1 October 2014
Lynch Syndrome (LS), also known as Hereditary non-polyposis colorectal cancer (HNPCC) is a familial cancer syndrome; affected individuals have disease-associated mutations in one of a number of key genes involved in normal DNA repair processes (most commonly the MLH1, MSH2 and MSH6 genes). This results in a significantly increased risk of developing certain forms of cancer, notably colorectal (bowel) cancer but also endometrial and ovarian cancers and a number of others.
New research published as a formal Heath Technology Assessment has examined the efficacy and cost-effectiveness of alternative strategies to diagnose LS in patients with early-onset colorectal cancer – those younger than 50.
Identifying LS has important health benefits for the patients – allowing appropriate close monitoring or preventative treatments for different forms of cancer as well as recurrences of colorectal cancer; for example, removal of the womb or ovaries in women. Moreover, cascade testing of close relatives can also identify family members at high risk of the same cancers who would benefit from risk reduction strategies.
The researchers compared the alternative approaches of microsatellite instability (MSI) testing or immunohistochemistry (IHC), including economic data. Analysis of the available evidence showed that testing for LS newly-diagnosed colorectal cancer patients aged under 50 is indeed cost-effective. No specific method emerged as a clear ‘gold-standard’ for testing but the most cost-effective approach was found to be the use of MSI and BRAF mutation testing; cascade testing of at-risk family members was recommended for all strategies.
Efforts to review the alternative techniques and develop a consensus optimal strategy for national implementation have been in progress for many years (see Biomarkers in familal colorectal cancer screening).
The new HTA findings, combined with a new clinical classification scheme for genetic variants associated with LS released by the International Society for Gastrointestinal Hereditary Tumours (InSiGHT) earlier this year, should underpin policy changes that will increase the numbers of people identified with LS and prevent cancers.
Dr Ian Frayling of Cardiff University's Institute of Medical Genetics, one of the researchers, told the BBC: "Now the cost of genetic testing is coming down there is a good argument for younger bowel cancer patients to be screened. It will save lives and save money for the NHS".
Looking further ahead, he and colleagues recommended new research into the cost-effectiveness of testing for LS in younger patients with newly diagnosed endometrial or ovarian cancer, and of the value of treatment with aspirin to reduce the risk of future cancers.