This page was reviewed under our medical and editorial policy by

Katherine Poruk, MD, Surgical Oncologist

This page was reviewed on December 14, 2021.

Patients who are diagnosed with colorectal cancer have a number of treatment options available, depending on the stage and grade of the cancer, as well as the person's health and preferences. One colorectal cancer treatment that may be recommended for some patients is a colectomy, also referred to as colon resection surgery.

What is a colectomy?

A colectomy is surgery to remove all or part of the colon and surrounding lymph nodes. It may be used to treat colorectal cancer, and may also be recommended for other non-cancerous conditions, including Crohn's disease, ulcerative colitis and diverticulitis. The procedure is performed on a portion of the colon and sometimes rectum. The rectum and colon are alternately called the large bowel, so a colectomy is also known as a large bowel resection.

A colectomy is a major surgery that requires a lot of healing time, but most patients recover fully and resume normal activities within a few months.

Why a colectomy is performed

To better understand the need for a colectomy, this quick overview of the digestive system may be helpful:

  • The food people eat ends up in the stomach. It then empties into the small intestine, where much of the digestive process happens.
  • The small intestine then passes food to the large intestine (or colon), which does the final breakdown and reabsorbs water from waste.
  • The large intestine includes the cecum (and the finger-shaped appendix attached to it), the ascending colon, the traverse colon, the descending colon, the sigmoid colon and the rectum.
  • The rectum ends in the anus, the orifice through which waste exits the body.

One of the major reasons for a colectomy is to remove cancerous or precancerous lesions. However, several diseases may cause issues that require a colectomy, including:

  • Crohn's disease
  • Severe constipation
  • Intestinal blockages (also known as a bowel obstruction)
  • Diverticular disease
  • Colorectal polyps
  • Intestinal injuries
  • Bleeding
  • Twisting of the colon (or volvulus)
  • Ulcerative colitis (UC), as well as other digestive disorders

Types of colectomies

The different types of colectomies are determined by which section or how much of the colon and rectum is being removed.


During this procedure, doctors remove either the descending colon, the section that travels down the left side or the ascending colon, the section that travels upward on the right side.

Subtotal colectomy

During a subtotal colectomy, the surgeons remove part of the colon but none of the rectum. This procedure may also be called a partial colectomy.


During this surgery, doctors remove both the colon and the rectum.

Total abdominal colectomy

During a total abdominal colectomy, doctors remove the entire large intestine and then attach the small intestine directly to the rectum.

Diverting colostomy

During a diverting colostomy, doctors attach the digestive tract to an opening made in the abdominal wall (a stoma) for waste to exit.

How colon resection surgery is performed

Surgeons perform colectomies in the two ways listed below.

Open colectomy: The surgeon makes a long incision and opens the abdominal cavity.

Laparoscopic-assisted or robotic-assisted colectomy: The surgeon makes small incisions into the abdominal cavity to insert surgical tools and a video camera.

Recovery typically takes longer with an open colectomy, although for either type, the patient may be in the hospital between two and seven days.

Colectomy risks

Because the patient is put under general anesthesia, and a colectomy is major surgery, the procedure carries some potential risks. Be sure to discuss these safety risks with the care team.

  • The patient may react badly to the anesthetic medications or develop a breathing problem while under anesthesia.
  • During surgery, nearby organs may be damaged, requiring repair or additional surgery.
  • Bleeding during or after surgery may require a blood transfusion or a repeat procedure to stop the bleeding
  • It may take longer than expected for the bowel to start working again after surgery—a condition called an ileus that may cause nausea or vomiting—and the doctor may delay allowing the patient to have solid foods. This often requires additional days in the hospital until the ileus resolves.
  • Right after surgery, the patient may have:
    • Blood clots in the legs (deep venous thrombosis), requiring treatment with blood thinners
    • Bleeding
    • Infection in the abdomen or at the incision site
    • Hernia at the site of surgery
    • Anastomotic leak (in which the internal wound breaks open)

How to prepare for a colectomy

To prepare for the surgery, the patient should consider the following steps.

