Some individuals have inherited genetic syndromes that increase their risk of developing colorectal cancer. About 5 to 10% of colorectal cancers are believed to be hereditary [1]. Hereditary colorectal cancer involves an abnormal gene being passed from parent to child. However, not everyone with an inherited abnormal gene will develop cancer.
Genetic testing can help show if an individual has inherited a higher risk of colorectal cancer due to inherited cancer syndromes. Here’s more on hereditary colorectal cancer and how genetic testing can empower individuals to take preventive measures and make informed decisions.
How hereditary cancer syndromes can increase the risk of colorectal cancer
Hereditary cancer syndromes are types of inherited disorders in which there is a higher-than-normal risk of developing certain types of cancer. They are caused by mutations in certain genes that can be passed from parents to children.
In a hereditary cancer syndrome, certain patterns of cancer may be apparent within families. These patterns include having several close family members with the same type of cancer, developing cancer at an early age (typically before age 50), having certain patterns of cancer in a family (such as colorectal and endometrial cancer), or having two or more types of cancer develop in the same person.
However, it's important to understand that not every cancer that seems to run in a family is caused by a family cancer syndrome. Only 5-10% of cancer is due to an inherited cancer syndrome. Lynch syndrome is an example of a hereditary cancer syndrome that increases an individual’s risk of developing colorectal, endometrial, and other cancers.
Understanding Lynch syndrome
Lynch syndrome, also called hereditary nonpolyposis colorectal cancer (HNPCC), is an inherited disorder that increases the risk of many types of cancer. Individuals with Lynch syndrome are more likely to develop colorectal cancer and other cancers, and often at a younger age (before 50), including:
- Endometrial (also called uterine)
- Ovarian
- Stomach
- Bladder
- Biliary Tract
- Pancreatic
- Brain
- Certain types of skin tumors
Lynch syndrome is the most common hereditary colorectal cancer syndrome, accounting for approximately 3% of all colorectal cancers [2]. This genetic condition occurs due to inherited changes (mutations) in genes that affect DNA mismatch repair, which fixes mistakes made when DNA is copied. These genes (MLH1, MSH2, MSH6, PMS2, and EPCAM) normally protect against certain cancers, but some mutations can prevent them from working correctly [3].
People with Lynch syndrome have up to an 80% lifetime risk of developing colorectal cancer by age 70. Lynch syndrome also causes colorectal cancer to occur at an earlier age than it might in the general population. Exact cancer risks and average age of onset vary by Lynch syndrome gene [2].
Genetic testing for Lynch syndrome
Genetic testing can reveal information that can help individuals and their healthcare providers make more informed healthcare and lifestyle decisions. Anyone who is curious about their genetic risk can take a genetic test to learn more about their body. When deciding whether to take a genetic test, individuals should consider their medical history and family health history and consult their healthcare provider to learn more.
An individual whose family has a strong history of colorectal or endometrial cancer is more likely to have Lynch syndrome. Family members who inherit Lynch syndrome usually share the same mutation. Genetic testing looks for inherited Lynch syndrome mutations and offers insight into cancer risk. Genetic counseling and genetic testing can help individuals determine appropriate medical management and improve clinical outcomes.
If an individual’s test results are positive, they can take preventive measures such as beginning cancer screening at an earlier age than the general population. Genetic testing and early cancer screening can also be offered to their family members who may be at an increased risk.
How LetsGetChecked provides genetic testing for hereditary colorectal cancer
LetsGetChecked’s myGeneticScreen test analyzes 11 genes associated with three conditions the CDC has designated as actionable Tier 1 conditions: Hereditary Breast and Ovarian Cancer syndrome, Lynch syndrome, and Familial Hypercholesterolemia [4]. This innovative testing solution includes pre and post-genetic counseling and cascade family testing to enable individuals and their families to take preventive measures and make informed decisions.
Pre-genetic counseling
Pre-genetic counseling allows individuals to learn about the three conditions they are being screened for, learn if the myGeneticScreen test is appropriate, and ask questions about the potential results or the testing process.
Post-genetic counseling
Post-genetic counseling allows individuals to understand their results in the context of their personal and family history. Our genetic counselor will explain the results in detail, provide resources, and discuss actionable next steps.
Cascade family testing
Cascade family testing is a follow-up genetic testing strategy for the immediate blood relatives of an individual diagnosed with a genetic condition or identified as having a pathogenic variant. Family testing can help identify at-risk relatives and enable healthcare providers to create a personalized screening plan to aid in the early detection and intervention of disease, inform family planning, and enable more robust prevention measures.
Design a genetic testing program with LetsGetChecked
LetsGetChecked’s end-to-end care services provide an unbeatable patient-centric experience that makes genetic testing more accessible, personalized, and impactful. Our powerful technology and configurable design make it easy to integrate our solution into your existing program infrastructure and achieve your goals. By partnering with us, we can improve health outcomes for diverse populations and drive positive change on a global scale.
