Lung Cancer
Source: MedlinePlus Health Topics, U.S. National Library of Medicine
What is lung cancer? Lung cancer is cancer that forms in tissues of the lung, usually in the cells that line the air passages. It is the leading cause of cancer death in both men and women. There are two main types: small cell lung cancer and non-small cell lung cancer . These two types grow differently and are treated differently. Non-small cell lung cancer is the more common type. Who is more likely to develop lung cancer? Anyone can develop lung cancer, but certain factors raise your risk of getting it: Smoking . This is the most important risk factor for lung cancer. Tobacco smoking causes about 9 out of 10 cases of lung cancer in men and about 8 out of 10 cases of lung cancer in women. The more years you smoke and the more cigarettes you smoke each day, the more your risk goes up. Your risk is also greater if you smoke a lot and drink alcohol every day or take beta carotene supplements. If you have quit smoking, your risk will be lower than if you had kept smoking. But you will still have a higher risk than people who never smoked. Secondhand smoke , which is the combination of the smoke that comes from a cigarette and the smoke breathed out by a smoker. When you breathe in secondhand smoke, you are exposed to the same cancer-causing agents as smokers, although in smaller amounts. A family history of lung cancer. Being exposed to asbestos , arsenic , chromium, beryllium, nickel, soot, or tar in the workplace. Being exposed to radiation , for example from: Radiation therapy to the breast or chest Radon in the home or workplace Certain imaging tests such as CT scans HIV infection . Your risk is higher if you have HIV. However, smoking rates are higher in people who have HIV, so it's not clear whether the increased risk is from the HIV infection or from smoking. Air pollution . Studies show that living in areas with higher levels of air pollution increases your risk of lung cancer. What are the symptoms of lung cancer? Lung cancer may not cause any signs or sympto