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Colon Cancer

(Colorectal Cancer)


The Manual's Editorial Staff

Reviewed/Revised Jan 2023
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Your colon is your large intestine. Your rectum is a pouch at the end of your colon where stool is stored until you pass it.

Locating the Large Intestine

Locating the Large Intestine

What is colon cancer?

Cancer Overview of Cancer Cancer is the out-of-control growth of cells in your body. Cells are the tiny building blocks of your body. Cells specialize in what they do. For example, your intestines have muscle cells to... read more is the out-of-control growth of cells in your body. Cells are the tiny building blocks of your body. Cells specialize in what they do. Different organs are made of different kinds of cells. Almost any kind of cell can become cancerous.

  • The most common symptoms are bleeding when you pass stool and feeling tired and weak

  • Everyone over the age of 45 should be screened for colorectal cancer

  • Colorectal cancer caught early is more curable

  • Doctors usually remove the cancer with surgery

What causes colon cancer?

What are the symptoms of colon cancer?

Colon cancer grows slowly and doesn't cause symptoms for a long time. Symptoms may include:

  • Feeling weak and tired—in some people this is the only symptom

  • Belly pain

  • Constipation (trouble passing stool)

  • Blood in your stool

  • Feeling like your rectum isn’t completely empty after passing stool

How can doctors tell if I have colon cancer?

If you have symptoms that doctors think might be from colon cancer, they usually do:

If colonoscopy shows cancer, then doctors usually do:

How do doctors screen for colon cancer?

Because colon cancer is so common, doctors recommend screening tests to look for cancer before it causes symptoms. Screening for colon cancer usually begins at age 45 but earlier if you have certain high risk factors. Talk to your doctor about when you need to start screening.

Screening tests include:

How do doctors treat colon cancer?

Doctors treat colon cancer with:

Understanding Colostomy

In a colostomy, the large intestine (colon) is cut. The healthy end of the large intestine, which is before the blockage, is brought to the skin surface through a surgically created opening in the abdominal wall. It is then stitched to the skin of the opening. Stool passes through the opening and into a disposable bag. The colostomy allows the remaining part of the large intestine to rest while the person recovers. After the person recovers from the surgery and the colon heals, the two ends can be reattached so that stool can pass normally.

Understanding Colostomy

For rectal cancer, doctors do:

If doctors have to take out your rectum, you usually will need a colostomy. With a colostomy, doctors attach the end of your colon to an opening in the wall of your belly. Your stool comes out of this opening into a plastic colostomy bag. The bag is stuck onto your belly with adhesive and you change it when it fills up.

After your treatment, doctors will continue to care for you and check on your health with regular testing, such as:

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