Studies link mobile phone signals to cancer growth, but there’s a big catch

1 Nov 2018

Image: © oatawa/

New research appears to link signals emitted by mobile phones and the development of heart tumours, but only in rats and mice.

Since mobile phones became commonplace in the 1990s, some campaigners have claimed that the radio frequency radiation (RFR) emitted by the devices using 2G or 3G connectivity could be directly linked to cancer growth in humans.

While this suggestion has been dismissed by a number of researchers, studies undertaken over a number of years by the US National Institute of Environmental Health Sciences appears to have found evidence that, at the outset, would appear to confirm these fears.

The final reports showed clear evidence that male rats exposed to high levels of RFR developed cancerous heart tumours as well as tumours of the brain and adrenal gland. For female rats, and male and female mice, the evidence was equivocal as to whether cancers observed were associated with exposure to RFR.

Costing $30m, the studies took 10 years to complete and are the most comprehensive assessment, to date, of health effects in animals exposed to RFR with modulations used in 2G and 3G mobile phones. If you’re wondering why 4G wasn’t included in this list, it’s because these two standards were the ones most commonly available when the studies started.

During testing, the animals were housed in a chamber, with exposure to RFR beginning in the womb for rats and at least five weeks old in mice for up to two years, or the duration of their lives. The RFR exposure was intermittent, 10 minutes on and 10 minutes off, totalling about nine hours each day. RFR levels ranged from 1.5 to six watts per kg in rats, and 2.5 to 10 watts per kg in mice.

Not comparable with humans

However, those thinking this is about to blow the lid on the mobile phone industry will need to think again, as the researchers stressed that “exposures used in the studies cannot be compared directly to the exposure that humans experience when using a cell phone”.

Researcher Dr John Bucher said: “In our studies, rats and mice received radio frequency radiation across their whole bodies. By contrast, people are mostly exposed in specific local tissues close to where they hold the phone. In addition, the exposure levels and durations in our studies were greater than what people experience.”

At the exposure’s lowest levels, it was equal to the maximum local tissue exposure allowed for mobile phone users, a level that rarely occurs during typical phone use. In fact, the highest exposure level in the study was four times higher than anything experienced in a mobile phone.

Strangely, however, the studies found that exposure in male rats actually lengthened their lifespan, possibly linked with a decrease in chronic kidney problems found in older rats.

An oversight of the study was that it did not investigate RFR used in Wi-Fi, 4G or 5G, the latter of which “likely differs dramatically from what we studied”, the researchers said. For future studies, researchers aim to build smaller RFR chambers to evaluate newer telecommunications technology in a matter of months, rather than years.

Colm Gorey was a senior journalist with Silicon Republic