Lung cancer

What is lung cancer?

Your body is made up of many different types of cells. Normally, your body tightly controls the production of new cells when they’re needed. Cancer develops when certain cells escape from your body’s control and start to change. These abnormal cells, also called cancer cells, start to increase and grow to form a lump. This is called a tumour.

If the cancer starts in your lung, it’s called primary lung cancer. If it starts in another part of your body and spreads to affect your lung, it’s called secondary lung cancer.

There are many different types of lung cancer. The two main types are:

  • non small cell lung cancer (NSCLC): This is the most common kind of lung cancer. There are three common types of non small cell lung cancer: adenocarcinoma, squamous cell carcinoma and large cell carcinoma.
  • small cell lung cancer (SCLC): This is much less common. It usually spreads more quickly and is often at an advanced stage when it’s diagnosed. 

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Last medically reviewed: February 2017. Due for review: February 2020

This information uses the best available medical evidence and was produced with the support of people living with lung conditions. Find out how we produce our information. If you’d like to see our references get in touch.