Hereditary Cancer Spotlight: Colorectal Cancer
Hereditary Cancer Spotlight
Colorectal Cancer
Colorectal cancer (CRC) is the third most diagnosed cancer and the third leading cause of cancer-related deaths in the United States. While a majority of CRC are sporadic, approximately 10% of CRCs are attributed to germline mutations with strong family history often associated with hereditary syndromes, including Lynch Syndrome (also known as hereditary non-polyposis colorectal cancer, HNPCC); Familial Adenomatous Polyposis (FAP); MUTYH-associated polyposis; and certain hamartomatous polyposis.
Genetic testing for key germline variants is essential to determine if a patient has a hereditary CRC syndrome and therefore increased risk of developing CRC. Germline cancer testing identifies inherited gene changes in DNA that are present in every cell of the body that can be passed from a parent to a child. This is different from somatic testing which looks for changes that occur in a specific tumor after birth. Identifying a pathogenic germline variant associated with CRC syndromes can help prevent the onset of disease in individuals who have not yet developed cancer by directing increased surveillance to detect precancerous polyps before they develop into cancer. In individuals who have already developed cancer, the identification of a germline variant assists in disease management and treatment. Individuals with a pathogenic variant require more frequent screening and monitoring methods, as well as family testing to determine if at-risk relatives have inherited the variant.
Genetic testing for hereditary colon cancer should be considered when there is:
- A significant family history of CRC or premalignant colon polyps in 2 or more first-degree relatives of the proband.
- A family history of other cancers associated with hereditary CRC, particularly endometrial cancer.
- Onset of CRC at an early age or under age 50.
- Multiple primary cancers in an individual, including CRC.
- CRC developed from ascending colon and/or mismatch repair deficient.
For more information on genetic testing for hereditary colon cancer and related syndromes visit the links below:
- https://myriad.com/patients-families/disease-info/colon-cancer/
- https://myriad.com/genetic-tests/myrisk-hereditary-cancer-risk-test/
The FCS Geneticists are available for clinical support: Dr. Jennifer Gass, Dr. Katy Phelan, Dr. Jeanine Ruggeri
References
- Ma H, Brosens LAA, Offerhaus GJA, Giardiello FM, de Leng WWJ, Montgomery EA. Pathology and genetics of hereditary colorectal cancer. Pathology. 2018 Jan;50(1):49-59. doi: 10.1016/j.pathol.2017.09.004. Epub 2017 Nov 21. PMID: 29169633.
