Mar 22, 2021 8:00 AM

Read Time: 4 minutes

Lynch syndrome is the most common cause of hereditary colon cancer. It is a genetic condition that puts people at an increased risk for cancer. People with Lynch syndrome typically get diagnosed with cancer at younger ages. They are more likely to get the following cancer types (in order of risk):

  • Colon cancer
  • Endometrial or uterine cancer
  • Ovarian cancer
  • Stomach cancer
  • Brain, gall bladder, bile duct, pancreatic, sebaceous gland, small bowel, and urinary tract cancer

People with Lynch syndrome need colon cancer screening more often and starting at a younger age. Colon cancer is 90% preventable with proper early screening.

What causes Lynch syndrome?

Lynch syndrome happens because of an inherited change (mutation) in a gene that protects your body from cancer. When the genes do not work properly, they cannot provide as much protection. This puts you at an increased risk for cancer.

There are five Lynch syndrome genes: MLH1, MSH2, MSH6, PMS2, and EPCAM. Having a mutation in any of these genes causes Lynch syndrome. Everyone has two copies of each of these genes—one passed down from the mother and one passed down from the father. If either of these copies has a mutation in it, that person has Lynch syndrome and has an increased risk for cancer. Between 1 in 300 to 1 in 400 people are thought to have Lynch syndrome.

Who should be tested for Lynch syndrome?

People with a striking family history of colon cancer are more likely to have Lynch syndrome. Knowing your family history of cancer is important in figuring out if you have Lynch syndrome. If you do not have any relatives with colon, uterine, or ovarian cancer, it is unlikely that you have Lynch syndrome.

These are some signs a person may have Lynch syndrome:

  • Colon or uterine cancer diagnosed under age 50
  • More than one kind of Lynch syndrome-related cancer in the same person
  • Having more than one relative on the same side of the family with Lynch syndrome-related cancers
  • Testing of a colon or uterine cancer that shows a high risk for Lynch syndrome

If you or your family members have any of these signs, you can schedule a genetic counseling appointment in the Family Cancer Assessment Clinic to learn more. To make a genetic counseling appointment, call 801-587-9555.

During the appointment, a genetic counselor reviews your medical and family history and talks about your cancer risk. The counselor may order genetic testing, which can help determine your personal cancer risk. They can also make a cancer screening or risk reduction plan for you based on this evaluation.

How does the Lynch syndrome genetic test work?

Genetic testing looks for mutations in your genes. The genetic test for Lynch syndrome looks at the genes MLH1, MSH2, MSH6, PMS2 and EPCAM to find out if they are working properly or if there is a mutation that affects how these genes function.

You usually need to give a blood or saliva sample for this test.

What cancer screenings should I get if I have Lynch syndrome?

Cancer screening for Lynch syndrome depends on which gene your mutation is found in and whether or not you have a uterus or ovaries.

For everyone:

  • Get a colonoscopy every 1–2 years. The age you should start getting colonoscopies differs:
    • If a parent or sibling was diagnosed with colorectal cancer at a younger age, start colonoscopies 2–5 years before the age their colon cancer was diagnosed.
    • For people with MLH1 and MSH2 mutations, start colonoscopies at age 20–25.
    • For people with MSH6 and PMS2 mutations, start colonoscopies at age 30–35.
  • You may need a urine test every year starting at age 30–35. This depends on your gene mutation, family history, and sex.
  • You may need pancreatic cancer screening starting at age 50. This depends on your gene mutation and family history.
  • Consider getting a physical exam every year starting at age 25–30.

For people with a uterus and/or ovaries, talk with your doctor about ways to prevent cancers or find them early. Your doctor may recommend some of these options:

  • Medicines to lower the risk of cancer developing
  • Surgery to remove your ovaries, fallopian tubes, or uterus
  • An endometrial biopsy every two years starting at age 30–35

Your doctor can help you decide which steps to take and at what age.

Where can I learn more?

You can schedule a genetic counseling appointment at the Family Cancer Assessment Clinic. We offer visits by phone, video, or in person. To make a genetic counseling appointment, call 801-587-9555.

Find more information for patients with Lynch syndrome here.

colorectal cancer genetics

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