Myth: If You've Smoked for Years, the Damage Is Done

Fact: It's never too late to stop smoking. Quitting has almost immediate benefits, including improved circulation and lung function. Risk of lung cancer begins to decline over time. Ten years after quitting, former smokers cut their risk of developing lung cancer by half.

Myth: Low-Tar or 'Light' Cigarettes Are Safer Than Regular

Fact: Light, ultra-light, and low-tar are just as dangerous as regular cigarettes. And beware of menthol: Some research suggests that menthol cigarettes may be more dangerous and harder to quit. Their cooling sensation can allow smokers to inhale more deeply.

Myth: Smoking Marijuana Doesn't Increase Lung Cancer Risk

Fact: Marijuana smoking may increase lung cancer risk, but more research is needed. Many people who use marijuana also smoke cigarettes, and marijuana smoking exposes a person to more tar and other cancer-causing substances that you would find in cigarettes.

Myth: Antioxidant Supplements Protect You From Cancer

Fact: Based on population studies, a diet rich in fruits and vegetables with antioxidants may help protect against cancer. But when researchers tested antioxidant supplements, they unexpectedly found an increased risk of lung cancer among smokers who took beta-carotene supplements. Talk to your doctor before taking any supplements.

Myth: Pipes and Cigars Don't Cause Lung Cancer

Fact: Smoking pipes or cigars increases not only lung cancer risk but also the risk for cancers of the mouth, throat, and esophagus. Cigar smoking puts you at much greater risk of both heart disease and lung disease. Cigars are just as toxic, maybe more so, than cigarettes.

Myth: Smoking Is Your Only Lung Cancer Risk Factor

Fact: The second leading cause of lung cancer, after tobacco smoke, is an odorless radioactive gas called radon. Emitted from rock and soil, it can seep up into homes and other buildings. The only way to know if you're living with dangerous levels is to test your house or office for it. Call your state or county health department for information.

Myth: Talcum Powder Causes Lung Cancer

Fact: Researchers have found no association between lung cancer and breathing in talcum powder. However, occupational exposure to asbestos, vinyl chloride, and other substances do increase lung cancer risk.

Myth: If Diagnosed With Lung Cancer, Quitting is Pointless

Fact: Continued smoking decreases the effectiveness of cancer treatment and may make side effects worse. Smokers undergoing surgery, for example, have more trouble healing than ex-smokers. Those who smoke while undergoing radiation for cancer of the larynx are less likely to regain normal voice quality. In some cases, quitting can cut the risk of a second cancer forming.

Myth: Exercise Doesn't Affect Lung Cancer Risk

Fact: Regular physical activity may reduce the risk of lung cancer by up to 20%, studies show. In addition, exercise improves lung function and reduces the danger of other diseases, including heart disease and stroke.

Myth: Air Pollution Is a Leading Cause of Lung Cancer

Fact: Outdoor air pollution is responsible for only about 5% of lung cancer cases. Tobacco smoke remains by far the biggest killer.

More Reading on Lung Cancer

• Lung Cancer
• Smoking Quiz: Test Your Medical IQ

Related Slideshows

• Lung Cancer Causes, Symptoms & Treatment
• How Smoking Affects Your Looks and Life
• Quit Smoking: 13 Tips to End Your Addiction
• Weight Control and Smoking Cessation