The cost-effectiveness of genetic testing strategies for Lynch syndrome among newly diagnosed patients with colorectal cancer

Real-world genetic testing outcomes of pan-cancer testing for mismatch repair deficiency

BACKGROUND

In 2017, the Food and Drug Administration approved pembrolizumab for treatment of any mismatch repair-deficient (dMMR) tumor making MMR immunohistochemistry (IHC) testing beneficial for all tumor types. For the first time, MMR IHC was not performed exclusively to screen for Lynch syndrome (LS).

METHODS

In this study, all MMR IHC reports issued between 2017 and 2021 at an academic hospital were reviewed and completion of genetic testing was determined through chart review. Colorectal cancers (CRCs), endometrial cancers (ECs), and noncancerous lesions were excluded.

RESULTS

Between 2017 and 2021, MMR IHC was completed in 1939 patients with a malignancy other than CRC or EC. Absent or weak staining for at least one MMR protein was detected in 115 (5.9%) patients and 59 (51%) of those completed germline genetic testing. Overall, the identification rate of LS in this cohort was 0.72%, which is similar to the rate in our previously reported CRC and EC universal screening cohort. A diagnosis of LS was most commonly made in patients with dMMR brain (18.75%) and small intestinal cancers (10.20%). Five additional patients were found to carry a pathogenic variant in a non-LS gene.

CONCLUSIONS

Pan-cancer MMR testing for pembrolizumab consideration can identify LS cases at a rate similar to universal CRC and EC screening programs. A persistent challenge is subsequent uptake of genetic testing. MMR testing should be prioritized in brain and small intestinal tumors, and multigene panel testing is recommended in patients with dMMR, as unexpected pathogenic variants in non-LS genes were found as frequently as LS gene variants.

Precision Medicine in the Era of Genetic Testing: Microsatellite Instability Evolved

The recognized importance of microsatellite instability (MSI) in cancer has evolved considerably in the past 30 years. From its beginnings as a molecular predictor for Lynch syndrome, MSI first transitioned to a universal screening test in all colorectal and endometrial cancers, substantially increasing the identification of patients with Lynch syndrome among cancer patients. More recently, MSI has been shown to be a powerful biomarker of response to immune checkpoint blockade therapy across a diversity of tumor types, and in 2017 was granted Food and Drug Administration approval as the first tumor histology-agnostic biomarker for a cancer therapy. Focusing on colorectal cancer specifically, immune checkpoint blockade therapy has been shown to be highly effective in the treatment of both MSI-high (MSI-H) colon and rectal cancer, with data increasingly suggesting an early role for immune checkpoint blockade therapy in MSI-H colorectal tumors in the neoadjuvant setting, with the potential to avoid more toxic and morbid approaches using traditional chemotherapy, radiation therapy, and surgery. The success of MSI as an immune checkpoint blockade target has inspired ongoing vigorous research to identify new similar targets for immune checkpoint blockade therapy that may help to one day expand the reach of this revolutionary cancer therapy to a wider swath of patients and indications.

An Australian mainstream genetic testing program: Clinicians views about current and future practices

PURPOSE

Germline genetic testing results can guide treatment decisions for oncology patients and are now offered to many cancer patients. Mainstream testing refers to genetic testing arranged by a non-genetics specialist. This repeated cross-sectional study aimed: (1) to capture clinician views on the existing mainstreaming genetic testing program for ovarian, breast, prostate, and endometrial cancer patients, and (2) to ascertain the interest of clinicians to consider changing practice to adopt mainstream testing.

METHODS

Mainstreaming has occurred since 2015 for patients with ovarian and some breast cancer patients, expanding to include prostate cancer patients in 2019, and endometrial cancer patients in 2020. Two web-based surveys were administered within two health districts, covering seven hospitals in NSW.

RESULTS

Fifty-four clinicians (70% response rate) participated. Clinicians who had arranged mainstream genetic testing (n = 30) were overall satisfied (76%), viewed the process as time-efficient and accessible for patients, and desired continuation of the program. Of those clinicians yet to engage in the program (n = 24), 88% expressed an interest in learning about mainstream testing. These clinicians identified time constraints, maintenance of current genetic knowledge, and completing the consenting and counseling process as barriers to mainstreaming. Future mainstreaming models are discussed.

CONCLUSION

From the clinician's perspective, the mainstreaming program is considered a desirable pathway for germline testing of oncology patients. Access to ongoing education and resources is needed for the ongoing success of the program.

Comprehensive Analysis of Early-onset Colorectal Cancer: A Review

Early-onset colorectal cancer (CRC), which refers to CRC diagnosed in individuals below the age of 50 years, is a growing health concern that presents unique challenges in diagnosis, treatment, and long-term outcomes. Although approximately 70% of early-onset CRC cases are sporadic, with no apparent family history, approximately 25% have a familial component, and up to 20% may be associated with germline mutations, indicating a higher prevalence compared with the general population. Despite the progress in identifying the environmental, molecular, and genetic risk factors of early-onset CRC, the underlying causes for the global increase in its incidence remain unclear. This comprehensive review aims to provide a thorough analysis of early-onset CRC by examining the trends associated with its incidence, clinical and pathological characteristics, risk factors, molecular and genetic profiles, prognosis and screening strategies. By deepening our understanding of early-onset CRC, significant advances related to improving the outcomes and alleviating the burden of this disease on individuals, families, and healthcare systems can be achieved.

Both MLH1 deficiency and BRAFV600E mutation are a unique characteristic of colorectal medullary carcinoma: An observational study

Although immunohistochemistry (IHC) for mismatch repair (MMR) proteins (MMR IHC) is used to identify DNA MMR status, universal screening of all patients with colorectal cancer (CRC) using a combination of both MMR IHC and genetic testing for the BRAFV600E mutation is limited in Japan. This study aimed to better understand the histopathological characteristics of CRCs, which exhibit both deficient mismatch repair (dMMR) and BRAFV600E mutation. MMR IHC of formalin-fixed paraffin-embedded tissues from tumor areas obtained from 651 patients with CRC who underwent surgical resection at Hamamatsu University Hospital (Hamamatsu, Japan) between August 2016 and March 2022 were used to evaluate MMR status, which was determined by staining for the expression of 4 MMR proteins (MLH1, MSH2, PMS2, and MSH6). All dMMR tumors were additionally evaluated for BRAFV600 mutation status via Sanger sequencing. Patient clinical characteristics (age, sex, tumor location, size, and tumor pathology) were then classified using their dMMR and BRAFV600 mutation statuses. Among the 651 patients with CRC, 58 carried tumors with dMMR, of which 52 were deficiency in MLH1 (dMLH1). Interestingly, all 16 medullary carcinomas that were analyzed showed characteristics corresponding to the presence of both dMLH1 and BRAFV600E mutation (P = .01). These results suggest that colorectal medullary carcinomas can be diagnosed based on their unique characteristics of harboring the BRAFV600E mutation and exhibiting dMLH1 expression.

