Do I Need Genetic Testing for Colorectal Cancer?

Jessica Kenney, certified genetic counselor and manager of Catholic Health’s Clinical Genetic Counseling multispecialty program, answers commonly asked questions about genetic counseling for identifying colorectal cancer risk. 

Q. Why should I get genetic counseling to identify my risk for colorectal cancer?

Colorectal cancer is on the rise in people who are in their 20s-30s. Identifying your risk factors and how soon you need your first colonoscopy is essential to catching colorectal cancer in its earliest stage. Genetic counseling is crucial in helping you and your doctor determine if you need to get screened earlier than the recommended age of 45 for a first colonoscopy. 

Q. At what age should I get genetic counseling for colorectal cancer?

Individuals should seek genetic counseling between the ages of 25 and 30, especially if there is a family history of colon cancer.

Q. If genetic counseling shows I am at risk for colorectal cancer, do I need to schedule my colonoscopy?

The gene with an identified mutation will indicate how early and at what age you should get your first colonoscopy. Many individuals are reluctant to get a colonoscopy and opt for an at-home stool DNA test. However, colonoscopies are relatively easy and the surest way to screen for colorectal cancer (especially if you are high-risk) and catch it early when most treatable. Many hereditary colon cancer syndromes initially present with colon polyps not detectable with a stool DNA test. 

Depending on when your first-degree relative was diagnosed with colorectal cancer or advanced polyps, you may need a colonoscopy at an earlier age than the recommended age of a first colonoscopy at the age of 45. Share your genetic counseling and testing information with your gastroenterologist to help determine when you should get screened. 

Q. How does genetic counseling tell me if I'm at risk for colorectal cancer?

Family history is a significant risk factor for colorectal cancer, especially if you have a first-degree relative (such as a parent or sibling) who was diagnosed with colorectal cancer or advanced polyps. Meeting with a genetic counselor helps determine if you have specific gene mutations that increase your risk for cancers like colorectal cancer. The colorectal cancer genes that may show mutations include APC, ATM, AXIN2, BMPR1A, CHEK2, EPCAM, GREM1, MLH1, MSH2, MSH3, MSH6, MUTYH, NF1, PMS2, POLD1, POLE, PTEN, and SMAD4.

Your genetic counselor will explain more about the different mutations when you meet for your session.

Q. What is Lynch syndrome?

Lynch syndrome, also known as hereditary non-polyposis colorectal cancer (HNPCC), is one of the most common hereditary colon cancer syndromes,  causing about 4,300 colorectal cancers each year. People with Lynch syndrome are more likely to get colorectal cancer and other cancers at a younger age, typically before 50.

For people who are aware of a genetic history of Lynch syndrome in their family, genetic counseling will help determine their risk by looking for inherited Lynch syndrome mutations. Most people with Lynch syndrome, however, do not even know they have it, making genetic testing a valuable tool to help them meet with a gastroenterologist at a younger age and get screened.

Q. What information will I need to bring to the genetic counseling session? 

Personal medical history is important. Genetic counselors need to know if you have had any biopsies for suspicion of cancer, not only in the colon but in other organs as well. A personal history of colon polyps is also essential. Knowing the number and the pathology type of polyps is helpful. Family history is also valuable to know if a first, second, or third-degree family member had colon, intestinal, pancreatic or stomach cancer diagnoses, and at what ages were they diagnosed. 

If there is no personal information, family history will help contribute to the medical necessity for genetic testing.

Learn more about the genetic counseling process.

Q. What if I do not know my family history?

Unknown family history can be anxiety-inducing. There are several reasons for unknown family history, such as being adopted, estrangement from relatives, or lacking information shared from previous generations. A reliance on personal medical history is vital in the absence of family history.  

Q. What should I expect at my genetic counseling session? 

Expect to spend at least an hour with the genetic counselor. The length of the visit allows the counselor to review your personal and family medical histories, general genetic concepts, cancer genes, and what genes to test. 

Your genetic counselor will also review the types of results and when to expect them. The results help determine recommendations and next steps. The information reviewed serves as an informed consent process for genetic testing. 

Learn more about what to expect at a genetic counseling session.

Q. Do I need more than one genetic session? 

It would be best to meet with your genetic counselor every three to five years to update your medical records and family health history.

Find Care at Catholic Health

Catholic Health offers genetic counseling at St. Francis Hospital & Heart Center® (Roslyn, NY), Good Samaritan University Hospital (West Islip, NY), Mercy Hospital (Rockville Centre, NY) and St. Catherine of Siena Hospital (Smithtown, NY). Your physician can provide a referral. Call your insurance provider for more information on coverage.

 Call 844-86-CANCER (866-993-0638) for more information. View Catholic Health's genetic counseling services.

Find a Catholic Health doctor near you. Or call 866-MY-LI-DOC (866-695-4362).