But the growing popularity of cell phones has prompted concerns about their cancer risk. Some think that low-level radiation produced by cell phones could increase that risk, particularly related to head or neck tumors.
Cancer Risk and the Cell Phone: About the Exposure
It is true that cell phone users are exposed to radiofrequency (RF) energy, which is a low-frequency form of radiation. Cell phones emit this radiation mainly through their antennas. A cell phone user's total exposure to RF energy from the device depends on:
- The amount of time they spend on the phone
- The amount of RF energy produced by their specific cell phone
- The distance from the cell phone to the nearest cellular tower — the farther away the phone is, the more RF energy it must produce to provide a clear signal
- The amount of cell phone traffic at the time — again, the phone must produce more RF energy to compete with other calls
- The use of a Bluetooth headset or other hands-free device, which puts distance between the cell phone and the user
Cancer Risk and the Cell Phone: Myth vs. Fact
Researchers are doubtful that RF energy in and of itself has the potential to be harmful, says Michael J. Thun, MD, vice-president emeritus of epidemiology and surveillance research for the American Cancer Society.
For one thing, RF energy is much less powerful than known forms of cancer radiation. "The radio frequencies that cell phones emit are halfway between a FM radio and a microwave," Dr. Thun says. "These emissions do not have enough energy to break DNA. They are different from X-rays and other types of ionizing radiation like cosmic rays and gamma rays."
Other people have postulated that RF energy could cause tumors by heating the cells in the head and neck, much as microwave ovens use energy to stimulate molecules and heat food. This, too, has been shown to be unlikely, Thun says. "This [theory] has been tested in mice and rats," explains Thun. "These studies have not shown any evidence that low-level radio frequencies from cell phones promote the development of tumors."
Cancer Risk and the Cell Phone: What Other Studies Show
Epidemiological studies and research using lab animals have so far found little evidence of a relationship between cell phones and cancer. These studies have:
- Compared cell phone users with non-users and found no significant difference in cancer rates
- Studied people with brain tumors and found that they do not report more cell phone use than other people
- Exposed lab rodents to known carcinogens and RF energy and found that the energy didn't have any impact on tumor development
- Found no evidence of a "dose response," in which increased use of cell phones equals increased risk of brain tumors
However, cell phones are such a new phenomenon that it's difficult to make any pronouncements regarding long-term effects. "We've only had 10 or 15 years of experience, so the final votes aren't in," Thun says.
Also, some studies have found slight evidence of a possible risk. For example, a few studies have found slightly increased cancer risk on the side of the head to which users hold their cell phones, although other studies found no such evidence.
Thun suggests a simple solution for those who worry about cancer from using a cell phone. "People who are concerned about the safety of cell phones can use a headset or speakerphone, or some other device that holds the phone away from their heads," Thun says. "That eliminates their exposure."
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