Staging and grading

The stage of a cancer describes its size, position and whether it has spread. There are different staging systems in use. The number staging system divides cancer into four stages.

If a cancer has spread to other parts of the body, it is called secondary cancer.

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.

Small cell lung cancer often spreads beyond the lung quite early on.

Non-small cell lung cancer is divided into four stages:

  • Stage 1 - The cancer is localised and hasn’t spread to the lymph nodes.
  • Stage 2 and 3 – the cancer may be larger in size and/or may affect the nearby lymph nodes or surrounding tissue.
  • Stage 4 – The cancer has spread to a distant part of the body such as the liver, bones or the brain.

Doctors break the stages down further into stage 2a and 2b, stage 3a and 3b.

Stages of lung cancer

The stage of a cancer describes its size, position and whether it has spread beyond where it started in the body. Knowing the extent of the cancer helps the doctors decide on the most appropriate treatment.

Generally, cancer is divided into four stages:

  • Stage 1 The cancer is small and localised.
  • Stages 2 or 3 The cancer has spread into surrounding areas.
  • Stage 4 The cancer has spread to other parts of the body.

If the cancer has spread to distant parts of the body, this is known as secondary or metastatic cancer .

If the cancer comes back after initial treatment it’s known as recurrent cancer.

The current staging system is used for both small cell and non-small cell lung cancers. This aims to help doctors plan the best treatment for people with lung cancer. It can also help to give an idea of the likely outcome of treatment.

We have information about the current staging system.


Non-small cell lung cancer is usually divided into four stages.

Non-small cell lung cancer is usually divided into four stages.

Stage 1

The cancer is very localised and hasn’t spread to the lymph nodes. This stage is divided in two:

  • Stage 1A The cancer is no bigger than 3cm in size.
  • Stage 1B The cancer is larger than 3cm, or is growing into the main airway of the lung (bronchus). The cancer may also have spread to the membrane covering the lung (pleura), or has made the lung partially collapse.

Stage 2

Stage 2 cancer is also divided in two:

  • Stage 2A The cancer is small and measures 3cm or less, and affects nearby lymph nodes.
  • Stage 2B Either the cancer is larger than 3cm and in the nearby lymph nodes; or there is no cancer in the lymph nodes but the tumour has made the lung collapse; or it has grown into the:
    • chest wall
    • membrane covering the lung (pleura)
    • muscle layer below the lungs (diaphragm)
    • covering of the heart (pericardium).

Stage 3

Stage 3 cancer is also divided in two:

  • Stage 3A The cancer is any size and has spread to the lymph nodes in the middle of the chest (mediastinum), but not to the other side of the chest; or the cancer has spread into tissue around the lung near to where it started. This can be into:
    • the chest wall
    • the covering of the lung (pleura)
    • the middle of the chest (mediastinum)
    • other lymph nodes close to the affected lung.
  • Stage 3B The cancer has spread to:
    • lymph nodes on either side of the chest or above
    • the collarbone
    • another major structure such as the gullet (oesophagus), the heart, windpipe (trachea) or to a main blood vessel; or there may be two or more tumours in the same lung or a collection of fluid containing cancer cells around the lung (pleural effusion).

Stage 4

The cancer has spread to a distant part of the body such as the liver, bones or the brain.


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