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Surgery for colon cancer

Find out about different types of surgery for cancer of the large bowel (the colon). The type of operation you have depends on the position of the cancer in the bowel.

If your cancer is in the back passage (rectum) the types of surgery are different.

Types of surgery

There are different types of surgery for bowel cancer. The operation that is most suitable for you depends on:

  • where your cancer is
  • type and size of cancer 
  • whether your cancer has spread to other parts of your body 

For a small early stage 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. 

If your cancer is larger, your surgeon might remove the part of the bowel where the cancer is, and join the two ends 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. 

To give the bowel time to heal, the surgeon might make a temporary ileostomy or colostomy. This is an opening from the bowel that leads to the surface of the abdomen and is called a stoma. Waste matter from the bowel collects into a special bag over the opening. You have another operation to repair the stoma after a few months (a stoma reversal).

The surgeon might have to make a permanent stoma if a lot of your bowel is removed. But most people don't need a permanent stoma.

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.  

Keyhole surgery can take longer than open surgery, but generally 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

Surgery to remove a small part of bowel lining (local resection)

Your surgeon removes the cancer and a border of healthy tissue (margin) around the cancer. The tissue goes to the laboratory for tests. 

A specialist doctor called a pathologist looks at the cancer cells under the microscope, to see how abnormal they are. If the cells look very abnormal (high grade), your surgeon may decide you need a second operation. This removes tissue that could contain cancer cells and lowers the chance of your cancer coming back. 

Diagram of bowel cancer early resection

Surgery to remove a section of your bowel (colectomy)

The type of operation you have depends on where your tumour is in the large bowel (colon). The surgeon removes the part of the colon containing the tumour. This is called a colectomy. How much your surgeon takes away depends on the exact position and size of the cancer. 

Removing 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 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:

  • if the small bowel (ileum) is bought out onto the abdominal wall, it is called an ileostomy
  • if the large bowel (colon) is bought out, it is called a colostomy.

The stoma is usually temporary and the ends of the bowel are joined back together in another operation a few months later. 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.

If you have a large area of bowel removed, or are in poor health, you may need to have a permanent colostomy or ileostomy. 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.

Surgery if cancer blocks the bowel

Sometimes bowel cancer can cause a blockage. This is called bowel obstruction. If this happens you will need an operation straight away. Your surgeon may put a tube called a stent into the bowel. This holds the bowel open allowing it to work properly again. Or your surgeon may remove your tumour from the bowel. 

Information and help

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