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Does Colon Cancer run in YOUR Family?

Learn more about the genetics of cancer; what you can do to discover if your family has a genetic risk for colon cancer; and what you can do with knowledge that may protect your loved ones and prevent disease.

This video series will introduce you to how colon cancer (and other cancers) can be found in genetics and what to do next.

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Genes are the building blocks of DNA; your genes are what you inherit from your parents and affect your height, eye color, and even the likelihood of developing cancers. Learning your family history allows you to take appropriate steps to decrease the risk of developing colon and other types of cancers.

About 5-10% of colon cancers are due to specific inherited conditions that make it more likely that some family members will get polyps, colon cancer, and possibly other cancers.

When there is an inherited cause for colon cancer in a family, some people have inherited it and some have not.  Knowing if you or your relatives have an inherited increased risk for colon cancer can save lives.  Family members, who have this inherited risk, can get the right screening, at the right time, and prevent cancers.

The chance that your family has a hereditary cause for colorectal cancer goes up when:

  • There are multiple close relatives with colorectal cancer and polyps
  • When cancer occurs in young people (under age 50 for colon cancer)
  • When someone has had more than one cancer (for example someone who has had two separate colon cancers)
  • When someone has had more than 10 colon polyps
  • When there is a pattern of cancers or polyps that fit with a known cause. (For example, uterine and colon cancer are seen with a condition called Lynch syndrome).

The genetic risk for colon and rectal cancer.

  • The risk of developing colorectal cancer increases 2-3 times when a parent, sibling, or child is diagnosed compared to those with no family history.
  • The risk increases 3-6 times over the general population, when a relative is diagnosed at a young age or if there is more than one relative with colorectal cancer.
  • About 20% of all colorectal cancer patients have a close relative who was also diagnosed with the disease.
  • About 5% of patients with colorectal cancer have a well-defined genetic syndrome that causes the disease like Lynch syndrome or familial adenomatous polyposis (FAP).  These conditions are linked with higher risks for colon and other cancers.
  • Lynch syndrome (which used to be called hereditary non-polyposis colorectal cancer) accounts for 2- 4% of all colorectal cancer cases.
  • FAP is the second most common predisposing genetic syndrome; for these individuals, lifetime risk of colorectal cancer approaches 100% without intervention.

Learn more from the American Society of Clinical Oncology about genetics and colon cancer.

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Information on these pages is provided for educational purposes only. Consult your own physician before making any medical decisions.