Treatment decisions for colon cancer

Bowel cancer can start in the large bowel (colon cancer) or the back passage (rectal cancer). Your treatment depends on whether you have colon or rectal cancer, as well as the stage of your cancer.

This page is about how your doctor decides which treatment you need for colon cancer that hasn’t spread to another part of your body. 

When colon and rectal cancer spread to another part of the body it is called advanced bowel cancer.

Deciding which treatment you need

Your doctor will talk to you about the treatment they suggest. They will explain its benefits and the possible side effects.

Your treatment will depend on:

  • where your cancer is
  • how big it is and whether it has spread (the stage)
  • the type of cancer
  • how abnormal the cells look under a microscope (the grade)
  • your general health and level of fitness

Treatment overview

The main treatments for colon cancer that hasn't spread are:

  • surgery
  • chemotherapy


Most people have surgery for colon cancer that hasn’t spread. Your surgeon might be able to take out all of your cancer. For some people this might cure the cancer.


Chemotherapy uses anti cancer (cytotoxic) drugs to destroy cancer cells. The drugs circulate throughout the body in your bloodstream.

Your doctor might suggest you have chemotherapy to lower the chance of your cancer coming back after surgery.

Chemotherapy aims to kill any cells left behind after your operation. This is called adjuvant chemotherapy.

Treatment by stage

The stage of your cancer means how big it is and whether it has spread.

Stage 1 colon cancer

Surgery is the main treatment.

People with very early colon cancer (stage 1) do not need chemotherapy after surgery.

Stage 2 colon cancer

You have surgery to remove your cancer.

Your surgeon might suggest chemotherapy after surgery if you are at higher risk of cancer coming back. This depends on the results of your surgery. Chemotherapy can lower the chance of your cancer coming back after surgery.

Stage 3 colon cancer

You have surgery to remove your cancer.

Most people have chemotherapy after surgery. This might be as part of a clinical trial.

Stage 4 colon cancer

Your doctor might recommend:

  • surgery
  • chemotherapy
  • radiotherapy
  • immunotherapy
  • targeted cancer drugs

Other treatments

Clinical trials are researching using targeted cancer drugs called monoclonal antibodies to treat early bowel cancer. 

Monoclonal antibodies recognise and attach to specific proteins produced by cells. Each monoclonal antibody recognises one particular protein. They work in different ways depending on the protein they are targeting. So, some monoclonal antibodies might block particular proteins that encourage a cancer to grow and others might stop cancer cells from making their own blood supply.

Clinical trials

Your doctor might ask if you’d like to take part in a clinical trial. Doctors and researchers do trials to make existing treatments better and develop new treatments.

  • Association of Coloproctology of Great Britain & Ireland (ACPGBI): Guidelines for the management of cancer of the colon, rectum and anus (2017) – diagnosis, investigations and screening 
    C Cunnigham and others  
    Colorectal disease, 2017. Volume 19, Pages 1-97

  • Localised colon cancer: ESMO Clinical Practice Guidelines for diagnosis, treatment and follow-up.
    G Argilés and others
    Annals of Oncology, 2020. Volume 31, Issue 10 Pages 1291-1305

  • Colorectal cancer 
    The National Institute for Health and Care Excellence (NICE), 2020. Updated December 2021

  • Metastatic colorectal cancer: ESMO Clinical Practice Guidelines for diagnosis, treatment and follow-up
    E. Van Cutsem and others
    Annals of Oncology, 2016. Volume 25 (Supplement 3)

Last reviewed: 
28 Jan 2022
Next review due: 
28 Jan 2025

Related links