The Diagnosis and Management of Lynch Syndrome Guideline Patient Companion

Clinical practice guidelines are developed under the guidance of the AGA Institute Clinical Guideline Committee and provide evidence-based recommendations for clinical practice in the field of gastroenterology. The clinical practice guidelines and related Clinical Decision Support Tools support evidence-based clinical decision-making by gastroenterologists and other health-care professionals at the point of care. The below information presents important content from those guidelines in a way that will help patients better understand AGA’s recommendations for evaluating, diagnosing or managing a condition.

AGA Clinical Guideline: The Diagnosis and Management of Lynch Syndrome

The information provided by the AGA Institute is not medical advice and should not be considered a replacement for seeing a medical professional.

What is Lynch Syndrome?

Lynch syndrome is a change of a gene that is in charge of fixing errors in your DNA. This mutation raises a person’s risk for certain cancers. 

  • The human body is always making new cells. Each time your body makes a new cell, it must copy your genes. There is always a chance that a “typo” will pop up in the new copy. In other words, the DNA for the new cell will not look quite like the DNA from the original cell. These DNA copying errors can change the way a cell grows, and may lead to cancer.
  • Usually, a gene called the DNA mismatch repair gene (MMR for short) looks out for these mistakes and fixes them before they harm the cell.
  • People with Lynch syndrome have a mutation of the MMR gene, which means their bodies are less able to fix errors in the DNA.
Lynch syndrome raises the risk of getting colorectal cancer by 80 percent and endometrial cancer by 60 percent. Lynch syndrome can also lead to other cancers, including:
  • Cancers of the stomach and small intestine.
  • Cancer of the pancreas.
  • Cancer of the urinary tract, including kidneys.
  • Cancer of the bile ducts.
  • Sebaceous (oil) gland tumors.
  • Ovarian cancer.
  • Skin cancer.
  • Glioblastoma multiforme (a type of brain cancer).

One in every 440 Americans has Lynch syndrome, but the majority of these people have not been diagnosed.

  • Lynch syndrome is the most common inherited cause of colorectal cancer.
  • The child of a person with Lynch syndrome has a 50 percent chance of inheriting it.
A doctor can estimate a person’s risk of having Lynch syndrome based on their family history of cancer.
  • Your doctor can use a risk prediction model to estimate the chance that you have Lynch syndrome. To estimate your risk, your doctor will need to know:
    • Whether you have ever had cancer, and what type(s).
    • The approximate age at which each family member was first diagnosed with cancer.
  • Based on this information, your doctor may decide to refer you to a genetic counselor or to order a genetic test.
  • You may already know that a family member has Lynch syndrome. If so, tell your doctor. If your family member has already had a genetic test, bringing those results to your doctor can make it easier to find out whether you, too, have Lynch syndrome.
  • If you have a strong family history of cancer, consider asking your doctor these questions:
    • With my family history of cancer, am I at risk for having Lynch syndrome?
    • If so, would you suggest that I get a genetic test done or see a genetic counselor?
    • What are the risks and benefits of genetic testing?
  • A blood test can confirm the diagnosis of Lynch syndrome.
    • This test uses a small amount of your blood to look for the mutations that cause Lynch syndrome.

How to Prevent Colorectal Cancer if You Have Lynch Syndrome

Get a colonoscopy every one to two years, starting in your twenties.

  • If you have Lynch syndrome, you should get a colonoscopy every one to two years to screen for colorectal cancer. Doing this will reduce your risk of colorectal cancer by 77 percent.
Exactly when should you get your first screening?
  • Find out the youngest age at which a family member first got colorectal cancer. Then, follow these guidelines:
    • If that person was younger than 25 when they were first diagnosed: subtract five from that age. For instance: if they were 24 at the time of diagnosis, get your first colonoscopy at 19.
    • If that person was 25 or older when they were first diagnosed: start between the ages of 20 and 25.
Talk to your doctor about taking aspirin every day.
  • Taking 600 milligrams of aspirin every day may lower your odds of getting colorectal cancer by 44 percent.
  • The ideal dosage of aspirin is not known, and there are risks from taking aspirin at such a high dose.
  • Some people, such as those with stomach bleeding or blood clotting disorders, should not take aspirin regularly.
  • Talk to your doctor to decide whether and how much aspirin to take.
  • Taking aspirin should not replace getting a colonoscopy every one to two years.

Remember, most people with Lynch syndrome do not know they have it. If you have Lynch syndrome, the most important thing to do is start getting screened as soon as possible to keep yourself healthy.

If you are diagnosed with Lynch Syndrome, prepare to ask your doctor the following questions:

  • How do I schedule and get ready for a colonoscopy?
  • How can I make sure I remember to schedule a colonoscopy every one to two years?
  • Would it be safe for me to take 600 milligrams of aspirin per day to lower my risk of colorectal cancer?