Raising the age limit for routine genetic testing in colorectal cancer could identify more cases of families affected by Lynch syndrome, a condition that accounts for approximately 5% of all colon cancers, according to new research presented at the annual conference of the European Society of Human Genetics (ESHG) in Copenhagen, Denmark, on May 29, 2017. Professor Nicoline Hoogerbrugge, Head of the Radboud University Medical Centre Expert Centre on Hereditary Cancers, Nijmegen, The Netherlands, will tell the conference that there is an urgent need to find families carrying a mutation for Lynch syndrome in order to decrease mortality from the disease. "We know that, at present, only between 20% and 30% of people with Lynch syndrome have been identified. Most countries rely on detection through family history and early age at diagnosis, and this leads to significant under-diagnosis. We have shown that, by raising the age limit for testing we are able to detect new affected families who would not have been identified previously," she says. The researchers studied results of mismatch repair (MMR) testing in patients up to 70 years of age with colorectal cancer from 14 pathology laboratories. Previously, in The Netherlands, such testing was carried routinely in patients who were aged up to 50. Of 87 patients whose results suggested that they are at high risk of Lynch syndrome, 35 were referred for genetic counseling. After further testing, Lynch syndrome mutations were definitely identified in 13 of 32 patients with complete genetic testing, and 11 of these patients came from families in which the disease had previously not been detected. Eight of them were aged between 50 and 70 and did not comply with previous referral criteria for genetic testing based on age and family history.
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