What Is Lung Cancer? | American Lung Association

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What Is Lung Cancer?

Though lung cancer is common, many people don't know much about it or are afraid to learn. Learning about lung cancer can help you better understand the disease and its risk factors. When you know more about lung cancer, you can feel more in control of your health and help educate others.

Lung Cancer Basics

Lung cancer happens when cells in the lung change (mutate). They grow uncontrollably and cluster together to form a tumor. There are two main types of lung cancer, small cell lung cancer, and non-small cell lung cancer. Learn more about the basics of lung cancer.

Lung Cancer Causes and Risk Factors

Anyone can get lung cancer. Lung cancer occurs when cells in the lung mutate or change. Most often, this change in lung cells happens when people breathe in dangerous, toxic substances. Smoking is the greatest risk factor, but there are others like exposure to radon gas and air pollution. Learn how to reduce your risk.

Lung Cancer Staging

Staging means finding out if and how much the lung cancer has spread. The tumor stage helps shape a treatment plan. Learn more about staging.

Is Lung Cancer on Your Radar?

Take this quiz to find out how much you know about lung cancer. Share it with your friends to help get lung cancer on their radar. Take the quiz.

How Serious Is Lung Cancer?

Lung cancer is very serious. Much progress has been made, but lung cancer is still the leading cancer killer of both men and women in the U.S. There are a few reasons why. Learn more about the impact of lung cancer.

    Reviewed and approved by the American Lung Association Scientific and Medical Editorial Review Panel. Last reviewed December 18, 2017.

    Page Last Updated: March 13, 2018

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