Cancer of the colon or rectum is one of the main causes of death from cancer in the United States.

 

 

 

 

 

Source:
National Cancer Institute.
Colorectal cancer screening.
October 2008. Available at http://www.cancer.gov/cancertopics/factsheet/detection (accessed on 10 December 2008).

 

 

 

 

 

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Colon and rectal cancer is sometimes called colorectal cancer or bowel cancer. Your bowel turns food your body doesn't need into solid waste. The waste then leaves your body when you go to the bathroom.

To find out more, see Colon and rectal cancer.

Doctors use many different tests to screen for colon and rectal cancer. We've described the four most common tests. To learn more about these tests, see What will happen to me during my test?

This is where a sample of your stool is tested for blood. It is called an occult blood test because blood may be hidden in your stools (the word "occult" can mean "hidden"). If you have blood in your stools, it might be because you have a tumor in your bowel.

In this test, a doctor puts a thin, bendy tube into your anus. This allows the doctor to look at your rectum and the lower part of your bowel.

In this test, a doctor puts a thin, bendy tube into your anus. This is pushed up your bowel so the doctor can see all the way along it.

In this test, a thick white liquid is put into your rectum through a tube in your anus. Then

 

 

 

 

 

X-ray
X-rays are pictures taken of the inside of your body. They are done by passing very small amounts of radiation through your body and onto film. X-rays can also be used as a treatment, such as in radiation therapy for cancer.

 

 

 

 

 

X-rays are taken of your bowel.

Screening is used to look for cancer at a very early stage, before it starts to cause symptoms. If your doctor suggests you have screening for cancer, it doesn't mean he or she thinks you have cancer. It means you might benefit from having the screening test, in case you do have cancer.

The earlier that colon or rectal cancer is found, the more likely it is to be cured. Studies show that:

 

 

 

 

 

Source:
Di Gregorio C, Benatti P, Losi L, et al.
Incidence and survival of patients with Dukes A (stages T1 and T2) colorectal carcinoma: a 15-year population-based study.
International Journal of Colorectal Diseases. 2005; 20: 147-154.

 

 

 

 

 

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Screening doesn't just help to spot colon or rectal cancer early. It can prevent it. Some types of screening can show up lumps called

 

 

 

 

 

polyp
A polyp is a growth that is found inside your body.

 

 

 

 

 

polyps in your bowel. These might turn into cancer if you don't have them removed.

 

 

 

 

 

Source:
National Cancer Institute.
Colorectal cancer screening.
October 2008. Available at http://www.cancer.gov/cancertopics/factsheet/detection (accessed on 10 December 2008).

 

 

 

 

 

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Polyps are harmless (doctors call them benign) lumps of cells that can grow on the wall of your bowel. You're more likely to get them as you get older.

 

 

 

 

 

Source:
Di Gregorio C, Benatti P, Losi L, et al.
Incidence and survival of patients with Dukes A (stages T1 and T2) colorectal carcinoma: a 15-year population-based study.
International Journal of Colorectal Diseases. 2005; 20: 147-154.

 

 

 

 

 

²

Most polyps never become cancerous. But some do, and colon or rectal cancer almost always start from a polyp. Doctors usually remove all polyps when they find them, to be safe. Most can be easily removed during a screening test.

 

 

 

 

 

Source:
WebMD Medical Reference in collaboration with The Cleveland Clinic.
Digestive diseases: colorectal polyps and cancer.
January 2007. Available at http://www.webmd.com/content/article/90/100620.htm (accessed on 10 December 2008).

 

 

 

 

 

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Screening tests don't exist for all types of cancer. When tests do exist, doctors need to be sure that their benefits are bigger than their risks before offering them to patients.

Regular screening for colon and rectal cancer is now recommended for most men and women over 50. People who are at high risk of colon and rectal cancer can get tested earlier and more often.

To read more, see Who should have screening?

There are some risks with the screening tests used to detect colon and rectal cancer. These include:

 

 

 

 

 

Source:
National Cancer Institute.
Colorectal cancer (PDQ): risks of colorectal cancer screening.
July 2007. Available at http://www.cancer.gov/cancertopics/pdq/screening/colorectal/Patient/page4 (accessed on 10 December 2008).

 

 

 

 

 

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Despite these risks, doctors recommend screening for colon and rectal cancer because there is good evidence that it reduces the number of people who die from colon and rectal cancer.

 

 

 

 

 

Source:
Scottish Intercollegiate Guidelines Network.
Management of colorectal cancer.
Scottish Intercollegiate Guidelines Network guideline No. 67. 2003. Available at: http://www.sign.ac.uk/guidelines/published/numlist.html (accessed on 10 December 2008).

 

 

 

 

 

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