Colorectal Cancer: Surgery

Surgery is often part of the treatment for colorectal cancer. Different kinds of surgery may be done. Which type you need depends on the type of cancer, where it is, how much it has spread, and other factors, such as your preferences and overall health. 

When surgery may be an option

Colorectal polyps and early stage colorectal cancers are often first found during a colonoscopy. In this case, your healthcare provider might be able to completely remove the polyp or cancer by passing small tools through the tube used to do the colonoscopy. No surgical incision (cut) is needed.  

But surgery might be needed if:

  • You've had a colonoscopy, but your healthcare provider could not remove all of the polyp.  Surgery is then needed 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 remove all of it and 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 cells are found, surgery might be needed because the cancer may have spread beyond the polyp. But if your provider thinks the cancer is only in the polyp that was removed and hasn't spread, you may not need surgery.

  • You have a stage I, II, or III colorectal cancer.  These cancers have not spread to distant parts of the body, so all of the cancer might be able to be removed with surgery. Other treatments, like chemotherapy or radiation therapy, may be used before or after surgery.

  • You have stage IV (advanced) colorectal cancer, but it has only spread to parts of the liver or lungs that can also be removed with surgery.  Surgery on both the main tumor and the site where it has spread may be able to remove all of the cancer. Other treatments, such as chemotherapy or radiation therapy, may be needed as well. They might be given before and/or after surgery.

  • You have advanced cancer that threatens to block (obstruct) the colon or cause other major problems.  In these cases, surgery may be used, but the goal is not to cure the cancer. Instead, it may be used to fix the problem and ease symptoms. For instance, if the colon is blocked by a tumor, surgery may be done to create a colostomy. This connects the part of the colon before the blockage to an opening on the skin of the belly. This allows waste to leave the body. 

Types of surgery

The type of surgery you have depends on the stage of the tumor, where it is, your overall health and preferences, and other factors. Surgery for colon and rectal cancers may include:

  • Polypectomy. This is the removal of a polyp. It's often done during a colonoscopy. No incision (cut) is made in the skin.

  • Local excision. This is the removal of 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 with surgery.

  • Surgical resection of the tumor. Read more about this below.

Surgical resection of the tumor

Resection is the removal of part of your colon or rectum and nearby lymph nodes. It's most often done by making an incision (or incisions) in your belly. The type of surgery depends on whether the cancer is in your colon or rectum.

Surgery for colon cancer

The most common surgery for colon cancer is called a partial colectomy or hemicolectomy. The surgeon takes out the part of the colon that has cancer, as well as a small amount of the normal colon on either side. Nearby lymph nodes are also removed and checked for cancer. This surgery can be done through 1 long incision in the belly, called an open colectomy. Or it can be done by using long, thin surgical tools passed through many small cuts in the belly. This is called a laparoscopic-assisted colectomy.

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.

Surgery for rectal cancer

There are several different types of surgeries for rectal cancer. The type of surgery will depend on the stage of cancer and where it is in your rectum. Some early stage cancers can be treated with transanal resection and transanal endoscopic microsurgery (TEM). They use tools passed through the anus. There is no surgical cut in the skin.

Other more extensive rectal cancer surgery options include:

  • Lower anterior resection (LAR). This surgery removes the part of the rectum that has cancer.

  • Proctectomy with colo-anal anastomosis. This removes the whole rectum. The colon is then joined to the anus.

  • Abdominoperineal resection (APR). This removes the anus and the tissues around it, including the sphincter muscle. This surgery results in a permanent colostomy.

  • Pelvic exenteration. This removes the 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. This surgery results in 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

Along with the risks above, colorectal surgery can sometimes cause these problems:


Colorectal surgery increases your risk of infection because of the bacteria in your colon. Treatments before surgery can help reduce this risk. But a small portion of people who have colorectal surgery get an infection. This can happen either at the incision site on the skin or inside the abdomen. Healthcare providers can treat some skin infections by letting them drain and by using clean dressings. More serious infections can occur inside the abdomen. These may need additional surgery. Antibiotics are very helpful to treat infections.

Anastomotic leak

After the surgeon removes a section of colon, he or she often links the 2 ends together. A leak can occur at this connection. Then what's in your intestine can leak into your abdomen. Leaks occur in a small number of people who have a colorectal resection. If the leak is small, the only treatment may be to watch the area and to be careful about your diet, letting the colon heal itself over time. If the leak is large, it can be life-threatening. You may need surgery to correct it.

Bowel blockage

Sometimes your colon develops scar tissue called adhesions while it heals. This can block your intestines and cause symptoms such as pain, bloating, nausea, and vomiting. If these adhesions block the intestines, you may need surgery to fix the problem.

Colostomy or ileostomy

Depending on the stage and location of the cancer, the surgeon might not always be able to reconnect the ends of the intestines after removing the tumor. In these cases, the piece of the colon (or the ileum, the last part of the small intestine) above the tumor is linked to a small hole or stoma made in the belly. This lets waste out of the body. A small bag is then placed over the stoma to collect the waste.

For some people, an ostomy (colostomy or ileostomy) might only be needed for a short time until the bowel can heal itself. Then the ostomy is reversed, and the ends of the intestines are reconnected in another surgery at a later time. Other people may need a permanent ostomy. 

