A possible link between cellphones and cancer (specifically brain tumors) has been hotly debated for years, mostly in the absence of concrete data to support either side of the argument. This seemed to change with a new study, in the form of a white paper rather than a study in a peer reviewed journal, issued towards the end of May 2016.
The study, issued by the National Institute of Health in the U.S. from Wade and colleagues, is titled “Report of Partial findings from the National Toxicology Program Carcinogenesis Studies of Cell Phone Radiofrequency Radiation in Hsd: Sprague Dawley® SD rats (Whole Body Exposure).”
The study was picked up by several media sites and science websites. For instance, STAT news tweeted:
And similarly with the Environmental Health Trust:
The basis of the study is data drawn from the U.S. National Toxicology Program (NTP) and it relates to experiments using rodents. The research conducted carcinogenesis studies (signs of cancer) in relation to radio frequency radiation. These frequencies were approximations of the modulations used by the U.S. telecommunications sector to transmit data to cellphones.
The outcomes was that some rats (Harlan Sprague Dawley breed) exposed to signals at the particular frequencies developed two types of tumor: malignant gliomas in the brain and schwannomas of the heart.
The study does acknowledge its limitations, although these were not, in many cases, represented by the media outlets that reported on them. First, the study has yet to be peer reviewed by independent academics. Second, the report issued presents only “partial findings.” Third, the sample size is small. Fourth, the sample is based on one geographical locale.
To add to this, the exposure time that the rats were subjected to far exceeded the typical time that a person would use a mobile phone pressed against their head for. The rats were subjected to radio frequencies for nine hours a day, seven days a week, for a period over two years.
After this only a small number of rats developed tumors and here all of the rats that developed cancer were male, with the female rat population apparently showing no signs of cancer at all. The differences by sex are unexplained. Parallel studies were run in mice, although this data does not form part of the reported study.
A further anomaly is that a proportion of rats will naturally develop the reported types of cancer, and when these are factored in, the proportion drops to below five percent. Another oddity with the experiment is that the control rats, unexposed to the radio frequencies, died before the test subject rats. As with other areas of the study, this is unexplained in the issued paper.
These limitations are, according to biostatistican Professor Donald Berry, from the University of Texas MD Anderson Cancer Center, within the normal variation expected within a population. He explained to the website Ars Technica: “there is nothing in this report that can be regarded to be statistically significant.” It is the academic’s view that the results presented cannot be reproduced.
Likewise others on social media were concerned about the lack or robustness with the study, for instance David Baltrus, who is an assistant professor at the University of Arizona tweeted:
Whether cellphones can cause cancer with people remains an on-going area of research. Whether it is proven demonstrably remains to be seen; however, this new study, as currently presented, is not it.
