The NHS has begun rolling out genetic testing for Lynch syndrome to improve rates of diagnosis for those suspected of having the condition and allow relatives to learn whether they were at enhanced risk from the hereditary disorder.
A national programme would ensure that all patients diagnosed with bowel and endometrial cancer would be offered a genetic test as an important step towards receiving more personalised treatment, NHS England said.
Current estimates are that 1 in 400 people in England have Lynch syndrome, which is equivalent to around 175,000 people, but only 5% are aware that they have it. Around 1100 bowel cancers are caused by Lynch syndrome each year in England. The lifetime risk up to age 70 years of colorectal cancer among people with Lynch syndrome is between 10% and 47%, dependent on sex and gene mutation, according to the British Society of Gastroenterology (BSG). The condition is also linked to the risk of people developing multiple cancers during their lifetime – and often at a younger age than would be typically expected.
People with Lynch syndrome who are diagnosed with bowel cancer tend to have tumours that are more responsive to immunotherapies such as pembrolizumab (Keytruda, Merck Sharp & Dohme), with the genetic testing enabling them to receive personalised treatment to help ensure the best chance of survival.
The NHS Genomic Medicine Service
Professor Dame Sue Hill, chief scientific officer for England, and the senior responsible officer for NHS Genomics, said: "This testing is made possible by the teams in the NHS Genomic Medicine Service across the country working together with cancer and pathology teams to drive up the level of genomic testing to diagnose Lynch syndrome as early as we can to deliver better outcomes for patients and to support the testing of potentially affected family members."
Bowel Cancer UK said it had been campaigning for testing for Lynch syndrome in England, Scotland, and Northern Ireland after Wales committed to a testing programme in 2019. Welcoming the latest development, Dr Lisa Wilde, director of research and external affairs at Bowel Cancer UK, described the move as "a huge step in the right direction". She said: "This important announcement means that those who haven't got bowel cancer but positively test for Lynch syndrome can be offered regular check-ups to reduce their risk of the disease in the future, and those who are already diagnosed with bowel cancer are offered effective treatment to save more lives from the disease."
Lynch syndrome is caused by germline mutations in mismatch repair genes, most commonly in MLH1, MSH2, MSH6, and PMS2, and rarely in EPCAM. More than 90% of cases are due to mutations in MLH1 or MSH2. Guidelines from the BSG are that access to specialist family cancer services and interventions, including high-quality screening and colonoscopic surveillance, is vital to reduce the risk of colorectal cancer incidence and mortality.
A survey last month by YouGov for charity The Eve Appeal found that only 3% of people polled had heard of Lynch syndrome.