a serious problem. To discuss it I have organized a session at the forthcoming meeting of the Bioelectromagnetics Society in Halifax, Canada, June 12-17, 2011. Welcome!
June 13, 2011 (Monday)
Plenary Tutorial Session: Science and News Media
Chair: D. Leszczynski; Co-Chair: A. Wood
16:30 – 17:00 – B. Stutz – Media interpretations of science
17:00 – 17:30 – J. Loukissas – Guidelines for scientists to inform the media
17:30 – 18:00 – D. Leszczynski – EMF scientist’s interaction with the media
18:00 – 18:30 – moderated panel discussion between the audience and the speakers (moderator: A. Wood)