Assessing the impact of systematic testing for Lynch syndrome
Lynch syndrome is a mistake in a person’s genes, usually inherited from a parent, and affects around 1 in 280 Australians. Cancer Council NSW researchers have found that routine testing bowel cancer cases would be a cost-effective way of revealing the thousands of currently undiagnosed Australians with Lynch syndrome around the country.
Background
Lynch syndrome is a hereditary cancer condition associated with an increased risk of up to twelve different cancers but most commonly bowel and endometrial cancers. It’s caused by the inheritance of sequence mutations, or spelling mistakes, within the code of a certain group of genes called ‘mismatch repair genes’. These genes help protect against the development of cancer cells, so someone with a mutation has a greatly increased chance of developing more than one aggressive cancer during their life, often at a younger age than the general population.
If Lynch syndrome is confirmed in one family member, genetic testing can be made available to at-risk relatives and lifestyle and surveillance risk management can reduce the number of cancers in that family. However, the referral rate for Lynch syndrome testing is low, leaving the conditional largely undiagnosed in Australia.
The research
The aim of this study was to evaluate the health impact and cost-effectiveness of systematic testing for Lynch syndrome in people with bowel cancer in Australia. The researchers considered eight different testing approaches in all bowel cancer cases including a ‘no testing’ strategy, with the assumption that the Lynch syndrome carriers who are identified would be offered an annual colonoscopy for surveillance. The team also assessed the impact of age at bowel cancer diagnosis and alternate surveillance intervals (annual vs 2-yearly colonoscopies) on the most cost-effective of the testing strategies.
The study found that routine testing of all bowel cancers in Australia for Lynch syndrome would be cost-effective and has the potential to prevent 80 bowel cancer deaths per year. This would also result in around 10-13% more colonoscopies in Australia per year targeted to people diagnosed with Lynch syndrome-related bowel cancer and their relatives who tested positive for Lynch syndrome. The cost-effectiveness ratio would range between A$28,915 to A$31,904/life-year saved (LYS), which is well within Australia’s indicative willingness-to-pay threshold of A$30,000-A$50,000/LYS.
The impact
Lynch syndrome-related cancers are fast-growing. Identifying those who are risk and offering regular checks is vital. The results of this study support efforts to introduce routine Lynch syndrome testing for new bowel cancer cases, showing that testing would save lives and be cost-effective.
The research team are taking the next step to address variability in Lynch syndrome clinical practice through implementation research which aims to ensure all bowel cancer patients carrying the Lynch syndrome gene are identified.
Research team
Cost-effectiveness evaluation
Dr Yoon-Jung Kang
Dr Michael Caruana
Dr Ian M Frayling
A/Prof Veerle MH Coupe
Prof Robyn L Ward
Professor Karen Canfell
Prof Alex Boussioutas
A/Prof Alison H Trainer
Dr Gillian Mitchell
Prof Finlay A Macrae
James Killen
Dr Kate Simms
Dr Natalie Taylor
Suzanne Hughes
Victoria Freeman
Dr Tristan Snowsill|
Ms Nicola Huxley
Implementation research
Dr Natalie Taylor
Prof Alexander Engel
Prof Michael Solomon
Prof Marina Wallace
Prof Finlay Macrae
A/Prof Marion Harris
Dr Peter Pockney
Dr James Toh
Dr Nicholas Patcher
Dr Mary Theophilus