Colorectal Cancer

Topic Overview

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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 tumors.

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

When it is found early, it is easily treated and often cured. But because it usually is not found early, it is the second leading cause of cancer deaths in the United States.¹ Screening tests can prevent this cancer, but fewer than half of people older than 50 are screened. According to the American Cancer Society, if everyone were tested, tens of thousands of lives could be saved each year.

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. And some people who are younger than 50 need regular tests if their medical history puts them at increased risk for colorectal cancer.

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 your 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 another test, such as a sigmoidoscopy, is 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 American Cancer Society chapter can help you find a support group.

How can you screen for 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. Experts recommend routine colon cancer testing for everyone age 50 and older who has a normal risk for colon cancer. People who have a higher risk, such as African Americans and people with a strong family history of colon cancer, should be tested sooner. Talk to your doctor about when you should be tested.

These are the most common screening tests:

• Stool tests that check for signs of cancer:
  • Fecal occult blood test (FOBT).
  • Fecal immunochemical test (FIT).
  • Stool DNA test (sDNA).
• 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. Doctors can remove polyps during this test also.
• 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.
• Computed tomographic colonography (CTC). This test is also called a virtual colonoscopy. A computer and X-rays make a detailed picture of the colon to help the doctor look for polyps.

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?
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:	Bets Davis, MFA	Last Updated: October 1, 2008
Medical Review:	Anne C. Poinier, MD - Internal Medicine Arvydas D. Vanagunas, MD - Gastroenterology
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