HELSINKI, March 14, 2012—On March 8, 2012 the US National Cancer Institute published a study dealing with the risk of glioma (a type of brain cancer) and cell phone radiation.
This study should have made headlines around the world similar to those made by the last year’s IARC classification of cell phone radiation as a possible carcinogen. But it did not. One must wonder: why?
When IARC classified cell phone radiation as a possible carcinogen in 2011, I commented in my science blog that it was:
“Big news because for the first time a very prominent evaluation report states it so openly and clearly: RF-EMF is possibly carcinogenic to humans. One has to remember that IARC monographs are considered as “gold standard” in evaluation of carcinogenicity of physical and chemical agents. If IARC says it so clearly then there must be sufficient scientific reason for it, or IARC would not put its reputation behind such claim. Furthermore, what we are used to, are statements that “so-and-so-many-review-
Similarly, the new study from the NCI should be considered big news, because for the first time scientists found that the prediction from the epidemiological study indicating that cell phone radiation might cause an increase in brain cancer has found confirmation in the study that followed the brain cancer trends.
It is BIG NEWS indeed.
This big news should force all scientists, decision makers, industry and research funding agencies to re-evaluate thinking about the possibility that a causal link between cell phone radiation and brain cancer may indeed exist.
In recent years there have been a few studies published attempting to dismiss the possibility of this link by examining brain cancer trends in the human population. I have criticized the shortcomings of these stories, both in this column at the Communities, and in my science blog. The authors of the NCI study agreed with me, pointing out the major problem of these trend-following-studies:
“However, none of these studies assessed the potential effect of latency or possible variation in excess relative risk with the cumulative duration of phone use on trends in brain cancer incidence.”
The latency of brain cancer is a serious problem that has affected all epidemiological studies published so far. We do not know the possible latency period for brain cancer induced by cell phone radiation. The time ranges from a few years to decades, but the fact is that it is an enigma. We really do not have the answer.
There are two reasons for this latency-enigma, and both are stated in the NCI paper:
- “Without data indicating substantial effects of mobile phone exposure on incidence rates of brain cancer, it is not possible to accurately estimate the minimum latency period.”
- “…since the cause of brain cancer is still unclear, we could not definitively state a minimum latency period, and therefore considered several periods between 1 and 10 years, similar to other studies.”
As long as we do not know what causes brain cancer, we are unable to pin down the latency time period. In turn, we cannot reliably predict when the effects of cell phone radiation exposures will show up in the population.
Lastly, there are two surprising and “puzzling” statements in the NCI article.
The first one is made in the article’s Introduction and refers to the lack of a causality link between cell phone radiation and brain cancer:
“…many large and well conducted studies have found little evidence to support such a link.”
Among those “well conducted” studies are INTERPHONE and the Danish Cohort. Both of them are anything but well conducted/designed studies and it might be just “pure luck” that the INTERPHONE study was able to detect a risk increase in avid phone users.
The other “puzzling” statement is made at the conclusion of the Discussion section of the article:
“No compelling data have suggested that microwave exposure can increase the risk of any type of cancer, or raise rates of somatic or germ cell mutation.37 In particular, a study of 480 Fischer rats did not find any excess risk of glioma or astrocytoma in those exposed to 835.62 MHz or 847.74 MHz of microwave radiation.”
As I have written in this column, the no-effect-result in animal studies does not prove that there is no risk to humans only that there is no risk to animals. The authors of the NCI study should be aware that their statement is incorrect
Where do we stand today? The NCI study suggests that the observed trend of a slow increase in brain cancer in the U.S. might verify the predictive findings of the INTERPHONE study that suggests a 40% risk increase for avid long term phone users.
Read more from Dariusz Leszczynski in his science blog “BRHP - Between a Rock and a Hard Place” at http://betweenrockandhardplace.wordpress.com Dariusz is a Research Professor at the Radiation and Nuclear Safety Authority in Finland.
Follow Dariusz on twitter: @blogBRHP
Disclaimer: the opinions presented in this column are author’s own and should NOT be considered as the official opinions of the STUK - Radiation and Nuclear Safety Authority in Finland.
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