1. Colorectal (Colon) Cancer Slideshow Pictures
2. Digestive Disease Myths Slideshow Pictures

Medical Author:

Dennis Lee, MD

Dennis Lee, MD

Dr. Lee was born in Shanghai, China, and received his college and medical training in the United States. He is fluent in English and three Chinese dialects. He graduated with chemistry departmental honors from Harvey Mudd College. He was appointed president of AOA society at UCLA School of Medicine. He underwent internal medicine residency and gastroenterology fellowship training at Cedars Sinai Medical Center.

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Medical Editor:

Jay W. Marks, MD

Jay W. Marks, MD

Jay W. Marks, MD, is a board-certified internist and gastroenterologist. He graduated from Yale University School of Medicine and trained in internal medicine and gastroenterology at UCLA/Cedars-Sinai Medical Center in Los Angeles.

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In this Article

• Introduction to colon cancer prevention
• What measures to prevent colo-rectal cancer have proven effectiveness and long term safety?
• What measures to prevent colo-rectal cancer probably are effective but may have long term adverse side effects?
• What measures to prevent colo-rectal cancer probably are effective and safe?
• What prevention measures have been found to be ineffective?
• What about genetic testing for colon cancer?
• Who should consider genetic counseling and testing?
• Why is genetic counseling and testing important in hereditary colon cancer syndromes?
• What can be done now to prevent colorectal cancer?
• Find a local Gastroenterologist in your town
• Colon Cancer Prevention Index

Who should consider genetic counseling and testing?

Genetic counseling followed by genetic testing should be considered for individuals as well as their family members when there are:

• Individuals in the family with early onset of colon cancer, before age 50
• Individuals in the family with numerous colon polyps
• Families in which multiple members have colon cancer
• Families with members with numerous colon polyps
• Families with members having colon cancers at young ages
• Families with members having certain non-colon cancers such as cancers of the uterus, thyroid, ureters, ovaries, small intestine, etc.

Genetic testing without prior counseling is discouraged because of the extensive family education that is involved and the complicated nature of interpreting the test results.

Why is genetic counseling and testing important in hereditary colon cancer syndromes?

Patients who have hereditary colon cancer syndromes usually have no symptoms and are unaware that they have colon polyps or early colon cancers. They usually will develop colon cancers early in life (often before ages 40-50). Therefore, to prevent colon cancers in patients with hereditary colon cancer syndromes, colon screening must begin early. For example, patients with FAP should have annual flexible sigmoidoscopies starting at age 12, patients with AFAP should have annual colonoscopies starting at age 25, and patients with HNPCC should have colonoscopies beginning at age 25 (or 10 years younger than the earliest colon cancer diagnosed in the family, whichever is earlier). The current screening recommendations for the general population (fecal occult blood testing, flexible sigmoidoscopy, and colonoscopy beginning at ages 40-50) are inadequate for most patients with hereditary colon cancer syndromes.

Genetic counseling and testing are important to identify patients and family members with hereditary colon cancer syndromes so that screening with flexible sigmoidoscopies and colonoscopies can begin early and, if necessary, the colon can be removed surgically to prevent colon cancer. Moreover, depending on which hereditary colon cancer syndrome is present, early screening for other types of cancer such as ovarian, uterine, stomach, ureter, and thyroid may be appropriate.