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Colorectal Cancer: Surgery

It can be daunting to hear you have colorectal cancer. As you learn more, you might wonder how it will be treated. One option? Surgery. The type of surgery you have will depend on the type of cancer, where it is, and how much it has spread. Other factors, such as your preferences and overall health, will also play a role. 

When do you need colorectal surgery

Sometimes your healthcare provider may find colorectal polyps or early-stage colorectal cancer during a colonoscopy. When that happens, they might be able to remove the polyps or cancer by passing small tools through the tube used to do the colonoscopy. That means no cut (incision) is needed.

But that might not always be the case. You might need surgery when:

  • You've had a colonoscopy, but your healthcare provider could not remove all of the polyp.  You’ll need surgery to take out the rest of the polyp. This is done because the remaining polyp might contain cancer cells that could spread over time. The only way to know if a polyp has cancer is to check it under a microscope.

  • You've had a polyp completely or partly removed, and that polyp has invasive cancer cells in it.  The removed polyp tissue is checked for cancer by looking at it under a microscope. If cancer is found and the polyp was not removed completely, you’ll need surgery to make sure all the cancer is gone. You’ll also need surgery if cancer is touching the edge of the area where the polyp was removed.

  • You have a stage I, II, or III colorectal cancer.  These stages mean that the cancer hasn’t spread to other parts of the body, so all of the cancer might be able to be removed with surgery . After your surgery, you may also need other treatments, such as radiation or chemotherapy.

  • You have stage IV (advanced) colorectal cancer that has spread only to parts of the liver or lungs that can also be removed with surgery.  Your surgeon will remove the cancerous areas of those organs. You may need additional treatments, such as radiation or chemotherapy, before or after surgery.

  • You have advanced cancer that threatens to block (obstruct) the colon or cause other major problems.  Sometimes surgery is used to fix problems related to the cancer and to ease symptoms. But it won’t cure the cancer. One example is when a tumor blocks the colon. To fix this, the surgeon will create a colostomy. This connects the part of your colon before the blockage to an opening made on the skin of your belly. This allows waste to leave your body. This procedure can be done in a person who isn’t healthy enough for surgery.

Types of colorectal surgery

There are several surgeries that can treat colorectal cancer. The three most common are:

  • Polypectomy. This surgery removes a polyp. It's often done during a colonoscopy. No incision is made in the skin.

  • Local excision. This removes the cancer and a small edge of the normal tissue around it. If the tumor isn't very deep, this can be done during a colonoscopy. It might also be done during a separate surgery.

  • Surgical resection of the tumor. Keep reading for more information about this surgery.

What is resection surgery?

During resection surgery, part of your colon or rectum is removed. So are the nearby lymph nodes. The surgery is most often done by making one or many incisions in your belly.

The surgery differs depending on whether the cancer is in your colon or rectum.

For colon cancer

If you have colon cancer, the resection surgery is called a partial colectomy or hemicolectomy. In this surgery, the surgeon takes out the cancerous part of your colon. They also take a small amount of the healthy colon tissue on either side. They may also remove nearby lymph nodes to check for cancer.

There are two ways to do this surgery:

  • Open colectomy is done through one long incision in the belly.

  • Laparoscopic-assisted colectomy is done by using long, thin surgical tools passed through many small cuts in the belly.

Colectomy is often done with anastomosis. This means the ends of the colon are sewn back together. A short-term colostomy is needed to divert stool out of the body until the reattached part of the colon heals.

For rectal cancer

If you have rectal cancer, there are several different potential surgeries. Your healthcare team will talk with you about the best type of surgery for you. It will depend on the stage of the cancer and where it is in your rectum.

The most common options for surgery are:

  • Transanal resection and transanal endoscopic microsurgery. These surgeries are used to treat some early-stage cancers. No cutting is needed. Instead, the surgery is done with tools passed into the anus.

  • Lower anterior resection. This surgery removes the part of your rectum that has cancer.

  • Proctectomy with colo-anal anastomosis. This removes your whole rectum. Afterwards, your colon is joined to the anus.

  • Abdominoperineal resection. This removes your anus and the tissues around it, including the sphincter muscle. You’ll need a permanent colostomy.

  • Pelvic exenteration. This removes your rectum as well as nearby organs if the cancer has spread there. These include the bladder, the prostate in men, or the uterus in women. You’ll need a permanent colostomy.

Risks and possible side effects

All surgery has risks. Some of the risks of any major surgery include:

  • Reactions to anesthesia

  • Excess bleeding

  • Blood clots in the legs or lungs

  • Damage to nearby organs

Common risks to this surgery

Some of the risks of any major surgery include:

  • Reactions to anesthesia

  • Excess bleeding

  • Blood clots in the legs or lungs

  • Damage to nearby organs

The following potential side effects and risks are related specifically to colorectal surgery:


Infection risk is higher because of the bacteria in your colon. Pre-surgery treatments can help reduce this risk. Infection can happen at either the incision site on the skin or inside the belly. Your healthcare team can treat some skin infections by draining them and by using clean dressings. If an infection occurs inside your abdomen, you may need additional surgery. Your team may also prescribe antibiotics.

Anastomotic leak

An anastomotic leak is when your intestine leaks into your abdomen. This happens in a small number of people who have had a colorectal resection. It occurs at the connection where the two ends of the colon are relinked after removal. For small leaks, your healthcare team will keep watch. You may have to be careful about your diet, but it will heal itself. But large leaks can be life-threatening. You may need surgery to correct the problem.

Bowel blockage

Bowel blockage happens when scar tissue (adhesion) develops in your colon while it heals. This can cause symptoms such as pain, bloating, nausea, and vomiting. You may need surgery to fix the problem.