In person and virtual process mapping experiences to capture and explore variability in clinical practice: application to genetic referral pathways across seven Australian hospital networks

Genetic referral for Lynch syndrome (LS) exemplifies complex clinical pathways. Identifying target behaviours (TBs) for change and associated barriers requires structured group consultation activities with busy clinicians - consolidating implementation activities whilst retaining rigour is crucial. This study aimed to: i) use process mapping to gain in-depth understandings of site-specific LS testing and referral practices in Australian hospitals and support identification of TBs for change, ii) explore if barriers to identified TBs could be identified through process mapping focus-group data, and iii) demonstrate pandemic-induced transition from in-person to virtual group interactive process mapping methods. LS clinical stakeholders attended interactive in-person or virtual focus groups to develop site-specific "process maps" visually representing referral pathways. Content analysis of transcriptions informed site-specific process maps, then clinical audit data was compared to highlight TBs for change. TBs were reviewed in follow-up focus groups. Secondary thematic analysis explored barriers to identified TBs, coded against the Theoretical Domains Framework (TDF). The transition from in-person to pandemic-induced virtual group interactive process mapping methods was documented. Process mapping highlighted six key areas of clinical practice variation across sites and site-specific TBs for change were identified. Key barriers to identified TBs emerged, categorised to seven TDF domains. Process mapping revealed variations in clinical practices surrounding LS referral between sites. Incorporating qualitative perspectives enhances process mapping by facilitating identification of TBs for change and barriers, providing a pathway to developing targeted interventions. Virtual process mapping activities produced detailed data and enabled comprehensive map development.

A review of the cost-effectiveness of genetic testing for germline variants in familial cancer

BACKGROUND

Targeted germline testing is recommended for those with or at risk of breast, ovarian, or colorectal cancer. The affordability of genetic sequencing has improved over the past decade, therefore the cost-effectiveness of testing for these cancers is worthy of reassessment.

OBJECTIVE

To systematically review economic evaluations on cost-effectiveness of germline testing in breast, ovarian, or colorectal cancer.

METHODS

A search of PubMed and Embase databases for cost-effectiveness studies on germline testing in breast, ovarian, or colorectal cancer, published between 1999 and May 2022. Synthesis of methodology, cost-effectiveness, and reporting (CHEERS checklist) was performed.

RESULTS

The incremental cost-effectiveness ratios (ICERs; in 2021-adjusted US$) for germline testing versus the standard care option in hereditary breast or ovarian cancer (HBOC) across target settings were as follows: (1) population-wide testing: 344-2.5 million/QALY; (2) women with high-risk: dominant = 78,118/QALY, 8,337-59,708/LYG; (3) existing breast or ovarian cancer: 3,012-72,566/QALY, 39,835/LYG; and (4) metastatic breast cancer: 158,630/QALY. Likewise, ICERs of germline testing for colorectal cancer across settings were: (1) population-wide testing: 132,200/QALY, 1.1 million/LYG; (2) people with high-risk: 32,322-76,750/QALY, dominant = 353/LYG; and (3) patients with existing colorectal cancer: dominant = 54,122/QALY, 98,790-6.3 million/LYG. Key areas of underreporting were the inclusion of a health economic analysis plan (100% of HBOC and colorectal studies), engagement of patients and stakeholders (95.4% of HBOC, 100% of colorectal studies) and measurement of outcomes (18.2% HBOC, 38.9% of colorectal studies).

CONCLUSION

Germline testing for HBOC was likely to be cost-effective across most settings, except when used as a co-dependent technology with the PARP inhibitor, olaparib in metastatic breast cancer. In colorectal cancer studies, testing was cost-effective in those with high-risk, but inconclusive in other settings. Cost-effectiveness was sensitive to the prevalence of tested variants, cost of testing, uptake, and benefits of prophylactic measures. Policy advice on germline testing should emphasize the importance of these factors in their recommendations.

Updates in gynecologic care for individuals with lynch syndrome

Lynch syndrome is an autosomal dominant hereditary cancer syndrome caused by germline pathogenic variants (PVs) in DNA mismatch repair genes (MLH1, MSH2, PMS2, MSH6) or the EPCAM gene. It is estimated to affect 1 in 300 individuals and confers a lifetime risk of cancer of 10-90%, depending on the specific variant and type of cancer. Lynch syndrome is the most common cause of inherited colorectal cancer, but for women, endometrial cancer is more likely to be the sentinel cancer. There is also evidence that certain PVs causing Lynch syndrome confer an increased risk of ovarian cancer, while the risk of ovarian cancer in others is not well defined. Given this, it is essential for the practicing gynecologist and gynecologic oncologist to remain up to date on the latest techniques in identification and diagnosis of individuals with Lynch syndrome as well as evidence-based screening and risk reduction recommendations for those impacted. Furthermore, as the landscape of gynecologic cancer treatment shifts towards treatment based on molecular classification of tumors, knowledge of targeted therapies well-suited for mismatch repair deficient Lynch tumors will be crucial. The objective of this review is to highlight recent updates in the literature regarding identification and management of individuals with Lynch syndrome as it pertains to endometrial and ovarian cancers to allow gynecologic providers the opportunity to both prevent and identify Lynch-associated cancers earlier, thereby reducing the morbidity and mortality of the syndrome.

DNA Mismatch Repair Proteins and BRAF V600E Detection by Immunohistochemistry in Colorectal Cancer Demonstrates Concordance with Next Generation Sequencing

Background and Aims: Multiple laboratory methods are used to screen patients with colorectal cancer (CRC) for mismatch repair (MMR) protein deficiency to identify possible Lynch syndrome patients. The goal of this study was to compare the agreement between ready-to-use immunohistochemistry (IHC) assays for MLH-1, PMS-2, MSH-2, MSH-6, and mutated BRAF at V600E and molecular methods in CRC cases. The inclusion of the BRAF V600E mutation testing is important for the identification of patients with sporadic CRC, as the BRAF V600E mutation is very rarely observed in patients with Lynch syndrome tumors. Methods: CRC cases were analyzed by ColoSeqTM tumor sequencing assay and VENTANA MMR IHC Panel that included anti-MLH1, anti-PMS2, anti-MSH2, anti-MSH6, and anti-BRAF V600E antibodies. Additionally, CRC cases with MLH1 IHC loss were evaluated for MLH1 promoter hypermethylation. Results: One hundred and eighteen cases were analyzed. The overall percent agreement (OPA) for each evaluated marker status compared to next-generation sequencing (NGS) exceeded 96%. Twenty-three cases were positive for the BRAF V600E mutation by IHC and NGS, and twenty cases showed loss of MLH1 protein and were positive for MLH1 hypermethylation. Samples with loss of MMR protein expression by IHC demonstrated genetic and/or epigenetic alterations that were consistent with the observed protein expression patterns. Conclusions: The results of this study indicate that ready-to-use IHC assays can correctly identify the loss of MMR proteins and the presence of mutated BRAF V600E protein, supporting the utility of the VENTANA MMR IHC Panel as an aid to stratify patients with sporadic CRC vs. potential Lynch syndrome.

