A systematic review and economic evaluation of diagnostic strategies for Lynch syndrome

Identification of people with Lynch syndrome from those presenting with colorectal cancer in England: baseline analysis of the diagnostic pathway

It is believed that >95% of people with Lynch syndrome (LS) remain undiagnosed. Within the National Health Service (NHS) in England, formal guidelines issued in 2017 state that all colorectal cancers (CRC) should be tested for DNA Mismatch Repair deficiency (dMMR). We used a comprehensive population-level national dataset to analyse implementation of the agreed diagnostic pathway at a baseline point 2 years post-publication of official guidelines. Using real-world data collected and curated by the National Cancer Registration and Analysis Service (NCRAS), we retrospectively followed up all people diagnosed with CRC in England in 2019. Nationwide laboratory diagnostic data incorporated somatic (tumour) testing for dMMR (via immunohistochemistry or microsatellite instability), somatic testing for MLH1 promoter methylation and BRAF status, and constitutional (germline) testing of MMR genes. Only 44% of CRCs were screened for dMMR; these figures varied over four-fold with respect to geography. Of those CRCs identified as dMMR, only 51% underwent subsequent diagnostic testing. Overall, only 1.3% of patients with colorectal cancer had a germline MMR genetic test performed; up to 37% of these tests occurred outside of NICE guidelines. The low rates of molecular diagnostic testing in CRC support the premise that Lynch syndrome is underdiagnosed, with significant attrition at all stages of the testing pathway. Applying our methodology to subsequent years' data will allow ongoing monitoring and analysis of the impact of recent investment. If the diagnostic guidelines were fully implemented, we estimate that up to 700 additional people with LS could be identified each year.

A 39 kb structural variant causing Lynch Syndrome detected by optical genome mapping and nanopore sequencing

Lynch Syndrome (LS) is a hereditary cancer syndrome caused by pathogenic germline variants in one of the four mismatch repair (MMR) genes MLH1, MSH2, MSH6 and PMS2. It is characterized by a significantly increased risk of multiple cancer types, particularly colorectal and endometrial cancer, with autosomal dominant inheritance. Access to precise and sensitive methods for genetic testing is important, as early detection and prevention of cancer is possible when the variant is known. We present here two unrelated Norwegian families with family histories strongly suggestive of LS, where immunohistochemical and microsatellite instability analyses indicated presence of a pathogenic variant in MSH2, but targeted exon sequencing and multiplex ligation-dependent probe amplification (MLPA) were negative. Using Bionano optical genome mapping, we detected a 39 kb insertion in the MSH2 gene. Precise mapping of the insertion breakpoints and inserted sequence was performed by low-coverage whole-genome sequencing with an Oxford Nanopore MinION. The same variant was present in both families, and later found in other families from the same region of Norway, indicative of a founder event. To our knowledge, this is the first diagnosis of LS caused by a structural variant using these technologies. We suggest that structural variant detection be performed when LS is suspected but not confirmed with first-tier standard genetic testing.

Comparison of immediate germline sequencing and multi-step screening for Lynch syndrome detection in high-risk endometrial and colorectal cancer patients

OBJECTIVE

Lynch syndrome (LS) is a hereditary cancer predisposition syndrome with a significantly increased risk of colorectal and endometrial cancers. Current standard practice involves universal screening for LS in patients with newly diagnosed colorectal or endometrial cancer using a multi-step screening protocol (MSP). However, MSP may not always accurately identify LS cases. To address this limitation, we compared the diagnostic performance of immediate germline sequencing (IGS) with MSP in a high-risk group.

METHODS

A total of 31 Taiwanese women with synchronous or metachronous endometrial and colorectal malignancies underwent MSP which included immunohistochemical staining of DNA mismatch repair (MMR) proteins, MLH1 promoter hypermethylation analysis, and germline sequencing to identify pathogenic variants. All patients who were excluded during MSP received germline sequencing for MMR genes to simulate IGS for the detection of LS.

RESULTS

Our findings indicate that IGS surpassed MSP in terms of diagnostic yield (29.0% vs. 19.4%, respectively) and sensitivity (90% vs. 60%, respectively). Specifically, IGS successfully identified nine LS cases, which is 50% more than the number detected through MSP. Additionally, germline methylation analysis revealed one more LS case with constitutional MLH1 promoter hypermethylation, bringing the total LS cases to ten (32.3%). Intriguingly, we observed no significant differences in clinical characteristics or overall survival between patients with and without LS in our cohort.

CONCLUSION

Our study suggests that IGS may potentially offer a more effective approach compared to MSP in identifying LS among high-risk patients. This advantage is evident when patients have been pre-selected utilizing specific clinical criteria.

Endometrial Cancer. Guideline of the DGGG, DKG and DKH (S3-Level, AWMF Registry Number 032/034-OL, September 2022). Part 1 with Recommendations on the Epidemiology, Screening, Diagnosis and Hereditary Factors of Endometrial Cancer, Geriatric Assessment and Supply Structures

Summary The S3-guideline on endometrial cancer, first published in April 2018, was reviewed in its entirety between April 2020 and January 2022 and updated. The review was carried out at the request of German Cancer Aid as part of the Oncology Guidelines Program and the lead coordinators were the German Society for Gynecology and Obstetrics (DGGG), the Gynecology Oncology Working Group (AGO) of the German Cancer Society (DKG) and the German Cancer Aid (DKH). The guideline update was based on a systematic search and assessment of the literature published between 2016 and 2020. All statements, recommendations and background texts were reviewed and either confirmed or amended. New statements and recommendations were included where necessary. Aim The use of evidence-based risk-adapted therapies to treat women with endometrial cancer of low risk prevents unnecessarily radical surgery and avoids non-beneficial adjuvant radiation therapy and/or chemotherapy. For women with endometrial cancer and a high risk of recurrence, the guideline defines the optimum level of radical surgery and indicates whether chemotherapy and/or adjuvant radiation therapy is necessary. This should improve the survival rates and quality of life of these patients. The S3-guideline on endometrial cancer and the quality indicators based on the guideline aim to provide the basis for the work of certified gynecological cancer centers. Methods The guideline was first compiled in 2018 in accordance with the requirements for S3-level guidelines and was updated in 2022. The update included an adaptation of the source guidelines identified using the German Instrument for Methodological Guideline Appraisal (DELBI). The update also used evidence reviews which were created based on selected literature obtained from systematic searches in selected literature databases using the PICO process. The Clinical Guidelines Service Group was tasked with carrying out a systematic search and assessment of the literature. Their results were used by interdisciplinary working groups as a basis for developing suggestions for recommendations and statements which were then modified during structured online consensus conferences and/or additionally amended online using the DELPHI process to achieve a consensus. Recommendations Part 1 of this short version of the guideline provides recommendations on epidemiology, screening, diagnosis, and hereditary factors. The epidemiology of endometrial cancer and the risk factors for developing endometrial cancer are presented. The options for screening and the methods used to diagnose endometrial cancer are outlined. Recommendations are given for the prevention, diagnosis, and therapy of hereditary forms of endometrial cancer. The use of geriatric assessment is considered and existing structures of care are presented.

Systematic Review and Narrative Synthesis of Economic Evaluations of Prostate Cancer Diagnostic Pathways Incorporating Prebiopsy Magnetic Resonance Imaging

Context

Prebiopsy magnetic resonance imaging (MRI) of the prostate has been shown to increase the accuracy of the diagnosis of clinically significant prostate cancer. However, evidence is still evolving about how best to integrate prebiopsy MRI into the diagnostic pathway and for which patients, and whether MRI-based pathways are cost effective.

Objective

This systematic review aimed to assess the evidence for the cost effectiveness of prebiopsy MRI-based prostate cancer diagnostic pathways.

Evidence acquisition

INTERTASC search strategies were adapted and combined with terms for prostate cancer and MRI, and used to search a wide range of databases and registries covering medicine, allied health, clinical trials, and health economics. No limits were set on country, setting, or publication year. Included studies were full economic evaluations of prostate cancer diagnostic pathways with at least one strategy including prebiopsy MRI. Model-based studies were assessed using the Philips framework, and trial-based studies were assessed using the Critical Appraisal Skills Programme checklist.

Evidence synthesis

A total of 6593 records were screened after removing duplicates, and eight full-text papers, reporting on seven studies (two model based) were included in this review. Included studies were judged to have a low-to-moderate risk of bias. All studies reported cost-effectiveness analyses based in high-income countries but had significant heterogeneity in diagnostic strategies, patient populations, treatment strategies, and model characteristics. Prebiopsy MRI-based pathways were cost effective compared with pathways relying on ultrasound-guided biopsy in all eight studies.

Conclusions

Incorporation of prebiopsy MRI into prostate cancer diagnostic pathways is likely to be more cost effective in than that into pathways relying on prostate-specific antigen and ultrasound-guided biopsy. The optimal prostate cancer diagnostic pathway design and method of integrating prebiopsy MRI are not yet known. Variations between health care systems and diagnostic approaches necessitate further evaluation for a particular country or setting to know how best to apply prebiopsy MRI.

Patient summary

In this report, we looked at studies that measured the health care costs and benefits and harms to patients of using prostate magnetic resonance imaging (MRI), to decide whether men need a prostate biopsy for possible prostate cancer. We found that using prostate MRI before biopsy is likely to be less costly for health care services and probably has better outcomes for patients being investigated for prostate cancer. It is still unclear what the best way to use prostate MRI is.