Colostomy or ileostomy

You may need a colostomy or ileostomy. In these procedures, a piece of the colon (or the ileum, part of the small intestine) above the tumor is linked to a small hole (stoma) made in the belly so waste can leave the body. The surgeon does this when they can’t reconnect the ends of the intestines after removing the tumor. A small bag is placed over the stoma to collect waste. Ostomies (colostomy or ileostomy) can be short-term or permanent. If your ostomy is short-term, the surgeon will reconnect the ends of intestines later.

Other risks

There are also some risks of surgery to remove a tumor from your rectum. These are:

  • Ureteral injury. Ureteral injury can occur during rectal surgery. Ureters are the tubes that carry urine from your kidneys to your bladder. If your surgeon notices the damage during the surgery, it can be fixed right away. Sometimes, they don’t notice the damage immediately. That can cause long-term problems.

  • Erectile dysfunction. Erectile dysfunction can occur in some men because the rectum is close to the prostate. The prostate is surrounded by the nerves involved in sexual function. If these nerves are damaged, it can cause problems getting or keeping an erection.

Getting ready for your surgery

To prepare for your surgery, you’ll have some extra meetings with your healthcare team.

Your surgeon will talk with you about the procedure. They’ll provide all the details for your surgery, and you’ll sign a consent form. By signing this, you give the surgeon permission to do the surgery. Be sure to ask any questions before you sign the consent.

You’ll also talk with an anesthesiologist. The anesthesiologist gives you general anesthesia. This is the medicine that puts you to sleep so you won’t feel any pain during surgery. They’ll also keep a close watch on you during surgery to keep you safe. During your meeting, you’ll talk about your medical history and your medicines.

A few days before your surgery, you may have to:

  • Clean out your colon with laxatives and enemas. Your healthcare provider will tell you when and how to use these.

  • Follow a special diet

Don’t worry. Your healthcare team will give you detailed instructions to follow.

What to expect during surgery

On the day of your surgery, you will be in an operating room with your healthcare team. This includes the anesthesiologist, surgeon, and nurses.

A typical surgery involves the following:

  • You’ll be moved onto the operating table.

  • Special stockings will be placed on your legs to prevent blood clots.

  • To keep track of your heart rate, your team will put ECG (electrocardiogram) electrodes on your chest and a blood pressure cuff on your arm.

  • The anesthesiologist will give you anesthesia through an IV (intravenous) line into your arm or hand.

  • Once you’re asleep, the surgeon will do the surgery.

  • The team will put a urinary catheter into your bladder during surgery if needed.

What to expect after surgery

After your surgery, you’ll probably feel very tired. Fortunately, you’ll be able to stay in the hospital for a while to recover. Your healthcare team will give you more details, but here are some general things to expect after surgery.

In the hospital

You’ll wake up in a recovery room after surgery. Your healthcare team will watch you closely. They’ll give you medicine to treat any pain you have.

Depending on your type of surgery, you can expect to stay in the hospital for up to seven days. If you have a laparoscopic-assisted colectomy, you can often go home sooner. That’s because they use smaller incisions that usually heal faster.

At home

Remember that it will take time to fully heal. Be patient with yourself. You may feel weak or tired for a while. Recovery time varies for each person. Be sure to listen to your body and take it easy.

Your healthcare team will give you specific instructions on how to resume your normal activities, but here’s what you can expect:

  • You can resume some exercise, but you shouldn’t lift heavy things for several weeks.

  • You might not be able to drive for a while. Discuss this with your healthcare team.

  • Care for your incision as instructed by your healthcare team. Don’t take baths or go swimming. Avoiding these activities will reduce your risk of infection.

  • If you have an ostomy, you'll have to take care of your stoma. Your team will teach you how to do this before you go home.

  • You may have a 5-inch to 7-inch scar on your belly if you had open surgery. This will likely heal into a thin scar.

Depending on the stage of your cancer, you may need either chemotherapy or radiation. Treatment given after surgery is called adjuvant therapy. This is done to reduce the chance that any remaining cancer cells will spread. Your team will discuss these options with you before surgery.

Eating after surgery 

You’ll have some food restrictions after the surgery. Your healthcare team will give you detailed instructions. You may also talk with a nutritionist or dietitian to help you plan your meals.

Typically, you’ll be advised to:

  • Follow a special diet right after the surgery. You may get your nutrients through an IV line. You may have to be on a clear liquid diet until your bowels are moving again. You then may be able to add some soft foods and, later, normal foods.

  • Follow a low-fiber diet to rest your bowels if advised by your provider. It can take several months for your colon to heal. This will remove pressure on it.

Bowel movements after surgery

Your bowel movements will take some time to return to normal. For some it can take as long as two years to fully adjust.

After colorectal surgery, you may notice these changes:

  • You may have more bowel movements than before. Some people have seven or eight a day in the first months post-surgery. Although you’ll have multiple bowel movements per day for a while, they will go down in number.

  • Your bowel movements may also be more urgent. You may find yourself rushing to the bathroom to prevent leaking more often.

Here are a few other things to consider:

  • If you had rectal cancer, you may have had a J-pouch inserted during surgery. This special pouch holds stool like your rectum did before surgery. The surgeon creates it by looping the colon back on itself and stapling it together (making a J-shaped pouch). Collecting the stool until you can get to a bathroom helps you get back to a stable bowel pattern more quickly. You may return to normal in as little as a few months.

  • Some surgeries require the surgeon to create an ostomy in your belly. This ostomy can be short-term or permanent and helps waste leave your body. While it can seem overwhelming, don’t worry. A specially trained therapist can help you adjust and learn how to care for it.

Online Medical Reviewer: Jessica Gotwals RN BSN MPH
Online Medical Reviewer: Sabrina Felson MD
Online Medical Reviewer: Todd Gersten MD
Date Last Reviewed: 5/1/2023
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