Each year, about 150,000 Americans get colon or rectal cancer.

 

 

 

 

 

Source:
American Cancer Society.
Colorectal cancer facts and figures: special edition 2005.
Available at http://www.cancer.org (accessed on 6 May 2009).

 

 

 

 

 

¹ The cancer starts because some cells in the bowel start growing out of control and damage the surrounding cells. You can get treatment to try to remove or kill the cancer and stop it from spreading to other parts of your body.

If you've been told you have colon or rectal cancer, you'll probably have lots of questions about your illness and what might happen to you. Learning about your disease may reassure you and help you cope.

You may also hear the phrases colorectal cancer or bowel cancer to describe these kinds of cancer.

People who have colon or rectal cancer say that when they have gotten over the shock, they find their illness has helped them focus on the things that mean a lot to them, such as their family and other important relationships.

 

 

 

 

 

Source:
Sahay TB, Gray RE, Fitch M.
A qualitative study of patient perspectives on colorectal cancer.
Cancer Practice. 2000; 8: 38-44.

 

 

 

 

 

²

Your intestines are part of your digestive system. This is the group of organs that break down the food you eat. The part right below your stomach is called the small intestine or small bowel. It's a narrow tube about 20 feet long.

Your small intestine leads into your large intestine (also called the large bowel), which is about 7 feet long and much wider.

Your colon is the first 6 feet of your large intestine, and your rectum is the last 8 inches to 10 inches.

Cancer usually grows in the large intestine. It is rare in the small intestine.

See More about your colon and rectum to learn more.

Your colon and rectum are made mostly of muscle. The inner lining is a thin layer of cells called the mucosa. Cells in this lining have a short life. They grow, divide in two, then die and get replaced. Your body carefully controls this activity, so that cells are replaced every five days or so.

But sometimes things go wrong. Cells keep dividing when they don't need to, and old ones don't die. If this happens, you can get a cluster of extra cells called a tumor. Some tumors are made up of normal cells and they aren't dangerous. Doctors call them benign tumors. They stay put and don't cause any problems. But other tumors are made up of cancer cells. Doctors call them malignant tumors.

Cancer cells are different from healthy cells in several ways.

Cells in tumors can break away and move to other parts of your body. These breakaway cells are carried in your bloodstream or in your

 

 

 

 

 

lymphatic system
The lymphatic system is the body's way of clearing and cleaning unwanted materials from the blood and tissues. It includes an interconnected network of lymph nodes that filter these materials to see if there is an infection that will require response by the immune system.

 

 

 

 

 

lymphatic system. When the cancer cells arrive at a different part of your body, they can start growing into another tumor. When cancer spreads like this, it's called metastasis. Blood from your bowel goes to your

 

 

 

 

 

liver
Your liver is a large organ that sits on the right side of your body, just below your rib cage. It does several important things, including processing and storing nutrients from food, and breaking down chemicals, such as alcohol.

 

 

 

 

 

liver, so this is where colon and rectal cancer cells might travel.

It's hard to say why some people get colon or rectal cancer and others don't. Some kinds of cancer run in the family, but there are many other things that make it more or less likely that you'll get this kind of cancer.

See Risk factors for colon and rectal cancer to find out more.

At least two-thirds of colon and rectal cancers start inside lumps of cells called polyps.

 

 

 

 

 

Source:
Rudy DR, Zdon MJ.
Update on colorectal cancer.
American Family Physician. 2000; 61: 1759-1770, 1773-1774.

 

 

 

 

 

³ These are small growths on the inside of the bowel wall.

A polyp is a harmless, fleshy lump (a benign tumor), but it can turn into cancer (a malignant tumor). Some doctors think that taking these polyps out makes it much less likely that you'll get colon or rectal cancer.

 

 

 

 

 

Source:
Doll R, Peto R.
The causes of cancer.
Oxford University Press, New York, U.S.A.; 1981.

 

 

 

 

 

⁴

 

 

 

 

 

Source:
Harvard Report on Cancer Prevention.
Volume 1: causes of human cancer.
Cancer Causes and Control. 1996; 7 (supplement 1): S1-S55.

 

 

 

 

 

⁵

To read more, see Colon and rectal cancer screening.

Here's what we know about polyps.

Your doctor will need to find out how advanced your cancer is. This is called staging your cancer. The doctor will check how big your cancer is and how far it has spread. These tests help doctors choose the best treatment.

Your doctor will also look at a few of the cancer cells under a microscope. This is called grading your cancer. The more "normal" the cells look, the less severe your cancer. If the cancer cells look very unlike normal cells, it can mean the tumor is growing quickly.

See What stage is your cancer? to read more.

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