Guidelines for genetic testing in people diagnosed with colorectal cancer
Up to 10% of people diagnosed with colorectal cancer have an inherited mutation that caused their cancer. There are national guidelines that outline who should consider genetic counseling and testing for an inherited mutation linked to cancer.
Guidelines for testing in newly-diagnosed patients
Experts recommend that any person with colorectal cancer have tumor biomarker testing to look for an abnormality known as "mismatch repair deficiency" (dMMR or MMR-D) at the time of diagnosis. This abnormality is commonly found in the cancers of people with an inherited gene mutation linked to Lynch syndrome.
People with MMR-D cancers are recommended to also have genetic counseling and testing for an inherited mutation associated with Lynch syndrome.
Not all people with MMR-D cancers will test positive for a Lynch syndrome mutation.
Additional guidelines for testing in any patient diagnosed with colorectal cancer
Genetic testing for an inherited mutation is also recommended for people diagnosed with colorectal cancer who have any of the following:
- Have a blood relative with a known inherited mutation in a colorectal cancer gene
- Diagnosed before age 50
- Diagnosed with another Lynch syndrome related cancer including endometrial, ovarian, pancreatic, stomach or other Lynch syndrome-related cancer
- Have a close relative with a Lynch syndrome-related cancer diagnosed under age 50
- Two or more relatives with a Lynch syndrome-related cancer diagnosed at any age
Other people who may benefit from genetic counseling and testing
You may benefit from additional genetic counseling and expanded genetic testing if you had genetic testing in the past, you tested negative, and the following applies to you:
- your situation matches any of the above, and
- you had a test that only looked for one or a few genes, or
- you had genetic testing before 2014. Genetic testing has improved, and laboratories can now find gene mutations that may have previously been missed.
Colorectal cancer survivors and those in treatment should speak with a genetics expert to see if testing is right for them.
Genetic testing for relatives of people who have been diagnosed with colorectal cancer
Genetic counseling and testing is also recommended for anyone with a first-degree or second-degree relative who has been diagnosed with colorectal cancer before age 50.
See our sections Testing Guidelines by Cancer Type and Genetic Testing for People Who Have Never Been Diagnosed with Cancer for additional guideline information.
Healthcare providers who are specially trained in genetics can help people diagnosed with cancer learn if it was caused by an inherited mutation. There are several ways to find a genetics expert:
- The National Society of Genetic Counselor website offers a searchable directory for finding a genetic counselor by state and specialty. To find a genetic counselor who specializes in cancer genetics, choose "cancer" under the options "Area of Practice/Specialization."
- InformedDNA is a network of board-certified genetic counselors providing this service by telephone. They can also help you find a qualified expert in your area for face-to-face genetic counseling if that is your preference.
- Grey Genetics provides access to genetic counselors who offer genetic counseling by telephone.
- The Genetic Support Foundation offers genetic counseling with board-certified genetic counselors.
- FORCE's toll-free helpline at: 866-288-RISK, ext. 704, can connect you with a volunteer board-certified genetic counselor who can answer general questions about genetic testing and hereditary cancer and help you find a genetic counselor near you.
- FORCE Peer Navigator Program will match you with a volunteer who has undergone genetic counseling and can help you navigate resources to find a genetic counselor near you.
- Ask your doctor for a referral to a genetics expert.
The following resources provide support for people with colorectal cancer who are considering genetic testing:
- FORCE support:
- Register for the FORCE Message Boards to connect with others who share your situation. Once you register, you can post on the Diagnosed With Cancer board to connect with other people who have been diagnosed.
- FORCE's Peer Navigation Program will match you with a volunteer who shares your mutation and situation and provide you with a free resource guide.
- Contact the FORCE impact leaders in your area to link to local support groups and other resources.
- Attend a virtual support meeting in your area.
- Read the stories from members of our community.
- AliveAndKickn is a nonprofit organization by and for people with Lynch syndrome.
- Lynch Syndrome International is a nonprofit organization that provides support for individuals afflicted with Lynch syndrome.
- Colorectal Cancer Alliance is a nonprofit organization with a focus on colorectal cancer treatment, detection and prevention.