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Lung Cancer


The Manual's Editorial Staff

Reviewed/Revised May 2023
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What is lung cancer?

Cancers that start growing in other organs may spread (metastasize) to the lungs. Cancers that have spread to your lungs aren't considered lung cancer. They are considered metastatic cancer of whatever organ they started in, such as the breast, colon, or prostate.

  • Cigarette smoking is the most common cause of lung cancer

  • One common symptom is a cough that won’t go away, or a change in a cough you've had for awhile

  • Lung cancer is most common in people between the ages of 45 and 70

  • Chest x-rays can find most lung cancers

  • Lung cancer is the leading cause of cancer death

What are the types of lung cancer?

There are 2 main types of lung cancer:

  • Non-small cell lung cancer (more common)

  • Small cell lung cancer (less common)

Both types are dangerous, but small cell is a little more dangerous. The type is important because the treatments differ.

What causes lung cancer?

The main cause of lung cancer is:

  • Cigarette smoking—smoking causes about 85 out of 100 cases of lung cancer

If you stop smoking, your risk of cancer goes down. You can still get lung cancer even if you don't smoke.

Other causes of lung cancer include:

  • Genetics (traits that you inherit from a parent or grandparent)

  • Air pollution

  • Being around other people smoking cigarettes or cigars (secondhand smoking)

  • Breathing in substances that can cause cancer (such as asbestos, radiation, or radon)

  • Using open fires for all cooking and heating

Asbestos is a mineral fiber used in insulation and other building materials. Radiation naturally is found in small amounts in the environment, but too much exposure to radiation during x-rays, CT scans, and other imaging tests is a concern. Radon is a radioactive gas that comes from the ground and can build up to harmful levels in basements.

What are the symptoms of lung cancer?

Symptoms may not appear for awhile. Sometimes doctors find lung cancer by accident when doing a chest x-ray for some other problem.

When people do have symptoms from lung cancer, they usually have:

  • Coughing

The cough is usually dry, but sometimes it's wet. You may cough up streaks of blood. The cough may not be bad, but it doesn't go away like coughs from a cold.

As the cancer gets bigger, you may have other symptoms such as:

  • Not feeling hungry

  • Losing weight

  • Feeling weak and tired

  • Chest pain

Lung cancer is often deadly, particularly if it isn’t found early.

How can doctors tell if I have lung cancer?

Doctors may suspect lung cancer from your symptoms. To know for sure, they will take pictures of your lungs using:

If the pictures show something that looks like cancer, your doctor will do a biopsy. A biopsy takes a sample of tissue from the lungs to send for testing. There are several ways to get a biopsy sample:

By looking at the biopsy sample under a microscope, your doctors can tell whether you have cancer. If you have cancer, they can tell what type it is.

How can doctors tell if the cancer has spread?

Who should be screened for lung cancer?

If you don't have any symptoms, you should have tests for lung cancer only if you're at high risk. You're at high risk if:

  • You smoked heavily for a long time AND

  • You're middle-aged or older

Doctors usually do a CT scan of the chest on high-risk people. Testing other people doesn't seem to save any lives.

How do doctors treat lung cancer?

How can I prevent lung cancer?

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