A comparative cost analysis of two screening strategies for colorectal cancer in Lynch Syndrome in a South African tertiary hospital

AIM

Lynch Syndrome (LS) individuals have a 25-75% lifetime risk of developing colorectal cancer. Colonoscopy screening decreases this risk. This study compared the cost of Strategy 1: screening colonoscopy for 1st degree relatives of patients that met the Revised Bethesda Criteria (i.e., probands) to Strategy 2: screening colonoscopy for 1^st degree relatives of probands with genetic mutations for Lynch Syndrome based in a resource-constrained health care system.

METHOD

A comparative, health care provider perspective, cost analysis was conducted at a tertiary hospital, using a micro-costing, ingredient approach. Forty probands that underwent genetic testing between November 01, 2014 and October 30, 2015 and their first-degree relatives were costed according to Strategy 1 and Strategy 2. Unit costs of colonoscopy and genetic testing were estimated and used to calculate and compare the total costs per strategy in South African rand (R) converted to UK pounds (£). Sensitivity analyses were performed on colonoscopy adherence, relatives' positivity, and variable discount rates.

RESULTS

The cost for Strategy 1 amounted to £653 344/R6 161 035 compared to £49 327/R 465 155 for Strategy 2 (Discount rate 3%; Adherence 75%; and Positivity rate of relatives 45%). Base case analysis indicated a difference of 92% less in the total cost for Strategy 2 compared to Strategy 1. Sensitivity analyses showed that the difference in cost between the two strategies was not sensitive to variations in adherence, positivity or discount rates.

CONCLUSION

Colonoscopy screening for LS and at-risk family members was tenfold less costly when combined with genetic analysis. The logistics of rolling out this strategy nationally should be investigated.

A Focused Clinical Review of Lynch Syndrome

Lynch syndrome (LS) is an autosomal dominant condition that increases an individual's risk of a constellation of cancers. LS is defined when an individual has inherited pathogenic variants in the mismatch repair genes. Currently, most people with LS are undiagnosed. Early detection of LS is vital as those with LS can be enrolled in cancer reduction strategies through chemoprophylaxis, risk reducing surgery and cancer surveillance. However, these interventions are often invasive and require refinement. Furthermore, not all LS associated cancers are currently amenable to surveillance. Historically only those with a strong family history suggestive of LS were offered testing; this has proved far too restrictive. New criteria for testing have recently been introduced including the universal screening for LS in associated cancers. This has increased the number of people being diagnosed with LS but has also brought about unique challenges such as when to consent for germline testing and questions over how and who should carry out the consent. The results of germline testing for LS can be complicated and the diagnostic pathway is not always clear. Furthermore, by testing only those with cancer for LS we fail to identify these individuals before they develop potentially fatal pathology. This review will outline these challenges and explore solutions. Furthermore, we consider the potential future of LS care and the related treatments and interventions which are the current focus of research.

Universal tumor screening for lynch syndrome on colorectal cancer biopsies impacts surgical treatment decisions

Universal tumor screening (UTS) for Lynch syndrome (LS) on colorectal cancer (CRC) can be performed on biopsies or resection specimens. The advantage of biopsies is the chance to provide preoperative genetic counseling/testing (GC/T) so patients diagnosed with LS can make informed decisions regarding resection extent. We evaluated utilization of UTS on biopsies, percentage of patients with deficient mismatch repair (dMMR) who underwent GC/T preoperatively, and whether surgical/treatment decisions were impacted. We performed a retrospective review of medical records to assess CRC cases with dMMR immunohistochemical staining from 1/1/2017 to 2/26/2021. 1144 CRC patients had UTS using MMR immunohistochemistry; 559 biopsies (48.9%) and 585 resections (51.1%). The main reason UTS was not performed on biopsy was it occurred outside our health system. 58 (5%) of CRCs were dMMR and did not have MLH1 promoter hypermethylation (if MLH1 and PMS2 absent). 28/58 (48.3%) of dMMR cases were diagnosed on biopsy. Of those 28, 14 (50%) eventually underwent GC/T, and 7 (25%) had GT results prior to surgery. One of the 7 had incomplete documentation of results affecting their treatment plan. Of the remaining 6 with complete documentation, 5 underwent surgery and one was treated with immunotherapy only. Three patients elected a more extensive surgery. 6/28 (21.4%) dMMR patients identified on biopsy made an informed surgical/treatment decision based on their dMMR status/LS diagnosis. When applied, UTS on biopsy followed by genetic counseling and testing informs surgical decision-making. Process and implementation strategies are in place to overcome challenges to more broadly optimize this approach.

Universal Screening for Lynch Syndrome Compared with Pedigree-Based Screening: 10-Year Experience in a Tertiary Hospital

PURPOSE

Universal screening for Lynch syndrome (LS) refers to routine tumor testing for microsatellite instability (MSI) among all patients with colorectal cancer (CRC). Despite its widespread adoption, real-world data on the yield is lacking in Korean population. We studied the yield of adopting universal screening for LS in comparison with pedigree-based screening in a tertiary center.

MATERIALS AND METHODS

CRC patients from 2007-2018 were reviewed. Family histories were obtained and were evaluated for hereditary nonpolyposis colorectal cancer (HNPCC) using Amsterdam II criteria. Tumor testing for MSI began in 2007 and genetic testing was offered using all available clinicopathologic data. Yield of genetic testing for LS was compared for each approach and step.

RESULTS

Of the 5,520 patients, tumor testing was performed in 4,701 patients (85.2%) and family histories were obtained from 4,241 patients (76.8%). Hereditary CRC (LS or HNPCC) was present in 69 patients (1.3%). MSI-high was present in 6.9%, and 25 patients had confirmed LS. Genetic testing was performed in 41.2% (47/114) of MSI-high patients, out of which 40.4% (19/47) were diagnosed with LS. There were six additional LS patients found outside of tumor testing. For pedigree-based screening, Amsterdam II criteria diagnosed 55 patients with HNPCC. Fifteen of these patients underwent genetic testing, and 11 (73.3%) were diagnosed with LS. Two patients without prior family history were diagnosed with LS and relied solely on tumor testing results.

CONCLUSION

Despite widespread adoption of routine tumor testing for MSI, this is not a fail-safe approach to screen all LS patients. Obtaining a thorough family history in combination with universal screening provides a more comprehensive 'universal' screening method for LS.

Extended family outreach in hereditary cancer using online genealogy, direct-to-consumer ancestry genetics, and social media: A mixed methods process evaluation of the ConnectMyVariant intervention (Preprint)

BACKGROUND

Cascade screening, defined as helping at-risk relatives get targeted genetic testing of familial variants for dominant hereditary cancer syndromes, is a proven component of cancer prevention; however, its uptake is low. We developed and conducted a pilot study of the ConnectMyVariant intervention, in which participants received support to contact at-risk relatives that extended beyond first-degree relatives and encourage relatives to obtain genetic testing and connect with others having the same variant through email and social media. The support that participants received included listening to participants' needs, assisting with documentary genealogy to find common ancestors, facilitating direct-to-consumer DNA testing and interpretation, and assisting with database searches.

OBJECTIVE

We aimed to assess intervention feasibility, motivations for participating, and engagement among ConnectMyVariant participants and their families.

METHODS

We used a mixed methods design including both quantitative and qualitative evaluation methods. First, we considered intervention feasibility by characterizing recruitment and retention using multiple recruitment mechanisms, including web-based advertising, dissemination of invitations with positive test results, provider recruitment, snowball sampling, and recruitment through web-based social networks and research studies. Second, we characterized participants' motivations, concerns, and engagement through project documentation of participant engagement in outreach activities and qualitative analysis of participant communications. We used an inductive qualitative data analysis approach to analyze emails, free-text notes, and other communications generated with participants as part of the ConnectMyVariant intervention.

RESULTS

We identified 84 prospective participants using different recruitment mechanisms; 57 participants were ultimately enrolled in the study for varying lengths of time. With respect to motivations for engaging in the intervention, participants were most interested in activities relating to genealogy and communication with others who had their specific variants. Although there was a desire to find others with the same variant and prevent cancer, more participants expressed an interest in learning about their genealogy and family health history, with prevention in relatives considered a natural side effect of outreach. Concerns about participation included whether relatives would be open to communication, how to go about it, and whether others with a specific variant would be motivated to help find common ancestors. We observed that ConnectMyVariant participants engaged in 6 primary activities to identify and communicate with at-risk relatives: sharing family history, family member testing, direct-to-consumer genealogy genetic testing analysis, contacting (distant) relatives, documentary genealogy, and expanding variant groups or outreach. Participants who connected with others who had the same variant were more likely to engage with several extended family outreach activities.

CONCLUSIONS

This study demonstrated that there is an interest in extended family outreach as a mechanism to improve cascade screening for hereditary cancer prevention. Additional research to systematically evaluate the outcomes of such outreach may be challenging but is warranted.

The predicted effect and cost-effectiveness of tailoring colonoscopic surveillance according to mismatch repair gene in patients with Lynch syndrome

PURPOSE

Lynch syndrome-related colorectal cancer (CRC) risk substantially varies by mismatch repair (MMR) gene. We evaluated the health impact and cost-effectiveness of MMR gene-tailored colonoscopic surveillance.

METHODS

We first estimated sex- and MMR gene-specific cumulative lifetime risk of first CRC without colonoscopic surveillance using an optimization algorithm. Next, we harnessed these risk estimates in a microsimulation model, "Policy1-Lynch," and compared 126 colonoscopic surveillance strategies against no surveillance.

