Is there a link between cell phone use and cancer? More research is needed, say experts who met last week to discuss the topic.

Cell phone safety has been debated for years, but current research is contradictory or inconclusive. Some studies have suggested a link between cell phone use and brain cancer, as well as some benign tumors. Most studies, though, do not show a clear link.

Cell phones operate with radio frequencies (RF); they do not emit ionizing radiation, the type that damages DNA and is known to have the ability to cause cancer. However, there is some concern that cell phone use may indirectly affect tumor growth.

Experts convene in Washington

The 3-day meeting was sponsored by the National Institute of Environmental Health Sciences, University of Pittsburgh, and the Environmental Health Trust, among others. It was organized by Devra L. Davis, PhD, MPH, Professor of Epidemiology, University of Pittsburgh, Graduate School of Public Health, and founder of the Environmental Health Trust, an organization devoted to researching environmental health risks.

It coincided with a Senate hearing on the topic, as well as a recent report on cell phone safety by the Environmental Working Group. According to the report, concerns about cell phone radiation exposure have prompted some countries – Germany, Switzerland, Israel, United Kingdom, France, and Finland – to recommend limiting exposure to it, especially for children. The report asks why the United States hasn't taken similar action.

The meeting featured discussions with notable researchers in the field, including experts from the National Institutes of Health and the American Cancer Society.

American Cancer Society researchers agree it's important to monitor the safety of cell phones because they are so widely used.

What current evidence shows

"Cell phones are now used worldwide by an estimated 3-4 billion people and there is increasing heavy use by children," says Michael J. Thun, MD, American Cancer Society Vice President Emeritus of Epidemiology and Surveillance Research. "Questions about the current evidence can only be resolved by longer term epidemiologic follow-up and by critical evaluation of experimental studies that report biological effects from cell phones."

According to Thun, approximately 30 epidemiological studies have looked at the relationship between cell phones and brain cancer or benign tumors (meningioma, acoustic neuroma, salivary gland tumors), but they have yielded contradictory results.

This may reflect the relatively short use (less than 20 years) of cell phones in most countries, differences in study design, or the fact that all but 2 of the studies are retrospective. Those studies asked people with and without cancer to remember details about their past cell phone use. Results of that kind of study are considered less definitive than studies that begin measuring cell phone use in participants before they ever develop cancer.

Thun says some important studies have not yet been published, such as the combined results from Interphone, a large study of cell phone use and brain tumors being done in 13 countries. In addition, there have been no long-term studies of children who have used cell phones since an early age. The heavy use of cell phones by young children is of particular concern because the radiofrequency (RF) waves from cell phones reach more brain tissue in children than in adults.

Some researchers at this meeting reported that RF waves from cell phones have biological effects that might affect tumor development, but those findings have not yet been replicated by independent scientists.

How to reduce your risk

While more research is needed, the American Cancer Society recommends that people who are concerned take simple steps to reduce their exposure:

• Use a speaker phone or other hands-free device. 
• Purchase a cell phone model with lower SAR (specific absorption rate) ratings. 
• Parents may wish to limit their children's use of cell phones.

Concerned about the radiation emitted from your phone? See this list of cell phone radiation levels from CNET.

For more information, see our document, Cellular Phones.

Reviewed by: Members of the ACS Medical Content Staff