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May 24, 2021
Why Screening for Lynch Syndrome is Important

Lynch syndrome is surprisingly common

Lynch syndrome (LS) is a genetic condition that confers increased risk of developing many types of cancer, including colorectal, endometrial, and ovarian cancers. This risk can be as high as 82%, depending on the cancer type.1 LS is linked to about 4,000 colorectal and 1,800 uterine (endometrial) cancers per year.2

LS occurs when an individual inherits a mutation (or change) in one of the genes that control DNA repair (MLH1, MSH2, MSH6, PMS2, or EPCAM).2 Inheriting one of these mutations does not mean that a patient has or will have cancer. It simply means that one of the patient’s two gene copies is dysfunctional and, as a result, the patient’s lifetime risk of developing cancer is increased. In other words, LS does not guarantee a cancer diagnosis, but it does increase the likelihood of one.

LS mutations are more common than BRCA mutations. Whereas LS affects 1 in 279 people, only 1 in 300-800 people are BRCA mutation carriers.

Screening improves outcomes for patients & families alike

Individuals with undiagnosed LS do not realize they are at risk. They are also unaware that genetic tests can detect LS. Indeed, one study found that only 63% knew about genetic tests for LS. The same study showed that 31% of patients were advised to undergo genetic testing, and only 7% followed through on that advice.3

Screening for LS can have a number of benefits, not only for patients with the mutation, but for their relatives as well. According to Giardiello and colleagues (2014), “Germline testing… can confirm the diagnosis of LS in a patient and / or family[;] determine the status of at-risk family members in pedigrees where the pathogenic mutation has been found[; and] direct the management of affected and unaffected individuals.”4

Ultimately, genetic test results can improve outcomes in patients with LS by providing increased access to screening. In the long run, these additional screenings are more cost-effective than foregoing surveillance altogether. According to a cost-effectiveness model, “Surveillance of people who are gene carriers for Lynch syndrome increased life expectancy by 7 years, and the cost of surveillance were less than the cost of no surveillance for colorectal cancer.”5

How to incorporate screening into your practice

The first step in screening for LS is obtaining a detailed family history. Recommendations from the American College of Gastroenterology (ACG) state, “A systematic and focused family history of cancer and premalignant conditions is the first step.”6 Guidelines from the AGA concur: “Diagnosing Lynch syndrome in patients without a personal history of cancer begins with obtaining a family history of cancers, and health care providers should be prepared to act on that information.”5

Once an individual’s LS risk has been established by their family history, more detailed risk assessment options can be pursued, including genetic testing. An estimated 10-15% of patients would benefit from this additional risk assessment.6 The Empower Hereditary Cancer Test from Natera can be used to screen for LS mutations, including MLH1, MSH2, MSH6, PMS2, or EPCAM.

Genetic counseling is an important part of the genetic testing process. Recommendations from the ACG dictate that genetic tests for LS must be accompanied by genetic education and counseling.6 In line with this recommendation, Natera supplements its genetic tests with pre- and post-test genetic information sessions with board-certified genetic counselors.

Interested in learning more about Lynch Syndrome? Listen as Dave Dubin, co-founder of the LS patient advocacy group AliveAndKickn, chats with patient turned advocate Elyse about her experience being diagnosed and living with LS.

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References

  1. CDC. Lynch Syndrome Fact Sheet for Healthcare Professionals. https://www.cdc.gov/genomics/implementation/toolkit/file/lynch_healthcare_professionals_fact_sheet.docx, accessed April 26, 2021.
  2. CDC. Lynch Syndrome. https://www.cdc.gov/genomics/disease/colorectal_cancer/lynch.htm#:~:text=Lynch%20syndrome%2C%20also%20known%20as,age%20(before%2050)%2C%20including, accessed April 26, 2021.
  3. Patel SG et al. Knowledge and Uptake of Genetic Counseling and Colonoscopic Screening Among Individuals at Increased Risk for Lynch Syndrome and their Endoscopists from the Family Health Promotion Project. Am J Gastroenterol. 2016 Feb;111(2):285-93.
  4. Giardiello FM et al. Guidelines on genetic evaluation and management of Lynch syndrome: a consensus statement by the US Multi-Society Task Force on colorectal cancer. Gastroenterology. 2014 Aug;147(2):502-26.
  5. Rubenstein JH et al. American Gastroenterological Association Institute Guideline on the Diagnosis and Management of Lynch Syndrome. Gastroenterology. 2015 Sep;149(3):777-82; quiz e16-7.
  6. Syngal S et al. ACG clinical guideline: Genetic testing and management of hereditary gastrointestinal cancer syndromes. Am J Gastroenterol. 2015 Feb;110(2):223-62; quiz 263.