- With Mayo Clinic medical oncologist
Timothy J. Moynihan, M.D.
read biographyclose windowBiography of
Timothy J. Moynihan, M.D.
Timothy Moynihan, M.D.
"As a practicing medical oncologist, I meet with patients and families every day to help manage their course through this disease called cancer. This experience provides unique insight into the needs of cancer patients, their families and loved ones and brings into sharp focus the need for reliable information to be readily available in terms that can be easily understood." — Dr. Timothy Moynihan
Dr. Timothy Moynihan believes that providing consumers with accurate, timely information on the broad, complex topic of cancer is the biggest challenge facing medical websites. As the guiding force behind our cancer content, he makes sure Mayo Clinic meets the test.
Dr. Moynihan, born in Las Vegas, N.M., and raised in Denver, is a consultant in medical oncology at Mayo Clinic and an associate professor at Mayo Clinic College of Medicine, Rochester, Minn. He's board certified in internal medicine, medical oncology, and hospice and palliative care medicine.
He did his medical oncology training at Johns Hopkins Hospital in Baltimore, and then went on to the University of Minnesota and St. Paul Regions Medical Center for seven years before moving to Mayo Clinic in 1999. Dr. Moynihan is medical director of the Mayo Clinic hospice.
Dr. Moynihan serves as the education chair for the Department of Oncology and the fellowship program director. Four times he has been selected as Teacher of the Year in medical oncology and elected to the Teacher of the Year Hall of Fame.
Past honors include distinguished clinical teacher at the University of Minnesota Medical School, best internist at the Medical College of Wisconsin and recipient of the Upjohn Achievement Award for Excellence in Medicine. Dr. Moynihan serves on several national committees for the American Society of Clinical Oncology.
"The Internet provides a ready source of information on a wide range of topics of interest to those affected by cancer," Dr. Moynihan says. "The difficulty is trying to decide which sites provide reputable information and which information is relevant to each individual patient. The long history and tradition of excellence associated with Mayo Clinic assures you that information provided will be reliable, up-to-date and comprehensive."
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Question
Cellphones and cancer: What's the risk?
Is there any link between cellphones and cancer?
Answer
from Timothy J. Moynihan, M.D.
The possible connection between cellphones and cancer is controversial. Many years' worth of studies on cellphones and cancer have yielded conflicting results. Currently, there's no consensus about the degree of cancer risk — if any — posed by cellphone use.
The primary concern with cellphones and cancer seems to be the development of brain tumors associated with cellphone use. Some research suggests a slight increase in the rate of brain tumors since the 1970s, but cellphones weren't in use during the 1970s. Instead, the subtle increases are more likely related to other factors — such as increased access to medical care and improvements in diagnostic imaging.
So what have researchers learned about cellphones and cancer? Here's an overview of various studies:
- In one study that followed more than 420,000 cellphone users over a 20-year period, researchers found no evidence of a link between cellphones and brain tumors.
- Another study found an association between cellphones and cancer of the salivary glands. However, only a small number of study participants had malignant tumors.
- Another recent study suggested a possible increased risk of glioma — a specific type of brain tumor — for the heaviest cellphone users, but no increase in brain tumor risk overall.
After evaluating several studies on the possibility of a connection between cellphones and glioma and a noncancerous brain tumor known as acoustic neuroma, members of the International Agency for Research on Cancer — part of the World Health Organization — agreed that there's limited evidence that cellphone radiation is a cancer-causing agent (carcinogenic). As a result, the group classified radiofrequency electromagnetic fields as possibly carcinogenic to people.
Still, a series of recent studies can't tell the entire story. It often takes many years between the use of a new cancer-causing agent — such as tobacco — and the observation of an increase in cancer rates. At this point, it's possible that too little time has passed to detect an increase in cancer rates directly attributable to cellphone use.
The bottom line? For now, no one knows if cellphones are capable of causing cancer. Although long-term studies are ongoing, to date there's no convincing evidence that cellphone use increases the risk of cancer. If you're concerned about the possible link between cellphones and cancer, consider limiting your use of cellphones — or use a speaker or hands-free device that places the cellphone antenna, which is typically in the cellphone itself, away from your head.
Next questionSitting risks: How harmful is too much sitting?
- Cardis E, et al. Brain tumour risk in relation to mobile telephone use: Results of the Interphone international case-control study. International Journal of Epidemiology. 2010;39:675.
- Vokow ND, et al. Effects of cell phone radiofrequency signal exposure on brain glucose metabolism. Journal of the American Medical Association. 2011;305:808.
- Dreyfuss JH. Mixed results on link between cellular telephones and cancer. CA: A Cancer Journal for Clinicians. 2010;60:5.
- Joachim S, et al. Cellular telephone use and cancer risk: Update of a nationwide Danish cohort. Journal of the National Cancer Institute. 2006;98:1707.
- Sadetzki S, et al. Cellular phone use and riskf of benign and malignant parotid gland tumors — A nationwide case-control study. American Journal of Epidemiology. 2008;167:457.
- Fisher JL, et al. Epidemiology of brain tumors. Neurologic Clinics. 2007;25:867.
- Myung S, et al. Mobile phone use and risk of tumors: A meta-analysis. Journal of Clinical Oncology. 2009;27:5565.
- Cell phones and cancer use. National Cancer Institute. http://www.cancer.gov/cancertopics/factsheet/Risk/cellphones. Accessed June 14, 2010.
- Baan R, et al. Carcinogenicity of radiofrequency electromagnetic fields. The Lancet Oncology. 2011;12:624.
- Frei P, et al. Use of mobile phones and risk of brain tumours: Update of Danish cohort study. British Medical Journal. 2011;343:d6387.
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