What is lung cancer?

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.

The cancer cells can spread, or metastasize, to the lymph nodes and other parts of the body.

What causes lung cancer?

Most lung cancer is caused by smoking. Secondhand smoke also can cause lung cancer. Lung cancer is the leading cause of cancer deaths.

Being exposed to arsenic, asbestos, radioactive dust, or radon can increase your chances of getting lung cancer. People who are exposed to radiation at work or elsewhere have a higher chance of getting lung cancer.

What are the symptoms?

Early lung cancer doesn't usually cause any symptoms. This is why it's not usually found early.

In its advanced stage, cancer may affect how your lungs work. The first signs of lung cancer may include:

• Coughing.
• Wheezing.
• Feeling short of breath.
• Having blood in any mucus that you cough up.

If you have these symptoms and are worried about lung cancer, call your doctor.

Lung cancer may spread to the chest and then to other parts of the body. For example, if it spreads to the spine or bones, it may cause pain in the back or other bones or weakness in the arms or legs. If it spreads to the brain, it may cause seizures, headaches, or vision changes.

How is lung cancer diagnosed?

Your doctor will check your symptoms and ask questions about whether you smoke or have been exposed to another person's smoke or to any cancer-causing substances. He or she will also ask about your medical history, including any history of cancer in your family. This information will help your doctor decide how likely it is that you have lung cancer and whether you need tests to be sure.

Lung cancer is usually first found on a chest X-ray or a CT scan. More tests are done to find out what kind of cancer cells you have and whether they have spread beyond your lung. These tests help determine what stage the cancer is in. The stage is a rating to measure how big the cancer is and how far it has spread.

How is it treated?

Treatment for lung cancer includes surgery, anti-cancer medicines (chemotherapy), radiation, or a mix of all three. It depends on what type of cancer you have and how much it has spread.

Few lung cancers are found in the early stages when treatment is most effective.

It can be very scary to learn that you may have lung cancer. Talking with your doctor or joining a support group may help you deal with your feelings. It can help if you have lots of support from family and friends. Staying as active as possible will also help.