Lynch Syndrome: Get the Facts

What Is Lynch Syndrome?

Lynch syndrome is a condition that makes people more likely to get certain cancers. It's passed down from parents to children through problem genes. People who have it have about a 40% to 80% chance of getting colorectal cancer by age 70. They’re also at risk for cancer of the uterus, ovaries, or stomach. And they tend to get cancer at younger ages than other people, often in their 30s and 40s.

Lynch syndrome is sometimes called hereditary non-polyposis colorectal cancer (HNPCC). Other forms of the condition are Muir-Torre syndrome and Turcot syndrome, both of which raise your risk of other cancers and, in the case of Muir-Torre, skin lesions.

What Causes It?

Lynch syndrome is caused by a problem in one of five genes in your DNA. These are the genes that affect how well your cells can spot mistakes and fix them as they grow and multiply.

When you have Lynch syndrome, your cells don't fix the errors. They make more and more flawed cells. Over time, that can cause cancer.

If one of your parents has it, you have a 50% chance of getting it, too.

Signs of Lynch Syndrome

If you get colon cancer before age 50, that's a possible sign. Other things that may suggest a risk of Lynch syndrome include:

  • Other people in your family had colon cancer when they were young.
  • Women in your family have had endometrial or uterine cancer.
  • Members of your family have had cancer of the kidney, liver, small intestine, stomach, or sweat glands.

Other Cancer Risks

Lynch syndrome is the most common reason why some women get cancer of the uterus. It also can raise your risk of these types of cancer:

If you have Lynch syndrome, you're also more likely to get noncancerous growths called polyps inside your colon. Polyps are common in older people, but people with Lynch syndrome may get them earlier in life.

How Is It Diagnosed?

If you or someone in your family gets cancer, the doctor can do one of these tests on a small sample of the tumor to look for signs of Lynch syndrome:

  • Immunohistochemistry (IHC) tests use dye to mark proteins in the tumor sample. If certain proteins aren't there, it's a sign of Lynch syndrome.
  • Microsatellite instability (MSI) tests look at the DNA in the tumor tissue. They can show errors in your genes that point to Lynch syndrome.

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Tumors that were taken out in the previous few years can sometimes be tested. Some hospitals store tumor samples after surgery in case they need to be tested later.

If someone in your family is diagnosed with Lynch syndrome, or if you think you’re at risk of getting it, you may want to get a gene test, which is done with a sample of your blood.

Your doctor can also refer you to a genetic counselor to discuss your risks and options. Your counselor can help you understand:

  • How Lynch syndrome is passed through families
  • What gene changes your test results may show
  • What these results mean for your cancer risk
  • The chances that you may pass the gene to your children
  • Your options to prevent cancer

A positive test for Lynch syndrome doesn't always mean you'll get cancer. Your risk is just much higher. A genetic counselor will work with you to decide what to do next. They can give you information about your options and emotional support.

What Are the Treatment Options?

If you have Lynch syndrome, be sure to get regular screenings in order to find any cancers at their earliest stages, when they’re easiest to treat. Colon cancer is 90% curable when you catch it early. If you’re at risk, you should start getting checkups much earlier than usual.

Your screening schedule will depend on your family history and whether you’ve had DNA testing. Here are some general guidelines:

  • Colonoscopies every 1 to 2 years, beginning at age 20 to 25. This test uses a long scope to look for polyps in your colon. People with Lynch syndrome often get polyps that are harder to see. So you may need to have a high-definition colonoscopy or a chromoendoscopy, which uses dyes to color the polyps. A colonoscopy may show polyps before they become cancer.
  • Endoscopies every 3 to 5 years, starting in your early to mid-30s. Both men and women can get an endoscopy to look in their stomach or intestines for signs of cancer.
  • Pelvic exams, uterine biopsies, or transvaginal ultrasounds to check your uterus and ovaries once a year starting around age 30. Your doctor may also recommend urine and stool testing plus blood tests to check how well your liver is working.

Some people with Lynch syndrome choose to have their colon taken out to help prevent cancer later on. Women who don’t want children in the future may also have their uterus and ovaries removed.

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Tips for Living With Lynch Syndrome

Aside from cancer screenings, a healthy lifestyle may help you prevent colorectal cancer. Diets high in veggies, fruit, and whole grains can help lower your risk. So can regular exercise, keeping a healthy weight, and limiting alcohol.

There is some evidence that taking aspirin every day for at least 2 years may decrease the risk of Lynch-related cancer, but more research is needed to find the best dose and length of time for treatment.

WebMD Medical Reference Reviewed by Nayana Ambardekar, MD on December 11, 2019

Sources

SOURCES:

American Cancer Society: "Six Ways to Lower Your Risk for Colon Cancer."

Cleveland Clinic: "Hereditary Non-Polyposis Colorectal Cancer (HNPCC)."

Dana-Farber Cancer Institute: "Cancer Genetics & Prevention: Lynch Syndrome."

Johns Hopkins Medicine: "HNPCC."

National Organization for Rare Diseases: "Lynch Syndrome."

Cancer.net: "Lynch Syndrome."

NIH/Genetic and Rare Diseases Information Center: "Turcot syndrome."

CDC: "Have You or a Family Member Had Colorectal (Colon) Cancer?"

MayoClinic.org: "Lynch Syndrome."

U.S. National Library of Medicine Genetics Home Reference: "Lynch Syndrome," "What Happens During a Genetics Consultation?"

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