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Bowel resection

Bowel resection is surgery to remove part of the small intestine, large intestine or both. The large intestine includes the colon, rectum and anus. Depending on which parts of the intestine are removed, bowel resection may also be called:

  • small intestine, or small bowel, resection
  • colon, or large bowel, resection
  • colectomy
  • segmental bowel resection

Why a bowel resection is done

A bowel resection is done to:

  • treat cancer in the small intestine, colon, rectum or anus
  • treat or relieve symptoms of cancer that has spread to the intestine
  • remove a blockage in the intestine (called bowel obstruction)
  • remove as much cancer as possible (called debulking)
  • remove precancerous conditions before they become cancer (called prophylactic surgery)
  • remove parts of the colon that are damaged by an inflammatory bowel disease (IBD) or diverticulitis
  • fix a tear or hole in the intestine (called bowel perforation)

Types of bowel resection

Different types of bowel resection are done to remove different parts of the intestine. Each type of bowel resection is named based on what it removes.

Segmental small bowel resection

A segmental small bowel resection removes part of the small intestine. The surgeon may also remove some of the mesentery (a fold of tissue that supports the small intestine) and lymph nodes in the area.

A segmental small bowel resection is used to remove tumours in the lower part of the duodenum (the first part of the small intestine). It is also used to remove tumours in the jejunum (the middle part of the small intestine) or the ileum (the last part of the small intestine) if the cancer is only in these structures or it has spread just beyond the small intestine.

Right hemicolectomy

A right hemicolectomy removes:

  • part of the ileum (the last part of the small intestine)
  • the cecum (the first part of the large intestine)
  • the ascending colon (the first part of the colon)
  • the hepatic flexure (the bend in the colon near the liver)
  • the first part of the transverse colon (the middle of the colon)
  • the appendix

A right hemicolectomy is used to remove tumours in the right colon, including the cecum and ascending colon. An extended right hemicolectomy, which also removes all of the transverse colon, may be done to remove tumours in the hepatic flexure or transverse colon.

Diagram of right hemicolectomy

Transverse colectomy

A transverse colectomy removes the transverse colon.

This surgery may used to remove a tumour in the middle of the transverse colon when the cancer hasn’t spread to any other parts of the colon. Some doctors prefer to do an extended right hemicolectomy rather than a transverse colectomy.

Diagram of transverse colectomy

Left hemicolectomy

A left hemicolectomy removes:

  • part of the transverse colon
  • the splenic flexure (the bend in the colon near the spleen)
  • the descending colon
  • part of the sigmoid colon

A left hemicolectomy is used to remove tumours in the left colon, including the splenic flexure.

Diagram of left hemicolectomy

Sigmoid colectomy

A sigmoid colectomy removes the sigmoid colon. It is used to remove tumours in the sigmoid colon.

Diagram of sigmoid colectomy

Low anterior resection

A low anterior resection removes the sigmoid colon and part of the rectum.

Low anterior resection is used to remove tumours in the middle or upper part of the rectum.

Diagram of low anterior resection

Proctocolectomy with coloanal anastomosis

Proctocolectomy (also called proctectomy) removes all of the rectum and part of the sigmoid colon. Coloanal anastomosis is a procedure the surgeon does to join the remaining colon to the anus.

This surgery is used to remove tumours in the lower part of the rectum. It is not used very often because many surgeons prefer to use a low anterior resection or abdominoperineal resection to remove rectal tumours.

Diagram of proctocolectomy with coloanal anastomosis

Abdominoperineal resection

An abdominoperineal resection removes the rectum, anus, anal sphincter and muscles around the anus. The surgeon makes one incision, or cut, in the abdomen and another one in the perineum (the area between the anus and vulva in women or between the anus and scrotum in men). A permanent colostomy is needed because the anal sphincter is removed.

An abdominoperineal resection is used to remove tumours that are close to the anus or have grown into muscles around the anus.

Diagram of abdominoperineal resection

Subtotal or total colectomy

Colectomy is surgery to remove part or all of the colon. If most of the colon is removed, it is called a subtotal, or partial, colectomy. If all of the colon is removed, including the cecum and the appendix, it is called a total colectomy.

A subtotal or total colectomy is done when there is cancer on both the right and left sides of the colon. These surgeries may also be offered to some people with familial adenomatous polyposis (FAP) or hereditary non-polyposis colon cancer (HNPCC) as a way to prevent colorectal cancer (called prophylactic colectomy). People with an inflammatory bowel disease (IBD) may have subtotal or total colectomy to remove the damaged or diseased colon.

Depending on the type of colectomy done, the surgeon may also need to do a colostomy or ileostomy.

Diagram of total colectomy

Whipple procedure

The Whipple procedure (also called pancreaticoduodenectomy) is surgery to remove part of the pancreas along with the duodenum (the first part of the small intestine). It also removes the lower part of the stomach, the gallbladder and part of the common bile duct

A Whipple procedure may be used to treat cancer of the pancreas, bile duct, gallbladder and small intestine.

Find out more about the Whipple procedure.

Preparing for a bowel resection

Before surgery, your healthcare team will usually do tests to check your general health and make sure you can have surgery. For example, blood tests, a chest x-ray and electrocardiogram (ECG) may be done to check the health of certain organs. You may also have blood tests to check for malnutrition. If you are malnourished, your healthcare team may postpone your bowel resection until your nutrition improves. Find out more about these tests and procedures and nutrition for people with cancer.

Your doctor or healthcare team will tell you if you need to follow a special diet before surgery. Your healthcare team will also tell you when to stop eating and drinking before surgery.

Depending on the type of bowel resection, you may need to clear the intestine before surgery. This usually includes taking a cleansing preparation, made with a type of laxative, 1–2 days before surgery. You may also be given cleansing enemas at the hospital to make sure the intestine is as empty as possible.