RESULTS

The most cost-effective strategy was 3-yearly surveillance from age 25 to 70 years (pathogenic variants [path_] in MLH1 [path_MLH1], path_MSH2) with delayed surveillance for path_MSH6 (age 30-70 years) and path_PMS2 (age 35-70 years) heterozygotes (incremental cost-effectiveness ratio = Australian dollars (A) $8,833/life-year saved). This strategy averted 60 CRC deaths (153 colonoscopies per death averted) over the lifetime of 1000 confirmed patients with Lynch syndrome (vs no surveillance). This also reduced colonoscopies by 5% without substantial change in health outcomes (vs nontailored 3-yearly surveillance from 25-70 years). Generally, starting surveillance at age 25 (vs 20) years was more cost-effective with minimal effect on life-years saved and starting 5 to 10 years later for path_MSH6 and path_PMS2 heterozygotes (vs path_MLH1 and path_MSH2) further improved cost-effectiveness. Surveillance end age (70/75/80 years) had a minor effect. Three-yearly surveillance strategies were more cost-effective (vs 1 or 2-yearly) but prevented 3 fewer CRC deaths.

CONCLUSION

MMR gene-specific colonoscopic surveillance would be effective and cost-effective.

Research on the Economics of Cancer-Related Health Care: An Overview of the Review Literature

We reviewed current literature reviews regarding economics of cancer-related health care to identify focus areas and gaps. We searched PubMed for systematic and other reviews with the Medical Subject Headings "neoplasms" and "economics" published between January 1, 2010, and April 1, 2020, identifying 164 reviews. Review characteristics were abstracted and described. The majority (70.7%) of reviews focused on cost-effectiveness or cost-utility analyses. Few reviews addressed other types of cancer health economic studies. More than two-thirds of the reviews examined cancer treatments, followed by screening (15.9%) and survivorship or end-of-life (13.4%). The plurality of reviews (28.7%) cut across cancer site, followed by breast (20.7%), colorectal (11.6%), and gynecologic (8.5%) cancers. Specific topics addressed cancer screening modalities, novel therapies, pain management, or exercise interventions during survivorship. The results indicate that reviews do not regularly cover other phases of care or topics including financial hardship, policy, and measurement and methods.

Accounting for Intergenerational Cascade Testing in Economic Evaluations of Clinical Genomics: A Scoping Review

OBJECTIVES

Clinical genomics is emerging as a diagnostic tool in the identification of blood relatives at risk of developing heritable diseases. Our objective was to identify how genetic cascade screening has been incorporated into health economic evaluations.

METHODS

A scoping review was conducted to identify how multiple generations of a family were included in economic evaluations of clinical genomic sequencing, how many and which relatives were included, and uptake rates. Databases were searched for full economic evaluations of genetic interventions that screened multiple generations of families and were in English language, and no restrictions were made for disease or publication type. Data were synthesized using a narrative approach.

RESULTS

Twenty-five studies were included covering a range of diseases in various countries. Markov cohort models were mostly used with hypothetical populations and unsupported by clinical evidence. Cascade testing was either the primary intervention or secondary to the index cases. The number and type of relatives were based on assumptions or identified through population or family records, clinical registry data, or clinical literature. Studies included only immediate family members and the uptake of testing ranged between 20% and 100%. All interventions were reported as cost-effective, and a higher number of relatives was a key driver.

CONCLUSIONS

Several economic evaluations have considered the impacts of cascade testing interventions within clinical genomics. Ideally, models supported with high-quality clinical data are needed and, in their absence, transparent and justifiable assumptions of uptake rates and choices about including relatives. Consideration of more appropriate modeling types is required.

The Risk-Reducing Effect of Aspirin in Lynch Syndrome Carriers: Development and Evaluation of an Educational Leaflet

Carriers of germline mutations in genes associated with Lynch syndrome are at increased risk for colorectal, endometrial, ovarian, and other cancers. There is evidence that daily consumption of aspirin may reduce cancer risk in these individuals. There is a need for educational resources to inform carriers of the risk-reducing effects of aspirin or to support decision-making. An educational leaflet describing the risks and benefits of using aspirin as risk-reducing medicine in carriers of Lynch-syndrome-related mutations is developed and pilot tested in 2017. Carriers are ascertained through a familial cancer clinic and surveyed using a mailed, self-administered questionnaire. The leaflet is highly rated for its content, clarity, length, relevance, and visual appeal by more than 70% of the participants. Most participants (91%) report "a lot" or "quite a bit" of improvement in perceived understanding in knowledge about who might benefit from taking aspirin, its benefits, how long to take it, the reduction in bowel cancer risk, and the optimal dosage. A few (14%) participants seek more information on the dosage of aspirin. This leaflet will be useful as an aid to facilitate discussion between patients and their health care professionals about the use of aspirin as a risk-reducing medication.

Preventive population genomics: The model of BRCA related cancers

Preventive population genomics offers the prospect of population stratification for targeting screening and prevention and tailoring care to those at greatest risk. Within cancer, this approach is now within reach, given our expanding knowledge of its heritable components, improved ability to predict risk, and increasing availability of effective preventive strategies. Advances in technology and bioinformatics has made population-testing technically feasible. The BRCA model provides 30 years of insight and experience of how to conceive of and construct care and serves as an initial model for preventive population genomics. Population-based BRCA-testing in the Jewish population is feasible, acceptable, reduces anxiety, does not detrimentally affect psychological well-being or quality of life, is cost-effective and is now beginning to be implemented. Population-based BRCA-testing and multigene panel testing in the wider general population is cost-effective for numerous health systems and can save thousands more lives than the current clinical strategy. There is huge potential for using both genetic and non-genetic information in complex risk prediction algorithms to stratify populations for risk adapted screening and prevention. While numerous strides have been made in the last decade several issues need resolving for population genomics to fulfil its promise and potential for maximizing precision prevention. Healthcare systems need to overcome significant challenges associated with developing delivery pathways, infrastructure expansion including laboratory services, clinical workforce training, scaling of management pathways for screening and prevention. Large-scale real world population studies are needed to evaluate context specific population-testing implementation models for cancer risk prediction, screening and prevention.

Brain Cancers in Genetic Syndromes

PURPOSE OF REVIEW

Although genetic conditions that cause primary central nervous system tumors are rare, their pathophysiology influences both treatment and surveillance. This article reviews the most frequently occurring genetic conditions associated with brain cancers and highlights the most recent therapeutic approaches in the treatment of Lynch syndrome (and other disorders of the mismatch repair system), neurofibromatosis 1, and Li-Fraumeni syndrome.

RECENT FINDINGS

Recent advances in molecular diagnostics have considerably improved the ability to diagnose genetic conditions in people with primary brain tumors. The common application of next-generation sequencing analyses of tissue increases the frequency with which clinicians are forced to address the possibility of an underlying genetic condition based on tissue molecular findings. Clinicians must be aware of the clinical presentation of genetic conditions predisposing to brain tumors in order to discern which patients are appropriate for germline genetic testing. Advances in therapeutics for specific genetic variants are increasingly available, and accurately diagnosing an underlying genetic condition may directly impact patient outcomes.

Low Referral Rates for Genetic Assessment of Patients With Multiple Adenomas in United Kingdom Bowel Cancer Screening Programs

BACKGROUND

Approximately 1 in 20 cases of colorectal cancer are caused by monogenic syndromes. Published guidelines recommend that patients with 10 or more adenomas be referred for genetic testing, based on evidence that colorectal cancer risk is associated with adenoma multiplicity.

OBJECTIVE

The aim of this study was to determine adherence to guidelines on referral for genetic screening in patients with 10 or more adenomas.

DESIGN

A cross-sectional study was performed of prospectively collected data from the UK Bowel Cancer Screening Programme between May 2007 and June 2018. Only histologically confirmed adenomas were included. Clinicopathological data were recorded from patient records, and referrals to clinical genetics services were ascertained.

SETTING

Data were obtained from 3 centers in London, United Kingdom.

PATIENTS

A total of 17,450 subjects underwent colonoscopy following an abnormal fecal occult blood test.

MAIN OUTCOME MEASURES

We quantified patients with 10 or more adenomas and the proportion referred for genetic screening.

RESULTS

The adenoma detection rate was 50.6% among 17,450 patients who underwent colonoscopy (8831 had 1 or more adenomas). Three hundred forty-seven patients (2.0%) had 10 or more adenomas. Patients with 10 or more adenomas were more likely to be male than those with fewer than 10 adenomas (76.9% vs 53.4%; p < 0.0001). A family history was collected in 37.8% of the multiple adenoma population. Of 347 patients with 10 or more adenomas, 28 (8.1%) were referred for genetic assessment.

LIMITATIONS

All 3 screening centers were in a single city. No genetic outcome data were available to permit analysis of actual rates of inherited cancer syndromes in this population.

CONCLUSIONS

In this study, almost 1 in 50 patients had 10 or more adenomas. Despite guidelines advising genetic testing in this group, referral rates are low. A referral pathway and management strategies should be established to address this patient population. See Video Abstract at http://links.lww.com/DCR/B630.

