Patient information from BMJ

Colon and rectal cancer: what treatments work?

Last published:Aug 05, 2021

Cancer in your intestines (bowels) is called colon or rectal cancer. You might also hear it called colorectal cancer. This kind of cancer is serious, but it can often be cured if it's caught early enough.

You can use our information to talk with your doctor and decide which treatments are right for you.

What is colon and rectal cancer?

Your colon and rectum make up the upper and lower part of your large intestine. Your large intestine turns food your body doesn't need into solid waste. The waste then leaves your body when you go to the bathroom.

Colon and rectal cancer starts when some of the cells in your large intestine begin to grow out of control. This can form a lump called a tumor.

Cancer cells can then break off from the tumor and spread to other parts of your body and cause damage there.

Your doctor will probably talk about what "stage" your cancer is. "Staging" cancers is all about how big they have grown and how far they have spread. So:

• stage I colon and rectal cancer is at an early stage and is usually treatable. About 95 in 100 people with stage I colon and rectal cancer are still alive five years after diagnosis

• stages II and III are larger and less easy to treat. But many people can still be cured. About 80 in 100 people with stage II colon and rectal cancer are still alive after 5 years. For stage III colon and rectal cancer, the number varies between 45 and 85 in 100

• stage IV (4) colon and rectal cancer is hard to treat, and most people are not cured. About 8 in 100 people are still alive after 5 years.

What treatments are available?

Cancer that grows in your colon or rectum can be treated. You have a good chance of being cured if the cancer hasn't spread very far.

Surgery is the main treatment for most people. You may also need radiation therapy or chemotherapy, or both.

What treatment you have depends on several things, including:

• where the cancer is

• how much it has spread

• your general health, and

• your individual preferences.

Surgery

Most people with colon or rectal cancer are treated with surgery. If your cancer is caught fairly early, your surgeon will try to remove all the cancer cells. This gives you a chance of getting rid of your cancer completely.

If your cancer has spread beyond your bowel, into other organs such as your liver and lungs, surgery won't cure you. But it can help to improve your quality of life and help you to live longer.

For example, your surgeon might recommend an operation to remove as much of the cancer as possible, or to clear a blockage in your bowel.

The type of surgery you will need depends on:

• where the cancer is

• how big it is, and

• how far it has spread.

Colon and rectal cancer usually starts in small growths called polyps. If you have a polyp, your doctor may remove it during your colonoscopy.

If the polyp tests positive for cancer cells but these cells seem to be all contained within the polyp, then you may not need any further surgery. However, to be sure all the cancer cells are gone, your doctor may recommend removing some of the tissue around the polyp.

If the tumor is bigger, you may need an operation to remove part of your intestine. A section is cut away and the ends from either side are joined together. Your surgeon may also need to remove some extra tissue from around your intestine.

Surgery can be done through a cut in your abdomen (open surgery) and often as keyhole surgery. That's when tiny instruments are put through small cuts in your body.

Keyhole surgery seems to work just as well as open surgery. And you're likely to recover more quickly afterward.

The part of your large intestine called your colon is quite long. So, an operation to remove part of it may not have much impact on your life afterward.

Your rectum (the last part of your large intestine before the anus) is much shorter. Surgery in this area is more difficult.

There's a chance you could need a colostomy after surgery for rectal cancer.

If you have a colostomy, the surgeon makes a hole in your abdomen. Part of your intestine is then attached to this hole.

Waste from your intestine then travels out through the hole in your abdomen, instead of traveling out through your rectum. The waste is collected in a bag.

Not everyone who has rectal cancer will need a colostomy. And some people need a colostomy only temporarily, while their intestine heals.

Lots of people worry about having a colostomy. But even if you do need one, you'll get plenty of help learning to cope.

Modern technology means that a colostomy is much less inconvenient than it used to be. The bags are small and they don't show through your clothes. They usually have a filter, so they don't smell. And a colostomy shouldn't stop you from doing things you did before, such as exercising or playing sports.

After surgery, you'll need to stay in the hospital for a few days. If you get pain, make sure you talk to a doctor or nurse. They'll be able to give you medication to help treat your pain.

Chemotherapy

Chemotherapy uses drugs to kill cancer cells. These drugs can be used to treat cancer before or after surgery. They can also be used if surgery isn't possible.

Chemotherapy drugs affect your whole body, so they're good for killing any cancer cells that might have been missed by surgery. Having chemotherapy before surgery can also help to shrink the cancer to make it easier to remove.

There are several chemotherapy drugs that can be used. They are usually given as injections.

Chemotherapy drugs are sometimes used along with medications called monoclonal antibodies. These help the chemotherapy drugs work better.

Having chemotherapy helps people with colon or rectal cancer live longer. But chemotherapy has side effects. These include diarrhea, swelling in your mouth and throat, and feeling very tired.

Some people feel sick to their stomach - you may be given medications to prevent this. Some people get problems with their blood that mean they bleed more easily and pick up more infections. You may also lose your hair.

Radiation therapy

Radiation therapy uses high-energy x-rays to kill cancer cells. It's not usually used for cancer in the colon, but it is sometimes used to treat cancer in the rectum.

Your doctor may recommend having radiation therapy to shrink your tumor before surgery, possibly combined with chemotherapy. This makes it easier for your surgeon to cut away all the cancer cells.

Radiation therapy is also sometimes used with chemotherapy after surgery. The aim is to kill any cancer cells left behind after your operation.

You'll need to go to the hospital to have radiation therapy. A machine aims a beam of radiation into the spot where your cancer is. You'll be given small doses of treatment each day for several days or weeks.

Radiation therapy doesn't usually hurt, although you'll have to stay still for a minute or so during treatment. This can be uncomfortable. Side effects during radiation therapy include feeling very tired, feeling sick to your stomach, or getting diarrhea.

Other problems can happen after treatment, including having problems controlling your bowel movements or having a blocked intestine, which may need emergency surgery.

If radiation therapy damages the nerves in your abdomen, you could have problems during sex. Men might find it hard to get an erection, and women can get a dry vagina.

For more background information on colon and rectal cancer see our leaflet Colon and rectal cancer: what is it?