Surgery to remove all of or a part of your bowel (colectomy)

Your surgeon might remove the part of your large bowel (colon) containing the cancer. This is called a colectomy. Your surgeon also removes nearby lymph nodes.

Surgery to remove part of the colon is called a hemicolectomy or partial colectomy. Surgery to remove the whole of the large bowel (colon) is called a total colectomy.

What type of surgery do I need?

The type of surgery you need for colon cancer depends on:

  • the stage of your cancer
  • where it is in your colon

For a small early stage colon cancer, your surgeon might just remove the cancer from the bowel lining, along with a border of healthy tissue. This is called a local resection. 

For larger cancers, your surgeon might remove the part of the bowel where the cancer is and join the 2 ends of your colon back together. This is called a colectomy. They might also remove the lymph nodes near to the bowel in case the cancer has spread to the nodes. 

There are different types of colectomy. The type you have depends on where the cancer is in your colon.

Removing part of the colon

The surgeon removes the part of the colon containing the cancer (a colectomy). How much your surgeon takes away depends on the exact position and size of the cancer. 

After your surgeon removes your cancer, they join the ends of the bowel back together. The join is called an anastomosis.


Sometimes the surgeon brings the end of the bowel out as an opening on your abdomen called a stoma. This is to give the bowel time to heal.

  • An ileostomy is an opening (stoma) of the small bowel (ileum) onto the surface of the tummy (abdomen)
  • A colostomy is an opening (stoma) of the large bowel (colon) onto the surface of the tummy (abdomen)

The stoma may be temporary or permanent.

If you have a temporary stoma you may have another operation a few months later to join the ends of the bowel back together.  This is called a stoma reversal. In the meantime you wear a colostomy or ileostomy bag over the opening of the bowel, to collect your poo.

You might need to have a permanent colostomy or ileostomy. This depends on where the cancer is in your colon, or if you are in poor health. Your surgeon will avoid this if at all possible. Sometimes your surgeon can't tell if you will need a permanent stoma until during the operation. They may not know how big the cancer is, or how much of the bowel it affects.

Type of surgery to remove part of the colon

Surgery to remove the left side of the colon is called a left hemi colectomy. 

Diagram of left hemicolectomy

Removing the middle part of the bowel (transverse colon) is called a transverse colectomy.

Diagram of transverse colectomy

Removing the right side of the bowel is called a right hemi colectomy. 

Diagram of right hemi colectomy

Removing the sigmoid part of the bowel (sigmoid colon) is called a sigmoid colectomy. 

Diagram of sigmoid colectomy

Removing all of the colon

Surgery to remove the whole of the large bowel (colon) is called a total colectomy. The surgeon brings the end of the small bowel to the surface of the abdomen to make an ileostomy.

Sometimes it is possible for the small bowel to be joined to the lower part of the bowel (the rectum).

A subtotal colectomy is where the surgeon removes most of the colon but is able to leave part of the left side of the colon called the sigmoid colon. The surgeon joins the small bowel to the remaining bit of large bowel (sigmoid colon).

Diagram showing the colon and rectum
Diagram showing the removal of the whole bowel called total colectomy

How you have surgery

Open surgery  

This means your surgeon makes one long cut down your abdomen to remove the cancer.  

Keyhole (laparoscopic) surgery  

Your surgeon makes several small cuts in your abdomen. They pass a long tube with a light and camera through one of the holes. Surgical instruments are put into the other holes and are used to remove the cancer.  

Generally, with keyhole surgery, people recover quicker.  

Your surgeon might offer you keyhole surgery if they need to remove part of your bowel. But it depends on your situation, and some people aren’t able to have keyhole surgery. Sometimes the surgeon has to switch from keyhole to open surgery during the operation. Your surgeon will talk to you about this before your operation.  

Robotic surgery  

Some surgeons use a robotic system to help with keyhole surgery. The surgeon sits slightly away from you and can see the operation on a magnified screen. The robotic machine is next to you. The machine has 4 arms. One arm holds the camera, and the others hold the surgical instruments. The surgeon controls the arms of the machine to remove the cancer. 

Robotic surgery is still a new technique and not all hospitals in the UK have this. Doctors hope that robotic surgery might lower the risk of:

  • your surgeon needing to switch to open surgery  
  • complications during and after surgery

But at the moment, specialist doctors are still looking into the overall benefit of robotic surgery in bowel cancer compared to open and keyhole surgery.

Last reviewed: 
21 Sep 2018
  • 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

  • Primary colon cancer: ESMO Clinical Practice Guidelines for diagnosis, adjuvant treatment and follow-up
    R Libianca and others
    Annals of Oncology, 2010. Volume 21, Pages 70-77

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