Think You Know A Lot About Cancer Risks? Study Says You Probably Don't

A new study that looks at people's beliefs about cancer risk factors found that the more someone thought they knew, the more inaccurate beliefs they held. According to the American Cancer Society:

... people who rated themselves as "very informed" about cancer were more likely than those who were "somewhat informed" to believe that underwire bras cause breast cancer, a largely discredited theory based on "extremely weak evidence," says (study co-author Ted) Gansler.

Similarly, the "very informed" respondents were more likely to believe that smokers cannot reduce their risk of cancer by quitting.

The take-home message: Make sure you can trust your sources of cancer information, says Gansler.

"There's a substantial number of people who are very concerned about cancer but are not paying attention to the right issues," Gansler says. "And they are not getting their information from the right sources."

The ACS press release also noted that "people to give a lot of weight to unproven theories or to risk factors that make a relatively small contribution to cancer."

Among the questions researchers asked:

• Living in a polluted city is a greater risk for lung cancer than smoking a pack of cigarettes a day: true or false? (answer: false -- smoking causes 87% of lung cancer deaths. Less than half those surveyed got this right.)
• What someone does as a young adult has little effect on their chance of getting cancer later in life: true or false? (answer: again, false. Risky behaviors such as smoking, sun exposure, and unprotected sex can respectively cause lung cancer, skin cancer, and cervical cancer later. A third of the respondents didn't get this right.)
• Some injuries can cause cancer later in life: true or false? (false ... DNA damage, whether inherited or from the environment, sparks most cancers. Nearly 40% got this wrong, and another 20% didn't know.)

The ACS implies that people who think they know a lot about cancer also pay too much attention to forwarded emails and other suspect sources of information.

This lack of knowledge persists despite many reputable sources of information, such as the American Cancer Society, and many web sites where internet rumors can be checked out. The ACS maintains a page of email hoaxes and rumors, including the supposed link between tight-fitting bras and breast cancer and the supposed risk of reusing plastic water bottles. Rumor debunking site Snopes.com has many more -- does drinking cold water after a meal cause cancer? Did Johns Hopkins issue a warning that sugar is a "cancer feeder?" Find out the truth at Snopes.

Or, better yet, talk to your doctor about your risks.

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Cancer is the second leading cause of death in the U.S., responsible for over 550,000 deaths per year.

Other Sources: Time article; MedPageToday story, source article in the medical journal Cancer.