Routine Immunohistochemical Analysis of Mismatch Repair Proteins in Colorectal Cancer—A Prospective Analysis

Simple Summary

Recognition of a hereditary colorectal cancer (CRC) syndrome is crucial. Our aim was to assess the value of routine immunohistochemistry screening for mismatch repair proteins deficiency in CRC patients under 70 years-old. In our cohort, this inclusive strategy allowed the identification of Lynch Syndrome patients that could otherwise be missed using a restrictive approach that relies only on Amsterdam and Bethesda criteria. This study strengthens current recommendations and highlights the role of universal CRC screening for MMR protein status.

Abstract

Recognition of a hereditary colorectal cancer (CRC) syndrome is crucial and Lynch Syndrome (LS) is the most frequent immunohistochemistry (IHC)—screening for mismatch repair proteins (MMR) deficiency in CRC is therefore advocated. An unicentric cohort study was conducted in a central Oncological Hospital to assess its results. All patients under 70 years-old admitted between July 2017–June 2019 and submitted to surgery for CRC were included. Of 275 patients, 56.0% were male, median age 61.0 (IQR:54.5–65.0), with synchronous tumors in six. Histology revealed high grade adenocarcinoma in 8.4%; mucinous and/or signet ring differentiation in 11.3%; and lymphocytic infiltration in 29.8%. Amsterdam (AC) and Bethesda (BC) Criteria were fulfilled in 11 and 74 patients, respectively. IHC revealed loss of expression of MMR proteins in 24 (8.7%), mostly MLH1 and PMS2 (n = 15) and PMS2 (n = 4). Among these, no patients fulfilled AC and 13 fulfilled BC. BRAF mutation or MLH1 promoter hypermethylation was found in four patients with MLH1 loss of expression. Genetic diagnosis was performed in 51 patients, 11 of them with altered IHC. LS was diagnosed in four, and BC was present in three. One patient would not have been diagnosed without routine IHC screening. These results strengthen the important role of IHC screening for MMR proteins loss of expression in CRC.

Evaluating the quality of the economic evidence in colorectal cancer genomics studies

The increase in the use of genome-based screening and diagnostic tests adds to the overall costs of oncologic care for colorectal cancer. This, in turn, has resulted in an increase in published economic analyses. Aim: To perform a systematic literature review of the available economic evidence evaluating the value of genomic testing for colorectal cancer and appraise the quality of the economic studies conducted to date. Methods: A systematic review of the literature for economic studies of colorectal cancer genomics from January 2006 through October 2020, and evaluation of study quality using the Quality of Health Economic Studies (QHES) instrument was conducted. The validated QHES was then applied to a final set of articles that met eligibility criteria. Results: Our search of the literature initially yielded 12,859 records. A final set of 49 articles met our inclusion criteria. The QHES score ranged from 24 to 100, with an average score of 82. Most of the studies (n = 40, 82%) scored above 75 and were considered of good quality. Conclusion: Our analysis revealed that most of the economic analyses of colorectal cancer genomic molecular diagnostics in the literature may be of good quality. There is, however, some variation in methodological rigor between the articles.

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.

Risk assessment and genetic counseling for Lynch syndrome - Practice resource of the National Society of Genetic Counselors and the Collaborative Group of the Americas on Inherited Gastrointestinal Cancer

Identifying individuals who have Lynch syndrome involves a complex diagnostic workup that includes taking a detailed family history and a combination of various tests such as immunohistochemistry and/or molecular which may be germline and/or somatic. The National Society of Genetic Counselors and the Collaborative Group of the Americas on Inherited Gastrointestinal Cancer have come together to publish this practice resource for the evaluation of Lynch syndrome. The purpose of this practice resource was to provide guidance and a testing algorithm for Lynch syndrome as well as recommendations on when to offer testing. This practice resource does not replace a consultation with a genetics professional. This practice resource includes explanations in support of this and a summary of background data. While this practice resource is not intended to serve as a review of Lynch syndrome, it includes a discussion of background information and cites a number of key publications which should be reviewed for a more in-depth understanding. This practice resource is intended for genetic counselors, geneticists, gastroenterologists, surgeons, medical oncologists, obstetricians and gynecologists, nurses, and other healthcare providers who evaluate patients for Lynch syndrome.

Measuring and Improving Quality of Colonoscopy for Colorectal Cancer Screening

Colorectal cancer (CRC) is largely preventable, yet it remains a major public health issue as it is the third most common and deadly malignancy in the United States. While there are many ways to screen for CRC, colonoscopy remains the gold standard as it is the only test that is both cancer-detecting and cancer-preventing through removal of precancerous polyps. Through identifying and removing neoplastic lesions, colonoscopy reduces CRC incidence by 31%-91% and CRC mortality by 65%-88%. However, colonoscopy is not an infallible test-there is a chance for missed lesions during the exam and there is substantial variation in outcomes among endoscopists. To enhance the quality of colonoscopic exams, and ultimately to improve CRC outcomes, quality indicators have been developed for measuring endoscopists' performance. In this review, we describe the colonoscopic quality indicators and benchmarks recommended by the American Society for Gastrointestinal Endoscopy/American College of Gastroenterology Task Force on Quality in Endoscopy for screening colonoscopies in average-risk individuals. Measuring and monitoring endoscopists' performance on these measures are critical first steps in striving toward conducting high quality exams. We also review the evidence for interventions that aim to improve critical measures including adenoma detection rate, withdrawal time, cecal intubation, and bowel preparation quality. Finally, we provide a preview of the forthcoming Advancing Care for Appropriate Colon Health Merit-Based Incentive Payment System Value Pathway by the Centers for Medicare & Medicaid Services and its potential impact on clinical practice.

Validity of a two-antibody testing algorithm for mismatch repair deficiency testing in cancer; a systematic literature review and meta-analysis

Reflex mismatch repair immunohistochemistry (MMR IHC) testing for MLH1, PMS2, MSH2 and MSH6 is used to screen for Lynch syndrome. Recently MMR-deficiency (MMRd) has been approved as a pan-cancer predictive biomarker for checkpoint inhibitor therapy, leading to a vast increase in the use of MMR IHC in clinical practice. We explored whether immunohistochemical staining with PMS2 and MSH6 can be used as a reliable substitute. This two-antibody testing algorithm has the benefit of saving tissue, cutting costs and saving time. PubMed, Embase and Cochrane library were systematically searched for articles reporting on MMR IHC. The weighed percentage of cases with isolated MLH1 or MSH2 loss or combined MLH1/MSH2 loss alone was analyzed using a random effects model meta-analysis in R. The search yielded 1704 unique citations, of which 131 studies were included, describing 9014 patients. A weighed percentage of 1.1% (95% CI 0.53-18.87, I = 87%) of cases with isolated MLH1 or MSH2 loss or combined MLH1/MSH2 loss alone was observed. In the six articles with the main aim of investigating the two-antibody testing algorithm all MMRd cases were detected with the two-antibody testing algorithm, there were no cases with isolated MLH1 or MSH2 loss or combined MLH1/MSH2 loss alone. This high detection rate of MMRd of the two-antibody testing algorithm supports its use in clinical practice by specialized pathologists. Staining of all four antibodies should remain the standard in cases with equivocal results of the two-antibody testing algorithm. Finally, educational sessions in which staining pattern pitfalls are discussed will continue to be important.