TASAS BAJAS DE DERIVACIN PARA LA EVALUACIN GENTICA DE PACIENTES CON ADENOMAS MLTIPLES EN LOS PROGRAMAS DE DETECCIN DEL CNCER DE INTESTINO DEL REINO UNIDO

ANTECEDENTES:Aproximadamente uno de cada veinte casos de cáncer colorrectal son causados por síndromes monogénicos. Las pautas publicadas recomiendan que los pacientes con diez o más adenomas sean derivados para pruebas genéticas, basándose en la evidencia de que el riesgo de cáncer colorrectal está asociado con la multiplicidad de adenomas.OBJETIVO:El objetivo de este estudio fue determinar la adherencia a las guías de derivación para cribado genético en pacientes con diez o más adenomas.DISEÑO:Se realizó un estudio transversal de datos recolectados prospectivamente del Programa de Detección de Cáncer de Intestino del Reino Unido entre mayo de 2007 y junio de 2018. Solo se incluyeron los adenomas confirmados histológicamente. Los datos clínico-patológicos se registraron a partir de los registros de los pacientes y se determinaron las derivaciones a los servicios de genética clínica.AJUSTE ENTORNO CLINICO:Los datos se obtuvieron de tres centros en Londres, Reino Unido.PACIENTES:Un total de 17.450 17450 sujetos pacientes se sometieron a una colonoscopia después de una prueba de sangre oculta en heces anormal positiva.PRINCIPALES MEDIDAS DE RESULTADO VOLARACION:cuantificamos los pacientes con diez o más adenomas y la proporción remitida para cribado genético.RESULTADOS:La tasa de detección de adenomas fue del 50,6% entre 17.450 17450 pacientes que se sometieron a colonoscopia (8.831 8831 tenían uno o más adenomas). 347 pacientes (2,0%) tenían 10 o más adenomas. Los pacientes con 10 o más adenomas tenían más probabilidades de ser hombres que aquellos con menos de 10 adenomas (76,9% frente versus a 53,4%; p <0,0001). Se recogieron antecedentes familiares en el 37,8% de la población de adenomas múltiples. De 347 pacientes con 10 o más adenomas, 28 (8,1%) fueron remitidos para evaluación genética.LIMITACIONES:Los tres centros de detección se encontraban en una sola ciudad. No se disponía de datos de resultados genéticos que permitieran el análisis de las tasas reales de síndromes de cáncer hereditario en esta población.CONCLUSIONES:En este estudio, casi uno de cada cincuenta pacientes tenía diez o más adenomas. A pesar de las pautas que recomiendan las pruebas genéticas en este grupo, las tasas de derivación son bajas. Se debe establecer una vía de derivación y estrategias de manejo para abordar esta población de pacientes. Consulte Video Resumen en http://links.lww.com/DCR/B630.

Testing strategies for Lynch syndrome in people with endometrial cancer: systematic reviews and economic evaluation

BACKGROUND

Lynch syndrome is an inherited genetic condition that is associated with an increased risk of certain cancers. The National Institute for Health and Care Excellence has recommended that people with colorectal cancer are tested for Lynch syndrome. Routine testing for Lynch syndrome among people with endometrial cancer is not currently conducted.

OBJECTIVES

To systematically review the evidence on the test accuracy of immunohistochemistry- and microsatellite instability-based strategies to detect Lynch syndrome among people who have endometrial cancer, and the clinical effectiveness and the cost-effectiveness of testing for Lynch syndrome among people who have been diagnosed with endometrial cancer.

DATA SOURCES

Searches were conducted in the following databases, from inception to August 2019 - MEDLINE ALL, EMBASE (both via Ovid), Cochrane Database of Systematic Reviews, Cochrane Central Register of Controlled Trials (both via Wiley Online Library), Database of Abstracts of Reviews of Effects, Health Technology Assessment Database (both via the Centre for Reviews and Dissemination), Science Citation Index, Conference Proceedings Citation Index - Science (both via Web of Science), PROSPERO international prospective register of systematic reviews (via the Centre for Reviews and Dissemination), NHS Economic Evaluation Database, Cost-Effectiveness Analysis Registry, EconPapers (Research Papers in Economics) and School of Health and Related Research Health Utilities Database. The references of included studies and relevant systematic reviews were also checked and experts on the team were consulted.

REVIEW METHODS

Eligible studies included people with endometrial cancer who were tested for Lynch syndrome using immunohistochemistry- and/or microsatellite instability-based testing [with or without mutL homologue 1 (MLH1) promoter hypermethylation testing], with Lynch syndrome diagnosis being established though germline testing of normal (non-tumour) tissue for constitutional mutations in mismatch repair. The risk of bias in studies was assessed using the Quality Assessment of Diagnostic Accuracy Studies-2 tool, the Consolidated Health Economic Reporting Standards and the Philips' checklist. Two reviewers independently conducted each stage of the review. A meta-analysis of test accuracy was not possible because of the number and heterogeneity of studies. A narrative summary of test accuracy results was provided, reporting test accuracy estimates and presenting forest plots. The economic model constituted a decision tree followed by Markov models for the impact of colorectal and endometrial surveillance, and aspirin prophylaxis with a lifetime time horizon.

RESULTS

The clinical effectiveness search identified 3308 studies; 38 studies of test accuracy were included. (No studies of clinical effectiveness of endometrial cancer surveillance met the inclusion criteria.) Four test accuracy studies compared microsatellite instability with immunohistochemistry. No clear difference in accuracy between immunohistochemistry and microsatellite instability was observed. There was some evidence that specificity of immunohistochemistry could be improved with the addition of methylation testing. There was high concordance between immunohistochemistry and microsatellite instability. The economic model indicated that all testing strategies, compared with no testing, were cost-effective at a willingness-to-pay threshold of £20,000 per quality-adjusted life-year. Immunohistochemistry with MLH1 promoter hypermethylation testing was the most cost-effective strategy, with an incremental cost-effectiveness ratio of £9420 per quality-adjusted life-year. The second most cost-effective strategy was immunohistochemistry testing alone, but incremental analysis produced an incremental cost-effectiveness ratio exceeding £130,000. Results were robust across all scenario analyses. Incremental cost-effectiveness ratios ranged from £5690 to £20,740; only removing the benefits of colorectal cancer surveillance produced an incremental cost-effectiveness ratio in excess of the £20,000 willingness-to-pay threshold. A sensitivity analysis identified the main cost drivers of the incremental cost-effectiveness ratio as percentage of relatives accepting counselling and prevalence of Lynch syndrome in the population. A probabilistic sensitivity analysis showed, at a willingness-to-pay threshold of £20,000 per quality-adjusted life-year, a 0.93 probability that immunohistochemistry with MLH1 promoter hypermethylation testing is cost-effective, compared with no testing.

LIMITATIONS

The systematic review excluded grey literature, studies written in non-English languages and studies for which the reference standard could not be established. Studies were included when Lynch syndrome was diagnosed by genetic confirmation of constitutional variants in the four mismatch repair genes (i.e. MLH1, mutS homologue 2, mutS homologue 6 and postmeiotic segregation increased 2). Variants of uncertain significance were reported as per the studies. There were limitations in the economic model around uncertainty in the model parameters and a lack of modelling of the potential harms of gynaecological surveillance and specific pathway modelling of genetic testing for somatic mismatch repair mutations.

CONCLUSION

The economic model suggests that testing women with endometrial cancer for Lynch syndrome is cost-effective, but that results should be treated with caution because of uncertain model inputs.

FUTURE WORK

Randomised controlled trials could provide evidence on the effect of earlier intervention on outcomes and the balance of benefits and harms of gynaecological cancer surveillance. Follow-up of negative cases through disease registers could be used to determine false negative cases.

STUDY REGISTRATION

This study is registered as PROSPERO CRD42019147185.

FUNDING

This project was funded by the National Institute for Health Research (NIHR) Evidence Synthesis programme and will be published in full in Health Technology Assessment; Vol. 25, No. 42. See the NIHR Journals Library website for further project information.

Cost-Effectiveness Analysis of Molecular Screening to Identify Lynch Syndrome in the Patients with Colorectal Cancer

Background: Identifying Lynch syndrome (LS) in patients with colorectal cancer (CRC) and monitoring their relatives can increase the life expectancy of these patients. Objectives: The aim of this study was to analyze the cost-effectiveness of 5 molecular testing strategies to screen LS among patients with newly diagnosed CRC and to conduct preventive surveillance in their first-degree relatives. Methods: A decision tree model was designed to identify the number of LS mutations and the related costs in the CRC patients. Five strategies were modeled, i.e., Amsterdam II criteria, microsatellite instability (MSI) testing, immunohistochemistry (IHC), and next-generation sequencing (NGS). A Markov model was also used to estimate the long-term outcome of monitoring (including colonoscopy and taking aspirin) among relatives of those patients with CRC who carried LS. Results: All strategies were cost-effective compared with no testing condition. The 2 most cost-effective strategies were strategy 2 (IHC testing followed by NGS testing) and strategy 4 (MSI testing followed by NGS testing), with the ICER of 4,604$ and 4,748$ per quality-adjusted life year (QALY), respectively. Based on one-way sensitivity analysis of IHC sensitivity, the Cost of colonoscopy, MSI sensitivity, and the number of families who inherited LS had the most effect on the results. Conclusions: The findings suggested that from an Iranian health care system perspective, IHC testing followed by NGS testing could be regarded as the most cost-effective strategy compared to the other strategies. These results can be useful in offering to screen LS in newly diagnosed CRC patients.

Model-Based Re-Examination of the Effectiveness of Tumor/Immunohistochemistry and Direct-to-Sequencing Protocols for Lynch Syndrome Case Finding in Endometrial Cancer

PURPOSE

Despite widespread provision of Lynch syndrome (LS) screening programs, questions remain about the most effective and efficient protocol for LS case finding. The purpose of this study was to explore the performance of the two protocols widely shown to be the most efficient and effective, respectively: immunohistochemical (IHC) staining of tumor and direct-to-sequencing (DtS) in endometrial cancer populations.

METHODS

Simulation models were developed to explore performance of the IHC and DtS protocols, updated to reflect current evidence. Analyses explicitly account for protocol complexity and failure points, as well as decreased sequencing costs. Key outcomes are percent of LS cases identified, total protocol costs and efficiency, and break-even analyses of sequencing costs. All costs are in 2020 US dollars (USD).