If you need a colostomy or ileostomy, your surgeon will usually mark the abdomen where the stoma will be to make sure it is in a convenient and comfortable place. Your surgeon or healthcare team may also discuss the type of pouch (also called ostomy appliance) that you will need to use after the surgery. You may be given antibiotics just before surgery to help prevent infection.

Approaches to surgery

The surgeon can use an open or laparoscopic technique. With the open technique, the surgeon makes a large cut, or incision, in the abdomen to reach the intestine. With the laparoscopic technique, the surgeon makes small cuts in the abdomen and then inserts an endoscope (a thin, tube-like instrument with a light and lens) and tools to do the surgery.

The laparoscopic technique tends to have a shorter hospital stay, faster recovery time, less pain at the incisions and fewer complications than the open technique. But some people may not be able to have a laparoscopic bowel resection because of the location and stage of the cancer, or other factors. In addition, surgeons need special training, skills and equipment to use the laparoscopic technique. It may not be available at all centres and it is not a standard way to do a bowel resection.

How a bowel resection is done

A bowel resection is done in the hospital under general anesthesia.

During a bowel resection, some parts of the intestine need to be mobilized. This means that the surgeon cuts membranes holding the intestines in place so they can be moved and stretched.

The surgeon then removes the diseased or damaged part of the intestine. The surgeon will also remove a margin of healthy tissue on either side of the diseased or damaged part of the intestine.


Once part of the intestine is removed, the surgeon joins the 2 remaining ends of the intestine together using stitches or staples. This procedure is called anastomosis.

When all of the large intestine is removed and the anastomosis is between the small intestine and anus, it is called ileoanal anastomosis. When it is between the colon and anus, it is called coloanal anastomosis.

For either of these procedures, the surgeon may form the ileum or colon into a pouch before joining it to the anus. This is called a J-pouch because it is shaped like the letter J. A J-pouch creates a holding place for stool when the rectum is removed. It helps lower the number of bowel movements the person has and manage incontinence (the inability to control bowel movements).

In some cases, the surgeon doesn’t join the ends of the intestines together. Instead, the surgeon attaches one or both ends of the intestines to an opening on the abdomen. This procedure is called colostomy or ileostomy (depending on the part of the intestine used).

Lymph node dissection

If the bowel resection is being done to remove cancer, the surgeon will also remove at least 12 nearby lymph nodes. Surgery to remove lymph nodes is called lymph node dissection.

A total mesorectal excision (TME) is a type of lymph node dissection that removes the mesorectum, which is fat surrounding the rectum that contains lymph nodes and blood vessels. TME is usually done during a bowel resection to remove cancer in the rectum. This surgery allows the surgeon to remove lymph nodes as well as a margin of tissue around the tumour (called the surgical margins).

Find out more about lymph node dissection.

Colostomy or ileostomy

Depending on which part of the intestine is diseased and how healthy the rest of the intestine is, the surgeon may need to do a colostomy or ileostomy after a bowel resection.

A colostomy is a surgical procedure to create an opening from the colon to the outside of the body through the abdominal wall. An ileostomy creates an opening from the ileum to the outside of the body through the abdominal wall.

A colostomy or ileostomy can be temporary or permanent. The doctor may do a temporary colostomy or ileostomy to allow the intestine to rest and heal after surgery. A colostomy or ileostomy will be permanent if the lower part of the rectum and anal sphincter are removed during the bowel resection.

Find out more about colostomy and ileostomy.

Side effects

Side effects can happen with any type of surgery, but everyone’s experience is different. Some people have many side effects. Other people have few or none at all.

Side effects of bowel resection are usually temporary. The side effects that you may have depend mainly on the type of bowel resection done and your overall health. Side effects of bowel resection include:

  • pain
  • fatigue
  • bleeding
  • blood clots
  • diarrhea
  • constipation
  • a blockage in the intestine (called bowel obstruction)
  • paralyzed or inactive intestine (called paralytic ileus)
  • damage to nearby organs, such as the small intestine, bladder, ureters or spleen
  • leaking from where the 2 ends of the intestines were joined (called anastomotic leak)
  • infection
  • sexual problems (for example, men may have erectile dysfunction and retrograde ejaculation, and women may have pain during sex)
  • inability to control urination (called incontinence)
  • the need to urinate often
  • an intense need to urinate

Find out more about side effects of surgery and managing symptoms and side effects.

After surgery

After a bowel resection, you will need to stay in the hospital for several days. You will be given pain medicines to keep you comfortable. These medicines are usually given through a needle in a vein (intravenous, or IV).

You will be offered clear fluids for 1–2 days after surgery. Solid foods and meals will be introduced slowly.

If the bowel resection was done to remove cancer, you may need more treatments. You may be referred to a doctor who specializes in treating cancer (called an oncologist).

If you had a colostomy or ileostomy, a specially trained healthcare professional, called an enterostomal therapist, will teach you how to live with and care for the ostomy. Before you go home, the healthcare team or enterostomal therapist will talk to you about:

  • changing the bandages or dressing
  • showering and bathing
  • how and when to take any medicines you need
  • eating and drinking
  • physical activity
  • what to do if you have problems
  • when to visit the surgeon for follow-up

If the colostomy or ileostomy is temporary, your healthcare team will talk to you about how long you need to have it. Temporary ostomies are usually in place for a few months. Once the rest of the large intestine has healed, you will have another surgery to rejoin the 2 ends of the ileum or colon. This procedure is called anastomosis. The surgeon will also close the opening on your abdomen. After this second surgery, you will be able to pass stool from the anus normally. Find out more about living with an ostomy.


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