Economic Evaluation of Universal Lynch Syndrome Screening Protocols among Newly Diagnosed Patients with Colorectal Cancer

We conducted an updated economic evaluation, from a healthcare system perspective, to compare the relative effectiveness and efficiency of eight Lynch syndrome (LS) screening protocols among newly diagnosed colorectal cancer (CRC) patients. We developed decision analytic models for a hypothetical cohort of 1000 patients. Model assumptions and parameter values were based on literature and expert opinion. All costs were in 2018 USD. For identifying LS cases, the direct germline sequencing (DGS) protocol provided the best performance (sensitivity 99.90%, 99.57-99.93%; specificity 99.50%, 97.28-99.85%), followed by the tumor sequencing to germline sequencing (TSGS) protocol (sensitivity, 99.42%, 96.55-99.63%; specificity, 96.58%, 96.46-96.60%). The immunohistochemistry (IHC) protocol was most efficient at $20,082 per LS case identified, compared to microsatellite instability (MSI) ($22,988), DGS ($31,365), and TSGS ($104,394) protocols. Adding double-somatic testing to IHC and MSI protocols did not change sensitivity and specificity, increased costs by 6% and 3.5%, respectively, but reduced unexplained cases by 70% and 50%, respectively. DGS would be as efficient as the IHC protocol when the cost of germline sequencing declines under $368 indicating DGS could be an efficient option in the near future. Until then, IHC and MSI protocols with double-somatic testing would be the optimal choices.

Swiss cost-effectiveness analysis of universal screening for Lynch syndrome of patients with colorectal cancer followed by cascade genetic testing of relatives

Background

We estimated the cost-effectiveness of universal DNA screening for Lynch syndrome (LS) among newly diagnosed patients with colorectal cancer (CRC) followed by cascade screening of relatives from the Swiss healthcare system perspective.

Methods

We integrated decision trees with Markov models to calculate incremental cost per quality-adjusted life-year saved by screening all patients with CRC (alternative strategy) compared with CRC tumour-based testing followed by DNA sequencing (current strategy).

Results

The alternative strategy has an incremental cost-effectiveness ratio of CHF65 058 compared with the current strategy, which is cost-effective according to Swiss standards. Based on annual incidence of CRC in Switzerland, universal DNA screening correctly identifies all 123 patients with CRC with LS, prevents 17 LS deaths and avoids 19 CRC cases, while the current strategy leads to 32 false negative results and 253 LS cases lost to follow-up. One way and probabilistic sensitivity analyses showed that universal DNA testing is cost-effective in around 80% of scenarios, and that the cost of DNA testing and the number of invited relatives per LS case determine the cost-effectiveness ratio.

Conclusion

Results can inform policymakers, healthcare providers and insurance companies about the costs and benefits associated with universal screening for LS and cascade genetic testing of relatives.

Universal Germline Testing of Unselected Cancer Patients Detects Pathogenic Variants Missed by Standard Guidelines without Increasing Healthcare Costs

Simple Summary

Clinical genetic testing likely underestimates the frequency of pathogenic germline variants (PGVs) in a cancer patient population due to strict qualifications designated by practice guidelines. Accurate ascertainment of PGVs in cancer patients can be paramount to the treatment of hereditary cancer syndromes. Our prospective study aimed to (1) elucidate PGV frequency in an unselected cohort of cancer patients by offering universal germline testing regardless of eligibility by clinical guidelines and to (2) evaluate the impact of receiving such testing on cost of care. Results confirmed that over 50% of patients who harbored a PGV would not have qualified for testing under current guidelines and there was no increase in healthcare costs for patients who tested positive for a PGV. It is therefore feasible to offer universal germline testing for cancer patients in the clinic to detect PGVs without increasing healthcare costs.

Abstract

Purpose: To accurately ascertain the frequency of pathogenic germline variants (PGVs) in a pan-cancer patient population with universal genetic testing and to assess the economic impact of receiving genetic testing on healthcare costs. Methods: In this prospective study, germline genetic testing using a 105-gene panel was administered to an unselected pan-cancer patient population irrespective of eligibility by current guidelines. Financial records of subjects were analyzed to assess the effect of PGV detection on cost of care one year from the date of testing. Results: A total of 284 patients participated in this study, of which 44 patients (15%) tested positive for a PGV in 14 different cancer types. Of the patients with PGVs, 23 patients (52%) were ineligible for testing by current guidelines. Identification of a PGV did not increase cost of care. Conclusion: Implementation of universal genetic testing for cancer patients in the clinic, beyond that specified by current guidelines, is necessary to accurately assess and treat hereditary cancer syndromes and does not increase healthcare costs.

Real-world outcome of universal screening for Lynch syndrome in Japanese patients with colorectal cancer highlights the importance of targeting patients with young-onset disease

Despite the recommendations of the latest guidelines, the practical efficacy of universal screening for identifying Lynch syndrome (LS) among patients with colorectal cancer (CRC) may be limited in the real world due to infrequent referrals and the difficulties of genetic testing. Thus, the present study aimed to retrospectively analyze the results of universal screening of patients with CRC at a referral hospital in Japan. Immunohistochemistry was performed for mismatch repair proteins [including DNA mismatch repair protein MSH6 (MSH6), mismatch repair endonuclease PMS2 (PMS2), DNA mismatch repair protein Msh2 (MSH2) and DNA mismatch repair protein Mlh1 (MLH1)] and BRAF V600E mutation. Tumors that showed the following were considered to indicate LS and patients with such tumors were designated as genetic testing candidates (GTCs): i) Loss of MSH6/MSH2; ii) loss of MSH6 alone; iii) loss of PMS2 alone; and iv) loss of PMS2/MLH1 with negative BRAF V600E. MLH1 methylation and BRAF V600E mutation were analyzed in deficient mismatch repair (dMMR) tumors retrospectively. The frequency of dMMR and GTCs in an independent cohort of patients with young-onset CRC were also investigated. Universal screening revealed dMMR tumors, GTCs and LS probands in 7.3, 3.9 and 0.4%, respectively, of 463 patients with CRC. Although dMMR tumors were observed in both younger (<50 years) and older (≥60 years) patients, the GTCs were enriched in younger individuals. Evaluation of mismatch repair status in an independent cohort confirmed the high rate of GTCs in patients with young-onset CRC. The low detection rate of LS demonstrated in this study questions the implementation of routine universal screening in regions with low prevalence of LS. Considering the enrichment of GTCs in young-onset CRCs, age-restricted strategies may be simple and efficient practical alternatives to universal screening in the real world.

