The type of surgery you have for cancer of the back passage (rectal cancer) depends on the position and the size of your cancer

Most people with rectal cancer have surgery. The 2 main types of surgery for rectal cancer are trans anal endoscopic microsurgery (TEM) and total mesorectal excision (TME).

Surgery to the large bowel (colon) is different to rectal cancer surgery.

Treatment decisions

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

• whether your cancer is in the low, middle or high part of the rectum
• how far it has grown or spread (the stage) - for rectal cancers, doctors use the TNM staging system
• how abnormal the cells look under a microscope (the grade)

The doctors use your MRI scan results to decide which surgery you need to completely remove your cancer with a clear border (margin) of tissue. They consider how likely it is that your cancer will come back after surgery and decide if you need:

• surgery on its own
• surgery combined with either radiotherapy or chemoradiotherapy (radiotherapy and chemotherapy together)

After your operation, a specialist doctor (pathologist) closely exams your cancer. You might need further treatment if the pathologist’s report shows your risk of the cancer coming back is higher than the surgeon previously thought.

Types of surgery

Most people with rectal cancer have surgery. The 2 main types of surgery for rectal cancer are:

• trans anal endoscopic microsurgery (TEM) - the surgeon removes the cancer along with a border (margin) of healthy tissue
• total mesorectal excision (TME) - the surgeon removes the part of the rectum that contains cancer, a border (margin) of healthy tissue around it, and the fatty tissue (mesorectum) around the rectum

Surgery to remove a small part of the rectum (trans anal endoscopic microsurgery)

Trans anal endoscopic microsurgery (TEMs) is for small early stage cancers with a low risk of coming back. Your surgeon will remove the cancer from the back passage, along with a border (margin) of healthy tissue.

The surgeon uses a flexible tube called a colonoscope. The tube has a small light and camera at one end. The surgeon puts the tube into your back passage. They can see pictures of the inside of your bowel on a TV monitor. 

Your surgeon removes the cancer and a border of healthy tissue (margin) around the cancer. They do this by passing cutting instruments down the colonoscope.

Total mesorectal excision

This is the most common type of surgery for rectal cancer. The surgeon removes the part of the rectum that contains cancer, as well as a border (margin) of healthy tissue around it. They also remove the fatty tissue (mesorectum) around the rectum. 

The mesorectum is a sheet of tissue surrounding the intestine, bowel, and rectum. It contains blood vessels and lymph nodes. It is possible that cancer cells might have spread to the mesorectum. 

A specialist doctor (pathologist) tests the cells in the surrounding tissue (margin) to check for cancer cells. If there are no cancer cells, this is called a clear margin.  

This operation lowers the risk of the cancer coming back. There are different types of total mesorectal excision depending on where the cancer is in your rectum, and how big it is. 

Cancer high in the back passage (rectum) 

Your surgeon will remove the cancer in the top part of the rectum. They attach the end of the colon to the remaining part of the rectum. The join is called an anastomosis.

 The surgeon removes the mesorectum to 5cm below the bottom edge of the tumour. Leaving some of the mesorectum in place, reduces the risk of a bowel join leaking after surgery. 

This operation is called an anterior resection. You might need to have a temporary stoma after this operation.

Cancer in the middle of your back passage (rectum)

Your surgeon will remove most of your rectum and attach the bowel (colon) to your anus.

Sometimes your surgeon will create a pouch by folding back a small section of colon or by enlarging a section of the bowel (colon). This small pouch works like the rectum did before surgery.  

This operation is called a colo anal anastomosis. You might need to have a temporary stoma after this operation.

Cancer low in the back passage (rectum) 

Your surgeon might not be able to leave enough of the rectum behind for it to work properly. Your surgeon removes the anus and rectum completely.

This operation is called an abdomino-perineal resection (AP resection). You will have a permanent colostomy after this operation.

After this surgery you will have one wound on your tummy. And you will have another wound on your bottom where the surgeon has removed your anus and closed the skin. 

Stomas

Sometimes the surgeon brings the end of the bowel out as an opening on your abdomen called a stoma. There are two different types of stomas:  

• ileostomy – the cut made in the small bowel is put through the lining of the abdomen  
• colostomy – the cut made in the large bowel is put through the lining of the abdomen 

Stomas can be temporary or permanent.

You have a temporary stoma to allow your bowel to heal after surgery.  The surgeon joins the ends of the bowel 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.

You are more likely to need a permanent colostomy if the cancer is very low in your rectum. Your surgeon will talk to you about whether you are likely to need a stoma, and whether the stoma will be temporary or permanent. They will refer you to a specialist stoma nurse who will provide you with information and support.  

Surgery if cancer blocks the bowel

Sometimes bowel cancer can cause a blockage, which stops you from being able to pass poo. Because of this you might become bloated. 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.  

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.

Doctors hope that robotic surgery might lower the risk of:

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

Robotic surgery is still a new technique and not all hospitals in the UK have this. It also isn’t possible for all types of rectal cancer. You can talk about this with your surgeon.