Primary brain tumors and mobile cell phone usage.

An ecological modelling paper by Chapman and colleagues in Cancer Epidemiology concludes that observed increases in the incidence of brain cancer in Australia are unlikely to be related to mobile phone use [1]. Their conclusion fails to take account of tumor location, and is at variance with a meta-analysis of 11 methodologically stronger studies from both the Hardell group and the international Interphone group with researchers in 13 countries, presented by Khurana and colleagues [2]. Criteria for inclusion in the Khurana et al. analysis were (1) publication in a peer reviewed journal, (2) inclusion of participants using their cell phones for more than 10 years, to ensure a minimum 10 year latency period, and (3) incorporation of a laterality analysis of longterm users (i.e. brain tumor site relative to the side of the head preferred for cell phone usage). This meta-analysis calculated an overall odds ratio of 1.9 (95% CI 1.4–2.4) for the risk of glioma for cell phone usage on the ipsilateral side, and 1.6 (CI 1.1–2.4) for acoustic neuroma. A preview of its findings led the editor of the journal Surgical Neurology to publish an editorial titled “Cell phones more dangerous than cigarettes! [sic]” [3]. Subsequent good quality studies have strengthened, not weakened this observation, with one showing an odds ratio for glioma increased to 3.0 (CI 1.7–5.2) in the > 25 year latency group [4]; the French CERENAT collaborative case-control study demonstrating an odds ratio for glioma of 2.89 (CI 1.41–5.93) in the heaviest users (>896 h) [5], and a third demonstrating significantly poorer outcome in patients with Astrocytoma grade IV (Glioblastoma Multiforme = GBM), in heavy compared with light cell phone users, when the latency was longer (>20 years), and particularly when first cell phone usage was before the age of 20 years [6]. The WHO International Agency on Research for Cancer (IARC), using strict criteria, has classified Radiofrequency Electromagnetic Fields from cell phones as a possible (Group 2B) carcinogen to humans (same as lead, DDT, and 2,4 D) in 2011 [7], with a reasoned request by the Hardell group to upgrade this to a clear Group 1 carcinogen in 2013 [8]. This latter group has also consistently called on the International regulating bodies to update safety standards for human non-ionising radiation/radiofrequency radiation (RFR) exposure. On 26 May 2016 the US National Toxicology Program under the NIH released important partial findings from their recent study of the effects of radiofrequency radiation on carcinogenesis in rats [9]. The study design used the standard frequencies and modulations available to the public from the US telecommunications industry.