  • Make sure the surgical team and anesthesiologist know about all the medications and supplements the patient takes. Ask how and when to take any regular medications on the day of surgery.
  • The patient may need to stop taking drugs that thin the blood, including aspirin, ibuprofen and naproxen.
  • The patient may be asked to drink only clear fluids and/or stop eating and drinking at a certain time prior to surgery.
  • Stop smoking (since smoking slows healing and creates a higher risk of complications).
  • Alert the surgical team if the patient develops a cold, flu or other illness prior to surgery.

Additionally, in the days leading up to surgery, the doctor may recommend bowel preparation, which may include a liquid diet, enemas and potentially laxatives to clear his or her bowel.

What to expect the day of colon resection surgery

During a colectomy, an anesthesiologist administers drugs to help the patient fall asleep, stay asleep and feel no pain (called general anesthesia). The surgery itself may take up to four hours, and the patient may be in the hospital recuperating for two to seven days.

The actual surgery differs depending on the surgical approach (either open or minimally invasive).

  • In an open colectomy, the surgeon cuts 6-8 inches long along the abdominal cavity.
  • In a laparoscopic surgery, which only requires a few small cuts, the surgeon inserts instruments and a video camera. To do so, the surgeon fills the area with gas to see better.

In either surgical method, the surgeon inspects the large intestine and removes diseased areas and nearby lymph nodes.

If there's enough healthy large intestine left, these two ends may be brought together and stitched or stapled in a procedure called an anastomosis. If there’s not enough healthy intestine or there are concerns about the healing of the anastomosis, the surgeon attaches the open end of the digestive tract to the abdominal wall. This attachment creates a stoma, to allow waste to pass out of the body. If this surgery connects the colon to the abdomen, it’s called a colostomy. If it connects the small intestine to the abdominal wall, it’s an ileostomy. These attachments may be either short-term or permanent.

What to expect after a colectomy

After surgery, the patient may recover in the hospital for several days, up to a week. He or she may only be able to drink clear liquids for the first few days. Eventually, the patient's diet expands to thicker fluids and soft foods.

To help the patient heal, the care team may provide specific instructions based on:

  • Which surgery was performed and why
  • How the surgery was performed
  • How much colon was removed
  • Whether or not the patient has a stoma 

Home care after colectomy

When the patient goes home, he or she may still be in pain for potentially up to several weeks. This is especially true if the patient coughs, sneezes or makes sudden movements.

To ease pain and expedite healing:

  • Take it slow
  • Try to take short walks
  • Avoid overexertion
  • Take pain medication regularly (and avoid driving while on it)

Bowel movements may be difficult and potentially painful at first. The patient's feces may be hard, and he or she may not be able to move the bowels at all, or they may get looser. If the patient is constipated (a possible side effect of pain medication or some foods during recovery), try:

  • Taking a walk or being active
  • Easing up on narcotic pain medications
  • Asking the doctor about stool softeners
  • Asking about milk of magnesia or other laxatives
  • Asking about high-fiber foods

Eating may also be challenging at first. Try to eat small amounts of food several times a day, but avoid foods that typically cause gas, loose stools or constipation. The patient is also encouraged to remain well-hydrated throughout the day.

When to call the doctor after colectomy

Call the care team if any of the following occur:

  • Vomiting
  • Diarrhea
  • Fever over 101
  • Swelling in the abdomen or legs
  • Constipation for more than four days
  • Black, tarry or bloody stools
  • Chest pains
  • Shortness of breath
  • Changes in the site of surgery such as redness or bleeding

Long-term side effects of colon resection surgery

The long-term side effects a patient experiences may differ based on the extent of the procedure and whether he or she had a colostomy or ileostomy. If the patient underwent a total abdominal colectomy, he or she may have four to six bowel movements a day after recovery.

Over time, scar tissue may form in the abdomen that blocks the intestines or cause adhesions where the organs stick together, causing twisting, pain and swelling.

If the patient had a colostomy or ileostomy, he or she may need to use bags to collect stool. A specially trained ostomy nurse or enterostomal therapist may show the patient how to care for the stoma and where to order supplies. The colostomy or ileostomy may be reversed in two to six months, or it may be permanent.

Expert cancer care

is one call away.
appointments in as little as 24 hrs.