Colorectal cancer, also called colon cancer or bowel cancer, includes cancerous growths in the colon, rectum and appendix. Colon cancer often causes no symptoms until it has reached a relatively advanced stage. Thus, many organizations recommend periodic screening for the disease with fecal occult blood testing and colonoscopy. The symptoms depend on the site of the lesion. The nearer the lesion is to the anus, the more bowel symptoms there will be. Certain factors increase a person's risk of developing the disease. These include: age, polyps of the colon, family history of colon cancer, diet, physical inactivity and other.

Colorectal cancer can take many years to develop and early detection of colorectal cancer greatly improves the chances of a cure. Therefore, screening for the disease is recommended in individuals who are at increased risk.

There are several different tests available for this purpose.

Digital rectal exam (DRE): The doctor inserts a lubricated, gloved finger into the rectum to feel for abnormal areas. It only detects tumors large enough to be felt in the distal part of the rectum, but is useful as an initial screening test.

Fecal occult blood test (FOBT): a test for blood in the stool.

Endoscopy, Sigmoidoscopy: A lighted probe (sigmoidoscope) is inserted into the rectum and lower colon to check for polyps and other abnormalities.

Colonoscopy: A lighted probe called a colonoscope is inserted into the rectum and the entire colon to look for polyps and other abnormalities that may be caused by cancer. A colonoscopy has the advantage that if polyps are found during the procedure they can be immediately removed. Tissue can also be taken for biopsy.

Whole-Body PET imaging is the most accurate diagnostic test for detection of recurrent colorectal cancer, and is a cost-effective way to differentiate resectable from non-resectable disease. A PET scan is indicated whenever a major management decision depends upon accurate evaluation of tumour presence and extent.

Surgery remains the primary treatment while chemotherapy and/or radiotherapy may be recommended depending on the individual patient's staging and other medical factors. Survival is directly related to detection and the type of cancer involved. Survival rates for early stage detection are about 5 times that of late stage cancers.

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