Lung cancer is a type of cancer that begins in the lungs. The lungs are two organs in the chest that take in oxygen when we inhale and release carbon dioxide when we exhale.
People who smoke have the greatest risk of lung cancer. The risk of lung cancer increases with the length of time and number of cigarettes smoked.
Symptoms
In its earliest stages, lung cancer typically doesn't cause signs and symptoms. Signs and symptoms usually don't occur until the disease has advanced and progressed.
Signs and symptoms of lung cancer may include:
- A new cough that doesn't go away
- Changes in a chronic cough or "smoker's cough"
- Coughing up blood, even a small amount
- Shortness of breath
- Chest pain
- Wheezing
- Hoarseness
- Losing weight without trying
- Bone pain
- Headache
Most often these symptoms are not due to cancer. Other health problems can cause some of these symptoms. Anyone with such symptoms should see a doctor to be diagnosed and treated as early as possible
Risk Factors
Studies have found the following risk factors for lung cancer:
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Tobacco smoke: Tobacco smoke causes most cases of lung cancer. It's by far the most important risk factor for lung cancer. Harmful substances in smoke damage lung cells. That's why smoking cigarettes, pipes, or cigars can cause lung cancer and why secondhand smoke can cause lung cancer in nonsmokers. The more a person is exposed to smoke, the greater the risk of lung cancer.
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Radon: Radon is a radioactive gas that you cannot see, smell, or taste. It forms in soil and rocks. People who work in mines may be exposed to radon. In some parts of the country, radon is found in houses. Radon damages lung cells, and people exposed to radon are at increased risk of lung cancer. The risk of lung cancer from radon is even higher for smokers.
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Asbestos and other substances: People who have certain jobs (such as those who work in the construction and chemical industries) have an increased risk of lung cancer. Exposure to asbestos, arsenic, chromium, nickel, soot, tar, and other substances can cause lung cancer. The risk is highest for those with years of exposure. The risk of lung cancer from these substances is even higher for smokers.
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Air pollution: Air pollution may slightly increase the risk of lung cancer. The risk from air pollution is higher for smokers.
- Family history of lung cancer: People with a father, mother, brother, or sister who had lung cancer may be at slightly increased risk of the disease, even if they don't smoke.
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Personal history of lung cancer: People who have had lung cancer are at increased risk of developing a second lung tumor.
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Age over 65: Most people are older than 65 years when diagnosed with lung cancer.
Diagnosis
Tests for lung cancer include:
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Physical exam: Your doctor checks for general signs of health, listens to your breathing, and checks for fluid in the lungs. Your doctor may feel for swollen lymph nodes and a swollen liver.
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Chest x-ray: X-ray pictures of your chest may show tumors or abnormal fluid.
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CT scan: Doctors often use CT scans to take pictures of tissue inside the chest. An x-ray machine linked to a computer takes several pictures. For a spiral CT scan, the CT scanner rotates around you as you lie on a table. The table passes through the center of the scanner. The pictures may show a tumor, abnormal fluid, or swollen lymph nodes.