Cost-effectiveness of prophylactic hysterectomy in first-degree female relatives with Lynch syndrome of patients diagnosed with colorectal cancer in the United States: a microsimulation study

Background

To evaluate the cost‐effectiveness of prophylactic hysterectomy (PH) in women with Lynch syndrome (LS).

Methods

We developed a microsimulation model incorporating the natural history for the development of hyperplasia with and without atypia into endometrial cancer (EC) based on the MISCAN‐framework. We simulated women identified as first‐degree relatives (FDR) with LS of colorectal cancer patients after universal testing for LS. We estimated costs and benefits of offering this cohort PH, accounting for reduced quality of life after PH and for having EC. Three minimum ages (30/35/40) and three maximum ages (70/75/80) were compared to no PH.

Results

In the absence of PH, the estimated number of EC cases was 300 per 1,000 women with LS. Total associated costs for treatment of EC were $5.9 million. Offering PH to FDRs aged 40–80 years was considered optimal. This strategy reduced the number of endometrial cancer cases to 5.4 (−98%), resulting in 516 quality‐adjusted life years (QALY) gained and increasing the costs (treatment of endometrial cancer and PH) to $15.0 million (+154%) per 1,000 women. PH from earlier ages was more costly and resulted in fewer QALYs, although this finding was sensitive to disutility for PH.

Conclusions

Offering PH to 40‐ to 80‐year‐old women with LS is expected to add 0.5 QALY per person at acceptable costs. Women may decide to have PH at a younger age, depending on their individual disutility for PH and premature menopause.

Gene-Specific Variation in Colorectal Cancer Surveillance Strategies for Lynch Syndrome

BACKGROUND AND AIMS

Lynch syndrome is associated with pathogenic variants in 4 mismatch repair (MMR) genes that increase lifetime risk of colorectal cancer. Guidelines recommend intensive colorectal cancer surveillance with colonoscopy every 1-2 years starting at age 25 years for all carriers of Lynch syndrome-associated variants, regardless of gene product. We constructed a simulation model to analyze the effects of different ages of colonoscopy initiation and surveillance intervals for each MMR gene (MLH1, MSH2, MSH6, and PMS2) on colorectal cancer incidence and mortality, quality-adjusted life-years, and cost.

METHODS

Using published literature, we developed a Markov simulation model of Lynch syndrome progression for patients with each MMR variant. The model simulated clinical trials of Lynch syndrome carriers, varying age of colonoscopy initiation (5-year increments from 25-40 years), and surveillance intervals (1-5 years). We assessed the optimal strategy for each gene, defined as the strategy with the highest quality-adjusted life-years and incremental cost-effectiveness ratio below a $100,000 willingness-to-pay threshold.

RESULTS

Optimal surveillance for patients with pathogenic variants in the MLH1 and MSH2 genes was colonoscopy starting at age 25 years, with 1- to 2-year surveillance intervals. Initiating colonoscopy at age 35 and 40 years, with 3-year intervals, was cost-effective for patients with pathogenic variants in MSH6 or PMS2, respectively.

CONCLUSIONS

We developed a simulation model to select optimal surveillance starting ages and intervals for patients with Lynch syndrome based on MMR variant. The model supports recommendations for intensive surveillance of patients with Lynch syndrome-associated variants in MLH1 or MSH2. However, for patients with Lynch syndrome-associated variants of MSH6 or PMS2, later initiation of surveillance at 35 and 40 years, respectively, and at 3-year intervals, can be considered.

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.

Predictive and prognostic biomarkers with therapeutic targets in colorectal cancer: A 2021 update on current development, evidence, and recommendation

Although therapeutically actionable molecular alterations are widely distributed across many cancer types, only a handful of them show evidence of clinical utility and are recommended for routine clinical practice in the management of cancers of colon and rectum (CRC). This 2021 update aims to provide a succinct summary on the use of prognostic and/or predictive biomarkers (expanded RAS, BRAF, microsatellite-high [MSI-H] or deficient mismatch repair [dMMR], neurotrophic tyrosine receptor kinase [NTRK] fusion genes, and human epidermal growth factor receptor type II [HER2] gene amplification) associated with CRC. Therapeutic implications of each relevant predictive or prognostic biomarker for patients with CRC are described, along with discussion on new developments on (1) biomarker-driven therapies such as testing of BRAF, MLH1 promoter methylation and MMR germline genes in differentiating sporadic CRC or hereditary conditions such as Lynch syndrome; (2) first-line use of immune checkpoint inhibitors in metastatic CRC; (3) risk stratification and therapy selection based on primary tumor location (left-sided vs. right-sided colon cancer); (3) atypical BRAF mutations; (4) use of EGFR directed therapy in the perioperative oligometastatic disease setting; (5) re-challenge of EGFR directed therapy and (6) personalizing therapy of fluoropyrimidine and irinotecan based on new evidence in pharmacogenomic testing. Data are collected and analyzed from available systematic reviews and meta-analyses of treatments with known therapeutic targets in CRC, which may be associated with predictive and/or prognostic biomarkers. Discussions are presented in an application-based format, with goal to empower pharmacists or other clinicians to gain awareness and understanding in biomarker-driven cancer therapy issues.

Historical review of Lynch syndrome

Lynch syndrome was formerly known as Hereditary Nonpolyposis Colorectal Cancer. Currently, these two nomenclatures each have their unique definitions and are no longer used interchangeably. The history of hereditary nonpolyposis colorectal cancer was first recognized formally in the literature by Henry Lynch in 1967. With advances of molecular genetics, there has been a transformation from clinical phenotype to genotype diagnostics. This has led to the ability to diagnose affected patients before they manifest with cancer, and therefore allow preventative surveillance strategies. Genotype diagnostics has shown a difference in penetrance of different cancer risks dependent on the gene containing the mutation. Surgery is recommended as prevention for some cancers; for others they are reserved for once cancer is noted. Various surveillance strategies are recommended dependent on the relative risk of cancer and the ability to intervene with surgery to impact on survival. Risk reduction through aspirin has shown some recent promise, and continues to be studied.

Comparison of Universal Genetic Testing vs Guideline-Directed Targeted Testing for Patients With Hereditary Cancer Syndrome

IMPORTANCE

Hereditary factors play a key role in the risk of developing several cancers. Identification of a germline predisposition can have important implications for treatment decisions, risk-reducing interventions, cancer screening, and germline testing.

