What are the types of lung cancer?

Non-small cell lung cancer (NSCLC)

Most lung cancers are this type. Some NSCLC cancers are linked to genetic changes (mutations) – which are not inherited. When these mutations occur, they affect the normal activity of the gene and lung cancer can develop. Mutations in the EGFR, KRAS, ROS1 and ALK genes are common in lung cancers – particularly in adenocarcinomas (see below).

There are four main types of NSCLC: 

• Adenocarcinoma: This is the most common type of lung cancer and is often found in the mucous-making glands that line the airways. 
• Squamous cell carcinoma: This type of cancer starts in squamous cells, which are flat cells that line the inside of the airways. 
• Large cell carcinoma: This cancer may appear in any part of your lung. The cells are large and round when viewed under the microscope. 
• Not otherwise specified (NOS): This is when the doctors cannot be sure which type of non-small cell lung cancer it is.

Small cell lung cancer (SCLC)

About 1 in 7 of all lung cancers is the small cell type. Small cell lung cancer begins in cells around the bronchi (airways) called neuroendocrine cells (NETs). SCLC cells appear small and round when looked at under a microscope and tend to grow quickly. They often spread to lymph nodes and other areas such as your bones, brain, adrenal glands and liver.

Small cell lung cancer is nearly always caused by smoking.

Mesothelioma

This rare cancer affects the protective linings that cover your lungs. Usually it happens when someone is exposed to a chemical called asbestos.

Read more about Mesothelioma.