RESULTS

Under plausible conditions, the IHC protocol is expected to identify 40%-78% of LS cases and DtS protocol from 49% to 97%. When the key variable success in proceeding to sequencing is fixed for both protocols at 50%, 75%, and 100%, the DtS protocol is 9%, 12%, and 16% better at case finding, respectively, than the IHC protocol. The break-even cost of sequencing is about $488 USD when the outcome is total direct testing protocol costs; it is about $670 USD when the outcome is cost per LS case detected.

CONCLUSION

This study quantifies the plausible differences in the clinical effectiveness and cost-effectiveness of the two LS case-finding protocols. We demonstrate the large influence of success in proceeding to sequencing and potential impact of decreasing sequencing prices.

What improves the likelihood of people receiving genetic test results communicating to their families about genetic risk?

OBJECTIVE

We currently rely on probands to communicate genetic testing results and health risks within a family to stimulate preventive behaviors, such as cascade testing. Rates of guidelines-based cascade testing are low, possibly due to low frequency or non-urgent communication of risk among family members. Understanding what is being communicated and why may help improve interventions that increase communication and rates of cascade testing.

METHODS

Participants (n = 189) who were to receive both positive and negative colorectal cancer (CRC) sequencing results completed surveys on family communication, family functioning, impact of cancer in the family, and future communication of risk and were participants in eMERGE3. Questions were taken from existing surveys and administered electronically using email and a web driven tool.

RESULTS

Common family member targets of CRC risk communication, before results were received, were mothers and fathers, then sisters and grandchildren and finally, children and brothers. A communication impact score of 0.66 (sd = 0.83) indicated low-to-moderate communication impact. Age and education were significantly associated with frequency of familial communication, but not on the cancer-related impact of familial communication.

CONCLUSIONS

There is infrequent communication about cancer risk from probands to family members.

PRACTICE IMPLICATIONS

These results demonstrate an opportunity to help families improve communication.

How Should We Test for Lynch Syndrome? A Review of Current Guidelines and Future Strategies

International guidelines for the diagnosis of Lynch syndrome (LS) recommend molecular screening of colorectal cancers (CRCs) to identify patients for germline mismatch repair (MMR) gene testing. As our understanding of the LS phenotype and diagnostic technologies have advanced, there is a need to review these guidelines and new screening opportunities. We discuss the barriers to implementation of current guidelines, as well as guideline limitations, and highlight new technologies and knowledge that may address these. We also discuss alternative screening strategies to increase the rate of LS diagnoses. In particular, the focus of current guidance on CRCs means that approximately half of Lynch-spectrum tumours occurring in unknown male LS carriers, and only one-third in female LS carriers, will trigger testing for LS. There is increasing pressure to expand guidelines to include molecular screening of endometrial cancers, the most frequent cancer in female LS carriers. Furthermore, we collate the evidence to support MMR deficiency testing of other Lynch-spectrum tumours to screen for LS. However, a reliance on tumour tissue limits preoperative testing and, therefore, diagnosis prior to malignancy. The recent successes of functional assays to detect microsatellite instability or MMR deficiency in non-neoplastic tissues suggest that future diagnostic pipelines could become independent of tumour tissue.

Testing for lynch syndrome in people with endometrial cancer using immunohistochemistry and microsatellite instability-based testing strategies - A systematic review of test accuracy

BACKGROUND

Lynch syndrome is an inherited genetic condition that is associated with an increased risk of cancer, including endometrial and colorectal cancer. We assessed the test accuracy of immunohistochemistry and microsatellite instability-based testing (with or without MLH1 promoter methylation testing) for Lynch syndrome in women with endometrial cancer.

METHODS

We conducted a systematic review of literature published up to August 2019. We searched bibliographic databases, contacted experts and checked reference lists of relevant studies. Two reviewers conducted each stage of the review.

RESULTS

Thirteen studies were identified that included approximately 3500 participants. None of the studies was at low risk of bias in all domains. Data could not be pooled due to the small number of heterogeneous studies. Sensitivity ranged from 60.7-100% for immunohistochemistry, 41.7-100% for microsatellite instability-based testing, and 90.5-100% for studies combining immunohistochemistry, microsatellite instability-based testing, and MLH1 promoter methylation testing. Specificity ranged from 60.9-83.3% (excluding 1 study with highly selective inclusion criteria) for immunohistochemistry, 69.2-89.9% for microsatellite instability-based testing, and 72.4-92.3% (excluding 1 study with highly selective inclusion criteria) for testing strategies that included immunohistochemistry, microsatellite instability-based testing, and MLH1 promoter methylation. We found no statistically significant differences in test accuracy estimates (sensitivity, specificity) in head-to-head studies of immunohistochemistry versus microsatellite instability-based testing. Reported test failures were rare.

CONCLUSIONS

Sensitivity of the index tests were generally high, though most studies had much lower specificity. We found no evidence that test accuracy differed between IHC and MSI based strategies. The evidence base is currently small and at high risk of bias.

Age-dependent performance of BRAF mutation testing in Lynch syndrome diagnostics

BRAF V600E mutations have been reported as a marker of sporadic microsatellite instability (MSI) colorectal cancer (CRC). Current international diagnostic guidelines recommend BRAF mutation testing in MSI CRC patients to predict low risk of Lynch syndrome (LS). We evaluated the age-specific performance of BRAF testing in LS diagnostics. We systematically compared the prevalence of BRAF mutations in LS-associated CRCs and unselected MSI CRCs in different age groups as available from published studies, databases and population-based patient cohorts. Sensitivity/specificity analysis of BRAF testing for exclusion of LS and cost calculations were performed. Among 969 MSI CRCs from LS carriers in the literature and German HNPCC Consortium, 15 (1.6%) harbored BRAF mutations. Six of seven LS patients with BRAF-mutant CRC and reported age were <50 years. Among 339 of 756 (44.8%) of BRAF mutations detected in unselected MSI CRC, only 2 of 339 (0.6%) BRAF mutations were detected in patients <50 years. The inclusion of BRAF testing led to high risk of missing LS patients and increased costs at age <50 years. BRAF testing in patients <50 years carries a high risk of missing a hereditary cancer predisposition and is cost-inefficient. We suggest direct referral of MSI CRC patients <50 years to genetic counseling without BRAF testing.

Genetic Susceptibility to Endometrial Cancer: Risk Factors and Clinical Management

Endometrial cancer (EC) is the most common cancer affecting the female reproductive organs in higher-income states. Apart from reproductive factors and excess weight, genetic predisposition is increasingly recognized as a major factor in endometrial cancer risk. Endometrial cancer is genetically heterogeneous: while a subgroup of patients belongs to cancer predisposition syndromes (most notably the Lynch Syndrome) with high to intermediate lifetime risks, there are also several common genomic polymorphisms contributing to the spectrum of germline predispositions. Germline variants and somatic events may act in concert to modulate the molecular evolution of the tumor, where mismatch-repair deficiency is common in endometrioid endometrial tumors whereas homologous recombinational repair deficiency has been described for non-endometrioid endometrial tumors. In this review, we will survey the currently known genomic predispositions for endometrial cancer and discuss their relevance for clinical management in terms of counseling, screening and novel treatments.

Cost-effectiveness analysis of genetic diagnostic strategies for Lynch syndrome in Italy

Lynch syndrome (LS) is an autosomal dominant condition caused by pathogenic variants in mismatch repair (MMR) genes that predispose individuals to different malignancies, such as colorectal cancer (CRC) and endometrial cancer. Current guidelines recommended testing for LS in individuals with newly diagnosed CRC to reduce cancer morbidity and mortality in relatives. Economic evaluations in support of such approach, however, are not available in Italy. We developed a decision-analytic model to analyze the cost-effectiveness of LS screening from the perspective of the Italian National Health System. Three testing strategies: the sequencing of all MMR genes without prior tumor analysis (Strategy 1), a sequential IHC and MS-MLPA analysis (Strategy 2), and an age-targeted strategy with a revised Bethesda criteria assessment before IHC and methylation-specific MLPA for patients ≥ than 70 years old (Strategy 3) were analyzed and compared to the “no testing” strategy. Quality Adjusted Life Years (QALYs) in relatives after colonoscopy, aspirin prophylaxis and an intensive gynecological surveillance were estimated through a Markov model. Assuming a CRC incidence rate of 0.09% and a share of patients affected by LS equal to 2.81%, the number of detected pathogenic variants among CRC cases ranges, in a given year, between 910 and 1167 depending on the testing strategy employed. The testing strategies investigated, provided one-time to the entire eligible population (CRC patients), were associated with an overall cost ranging between €1,753,059.93-€10,388,000.00. The incremental cost-effectiveness ratios of the Markov model ranged from €941.24 /QALY to €1,681.93 /QALY, thus supporting that “universal testing” versus “no testing” is cost-effective, but not necessarily in comparison with age-targeted strategies. This is the first economic evaluation on different testing strategies for LS in Italy. The results might support the introduction of cost-effective recommendations for LS screening in Italy.