OBJECTIVE

To examine the prevalence of pathogenic germline variants (PGVs) in patients with cancer using a universal testing approach compared with targeted testing based on clinical guidelines and the uptake of cascade family variant testing (FVT).

DESIGN, SETTING, AND PARTICIPANTS

This prospective, multicenter cohort study assessed germline genetic alterations among patients with solid tumor cancer receiving care at Mayo Clinic cancer centers and a community practice between April 1, 2018, and March 31, 2020. Patients were not selected based on cancer type, disease stage, family history of cancer, ethnicity, or age.

EXPOSURES

Germline sequencing using a greater than 80-gene next-generation sequencing platform.

MAIN OUTCOMES AND MEASURES

Proportion of PGVs detected with a universal strategy compared with a guideline-directed approach and uptake of cascade FVT in families.

RESULTS

A total of 2984 patients (mean [SD] age, 61.4 [12.2] years; 1582 [53.0%] male) were studied. Pathogenic germline variants were found in 397 patients (13.3%), including 282 moderate- and high-penetrance cancer susceptibility genes. Variants of uncertain significance were found in 1415 patients (47.4%). A total of 192 patients (6.4%) had incremental clinically actionable findings that would not have been detected by phenotype or family history-based testing criteria. Of those with a high-penetrance PGV, 42 patients (28.2%) had modifications in their treatment based on the finding. Only younger age of diagnosis was associated with presence of PGV. Only 70 patients (17.6%) with PGVs had family members undergoing no-cost cascade FVT.

CONCLUSIONS AND RELEVANCE

This prospective, multicenter cohort study found that universal multigene panel testing among patients with solid tumor cancer was associated with an increased detection of heritable variants over the predicted yield of targeted testing based on guidelines. Nearly 30% of patients with high-penetrance variants had modifications in their treatment. Uptake of cascade FVT was low despite being offered at no cost.

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.

Mismatch Repair Universal Screening of Endometrial Cancers (MUSE) in a Canadian Cohort

Background: Approximately 2–6% of endometrial cancers (ECs) are due to Lynch Syndrome (LS), a cancer predisposition syndrome caused by germline pathogenic variants (PVs) affecting the DNA mismatch repair (MMR) pathway. Increasingly, universal tissue-based screening of ECs has been proposed as an efficient and cost-effective way to identify families with LS, though few studies have been published on Canadian cohorts. The purpose of this study was to evaluate the feasibility and overall performance of a universal immunohistochemistry (IHC) screening program for women with EC within a single Canadian university hospital centre. Methods and Results: From 1 October 2015 to 31 December 2017, all newly diagnosed ECs (n = 261) at our centre were screened for MMR protein deficiency by IHC. MMR deficiency was noted in 69 tumours (26.4%), among which 53 had somatic MLH1 promoter hypermethylation and were considered “screen-negative”. The remaining MMR-deficient cases (n = 16) were considered “screen-positive” and were referred for genetic counselling and testing. Germline PVs were identified in 12/16 (75%). One additional PV was identified in a screen-negative individual who was independently referred to the Genetics service. This corresponds to an overall LS frequency of 5.0% among unselected women with EC, and 6.4% among women diagnosed under age 70 years. Our algorithm detected MMR gene pathogenic variants in 4.6% and 6.2% of unselected individuals and individuals under age 70 years, respectively. Four germline PVs (30.8%) were identified in individuals who did not meet any traditional LS screening criteria. Conclusions: Universal IHC screening for women with EC is an effective and feasible method of identifying individuals with LS in a Canadian context.

Is tumor testing efficiency for Lynch syndrome different in rectal and colon cancer?

BACKGROUND

Tumor testing utility in Lynch syndrome (LS) diagnosis is established.

AIMS

Analyze the differences between tumor testing efficiency in rectal (RC) and colon cancer (CC).

METHODS

We performed immunohistochemistry (IHC) for MisMatch Repair (MMR) proteins (IHC-MMR) and MicroSatellite Instability analysis (MSI) on 482 unselected primary tumors: 320 CCs and 162 RCs. Samples had proficient-IHC, deficient-IHC or borderline-IHC ("patchy" expression). MSI-H borderline-IHC tumors were considered as likely MMR-deficient. Germline testing was offered to MMR-deficient patients without BRAF mutation or MLH1 promoter hypermetilation (MLH1-Hy).

RESULTS

We identified 51/482 (10.6%) MMR-defective tumors. Multivariable analysis demonstrated a significant correlation between tumor testing results with histotype, lymph-node involvement and tumor location. In particular, RC showed a lower MMR-deficiency rate than CC (p<0.0001). Interestingly, MLH1 loss was detected in 0% RCs and 76.1% CCs, with 80% of them showing BRAF mutation/MLH1-Hy. A germline variant was detected in 12 out of 18 patients (mutation detection rate of 66.7%).

CONCLUSION

Tumor testing results showed molecular differences between CCs and RCs, in terms of MMR proteins expression, and presence of BRAF mutation/MLH1-Hy. MSH6 variants were the most frequent ones (50%). Although young age at diagnosis was associated with mutation detection (p = 0.045), 33.3% of LS patients were >50 years.

The health and economic impact of implementation strategies for improving detection of hereditary cancer patients—protocol for an in-depth cost-effectiveness evaluation with microsimulation modelling

Background

Patients with Lynch syndrome (an inherited cancer predisposition syndrome) remain largely underdiagnosed despite clinically and cost-effective testing strategies to detect patients. This is largely due to poor referral rates for high-risk patients for consideration of genetic testing. Targeted approaches to improve the implementation of guidelines and thus uptake rates of genetic testing require the use of limited and valuable healthcare resources. Decision makers must carefully balance the potential health impacts of implementation approaches against the associated costs, similar to when assessing the direct impact of health interventions. This protocol outlines the methods used to conduct an economic evaluation of different implementation approaches aimed at improving referral rates of high-risk patients, including estimating implementation approach costs.

Methods

A cluster randomised controlled trial (the Hide and Seek Project, HaSP) is underway to compare two different implementation approaches aimed at improving referral rates, and thus detection, of Lynch syndrome among colorectal cancer patients across eight Australian hospital networks. An in-depth process evaluation is being conducted alongside the trial and includes measures to collect comprehensive data on both implementation and intervention costs. These costs, in addition to HaSP outcome data, will be incorporated as inputs into an existing microsimulation model—Policy1-Lynch—to project the downstream economic and health impacts and determine the more cost-effective implementation approach from the Australian healthcare perspective.

Discussion

The ability to model the impact of different implementation approaches will enable the most efficient way of improving Lynch syndrome detection. The approach used in this study could also be applied to assess other implementation approaches aimed at increasing the uptake of cost-effective health interventions.

Trial registration

ANZCTR, ACTRN12618001072202. Registered on 27 June 2018.

