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Number stages

Find out about the number stages for bowel cancer.

There are 5 main stages in the number stage system.

Doctors may also use the TNM staging system.

Stage 0 or carcinoma in situ (CIS)

Stage 0 or CIS means that you have an early stage of bowel cancer. There are cancer cells in your bowel lining, but they’re completely contained.

There is little risk of any cancer cells having spread. 

Stage 1

Stage 1 means that the cancer has grown through the inner lining of the bowel, or into the muscle wall, but no further.

There is no cancer in the lymph nodes. In the TNM staging, this is the same as T1, N0, M0 or T2, N0, M0. 

Stage 2

The cancer is localised and there is no cancer in the lymph nodes. Stage 2 can be divided into 2A and 2B

Stage 2A

Stage 2A means that the cancer has grown into the outer covering of the bowel. In the TNM staging, this is the same as T3, N0, M0.  

Stage 2B

Stage 2B means that the cancer has grown through the outer covering of the bowel, and has spread into the tissue layer covering the organs in the tummy (abdomen).

In the TNM staging, this is the same as T4, N0, M0. 

Stage 3

Stage 3 is divided into 3A, 3B and 3C. 

Stage 3A

Stage 3A means that the cancer is still in the inner layer of the bowel wall. Or has grown into the muscle layer. Between 1 to 3 nearby lymph nodes may contain cancer cells.

In the TNM staging, this is the same as T1, N1, M0 or T2, N1, M0.  

Stage 3B

Stage 3B means that the cancer has grown into the outer lining of the bowel wall. Or into the surrounding body tissues or organs. Between 1 to 3 nearby lymph nodes can contain cancer cells.

In the TNM staging, this is the same as T3, N1, M0 or T4, N1, M0.    

Stage 3C

Stage 3C means that the cancer can be any size. It has spread to 4 or more nearby lymph nodes. The cancer has not spread to any other part of the body. 

In the TNM staging, this is the same as any T, N2, M0. 

Stage 4A

Stage 4 means that the cancer has spread to other parts of the body. Such as the liver, lungs or bones. 

The cancer spreads through the lymphatic system or the bloodstream. In the TNM staging, this is the same as any T, any N, M1. 

Treatment

The stage of your cancer helps your doctor to decide what 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

Surgery is the main treatment for people with early stage bowel cancer. But some people may also have chemotherapy and radiotherapy. This is to shrink the cancer before surgery.  

If you have advanced bowel cancer, you might have chemotherapy or radiotherapy. Sometimes you can also have surgery. This is to remove as much cancer as possible and help with your symptoms. 

Last reviewed: 
09 Aug 2018
  • Colorectal cancer: the diagnosis and management of colorectal cancer
    The National Institute for Health and Care Excellence (NICE), 2011 

  • Primary colon cancer: ESMO Clinical Practice Guidelines for diagnosis, adjuvant treatment and follow-up
    Labianca and others. Annals of Oncology, 2010. Vol 21 

  • Rectal cancer: ESMO clinical practical guidelines for diagnosis, treatment and follow up
    R Glynne-Jones and others
    Annals of Oncology, 2017. Volume 28, Pages 422-440

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