Changes in bowel function or what you can eat

Some people might need to change their diets and might have different bowel patterns after surgery (see below). 

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

  • Ureteral injury. The tubes that carry urine from your kidney to your bladder are called ureters. Sometimes they can be damaged during surgery. If they are, the healthcare provider can usually fix them during the procedure. If the damage isn't noticed, sometimes there can be long-term problems.

  • Erectile dysfunction. In men, the rectum is close to the prostate. The nerves that are involved in sexual function wrap around the prostate. Sometimes these nerves are damaged. This can cause problems with getting an erection, or erectile dysfunction.

In most cases, the benefits of removing a tumor outweigh these risks.

Getting ready for your surgery

A few days before your surgery, your healthcare provider will prescribe laxatives and enemas to help clean out your colon. Your healthcare provider will tell you when and how to use these. You may also be told to follow a special diet.

Before you have surgery, you will meet with your surgeon to talk about the procedure. After you have discussed all the details of the surgery, you will sign a consent form. This gives the healthcare provider permission to perform the surgery.

You will also meet with the anesthesiologist. This is the provider who will give you general anesthesia, the medicine that puts you to sleep so that you won't feel any pain during surgery. He or she also monitors you during surgery to keep you safe. He or she will ask about your medical history and your medicines.

What to expect during surgery

When it is time for your surgery, you will be taken into the operating room. Your healthcare team will include the anesthesiologist, the surgeon, and nurses.

During a typical surgery:

  • You will be moved onto the operating table.

  • Someone will place special stockings on your legs. These are to help prevent blood clots.

  • You will have electrocardiogram (EKG) electrodes put on your chest. These are to keep track of your heart rate. You will also have a blood pressure cuff on your arm.

  • You will be given anesthesia through an IV or intravenous line into your arm or hand.

  • When you are asleep, the surgeon will do the surgery.

  • A urinary catheter will be put into the bladder during surgery.

What is removed during surgery and where your incisions are will depend on the type of surgery you have. This is based on where the tumor is.

What to expect after surgery

You will wake up in a recovery room. You will be watched closely by healthcare providers. You will be given medicine to treat pain.

You may have to stay in the hospital for up to 7 days, depending on the type of surgery you have. People who have a laparoscopic-assisted colectomy can often go home sooner. That’s because they have smaller incisions that can usually heal faster.

You can slowly return to most normal activities once you leave the hospital. But you should not lift heavy things for several weeks. Always follow the instructions you get from your healthcare provider or nurse.

It will take time to get back to eating normally and having regular bowel movements. If you have an ostomy, you'll also learn how to take care of your hole or stoma. You will still have the urinary catheter in your bladder to drain urine. It is usually removed before you go home.

After surgery, you may feel weak or tired for a while. The amount of time it takes to recover after surgery will vary for each person. But you will probably not feel like yourself for a few months. You will be able to get your incision wet. But to reduce your risk of infection, don’t take baths or go swimming. You likely won't be able to drive for a while, as directed by your healthcare providers.

If you had an open surgery, you may have a 5-inch to 7-inch scar running up and down through your belly button. This will likely heal into a thin scar.

After surgery, you may have either chemotherapy or radiation to reduce the chance that any remaining cancer cells will spread. Treatment after surgery is called adjuvant therapy.

Eating after surgery 

You may not be able to eat for the first few days after surgery. You may get some nutrients through an IV line that’s put into one of your veins. At first, you will be on a clear liquid diet until there are signs that your bowels are moving again. Then you may be able to add some soft foods and then normal foods.

It may take your colon several months to heal after surgery. To rest your bowels, your healthcare provider may advise that you eat a low-fiber diet. Be sure you talk about your diet with your provider. He or she may refer you to a nutritionist or dietitian to help you plan your meals.

Bowel function after surgery

After having a section of your colon removed, you may have more bowel movements than normal. Some people have 7 or 8 a day in the first months after surgery. You may also have a more urgent need to have a bowel movement. This means that once you feel the urge, you may have to get to the bathroom quickly to avoid leaking. These side effects usually get better over time. It may take as long as 2 years to fully adjust. Even then, you’re likely to have bowel movements several times a day. And you may still have bowel urgency.

If your tumor was in the rectum, your surgeon may have made a special pouch called a J-pouch. It holds stool as your rectum did before surgery. Your surgeon forms the J-pouch during the same surgery to remove your rectum. The surgeon loops the colon back on itself and staples it together. This creates a pouch that looks like the letter J. Stool collects there until you can get to a bathroom. This helps you to get back to a stable bowel pattern more quickly after surgery. You may be able to have stable bowel function after a few months.

Depending on the type of surgery you had, your healthcare provider may have created an ostomy in your belly. This allows waste to leave your body. This may be short-term or permanent. If you have an ostomy, a specially trained therapist can help you learn how to care for it and adjust to having one.

Online Medical Reviewer: Kimberly Stump-Sutliff RN MSN AOCNS
Online Medical Reviewer: Louise Cunningham RN BSN
Online Medical Reviewer: Todd Gersten MD
Date Last Reviewed: 2/1/2021
© 2023 The StayWell Company, LLC. All rights reserved. This information is not intended as a substitute for professional medical care. Always follow your healthcare provider's instructions.