Universal tumor screening for lynch syndrome: perspectives of patients regarding willingness and informed consent

Aim: Lynch Syndrome is associated with a significant risk of colorectal carcinoma (CRC) and other cancers. Universal tumor screening is a strategy to identify high-risk individuals by testing all CRC tumors for molecular features suggestive of Lynch Syndrome. Patient interest in screening and preferences for consent have been underexplored. Methods: A postal survey was administered to CRC patients in a Canadian province. Results: Most patients (81.4%) were willing to have tumors tested if universal tumor screening were available and were willing to discuss test results with family members and healthcare professionals. The majority (62.6%) preferred informed consent be obtained prior to screening. Conclusion: Patients were supportive of universal screening. They expected consent to be obtained, contrary to current practice across Canada and elsewhere.

Shrestha T, Zilfalil BA. MLH1 and MSH2 mismatch repair protein profile using immunohistochemistry in Nepalese colorectal cancer patients

BACKGROUND Hereditary nonpolyposis colorectal cancer, or Lynch syndrome, caused by germline mutations or genetic defects in mismatch repair (MMR) genes (MLH1, MSH2, PMS2, MSH6, and epithelial cellular adhesion molecule), is an autosomal dominant condition accounting for 2–5% of all colorectal carcinomas (CRCs). Reports on MMR loss in many populations are available; however, there are no reports on the frequency of MMR protein expression in Nepalese cohorts. Therefore, this study was aimed to assess the expression profiles of MLH1 and MSH2 protein by immunohistochemistry (IHC) in Nepalese CRC patients. METHODS This retrospective study used archived formalin-fixed paraffin-embedded tissue blocks from 43 Nepalese CRC patients. IHC staining was performed using MLH1 and MSH2 antibodies. IHC scoring analysis was assessed using semiquantitative scoring. RESULTS Of the 43 CRC patients, 8 (18.6%) showed loss of staining for MLH1 antibody, 5 (11.6%) showed loss of staining for MSH2 antibody, and 4 (9.3%) showed loss of staining for both MLH1 and MSH2 antibodies. CONCLUSIONS IHC is a potential screening method of determining the MMR expression profile of Nepalese CRC patients. IHC can be performed in local clinical laboratories to find MMR protein defects in selected cases prior to expensive molecular tests.

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.

Mainstream consent programs for genetic counseling in cancer patients: A systematic review

As demand for germline genetic testing for cancer patients increases, novel methods of genetic counseling are required. One such method is the mainstream consent pathway, whereby a member of the oncology team (rather than a genetic specialist) is responsible for counseling, consenting, and arranging genetic testing for cancer patients. We systematically reviewed the literature for evidence evaluating mainstream pathways for patients with breast, ovarian, colorectal, and prostate cancer. Medline, EMBASE, and Cochrane Library were searched for studies that met inclusion and exclusion criteria. Article references were checked for additional studies. Trial databases were searched for ongoing studies. Of the 13 papers that met inclusion criteria, 11 individual study groups were identified (two study groups had two publications each). Ten of the 11 studies evaluated the acceptability, feasibility, and impact of BRCA testing for patients and/or clinicians in different clinical settings in breast and ovarian cancer, while the final study explored the attitudes of colorectal specialists toward genetic testing for colorectal cancer. None involved prostate cancer. Overall, mainstream pathways were acceptable and feasible. Medical oncologist- and nurse-driven pathways were particularly successful, with both patients and clinicians satisfied with this process. Although the content of pretest counseling was less consistent compared with counseling via the traditional model, patients were largely satisfied with the education they received. Further research is required to evaluate the mainstream pathway for men with prostate cancer.

Addressing perceived economic obstacles to genetic testing as a way to mitigate disparities in family health history for adoptees

In this paper, we ask whether or not we can afford to realize the potential benefits of genetic testing as a screening tool for adoptees. Our method is to provide reasonable cost and savings estimates. We argue that the prospect of cost neutrality should be sufficient to explore the targeted screening for a population who will otherwise suffer an avoidable health disparity in access to inherited disease information. Our goal here is to establish that the investment needed to attain these benefits is not beyond our means.

Effective Identification of Lynch Syndrome in Gastroenterology Practice

Purpose of review:

Identification of Lynch syndrome is important from an individual patient and public health standpoint. As paradigms for Lynch syndrome diagnosis have shifted in recent years, this review will discuss rationale and limitations for current strategies as well as provide an overview of future directions in the field.

Recent findings:

In recent years, the use of clinical criteria and risk scores for identification of Lynch syndrome have been augmented by universal testing of all newly diagnosed colorectal cancers with molecular methods to screen for mismatch repair deficiency with high sensitivity and specificity. Studies of implementation and outcomes of universal testing in clinical practice have demonstrated significant heterogeneity that results in suboptimal uptake and contributes to disparities in diagnosis. Emerging technologies, such as next-generation sequencing, hold significant promise as a screening strategy for Lynch syndrome.

Summary:

Universal testing for Lynch syndrome is being performed with increasing frequency, although real-world outcomes have demonstrated room for improvement. Future directions in Lynch syndrome diagnosis will involve optimization of universal testing workflow and application of new genetics technologies.

Impact of free cancer predisposition cascade genetic testing on uptake in Singapore

Cascade testing for cancer predisposition offers a highly efficient and cost-effective method for identifying individuals at increased risk for cancer, in whom targeted interventions can often improve survival. The aim of this study was to determine the impact of free cascade testing on uptake and identify other associated factors. Demographic and clinical data were gathered prospectively for 183 probands found to have a pathogenic variant associated with cancer predisposition and their 826 first-degree relatives (FDRs). The provision of free cascade testing was significantly associated with uptake (21.6% vs 6.1%; χ ², P < 0.001). Relationship type between FDR and proband and FDR age also demonstrated significant associations, suggesting greater engagement amongst younger generations. Overall, 29.0% (53/183) of families had at least 1 FDR who underwent cascade testing. Of these families, 67.9% (36/53) had an uptake rate of at least 40.0%. Cost is a significant barrier to cascade testing uptake in Singapore. Tailored interventions targeting underrepresented groups and genetic counseling approaches supporting family communication and decision-making are necessary.

NCCN Guidelines Insights: Genetic/Familial High-Risk Assessment: Colorectal, Version 2.2019

Identifying individuals with hereditary syndromes allows for improved cancer surveillance, risk reduction, and optimized management. Establishing criteria for assessment allows for the identification of individuals who are carriers of pathogenic genetic variants. The NCCN Guidelines for Genetic/Familial High-Risk Assessment: Colorectal provide recommendations for the assessment and management of patients with high-risk colorectal cancer syndromes. These NCCN Guidelines Insights focus on criteria for the evaluation of Lynch syndrome and considerations for use of multigene testing in the assessment of hereditary colorectal cancer syndromes.

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.