Cost-Effectiveness of the Manchester Approach to Identifying Lynch Syndrome in Women with Endometrial Cancer

Lynch syndrome (LS) is a hereditary cancer syndrome responsible for 3% of all endometrial cancer and 5% in those aged under 70 years. It is unclear whether universal testing for LS in endometrial cancer patients would be cost-effective. The Manchester approach to identifying LS in endometrial cancer patients uses immunohistochemistry (IHC) to detect mismatch repair (MMR) deficiency, incorporates testing for MLH1 promoter hypermethylation, and incorporates genetic testing for pathogenic MMR variants. We aimed to assess the cost-effectiveness of the Manchester approach on the basis of primary research data from clinical practice in Manchester. The Proportion of Endometrial Tumours Associated with Lynch Syndrome (PETALS) study informed estimates of diagnostic performances for a number of different strategies. A recent microcosting study was adapted and was used to estimate diagnostic costs. A Markov model was used to predict long-term costs and health outcomes (measured in quality-adjusted life years, QALYs) for individuals and their relatives. Bootstrapping and probabilistic sensitivity analysis were used to estimate the uncertainty in cost-effectiveness. The Manchester approach dominated other reflex testing strategies when considering diagnostic costs and Lynch syndrome cases identified. When considering long-term costs and QALYs the Manchester approach was the optimal strategy, costing £5459 per QALY gained (compared to thresholds of £20,000 to £30,000 per QALY commonly used in the National Health Service (NHS)). Cost-effectiveness is not an argument for restricting testing to younger patients or those with a strong family history. Universal testing for Lynch syndrome in endometrial cancer patients is expected to be cost-effective in the U.K. (NHS), and the Manchester approach is expected to be the optimal testing strategy.

Colorectal Cancer Stratification in the Routine Clinical Pathway: A District General Hospital Experience

Colorectal cancer (CRC) has many subtypes with different prognoses and response to treatment. Patients must be characterized to access the most appropriate treatment and improve outcomes. An increasing number of biomarkers are required for characterization but are not in routine use. We investigated whether CRC can be stratified routinely within a small district general hospital to inform clinical decision making at local multidisciplinary team meeting/tumor board level. We evaluated mismatch repair (MMR) and EGFR signaling pathways using predominantly in-house immunohistochemical (IHC) tests (MSH2, MSH6, MLH1, PMS2, BRAF-V600E, Her2, PTEN, cMET) as well as send away PCR/NGS tests (NRAS, KRAS, and BRAF). We demonstrated that many of the tests required for personalized treatment of CRC can be done locally and timely. Send away tests need to be requested shortly after cut-up and this needs to be firmly established in the tissue pathways for the results to be considered at multidisciplinary team meeting/tumor board. We have shown that MMR IHC combined with BRAFV600E IHC is practical and easy to perform in a small district general hospital, has full concordance with DNA-based tests and satisfies the latest NICE requirements for the identification of potential Lynch syndrome patients. We provide a framework for the interpretation and presentation of test results. It is a practical classification that clinical pathologists can use to communicate effectively with the clinical team. It is broadly based on molecular subtyping, firmly focused on treatment decisions and dependent on the panel of molecular tests currently available.

Molecular pathology of Lynch syndrome

Lynch syndrome (LS) is characterised by predisposition to colorectal, endometrial, and other cancers and is caused by inherited pathogenic variants affecting the DNA mismatch repair (MMR) genes MLH1, MSH2, MSH6, and PMS2. It is probably the most common predisposition to cancer, having an estimated prevalence of between 1/100 and 1/180. Resources such as the International Society for Gastrointestinal Hereditary Cancer's MMR gene variant database, the Prospective Lynch Syndrome Database (PLSD), and the Colon Cancer Family Register (CCFR), as well as pathological and immunological studies, are enabling advances in the understanding of LS. These include defined criteria by which to interpret gene variants, the function of MMR in the normal control of apoptosis, definition of the risks of the various cancers, and the mechanisms and pathways by which the colorectal and endometrial tumours develop, including the critical role of the immune system. Colorectal cancers in LS can develop along three pathways, including flat intramucosal lesions, which depend on the underlying affected MMR gene. This gives insights into the limitations of colonoscopic surveillance and highlights the need for other forms of anti-cancer prophylaxis in LS. Finally, it shows that the processes of autoimmunisation and immunoediting fundamentally constrain the development of tumours in LS and explain the efficacy of immune checkpoint blockade therapy in MMR-deficient tumours. © 2020 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.

Sequencing-based microsatellite instability testing using as few as six markers for high-throughput clinical diagnostics

Microsatellite instability (MSI) testing of colorectal cancers (CRCs) is used to screen for Lynch syndrome (LS), a hereditary cancer-predisposition, and can be used to predict response to immunotherapy. Here, we present a single-molecule molecular inversion probe and sequencing-based MSI assay and demonstrate its clinical validity according to existing guidelines. We amplified 24 microsatellites in multiplex and trained a classifier using 98 CRCs, which accommodates marker specific sensitivities to MSI. Sample classification achieved 100% concordance with the MSI Analysis System v1.2 (Promega) in three independent cohorts, totaling 220 CRCs. Backward-forward stepwise selection was used to identify a 6-marker subset of equal accuracy to the 24-marker panel. Assessment of assay detection limits showed that the 24-marker panel is marginally more robust to sample variables than the 6-marker subset, detecting as little as 3% high levels of MSI DNA in sample mixtures, and requiring a minimum of 10 template molecules to be sequenced per marker for >95% accuracy. BRAF c.1799 mutation analysis was also included to streamline LS testing, with all c.1799T>A variants being correctly identified. The assay, therefore, provides a cheap, robust, automatable, and scalable MSI test with internal quality controls, suitable for clinical cancer diagnostics.

Cost-effectiveness of precision medicine: a scoping review

Objectives

Precision medicine (PM) aims to improve patient outcomes by stratifying or individualizing diagnosis and treatment decisions. Previous reviews found inconclusive evidence as to the cost-effectiveness of PM. The purpose of this scoping review was to describe current research findings on the cost-effectiveness of PM and to identify characteristics of cost-effective interventions.

Methods

We searched PubMed with a combination of terms related to PM and economic evaluations and included studies published between 2014 and 2017.

Results

A total of 83 articles were included, of which two-thirds were published in Europe and the USA. The majority of studies concluded that the PM intervention was at least cost-effective compared to usual care. However, the willingness-to-pay thresholds varied widely. Key factors influencing cost-effectiveness included the prevalence of the genetic condition in the target population, costs of genetic testing and companion treatment and the probability of complications or mortality.

Conclusions

This review may help inform decisions about reimbursement, research and development of PM interventions.

Electronic supplementary material

The online version of this article (10.1007/s00038-019-01298-x) contains supplementary material, which is available to authorized users.

The predicted impact and cost-effectiveness of systematic testing of people with incident colorectal cancer for Lynch syndrome

OBJECTIVES

To evaluate the health impact and cost-effectiveness of systematic testing for Lynch syndrome (LS) in people with incident colorectal cancer (CRC) in Australia.

DESIGN, SETTING, PARTICIPANTS

We investigated the impact of LS testing strategies in a micro-simulation model (Policy1-Lynch), explicitly modelling the cost of testing all patients diagnosed with incident CRC during 2017, with detailed modelling of outcomes for patients identified as LS carriers (probands) and their at-risk relatives throughout their lifetimes. For people with confirmed LS, we modelled ongoing colonoscopic surveillance.

MAIN OUTCOME MEASURES

Cost-effectiveness of six universal tumour testing strategies (testing for DNA mismatch repair deficiencies) and of universal germline gene panel testing of patients with incident CRC; impact on cost-effectiveness of restricting testing by age at CRC diagnosis (all ages, under 50/60/70 years) and of colonoscopic surveillance interval (one, two years).

RESULTS

The cost-effectiveness ratio of universal tumour testing strategies (annual colonoscopic surveillance, no testing age limit) compared with no testing ranged from $28 915 to $31 904/life-year saved (LYS) (indicative willingness-to-pay threshold: $30 000-$50 000/LYS). These strategies could avert 184-189 CRC deaths with an additional 30 597-31 084 colonoscopies over the lifetimes of 1000 patients with incident CRC with LS and 1420 confirmed LS carrier relatives (164-166 additional colonoscopies/death averted). The most cost-effective strategy was immunohistochemistry and BRAF V600E testing (incremental cost-effectiveness ratio [ICER], $28 915/LYS). Universal germline gene panel testing was not cost-effective compared with universal tumour testing strategies (ICER, $2.4 million/LYS). Immunohistochemistry and BRAF V600E testing was cost-effective at all age limits when paired with 2-yearly colonoscopic surveillance (ICER, $11 525-$32 153/LYS), and required 4778-15 860 additional colonoscopies to avert 46-181 CRC deaths (88-103 additional colonoscopies/death averted).

CONCLUSIONS

Universal tumour testing strategies for guiding germline genetic testing of people with incident CRC for LS in Australia are likely to be cost-effective compared with no testing. Universal germline gene panel testing would not currently be cost-effective.

Cost-effectiveness analysis of reflex testing for Lynch syndrome in women with endometrial cancer in the UK setting

Background

Lynch syndrome is a hereditary cancer syndrome caused by constitutional pathogenic variants in the DNA mismatch repair (MMR) system, leading to increased risk of colorectal, endometrial and other cancers. The study aimed to identify the incremental costs and consequences of strategies to identify Lynch syndrome in women with endometrial cancer.

Methods

A decision-analytic model was developed to evaluate the relative cost-effectiveness of reflex testing strategies for identifying Lynch syndrome in women with endometrial cancer taking the NHS perspective and a lifetime horizon. Model input parameters were sourced from various published sources. Consequences were measured using quality-adjusted life years (QALYs). A cost-effectiveness threshold of £20 000/QALY was used.

Results

Reflex testing for Lynch syndrome using MMR immunohistochemistry and MLH1 methylation testing was cost-effective versus no testing, costing £14 200 per QALY gained. There was uncertainty due to parameter imprecision, with an estimated 42% chance this strategy is not cost-effective compared with no testing. Age had a significant impact on cost-effectiveness, with testing not predicted to be cost-effective in patients aged 65 years and over.

