Cell phones and cancer

Cellphones emit non-ionizing radiation, waves of energy that are too weak to break chemical bonds or to set off the DNA damage known to cause cancer.

There is no known biological mechanism to explain how non-ionizing radiation might lead to cancer.

But researchers who have raised concerns say that just because science can't explain the mechanism doesn't mean one does not exist.

Concerns have focused on the heat generated by cellphones and the fact that the radio frequencies are absorbed mostly by the head and neck.

In recent studies that suggest a risk, the tumors tend to occur on the same side of the head where the patient typically holds the phone.

Like most research on the subject, the studies are observational, showing only an association between cellphone use and cancer, not a causal relationship.

The most important of these studies is called Interphone, a vast research effort in 13 countries, including Canada, Israel and several in Europe.

Some of the research suggests a link between cellphone use and three types of tumors: glioma; cancer of the parotid, a salivary gland near the ear; and acoustic neuroma, a tumor that essentially occurs where the ear meets the brain. All these cancers are rare.

Last year, The American Journal of Epidemiology published data from Israel finding a 58 percent higher risk of parotid gland tumors among heavy cellphone users.

Also last year, a Swedish analysis of 16 studies in the journal Occupational and Environmental Medicine showed a doubling of risk for acoustic neuroma and glioma after 10 years of heavy cellphone use.

Some doctors say the real concern is not older cellphone users, who began using phones as adults, but children who are beginning to use phones today and face a lifetime of exposure.

The fear is that even if the individual risk of using a cellphone is low, with three billion users worldwide, even a minuscule risk would translate into a major public health concern.

IHT