Types of lung cancer

The type of lung cancer you have tells you the type of cell that cancer started in. Knowing this helps your doctor decide which treatment you need.

Cancer that starts in the lung is called primary lung cancer. Cancer that spreads to your lungs from somewhere else in your body is called secondary lung cancer.

There are different types of primary lung cancer and they are divided into 2 main groups:

• small cell lung cancer (SCLC)
• non small cell lung cancer (NSCLC)

The most common type is non small cell lung cancer.

Small cell lung cancer (SCLC)

Around 15 to 20 out of every 100 lung cancers (around 15 to 20%) diagnosed are this type. It is usually caused by smoking. These cancers tend to spread quite early on.

Small cell lung cancers are also classed as neuroendocrine tumours. Neuroendocrine tumours (NETs) are rare tumours that develop in cells of the neuroendocrine system. In small cell lung cancer, the tumour starts in the neuroendocrine cells of the lung.

Non small cell lung cancer (NSCLC)

Around 80 to 85 out of 100 lung cancers (around 80 to 85%) are non small cell lung cancer (NSCLC). The three main types are adenocarcinoma, squamous cell carcinoma and large cell carcinoma.

Adenocarcinoma

This is the most common type and starts in the mucus making gland cells in the lining of your airways.

Squamous cell cancer

This type develops in the flat cells that cover the surface of your airways. It tends to grow near the centre of the lung.

Large cell carcinoma

The cancer cells appear larger than a typical cell under the microscope.

Other types of non small cell cancer

Less common types of non small cell lung cancer include:

• adenosquamous carcinoma
• sarcomatoid carcinoma

If your cancer cells look very undeveloped under the microscope, your doctor won’t be able to tell what type of cancer you have. There are other tests the team can do, so they can get more information from the sample.

Other cancers affecting the lungs

There are other types of tumours found in the lung. They are rare. Examples are:

• salivary gland type tumours
• lung sarcoma
• lung lymphoma

The treatment for these is different than for SCLC and NSCLC. 

Cancers in the top area of the lung are called Pancoast tumours.

Mesothelioma is a rare type of cancer that starts in the covering of the lung (the pleura).

Some cancers can spread into the lung. This is called secondary lung cancer.