Investigator

Katie Snape

Reader in Clinical Genomics · City St George's, University of London, IMBE

KSKatie Snape
Papers(3)
Impact of NICE Guidel…Lynch syndrome diagno…The avoiding late dia…
Collaborators(10)
Louise IzattMalcolm ScottMichelle LockleyNaveena SinghRanjit ManchandaSophie AllenSue PhilpottVishakha TripathiAdam N RosenthalAdam Shaw
Institutions(8)
University College Lo…Guy's and St Thomas' …University College Ho…Vancouver General Hos…Wolfson Institute of …The Institute of Canc…University College Lo…Guys And St Thomas Ch…

Papers

Impact of NICE Guideline NG241 ‘Ovarian Cancer: identifying and managing familial and genetic risk’ on a regional NHS family history and clinical genetics service

Background NICE Guideline NG241: identifying and managing familial and genetic risk of ovarian cancer (OC) was published by the National Institute for Health and Care Excellence (NICE) in March 2024. NG241 advises germline genetic testing of genes predisposing to OC in unaffected individuals with an OC family history at different mutation likelihood thresholds depending on age and sex, ranging from 2% to 10% likelihood of finding a germline pathogenic variant (GPV). Prior to implementation of NG241, updates to the NHS England National Genomic Test Directory would be required. Clinical genetics services have to consider equity of access to assessment and testing across all familial cancer types, best use of their limited resources and other factors such as complexity of delivery of clinical pathways. Methods We analysed data from 8011 patients who provided digital family histories to the South West Thames Centre for Genomics between October 2019 and June 2024. Results We estimate 527/782 (68%) females and 28/77 (36%) males would meet test criteria for NICE NG241. We estimate we would reject 2919/5485 (53%) females and 135/1208 (11%) males with the same likelihood of carrying a GPV, but with a breast cancer rather than OC family history. Testing the familial OC cohort at a universal 5% threshold in OC families would detect ~11 carriers for 229 tests compared with ~8 carriers for 278 tests following NG241 criteria. Conclusion Our data highlight additional factors needing to be considered before the NICE Guideline NG241 can be implemented by regional genetics services.

Lynch syndrome diagnostic testing pathways in endometrial cancers: a nationwide English registry-based study

Background For female patients with Lynch syndrome (LS), endometrial cancer (EC) is often their first cancer diagnosis. A testing pathway of somatic tumour testing triage followed by germline mismatch repair (MMR) gene testing is an effective way of identifying the estimated 3% of EC caused by LS. Methods A retrospective national population-based observational study was conducted using comprehensive national data collections of functional, somatic and germline MMR tests available via the English National Cancer Registration Dataset. For all EC diagnosed in 2019, the proportion tested, median time to test, yield of abnormal results and factors influencing testing pathway initiation were examined. Results There was an immunohistochemistry (IHC) or microsatellite instability (MSI) test recorded for 17.8% (1408/7928) of patients diagnosed with EC in 2019. Proportions tested varied by Cancer Alliance and age. There was an MLH1 promoter hypermethylation test recorded for 43.1% (149/346) of patients with MLH1 protein IHC loss or MSI. Of patients with EC eligible from tumour-testing, 25% (26/104) had a germline MMR test recorded. Median time from cancer diagnosis to germline MMR test was 315 days (IQR 222–486). Conclusion This analysis highlights the regional variation in recorded testing, patient attrition, delays and missed opportunities to diagnose LS, providing an informative baseline for measuring the impact of the national guidance from the National Institute for Health and Care Excellence on universal reflex LS testing in EC, implemented in 2020.

The avoiding late diagnosis of ovarian cancer (ALDO) project; a pilot national surveillance programme for women with pathogenic germline variants inBRCA1andBRCA2

BackgroundOur study aimed to establish ‘real-world’ performance and cost-effectiveness of ovarian cancer (OC) surveillance in women with pathogenic germlineBRCA1/2variants who defer risk-reducing bilateral salpingo-oophorectomy (RRSO).MethodsOur study recruited 875 femaleBRCA1/2-heterozygotes at 13 UK centres and via an online media campaign, with 767 undergoing at least one 4-monthly surveillance test with the Risk of Ovarian Cancer Algorithm (ROCA) test. Surveillance performance was calculated with modelling of occult cancers detected at RRSO. The incremental cost-effectiveness ratio (ICER) was calculated using Markov population cohort simulation.ResultsOur study identified 8 OCs during 1277 women screen years: 2 occult OCs at RRSO (both stage 1a), and 6 screen-detected; 3 of 6 (50%) were ≤stage 3a and 5 of 6 (83%) were completely surgically cytoreduced. Modelled sensitivity, specificity, Positive Predictive Value (PPV) and Negative Predictive Value (NPV) for OC were 87.5% (95% CI, 47.3 to 99.7), 99.9% (99.9–100), 75% (34.9–96.8) and 99.9% (99.9–100), respectively. The predicted number of quality-adjusted life years (QALY) gained by surveillance was 0.179 with an ICER cost-saving of -£102,496/QALY.ConclusionOC surveillance for women deferring RRSO in a ‘real-world’ setting is feasible and demonstrates similar performance to research trials; it down-stages OC, leading to a high complete cytoreduction rate and is cost-saving in the UK National Health Service (NHS) setting. While RRSO remains recommended management, ROCA-based surveillance may be considered for femaleBRCA-heterozygotes who are deferring such surgery.

1Works
3Papers
18Collaborators
Ovarian NeoplasmsEndometrial NeoplasmsBreast NeoplasmsDelayed DiagnosisCentral Nervous System NeoplasmsCerebellar Neoplasms

Positions

2014–

Reader in Clinical Genomics

City St George's, University of London · IMBE

2012–

Consultant Geneticist

Saint George's Hospital · Clinical Genetics

Education

2012

PhD

Institute of Cancer Research · Genetics and Epidemiology

2003

MBBS

Guys, Kings and St Thomas' School of Medicine · Medicine