Lung cancer starts when abnormal cells grow out of control in the lung. They can invade nearby tissues and form tumors. Lung cancer can start anywhere in the lungs and affect any part of the respiratory system.
What causes lung cancer?
Lung cancer is often caused by cigarette smoking. Tobacco smoke contains carcinogens. These are substances that cause cancer. They damage lung cells, and over time the damaged cells can turn into lung cancer.
Sometimes lung cancer develops in people who have never smoked. A few people get lung cancer after being exposed to other harmful substances, including asbestos, radioactive dust, radon, or radiation such as X-rays. Cancer also may be caused by gene changes (mutations) that occur as you get older.
What puts you at risk for lung cancer?
A risk factor for lung cancer is something that increases your chance of getting this cancer. Having one or more of these risk factors can make it more likely that you will get lung cancer. But it doesn't mean that you will definitely get it. And many people who get lung cancer don't have any of these risk factors.
Most lung cancers are caused by cigarette smoking. Smoking cigars or a pipe may also increase your risk for lung cancer.
Your risk of getting lung cancer is higher:
- The longer you smoke.
- The more cigarettes you smoke each day.
Quitting smoking lowers your risk for getting cancer. And your risk keeps going down as long as you don't smoke. Even cutting down how much you smoke may reduce your risk (but not as much as quitting completely).
If you live with a smoker, you have a higher risk for lung cancer compared with a person who lives in a nonsmoking household.
Exposure to some substances may increase your risk for lung cancer, including:
- Certain chemicals. These include arsenic and asbestos.
- Radiation. This includes exposure from your workplace, medical tests, and the environment (such as radioactive dust).
- Radon gas. This includes exposure from your home or workplace.
- Air pollution. Living where the air is very polluted can increase your risk for lung cancer.
Some gene changes (mutations) can increase the risk of getting lung cancer. These gene changes mostly occur as a person gets older.
What are the symptoms of lung cancer?
Symptoms of lung cancer may include:
- Coughing symptoms, such as:
- A new cough or a cough that doesn't go away.
- In smokers who have a chronic cough, a change in how severe their cough is or how much they cough.
- Coughing up blood or mucus tinged with blood.
- Chest symptoms, such as:
- Chest, shoulder, or back pain that doesn't go away and often gets worse with deep breathing.
- New wheezing.
- Shortness of breath.
- General symptoms, such as:
- Swelling in the neck and face.
- Difficulty swallowing.
- Weight loss and loss of appetite.
- Increasing fatigue and weakness.
- Recurring respiratory infections, such as pneumonia.
How is lung cancer diagnosed?
Your symptoms, your medical history, and any history of cancer in your family will help your doctor decide how likely it is that you have lung cancer. You may need tests to be sure. Lung cancer is usually first found on a chest X-ray or a CT scan.
How is lung cancer treated?
Treatment for lung cancer is based on the type and stage of the cancer and other things, such as your overall health. The main treatments are:
Surgery may be an option if your doctor thinks all of the cancer can be removed. The doctor may remove just the tumor, the affected part of the lung, or one whole lung.
This uses high-dose X-rays to kill cancer cells and shrink tumors. It may be used with surgery. Or it may be used instead of surgery.
These medicines kill fast-growing cells, including cancer cells and some normal cells. Chemotherapy and radiation may be given together (chemoradiation).
Other options may include immunotherapy or targeted therapy. Your doctor may suggest a clinical trial.