Conclusions

Testing for Lynch syndrome in younger women with endometrial cancer using MMR immunohistochemistry and MLH1 methylation testing may be cost-effective. Age cut-offs may be controversial and adversely affect implementation.

[S3 guidelines on the diagnosis and treatment of carcinoma of the endometrium : Requirements for pathology]

The present article summarises the relevant aspects of the S3 guidelines on endometrioid carcinomas. The recommendations include the processing rules of fractional currettings as well as for hysterectomy specimens and lymph node resections (including sentinel lymph nodes). Besides practical aspects, the guidelines consider the needs of the clinicians for appropriate surgical and radiotherapeutic treatment of the patients. Carcinosarcomas are assigned to the endometrial carcinoma as a special variant. For the first time, an algorithmic approach for evaluation of the tumour tissue for Lynch syndrome is given. Prognostic factors based on morphologic findings are summarised.

A dedicated high-quality service for the management of patients with an inherited risk of colorectal cancer

AIM

To demonstrate the quality improvement associated with the implementation of a specialist family history of bowel cancer service in secondary care.

METHOD

The following outcomes were assessed: (1) adherence to the British Society of Gastroenterology (BSG) guidelines for colonoscopic surveillance of individuals with a family history of colorectal cancer (CRC); (2) adherence to the revised Bethesda criteria for the identification of CRC patients with suspected Lynch syndrome; (3) identification of inherited syndromes with increased CRC risk; and (4) colonoscopic adenoma detection rate. Data were collected for a 21-month period before and after the establishment of this service for all patients who underwent colonoscopic surveillance for a family history of CRC and all patients newly diagnosed with CRC. Analyses compared the number of colonoscopies performed that were not indicated by BSG guidelines, the average number of years early that patients were screened, the adenoma detection rate and the rate of tumour testing for mismatch repair genes before and after the implementation of the service.

RESULTS

Following the establishment of the service there was a reduction in the number of colonoscopies not indicated by BSG guidelines (39.6% before and 5.8% after, P < 0.001, chi-square test) and surveillance colonoscopy took place at a more appropriate age (10.6 years too early before and 5.9 years early after, P = 0.01, t-test). There was an increased adenoma detection rate (17% before and 31.9% after, P < 0.01, chi-square test) and increased tumour MMR testing (3.4% before and 91.8% after, P < 0.01, chi-square test).

CONCLUSION

The introduction of a family history of bowel cancer service results in improved patient care through improved adherence to guidelines for colonoscopic surveillance and increased cancer detection rates.

Is immunohistochemistry-based screening for Lynch syndrome in endometrial cancer effective? The consent's the thing

PURPOSE

To investigate the plausible failure rate of the immunohistochemistry (IHC)-based screening protocol to identify Lynch syndrome (LS) index cases among endometrial cancer (EC) patients.

METHODS

We developed a simulation model of the IHC protocol in this context. The model was populated from systematic and focused reviews, augmented with local data and expert opinion. The virtual cohort represents the number of women expected to be diagnosed with EC in the U.S. in 2018. The outcomes include protocol failure rates and LS cases missed in a variety of hypothetical scenarios.

RESULTS

The best estimate of failure rate of the IHC protocol is 58%; minimum and maximum estimates are 33% and 80%, respectively. These failure rates are driven primarily by the high rates of failure to obtain consent from patients for sequencing (25% to 80%). The multiple imperfect tests and potential failure points in this protocol, collectively, make up 7% to 20% of the total failure rate. When consent for sequencing was fixed in the model at 25%, 50%, and 80%; the expected ranges for index case identification failure are 78%-82%, 57%-64%, and 29%-42%, respectively.

CONCLUSION

The primary driver of failure to identify index cases remains consent for sequencing. Consent rates have shown little improvement since LS screening programs were instituted in the U.S., leaving us to conclude these high failure rates are resistant to substantial improvement. These missed opportunities will be magnified because cascade screening for carrier status among family members will not be pursued.

Modified capture-recapture estimates of the number of families with Lynch syndrome in Central Ohio

Past methods for estimating the population frequency of familial cancer syndromes have used cases and controls ignoring the familial nature of genetic disease. In this study we modified the capture-recapture method from ecology to estimate the number of families in central Ohio with Lynch syndrome (LS). We screened 1566 colorectal cancer cases and 545 endometrial cancer cases in central Ohio from 1999 to 2005 and identified 58 with LS. We screened an additional 3346 colorectal and 342 endometrial cancer cases from 2013 to 2016 and identified 149 with LS. We found 12 LS mutations shared between families observed in the first and second studies. We identified three individuals between studies who were closely related and eight who were more distantly related. We used identified family relationships and genetic test results to estimate family size and structure. Applying a modified capture-recapture method we estimate 1693 3-generation families in the area who have 288 unique LS causing mutations. Comprehensive colorectal and endometrial cancer screening will take about 20 years to identify 50% of families with LS. This is the first time that the capture-recapture method has been applied to estimate the burden of families with a specific heritable disease. Family structure reveals the potential extent of prevention and the time necessary to identify a proportion of families with LS.

A Micro-Costing Study of Screening for Lynch Syndrome-Associated Pathogenic Variants in an Unselected Endometrial Cancer Population: Cheap as NGS Chips?

Background: Lynch syndrome is the most common inherited cause of endometrial cancer. Identifying individuals affected by Lynch syndrome enables risk-reducing interventions including colorectal surveillance, and cascade testing of relatives.

Methods: We conducted a micro-costing study of screening all women with endometrial cancer for Lynch syndrome using one of four diagnostic strategies combining tumor microsatellite instability testing (MSI), immunohistochemistry (IHC), and/or MLH1 methylation testing, and germline next generation sequencing (NGS). Resource use (consumables, capital equipment, and staff) was identified through direct observation and laboratory protocols. Published sources were used to identify unit costs to calculate a per-patient cost (£; 2017) of each testing strategy, assuming a National Health Service (NHS) perspective.

Results: Tumor triage with MSI and reflex MLH1 methylation testing followed by germline NGS of women with likely Lynch syndrome was the cheapest strategy at £42.01 per case. Tumor triage with IHC and reflex MLH1 methylation testing of MLH1 protein-deficient cancers followed by NGS of women with likely Lynch syndrome cost £45.68. Tumor triage with MSI followed by NGS of all women found to have tumor microsatellite instability cost £78.95. Immediate germline NGS of all women with endometrial cancer cost £176.24. The cost of NGS was affected by the skills and time needed to interpret results (£44.55/patient).

Conclusion: This study identified the cost of reflex screening all women with endometrial cancer for Lynch syndrome, which can be used in a model-based cost-effectiveness analysis to understand the added value of introducing reflex screening into clinical practice.

Stratification of patients with colorectal cancer without the recorded family history

Colorectal cancer (CRC) is a multifactorial disease and one of the most malignant tumours. In addition to the sporadic form, familial occurrences, particularly hereditary non-polyposis CRC-Lynch syndrome (LS)-are often observed. LS is caused by a germline mutation in mismatch repair (MMR) genes, whose task it is to correct errors in the DNA structure that result from its replication. The aim of the present study was to stratify CRC patients using molecular diagnostics and next generation sequencing, according to the chosen criteria [positive for microsatellite instability (MSI) and negative for a BRAF mutation and MutL homolog 1 (MLH1) methylation], and subsequently to detect pathological germline mutations in MMR genes in Slovak patients. To exclude patients with MSI from further testing, the present study detected the BRAF V600E mutation and examined MLH1 methylation status. From the 300 CRC patients, 37 cases with MSI were identified. In the MSI-positive samples, 13 cases of BRAF V600E mutation were recorded. In 24 BRAF-negative patients, 11 cases of epigenetic methylation of MLH1 and 12 cases without MLH1 methylation suspected for LS were detected, and it was not possible to analyse the methylation phenotype of 1 sample. Thus, the present study reports the novel deletion of four nucleotides, 1627_1630del AAAG (Glu544Lysfs*26) in MSH6, probably associated with LS. A second case with a nonsense mutation in MSH was also detected, namely MMR_c.1030C>T (p.Q344X).

Cost-effectiveness of targeted screening for abdominal aortic aneurysm in siblings

Background

Population screening for abdominal aortic aneurysm (AAA) in 65‐year‐old men has been shown to be cost‐effective. A risk group with higher prevalence is siblings of patients with an AAA. This health economic model‐based study evaluated the potential cost‐effectiveness of targeted AAA screening of siblings.

Methods

A Markov model validated against other screening programmes was used. Two methods of identifying siblings were analysed: direct questioning of patients with an AAA (method A), and employing a national multigeneration register (method B). The prevalence was based on observed ultrasound data on AAAs in siblings. Additional parameters were extracted from RCTs, vascular registers, literature and ongoing screening. The outcome was cost‐effectiveness, probability of cost‐effectiveness at different willingness‐to‐pay (WTP) thresholds, reduction in AAA death, quality‐adjusted life‐years (QALYs) gained and total costs on a national scale.

Results

Methods A and B were estimated to reduce mortality from AAA, at incremental cost‐effectiveness ratios of €7800 (95 per cent c.i. 4627 to 12 982) and €7666 (5000 to 13 373) per QALY respectively. The probability of cost‐effectiveness was 99 per cent at a WTP of €23 000. The absolute risk reduction in AAA deaths was five per 1000 invited. QALYs gained were 27 per 1000 invited. In a population of ten million, methods A and B were estimated to prevent 12 and 17 AAA deaths, among 2418 and 3572 siblings identified annually, at total costs of €499 500 and €728 700 respectively.

