Hereditary Colorectal Cancer
Between 2 and 6 percent of men and women will develop colorectal cancer, a disease of the large intestine. Of those, 5 percent inherited the cancer from a parent. Genetic counseling can help identify families at risk for hereditary forms of colorectal cancer. Empowered with information about the cancer risk, these families can take steps toward preventing and detecting the disease early.
FAP (familial adenomatous polyposis) and HNPCC (hereditary nonpolyposis colorectal cancer) are the two types of colon cancer conditions that most commonly run in families. FAP is characterized by many polyps in the colon. People who inherit the changed APC gene are nearly 100 percent likely to develop colon cancer by age 40. People with a changed HNPCC gene have an 80 percent risk of developing colon or rectal cancer over their lifetime, and a 40 to 60 percent chance of developing endometrial cancer.
If your diagnosis or family history includes any of these signs, genetic counseling can help:
- colon cancer diagnosis before age 50
- multiple colon cancers or more than one HNPCC-related cancer*
- colon cancer diagnosis and one blood relative with an HNPCC-related tumor* before age 50
- colon cancer diagnosis and two or more first- or second-degree relatives (parent, grandparent, sibling, aunt, uncle) with HNPCC-related cancer at any age.
*colon, endometrial, ovarian, stomach, small bowel, biliary tract or transitional cell of the renal pelvis