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Stage 3

Find out what stage 3 lung cancer means and about treatments.

The stage of a cancer tells you how big it is and whether it has spread. Knowing the stage helps your doctor decide which treatment you need. It can also give some idea of your outlook (prognosis).

Stage 3 is part of the number staging system. 

Stage 3 can be divided into 3A, 3B and 3C.

Stage 3A

Stage 3A can mean different things.

Your cancer is up to 5cm in size and has spread to the lymph nodes in the centre of the chest on the same side as the tumour.

Diagram 1 of 5 showing stage 3A lung cancer

Or it is between 5cm and 7cm and there is more than one tumour in the same lobe of the lung:

Diagram 2 of 5 showing stage 3A lung cancer

Or the cancer has spread into one or more of the following areas:

  • the chest wall (ribs, muscle or skin)
  • the nerve close to the lung (the phrenic nerve)
  • the layers that cover the heart (mediastinal pleura and parietal pericardium)
  • lymph nodes in the lung or close to the lung
Diagram 3 of 5 showing stage 3A lung cancer

Or your cancer is larger than 7 cm. It hasn't spread into lymph nodes but has spread into one or more of the following areas:

  • the muscle under the lung (diaphragm)
  • the centre area of the chest (mediastinum)
  • the heart
  • a main blood vessel
  • the wind pipe (trachea)
  • the nerve that goes to the voice box (larynx)
  • the food pipe (oesophagus)
  • a spinal bone
  • the area where the wind pipe divides (the carina)
Diagram 4 of 5 showing stage 3A lung cancer

Or your cancer is in more than one lobe of the same lung and there might also be cancer cells in lymph nodes close to the affected lung.

Diagram 5 of 5 showing stage 3A lung cancer

Stage 3B

Stage 3B can also mean different things.

Your cancer is less than 5cm and has spread into lymph nodes in one of these places:

  • the opposite side of the chest from the affected lung
  • the neck
  • above the collarbone
Diagram 1 of 4 showing stage 3B lung cancer

Or your cancer is between 5cm to 7cm and has spread into lymph nodes in the centre of the chest.

Diagram 2 of 4 showing stage 3B lung cancer

Or the cancer is any size, has spread into lymph nodes in the centre of the chest, and has spread into one or more of the following areas:

  • the chest wall
  • the muscle under the lung (diaphragm)
  • the layers that cover the heart (mediastinal pleura and parietal pericardium)
Diagram 3 of 4 showing stage 3B lung cancer

Or stage 3B means that your cancer has spread into the lymph nodes in the centre of the chest. The lung tumour is more than 7cm or it has spread into a major structure in your chest such as:

  • the heart
  • the wind pipe (trachea)
  • the food pipe (oesophagus)
  • a main blood vessel
Diagram 4 of 4 showing stage 3B lung cancer

Stage 3C

Stage 3C can also mean different things. 

Your cancer is between 5cm and 7cm in size or has spread into one or more of the following:

  • the nerve close to the lung (phrenic nerve)
  • the covering of the heart (parietal pericardium)

and it has spread into lymph nodes:

  • in the centre of the chest on the opposite side from the affected lung or
  • at the top of the lung on the same side or opposite side or
  • above the collar bone
Diagram 1 of 4 showing stage 3C lung cancer

Or there is more than one tumour in a different lobe of the same lung.

Diagram 2 of 4 showing stage 3C lung cancer

Or stage 3C can mean the cancer is bigger than 7cm or it has spread into one of the following:

  • the muscle under the lung (the diaphragm)
  • the centre of the chest (mediastinum)
  • the heart
  • a major blood vessel
  • the wind pipe (trachea)
  • the nerve going to the voice box (the recurrent laryngeal nerve)
  • the food pipe (oesophagus)
  • a spinal bone
  • the area where the windpipe divides (the carina)

and it has spread into lymph nodes:

  • in the centre of the chest on the opposite side from the affected lung or
  • at the top of the lung on the same side or opposite side or
  • above the collar bone
Diagram 3 of 4 showing stage 3C lung cancer

Or there are tumours in more than one lobe of the lung.

Diagram 4 of 4 showing stage 3C lung cancer

TNM stages

The TNM staging system stands for Tumour, Node, Metastasis.

  • T describes the size of the tumour
  • N describes whether there are any cancer cells in the lymph nodes
  • M describes whether the cancer has spread to a different part of the body

In the TNM staging system stage 3A is the same as one of the following:

  • T1a-c, N2, M0
  • T2a-b, N2, M0
  • T3, N1, M0
  • T4, N0, M0
  • T4, N1, M0

Stage 3B is the same as one of the following:

  • T1a-c, N3, M0
  • T2a-b, N3, M0
  • T3, N2, M0
  • T4, N2, M0

Stage 3C is the same as:

  • T3, N3, M0
  • T4, N3, M0

Treatment

The stage of your cancer helps your doctor to decide which treatment you need. Treatment also depends on:

  • your type of cancer (the type of cells the cancer started in)
  • where the cancer is 
  • other health conditions that you have

The treatment for small cell lung cancer is different to the treatment for non small cell lung cancer.

Non small cell lung cancer

There are many different treatment possibilites for stage 3 non small cell lung cancer. Your doctor will discuss your options with you.

Chemotherapy followed by surgery

You might have chemotherapy followed by surgery to remove part or all of the lung. Your fitness for surgery depends on your general health and how well you are likely to recover.

After the surgery you might have more chemotherapy. 

Surgery followed by chemotherapy

You might have surgery to remove all or part of the lung, followed by chemotherapy. You might then have radiotherapy.

If you can’t have surgery

If you can’t have surgery you might have radiotherapy, chemotherapy or chemoradiotherapy (chemotherapy with radiotherapy).

Small cell lung cancer

The main treatment is chemotherapy, followed by radiotherapy to the chest.

If you are fit enough you might have chemoradiotherapy. This means you have chemotherapy at the same time as radiotherapy.

After you finish treatment, you might have radiotherapy to your head. This treatment is called prophylactic cranial radiotherapy (PCR). You have this because it is quite common for small cell lung cancer to spread to the brain. The radiotherapy aims to kill any cancer cells that may have already spread to the brain but are still too small to see on scans.

You have might have prophylactic cranial radiotherapy if:

  • your chemotherapy or radiotherapy treatment has stopped your cancer growing
  • you are well enough

Other stages

Last reviewed: 
01 Aug 2017
  • TNM Classification of Malignant Tumours (8th edition)
    International Union Against Cancer   
    John Wiley and Sons, 2016

  • AJCC Cancer Staging Manual (8th edition)
    American Joint Committee on Cancer
    Springer, 2016

  • Lung cancer: diagnosis and management
    National Institute for Health and Care Excellence (NICE), 2011

  • Management of lung cancer
    Scottish Intercollegiate Guideline Network, 2014

  • The IASLC Lung Cancer Staging Project: Proposals for Revision of the TNM Stage Groupings in the Forthcoming (Eighth) Edition of the TNM Classification for Lung Cancer
    Peter Goldstraw and others for the Study of Lung Cancer Staging and Prognostic Factors Committee
    Journal of Thoracic Oncology, 2015, vol.11, No.1:39-51

  • Guidelines on the Radical Management of Patients with lung cancer
    British Thoracic Society guidelines
    Thorax, October 2010 Vol 65 Supplement 3 October

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