Staging lung cancer

The stage of a cancer describes its size, position and whether it has spread. The number staging system, which can be used for small cell and non-small cell lung cancer divides cancer into four stages:

  • Stage 1 – the cancer is still inside the lung (localised) and hasn’t spread to the lymph nodes. The tumour is no bigger than 5cm.
  • Stage 2 – the cancer is no bigger than 7cm and may or may not affect the nearby lymph nodes. Or it is bigger than 7cm and has spread to surrounding tissues but not to the lymph nodes.
  • Stage 3 – the cancer can be any size and has spread to the lymph nodes. It may be in other parts of the lungs or surrounding areas.
  • Stage 4 – the cancer has spread to a distant part of the body such as the liver, bones or the brain.

Small cell lung cancer can be divided into two stages:

  • Limited disease – the cancer is limited to the lung or lymph nodes near the lung.
  • Extensive disease – the cancer has spread outside the lung within the chest or to other parts of the body.

The staging system

The stage of a cancer describes its size and position, and if it has spread from where it started. Knowing the stage helps your doctors advise you on the best treatment.

Doctors use the same staging system for both non-small cell lung cancer and small cell lung cancer.

Your doctor may tell you the stage of the cancer using a number staging system, from 1–4. It looks at:

  • the size of the tumour
  • whether it has spread into nearby parts of the lung, or outside the lung
  • whether it is in lymph nodes nearby, in the chest, or further away 
  • whether it has spread further outside the lung or to other parts of the body.

This staging also includes other things, such as whether the lung has partly or fully collapsed.

Most of the number stages are also sub-divided. We haven’t included these here to try to keep it simple. Your doctor or nurse can explain more about your stage of lung cancer.

Stage 1

This is when the cancer is no bigger than 5cm. It is still inside the lung (localised) and not in any lymph nodes. 

This is early or localised lung cancer.

Stage 2

The cancer is no bigger than 7cm and may or may not have spread to nearby lymph nodes. Or, the cancer is bigger than 7cm and has not spread to the lymph nodes, but it is growing into other parts of the lung, or the airway, or to surrounding areas just outside the lung.

Stage 3

The cancer can be any size and has spread to lymph nodes. The cancer may also be growing into other parts of the lung, or the airway, or to surrounding areas outside the lung. The cancer may also have spread to tissues and structures further away from the lung. But it hasn’t spread to other parts of the body.

Stage 2 and Stage 3 lung cancer are usually called locally advanced lung cancer.

Stage 4

The cancer can be any size, may have spread to lymph nodes and one of the following:

  • The cancer has spread to the lung on the other side.
  • There are cancer cells in fluid in the pleura or around the heart.
  • The cancer has spread to another part of the body, such as the liver, bones or brain.

Stage 4 lung cancer is called metastatic or secondary lung cancer.


Small cell lung cancer

Doctors may divide small cell lung cancers into two stages:

  • Limited disease – the cancer cells can be seen in one lung and in nearby lymph nodes.
  • Extensive disease – the cancer has spread outside the lung, to the chest area or to other parts of the body.

Small cell lung cancers are usually treated as if they have spread, even if doctors can’t see any evidence of this on your scans.

This is because the cancer can spread outside the lung quite early on. Some cancer cells are likely to have already spread through the blood or lymphatic system, but this may be too small to show up on scans.

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