New Guidelines Recommend Genetic Testing for Lynch Syndrome

In February, the National Comprehensive Cancer Network (NCCN) recommended universal testing for Lynch syndrome (LS) for at-risk individuals who have a family history of associated cancers, regardless of whether they’ve received a colorectal cancer (CRC) diagnosis. LS results from a genetic mutation that’s thought to be a factor in about 2 to 4 percent of colorectal cancer cases. And while it’s estimated that one out of every 440 people in the U.S. have LS, only a small percentage are tested for it.

Universal screening, which was originally added to the NCCN’s colorectal cancer guidelines in 2013, helps to identify individuals who carry the mutation. But because these guidelines focused more on screening patients who had already received a colorectal cancer diagnosis, the addition emphasizes the importance of testing family members. People with LS have a lifetime risk of up to 80 percent for developing colorectal cancer and are at high risk for other cancers, including endometrial, gastric, ovarian and pancreatic. Early testing enables affected individuals to take advantage of preventive measures, such as increased screening, chemoprevention or prophylactic surgery to reduce their cancer risk.

“This new criterion takes into account individuals with or without colorectal cancer, whereas previous guidelines primarily focused on patients with a diagnosis of colorectal cancer,” says Kory Jasperson, vice chairman of the NCCN panel that developed the guidelines (view the new guidelines). “Once we confirm Lynch syndrome in someone with CRC, we can then test at-risk relatives for the familial mutation and determine if they have LS and need increased screening and risk reduction; or if they don’t have LS, we know they are likely at average risk for cancer.”

For patients who have received a cancer diagnosis, a confirmation of LS can help guide treatment, follow-up and surveillance for other cancers.