title: A model-based assessment of the cost-utility of strategies to identify Lynch syndrome in early-onset colorectal cancer patients.
abstract: BACKGROUND
  Lynch syndrome is an autosomal dominant cancer predisposition syndrome caused by mutations in the DNA mismatch repair genes MLH1, MSH2, MSH6 and PMS2. Individuals with Lynch syndrome have an increased risk of colorectal cancer, endometrial cancer, ovarian and other cancers. Lynch syndrome remains underdiagnosed in the UK. Reflex testing for Lynch syndrome in early-onset colorectal cancer patients is proposed as a method to identify more families affected by Lynch syndrome and offer surveillance to reduce cancer risks, although cost-effectiveness is viewed as a barrier to implementation. The objective of this project was to estimate the cost-utility of strategies to identify Lynch syndrome in individuals with early-onset colorectal cancer in the NHS.
  
  
  METHODS
  A decision analytic model was developed which simulated diagnostic and long-term outcomes over a lifetime horizon for colorectal cancer patients with and without Lynch syndrome and for relatives of those patients. Nine diagnostic strategies were modelled which included microsatellite instability (MSI) testing, immunohistochemistry (IHC), BRAF mutation testing (methylation testing in a scenario analysis), diagnostic mutation testing and Amsterdam II criteria. Biennial colonoscopic surveillance was included for individuals diagnosed with Lynch syndrome and accepting surveillance. Prophylactic hysterectomy with bilateral salpingo-oophorectomy (H-BSO) was similarly included for women diagnosed with Lynch syndrome. Costs from NHS and Personal Social Services perspective and quality-adjusted life years (QALYs) were estimated and discounted at 3.5% per annum.
  
  
  RESULTS
  All strategies included for the identification of Lynch syndrome were cost-effective versus no testing. The strategy with the greatest net health benefit was MSI followed by BRAF followed by diagnostic genetic testing, costing £5,491 per QALY gained over no testing. The effect of prophylactic H-BSO on health-related quality of life (HRQoL) is uncertain and could outweigh the health benefits of testing, resulting in overall QALY loss.
  
  
  CONCLUSIONS
  Reflex testing for Lynch syndrome in early-onset colorectal cancer patients is predicted to be a cost-effective use of limited financial resources in England and Wales. Research is recommended into the cost-effectiveness of reflex testing for Lynch syndrome in other associated cancers and into the impact of prophylactic H-BSO on HRQoL.
authors.affiliation: Institute of Health Research, University of Exeter Medical School, University of Exeter, Exeter, UK. t.m.snowsill@exeter.ac.uk.
authors.forename: Tristan
authors.initials: T
authors.lastname: Snowsill
authors.affiliation: Institute of Health Research, University of Exeter Medical School, University of Exeter, Exeter, UK. n.j.huxley@exeter.ac.uk.
authors.forename: Nicola
authors.initials: N
authors.lastname: Huxley
authors.affiliation: Institute of Health Research, University of Exeter Medical School, University of Exeter, Exeter, UK. m.w.hoyle@exeter.ac.uk.
authors.forename: Martin
authors.initials: M
authors.lastname: Hoyle
authors.affiliation: Institute of Health Research, University of Exeter Medical School, University of Exeter, Exeter, UK. t.jones-hughes@exeter.ac.uk.
authors.forename: Tracey
authors.initials: T
authors.lastname: Jones-Hughes
authors.affiliation: Institute of Health Research, University of Exeter Medical School, University of Exeter, Exeter, UK. h.coelho@exeter.ac.uk.
authors.forename: Helen
authors.initials: H
authors.lastname: Coelho
authors.affiliation: Institute of Health Research, University of Exeter Medical School, University of Exeter, Exeter, UK. christopher.cooper@exeter.ac.uk.
authors.forename: Chris
authors.initials: C
authors.lastname: Cooper
authors.affiliation: Institute of Cancer & Genetics, Cardiff University, Cardiff, UK. fraylingim@cardiff.ac.uk.
authors.forename: Ian
authors.initials: I
authors.lastname: Frayling
authors.affiliation: Institute of Health Research, University of Exeter Medical School, University of Exeter, Exeter, UK. c.j.hyde@exeter.ac.uk.
authors.forename: Chris
authors.initials: C
authors.lastname: Hyde
mesh_terms: D017668:Age of Onset; D000368:Aged; D003123:Colorectal Neoplasms, Hereditary Nonpolyposis / Q000175:diagnosis* / Q000191:economics / Q000235:genetics; D003362:Cost-Benefit Analysis; D004252:DNA Mutational Analysis; D003658:Decision Making, Computer-Assisted; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D018803:Models, Economic; D025202:Molecular Diagnostic Techniques / Q000191:economics; D019057:Quality-Adjusted Life Years; D012306:Risk; D012680:Sensitivity and Specificity