Colorectal Cancer

Topic Overview

Is this topic for you?

This topic will tell you about the initial testing, diagnosis, and treatment of colorectal cancer.

If you want to learn about colorectal cancer that has come back or has spread, see the topic Colorectal Cancer, Metastatic or Recurrent.

What is colorectal cancer?

Colorectal cancer happens when cells that are not normal grow in your colon or rectum . These cells grow together and form tumours.

This cancer is also called colon cancer or rectal cancer. It is the third most common cancer in Canada. And it occurs most often in people older than 50.

When it is caught in its early stages, it is easily treated and often cured. But because it is usually not discovered early, it is the second leading cause of cancer deaths in Canada.¹ Fairly simple screening tests can prevent this cancer, but most people older than 50 are not regularly screened.

What causes colorectal cancer?

Most cases begin as polyps , which are small growths inside the colon or rectum. Colon polyps are very common, and most of them do not turn into cancer. But doctors cannot tell ahead of time which polyps will turn into cancer. This is why people older than 50 need regular tests to find out if they have any polyps and then have them removed.

What are the symptoms?

Colorectal cancer usually does not cause symptoms until after it has begun to spread. See your doctor if you have any of these symptoms:

• Pain in the belly.
• Blood in your stool or very dark stools.
• A change in your bowel habits, such as more frequent stools or a feeling that your bowels are not emptying completely.

How is colorectal cancer diagnosed?

If your doctor thinks that you may have this cancer, you will need a test, called a colonoscopy, that lets the doctor see the inside of your entire colon and rectum. During this test, your doctor will remove polyps or take tissue samples from any areas that don't look normal. The tissue will be looked at under a microscope to see if it contains cancer.

Sometimes other tests, such as a barium enema or a sigmoidoscopy, are used to diagnose colorectal cancer.

How is it treated?

Surgery is almost always used to treat colon and rectal cancer. The cancer is easily removed and often cured when it is found early.

If the cancer has spread into the wall of the colon or farther, you may also need radiation or chemotherapy. These treatments have side effects, but most people can manage the side effects with medicines or home care.

Learning that you have cancer can be upsetting. It may help to talk with your doctor or with other people who have had cancer. Your local Canadian Cancer Society chapter can help you find a support group.

How can you prevent colorectal cancer?

Screening tests can prevent many cases of colon and rectal cancer. They look for a certain disease or condition before any symptoms appear. Regular screening is advised for most people age 50 and older. If you have a family history of this cancer, you may need to begin screening earlier than that.

These are the most common screening tests:

• Fecal occult blood test. You smear a small sample of your stool on a special card and send it to your doctor or to a lab. Drops of a special solution are placed on the card. If the solution changes colour, there is blood in the stool.
• Sigmoidoscopy. A doctor puts a flexible viewing tube into your rectum and into the first part of your colon. This lets the doctor see the lower portion of the intestine, which is where most colon cancers grow.
• Barium enema. Barium, a whitish liquid, is put into your rectum and colon. The white liquid outlines the inside of the colon so that it can be more clearly seen on an X-ray.
• Colonoscopy. A doctor puts a long, flexible viewing tube into your rectum and colon. The tube is usually linked to a video monitor similar to a TV screen. With this test, the doctor can see the entire large intestine.

Frequently Asked Questions

Learning about colorectal cancer:	What is colorectal cancer? What causes it? How can I prevent it? What are the symptoms? What increases my risk? What else could be causing my symptoms? Who gets this cancer?
Being diagnosed:	How is colorectal cancer diagnosed? What are the stages of colorectal cancer? What is a colonoscopy? What is a sigmoidoscopy? What is a fecal occult blood test? What is a barium enema?
Getting treatment:	How is colorectal cancer treated? Will I need surgery? What medicines are used to treat this cancer? What is radiation therapy?
Ongoing concerns:	How often will I need to see my doctor? When should I call my doctor?
Living with colorectal cancer:	What can I do at home to relieve symptoms of the cancer or cancer treatment?

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Author:	Douglas Dana Shannon Erstad, MBA/MPH	Last Updated March 19, 2007
Medical Review:	Adam Husney, MD - Family Medicine Jerome B. Simon, MD, FRCPC, FACP - Gastroenterology Arvydas D. Vanagunas, MD - Gastroenterology
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