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What Is Lung Cancer?

Lung cancer causes some cells in the lungs to grow out of control. These cells are called cancer cells. Cancer cells grow at a different rate than normal cells. Their size and shape are also not normal. Cancer cells can spread to other areas in the lungs. Or, they can travel to other parts of the body.

Outline of human figure with head turned to side showing brain, arm bone, lungs, and liver.


Image of cancer cells

Non-Small Cell Lung Cancer

Most cases of lung cancer are called non-small cell. There are a few different types of non-small cell lung cancer. These include squamous cell carcinoma, adenocarcinoma, and large cell carcinoma. When cancer cells grow together in one area, they form a tumor.


Small Cell Lung Cancer

Small cell lung cancer is less common than non-small cell lung cancer. Small cell cancer is sometimes called oat cell. (The cells are shaped like oats when viewed under a microscope.) This type of lung cancer may grow and spread faster than non-small cell cancer.

Cutaway view of upper body
Lung cancer can spread to the other lung, the liver, brain, or bones.

How Cancer Spreads

Cancer cells don’t always stay in one place. They may enter the lymph system (a network of nodes and vessels that help your body fight disease). Cancer can also enter the bloodstream and spread to other parts of the body. When cancer spreads, the process is called metastasis. Lung cancer that spreads (metastasizes) often goes to the other lung or the liver, brain, or bones.

Author: StayWell Custom Communications
Last Annual Review Date: 1/15/2007
Copyright © The StayWell Company, LLC. except where otherwise noted.
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