Conclusion

The analysis indicates that aneurysm‐related mortality could be decreased cost‐effectively by applying a targeted screening method for siblings of patients with an AAA.

Challenges and Opportunities for Cancer Predisposition Cascade Screening for Hereditary Breast and Ovarian Cancer and Lynch Syndrome in Switzerland: Findings from an International Workshop

BACKGROUND

An international workshop on cancer predisposition cascade genetic screening for hereditary breast and ovarian cancer (HBOC) and Lynch syndrome (LS) took place in Switzerland, with leading researchers and clinicians in cascade screening and hereditary cancer from different disciplines. The purpose of the workshop was to enhance the implementation of cascade genetic screening in Switzerland. Participants discussed the challenges and opportunities associated with cascade screening for HBOC and LS in Switzerland (CASCADE study); family implications and the need for family-based interventions; the need to evaluate the cost-effectiveness of cascade genetic screening; and interprofessional collaboration needed to lead this initiative.

METHODS

The workshop aims were achieved through exchange of data and experiences from successful cascade screening programs in the Netherlands, Australia, and the state of Ohio, USA; Swiss-based studies and scientific experience that support cancer cascade screening in Switzerland; programs of research in psychosocial oncology and family-based studies; data from previous cost-effectiveness analyses of cascade genetic screening in the Netherlands and in Australia; and organizational experience from a large interprofessional collaborative. Scientific presentations were recorded and discussions were synthesized to present the workshop findings.

RESULTS

The key elements of successful implementation of cascade genetic screening are a supportive network of stakeholders and connection to complementary initiatives; sample size and recruitment of relatives; centralized organization of services; data-based cost-effectiveness analyses; transparent organization of the initiative; and continuous funding.

CONCLUSIONS

This paper describes the processes and key findings of an international workshop on cancer predisposition cascade screening, which will guide the CASCADE study in Switzerland.

Universal screening for Lynch syndrome in a large consecutive cohort of Chinese colorectal cancer patients: High prevalence and unique molecular features

The prevalence of Lynch syndrome (LS) varies significantly in different populations, suggesting that ethnic features might play an important role. We enrolled 3330 consecutive Chinese patients who had surgical resection for newly diagnosed colorectal cancer. Universal screening for LS was implemented, including immunohistochemistry for mismatch repair (MMR) proteins, BRAF^V600E mutation test and germline sequencing. Among the 3250 eligible patients, MMR protein deficiency (dMMR) was detected in 330 (10.2%) patients. Ninety-three patients (2.9%) were diagnosed with LS. Nine (9.7%) patients with LS fulfilled Amsterdam criteria II and 76 (81.7%) met the revised Bethesda guidelines. Only 15 (9.7%) patients with absence of MLH1 on IHC had BRAF^V600E mutation. One third (33/99) of the MMR gene mutations have not been reported previously. The age of onset indicates risk of LS in patients with dMMR tumors. For patients older than 65 years, only 2 patients (5.7%) fulfilling revised Bethesda guidelines were diagnosed with LS. Selective sequencing of all cases with dMMR diagnosed at or below age 65 years and only of those dMMR cases older than 65 years who fulfill revised Bethesda guidelines results in 8.2% fewer cases requiring germline testing without missing any LS diagnoses. While the prevalence of LS in Chinese patients is similar to that of Western populations, the spectrum of constitutional mutations and frequency of BRAF^V600E mutation is different. Patients older than 65 years who do not meet the revised Bethesda guidelines have a low risk of LS, suggesting germline sequencing might not be necessary in this population.

Interdisciplinary Diagnosis, Therapy and Follow-up of Patients with Endometrial Cancer. Guideline (S3-Level, AWMF Registry Nummer 032/034-OL, April 2018) - Part 1 with Recommendations on the Epidemiology, Screening, Diagnosis and Hereditary Factors of Endometrial Cancer

Summary The first German interdisciplinary S3-guideline on the diagnosis, therapy and follow-up of patients with endometrial cancer was published in April 2018. Funded by German Cancer Aid as part of an Oncology Guidelines Program, the lead coordinators of the guideline were the German Society of Gynecology and Obstetrics (DGGG) and the Gynecological Oncology Working Group (AGO) of the German Cancer Society (DKG).

Purpose The use of evidence-based, risk-adapted therapy to treat low-risk women with endometrial cancer avoids unnecessarily radical surgery and non-useful adjuvant radiotherapy and/or chemotherapy. This can significantly reduce therapy-induced morbidity and improve the patientʼs quality of life as well as avoiding unnecessary costs. For women with endometrial cancer and a high risk of recurrence, the guideline defines the optimal surgical radicality together with the appropriate chemotherapy and/or adjuvant radiotherapy where required. The evidence-based optimal use of different therapeutic modalities should improve survival rates and the quality of life of these patients. The S3-guideline on endometrial cancer is intended as a basis for certified gynecological cancer centers. The aim is that the quality indicators established in this guideline will be incorporated in the certification processes of these centers.

Methods The guideline was compiled in accordance with the requirements for S3-level guidelines. This includes, in the first instance, the adaptation of source guidelines selected using the DELBI instrument for appraising guidelines. Other consulted sources include reviews of evidence which were compiled from literature selected during systematic searches of literature databases using the PICO scheme. In addition, an external biostatistics institute was commissioned to carry out a systematic search and assessment of the literature for one area of the guideline. The identified materials were used by the interdisciplinary working groups to develop suggestions for Recommendations and Statements, which were then modified during structured consensus conferences and/or additionally amended online using the DELPHI method with consent being reached online. The guideline report is freely available online.

Recommendations Part 1 of this short version of the guideline presents recommendations on epidemiology, screening, diagnosis and hereditary factors, The epidemiology of endometrial cancer and the risk factors for developing endomentrial cancer are presented. The options for screening and the methods used to diagnose endometrial cancer including the pathology of the cancer are outlined. Recommendations are given for the prevention, diagnosis, and therapy of hereditary forms of endometrial cancer.

Current mismatch repair deficiency tumor testing practices and capabilities: A survey of Australian pathology providers

AIM & METHODS

An electronic survey of the Royal College of Pathologists of Australasia accredited pathology services was conducted to assess Lynch syndrome tumor screening practices and to identify barriers and capabilities to screen newly diagnosed colorectal and endometrial tumors in Australia.

RESULTS

Australia lacks a national policy for universal mismatch repair-deficient (dMMR) testing of incident colorectal and endometrial tumors cases. Routine Lynch syndrome tumor screening program for colorectal and/or endometrial tumors was applied by 95% (37/39) of laboratories. Tumor dMMR screening methods varied; MMR protein immunohistochemistry (IHC) alone was undertaken by 77% of 39 laboratories, 18% performed both IHC and microsatellite instability testing, 5% did not have the capacity to perform in-house testing. For colorectal tumors, 47% (17/36) reported following a universal approach without age limit, 30% (11/36) tested only "red flag" cases; 6% (3/36) on clinician request only. For endometrial tumors, 37% (12/33) reported clinician request generated testing, 27% (9/33) were screening only "red flag" cases, and 12% (4/33) carried out universal screening without an age criteria. BRAF V600E mutation testing of colorectal tumors demonstrating aberrant MLH1 protein expression by IHC was the most common secondary tumor test, with 53% of laboratories performing the test; 15% of laboratories also applied the BRAF V600E test to endometrial tumors with aberrant MLH1 expression despite no evidence for its utility. Tumor testing for MLH1 promoter methylation was performed by less than 15% laboratories.

CONCLUSION

Although use of tumor screening for evidence of dMMR is widely available, protocols for its use in Australia vary widely. This national survey provides a snapshot of the current availability and practice of tumor dMMR screening and identifies the need for a uniform national testing policy.

Lynch syndrome - cancer pathways, heterogeneity and immune escape

Recent work has provided evidence for genetic and molecular heterogeneity in colorectal cancers (CRCs) arising in patients with Lynch syndrome (LS), dividing these into two groups: G1 and G2. In terms of mutation and gene expression profile, G1 CRCs bear resemblance to sporadic CRCs with microsatellite instability (MSI), whereas G2 CRCs are more similar to microsatellite-stable CRCs. Here we review the current state of knowledge on pathways of precursor progression to CRC in LS and how these might tie in with the new findings. Immunotherapies are an active field of research for MSI cancers and their potential use for cancer therapy for both sporadic and LS MSI cancers is discussed. Copyright © 2018 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.

A novel panel of short mononucleotide repeats linked to informative polymorphisms enabling effective high volume low cost discrimination between mismatch repair deficient and proficient tumours

Somatic mutations in mononucleotide repeats are commonly used to assess the mismatch repair status of tumours. Current tests focus on repeats with a length above 15bp, which tend to be somatically more unstable than shorter ones. These longer repeats also have a substantially higher PCR error rate, and tests that use capillary electrophoresis for fragment size analysis often require expert interpretation. In this communication, we present a panel of 17 short repeats (length 7-12bp) for sequence-based microsatellite instability (MSI) testing. Using a simple scoring procedure that incorporates the allelic distribution of the mutant repeats, and analysis of two cohort of tumours totalling 209 samples, we show that this panel is able to discriminate between MMR proficient and deficient tumours, even when constitutional DNA is not available. In the training cohort, the method achieved 100% concordance with fragment analysis, while in the testing cohort, 4 discordant samples were observed (corresponding to 97% concordance). Of these, 2 showed discrepancies between fragment analysis and immunohistochemistry and one was reclassified after re-testing using fragment analysis. These results indicate that our approach offers the option of a reliable, scalable routine test for MSI.