Consideration for Employer-Based and Geographic Attributes Included in Value Assessment Methods of Next-Generation Sequencing Tests

There is a need for formal cost-effectiveness evidence to better model the real-world payer decision context in which general economic models are currently being used, specifically regarding clinical genomics health services (for next-generation sequencing (NGS) tests). We reviewed literature focused on cost-effectiveness studies after completion of the Human Genome Project within the Tufts Cost-Effectiveness Analysis (CEA) Registry and found that only 33% of eligible studies were conducted from the U.S. payer perspective. Additional interpretation challenges include economic models that do not account for true payer-negotiated costs, limits in internal expertise for quality-adjusted life-year inferences, and limited internal policies to use CEA research in decision making. This Viewpoints article highlights numerous opportunities to increase the translational effect of economic modeling work. Specifically, geographically relevant cost and outcomes data should be considered for integration within best practices for economic evaluations of NGS tests. Such data integration may provide more informed decision making regarding the allocation of constrained resources for health care services and technology. DISCLOSURES: No outside funding supported the writing of this article. Hart is supported by an unrestricted gift from Pfizer, which played no role in the study referred to in this article. The authors have no conflicts of interest to report.

Universal tumor screening for Lynch syndrome: perspectives of Canadian pathologists and genetic counselors

Universal screening of all newly diagnosed colorectal cancer tumors can identify individuals at high risk for Lynch syndrome (LS), a hereditary cancer syndrome predisposing carriers to increased risk of colorectal, endometrial, and other cancers. To inform planning of a universal tumor screening program for LS in our jurisdiction, we undertook online surveys of Canadian pathologists and genetic counselors to describe existing tumor screening programs. Online surveys were hosted on SurveyMonkey between October 2016 and March 2017. Fifty-three pathologists and 66 genetic counselors completed surveys (total n = 119). While attitudes towards tumor screening were positive, considerable variability was observed in the existence of tumor screening, test ordering criteria, and practices. Most respondents indicated consent was not obtained for tumor screening nor were educational materials provided to patients; however, opting out of additional mutation testing in the event of a positive tumor screen was endorsed. Results add to the growing literature on providers' perspectives on population-based tumor screening programs and inform ways to offer these. Findings highlight the need to develop methods of patient education that allow meaningful opt-out decisions. The variability we observed also suggests the need for national standards and guidance on tumor screening for LS.

Microsatellite instability in endometrial cancer: New purpose for an old test

Historically, microsatellite instability testing has been used to identify endometrial cancer patients with Lynch Syndrome. Now, it is also being used to identify those who may be immunotherapy candidates.

Universal tumor screening for Lynch syndrome: Perceptions of Canadian pathologists and genetic counselors of barriers and facilitators

BACKGROUND

People at risk of developing hereditary cancers associated with Lynch Syndrome (LS) can be identified through universal screening of colorectal tumors. However, tumor screening practices are variable across Canada and few studies explore the perspectives of genetic counselors and pathologists about tumor screening. This study was conducted to better understand the barriers and facilitators of implementing universal tumor screening in health centers across Canada.

METHODS

An online survey about tumor screening programs was administered to genetic counselors and pathologists across Canada through communication channels of professional organizations. It was hosted on SurveyMonkey and accessible from October 2016 to March 2017.

RESULTS

Barriers to tumor screening included a lack of sustainable resources, including funding and genetic counselors. Respondents strongly identified the need for a coordinated, interdisciplinary approach to program planning with the "right people at the table." Respondents currently with a screening program provided advice such as carefully designing the program structure, developing patient and family follow-up protocols, and ensuring adequate resources (funding, staff, training for providers) were available prior to program initiation.

CONCLUSION

There is no national approach to universal tumor screening in Canada. However, future efforts can be informed by the experiences of those centers that have already created a universal tumor screening program for LS. These data suggest the need for an interdisciplinary approach, initial and sustained funding, and careful advanced planning of program structures and policies.

The nonsense mutation MSH2 c.2152C>T shows a founder effect in Portuguese Lynch syndrome families

The mutational spectrum of the MMR genes is highly heterogeneous, but specific mutations are observed at high frequencies in well-defined populations or ethnic groups, due to founder effects. The MSH2 mutation c.2152C>T, p.(Gln718*), has occasionally been described in Lynch families worldwide, including in Portuguese Lynch syndrome families. During genetic testing for Lynch syndrome at the Portuguese Oncology Institutes of Porto and Lisbon, this mutation was identified in 28 seemingly unrelated families. In order to evaluate if this alteration is a founder mutation, haplotype analysis using microsatellite and SNP markers flanking the MSH2 gene was performed in the 28 probands and 87 family members. Additionally, the geographic origin of these families was evaluated and the age of the mutation estimated. Twelve different haplotypes were phased for 13 out of the 28 families and shared a conserved region of ∼3.6 Mb. Based on the mutation and recombination events observed in the microsatellite haplotypes and assuming a generation time of 25 years, the age estimate for the MSH2 mutation was 273 ± 64 years. The geographic origins of these families were mostly from the Northern region of Portugal. Concluding, these results suggest that the MSH2 c.2152C>T alteration is a founder mutation in Portugal with a relatively recent origin. Furthermore, its high proportion indicates that screening for this mutation as a first step, together with the previously reported Portuguese founder mutations, may be cost-effective in genetic testing of Lynch syndrome suspects of Portuguese ancestry.

The Healthcare Systems Research Network (HCSRN) as an Environment for Dissemination and Implementation Research: A Case Study of Developing a Multi-Site Research Study in Precision Medicine

CONTEXT

In existence for nearly 25 years, the Healthcare Systems Research Network (HCSRN) is an established and sustainable network of health care systems that serves as a "real world" laboratory to enable the integration of research findings into practice. The objective of this paper is to demonstrate how the HCSRN serves as an ideal environment for studying dissemination and implementation of evidence-based practices into health care systems through the example of developing a multi-site study on the implementation of evidence-based precision medicine practices.

CASE DESCRIPTION

The "Implementing Universal Lynch Syndrome Screening (IMPULSS)" study (NIH R01CA211723) involves seven HCSRN health care systems and two external health care systems. The IMPULSS study will describe and explain organizational variability around Lynch syndrome (LS) screening to identify which factors in different organizational contexts are important for successful implementation of LS screening programs and will create a toolkit to facilitate organizational decision making around implementation and improvement of precision medicine programs in health care systems.

MAJOR THEMES

The strengths of the HCSRN that facilitate D&I research include: 1) a culture of collaboration, 2) standardization of data and processes across systems, and 3) researchers embedded in diverse health care systems. We describe how these strengths contributed to developing the IMPULSS study.

CONCLUSION

Given the importance of conducting research in real world settings to improve patient outcomes, the unique strengths of the HCSRN are of vital importance. The IMPULSS study is one case example of how the strengths of the HCSRN make it an excellent environment for research on implementing evidence-based precision medicine practices in health care systems.