Screening for mismatch repair deficiency in colorectal cancer: data from three academic medical centers

A registry-based study on universal screening for defective mismatch repair in colorectal cancer in Denmark highlights disparities in screening uptake and counselling referrals

Universal screening for defective mismatch repair (dMMR) in colorectal cancer utilizes immunohistochemical staining for MLH1, MSH2, MSH6 and PSM2. Additionally, BRAF V600E mutations status and MLH1 hypermethylation should be performed to distinguish germline and somatic dMMR alterations. A decade of Danish population-based registries has been analysed regarding screening uptake, detection rate and referral to genetic counselling. MMR testing was performed in 71·8% (N = 34,664) of newly diagnosed colorectal cancers with an increasing trend to 88·8% coverage in the study's final year. The likelihood of undergoing MMR testing was reduced in males with 2% (95% CI 0·4-2·7, p = 0·008), with 4·1% in patients above age 70 years (95% CI 1·5-6·6, p = 0·003) compared in patients below age 51 years, with 16·3% in rectal cancers (95% CI 15·1-17·6, p < 0·001) and 1·4% left-sided colon cancers (95% CI 0·1-1·7, p = 0·03) compared to right-sided colon cancers. Tumour stage II and III increased the likelihood of being tested, with 3·7% for stage II (95% CI 2·2-5·6, p < 0·001) and 3·3% for stage III tumours (95% CI 1·8-4·8, p < 0·001) compared to stage I tumours, whereas the likelihood for stage IV tumours is reduced by 35·7% (95% CI 34·2-37·2, p < 0·001). Test rates significantly differed between the Danish health care regions. dMMR was identified in 15·1% (95% CI 14·8-15·6, p < 0·001) cases with somatic MMR inactivation in 6·7% of the cases. 8·3% tumours showed hereditary dMMR expression patterns, and 20·0% of those were referred to genetic counselling. Despite the high uptake rates, we found disparities between patient groups and missed opportunities for genetic diagnostics.

Prevalence and characteristics of patients with upper urinary tract urothelial carcinoma having potential Lynch syndrome identified by immunohistochemical universal screening and Amsterdam criteria II

BACKGROUND

This study aimed to identify patients with upper urinary tract urothelial carcinoma (UTUC) having potential Lynch syndrome (pLS) by immunohistochemistry (IHC) of DNA mismatch repair gene-related proteins (MMRPs) and Amsterdam criteria II and explore their clinical characteristics.

METHODS

We retrospectively collected the clinical data of 150 consecutive patients with UTUC who underwent surgical resection at our institution between February 2012 and December 2020, and immunohistochemistry (IHC) of four MMRPs (MLH1, MSH2, MSH6, and PMS2) on all UTUC specimens was performed. Patients who tested positive for Amsterdam criteria (AMS) II and/or IHC screening were classified as having pLS and others as non-pLS, and their characteristics were explored.

RESULTS

In this study, 5 (3%) and 6 (4%) patients were positive for AMS II and IHC screening, respectively. Two patient were positive for both AMS II and IHC screening, resulting in 9 (6%) patients with pLS. The pLS group was predominantly female (67% vs. 36%; p = 0.0093) and had more right-sided tumors (100% vs. 43%; p = 0.0009) than the non-pLS group. Of the 6 patients who were positive for IHC screening, 4 showed a combined loss of MSH2/MSH6 (n = 3) and MLH1/PMS2 (n = 1). Other two patients showed single loss of MSH6 and PSM2.

CONCLUSIONS

AMS II and IHC screening identified pLS in 6% of patients with UTUC. The IHC screening-positive group tends to have relatively high rate of combined loss, but some patients have single loss. AMS II may overlook patients with LS, and a universal screening may be required for patients with UTUC as well as those with colorectal and endometrial cancer.

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 Canadian Provincial Screening Program for Lynch Syndrome

INTRODUCTION

Manitoba implemented the first Canadian provincial program of reflex screening through mismatch repair immunohistochemistry (MMR-IHC) for all colorectal cancers diagnosed at age 70 years or younger in December 2017. We evaluated compliance to universal reflex testing and for referrals to Genetics for individuals with MMR-deficient tumors.

METHODS

We searched the provincial pathology database with "adenocarcinoma" in the colorectal specimen pathology reports between March 2018 and December 2020. We cross-referenced with paper and electronic records in the Program of Genetics and Metabolism to determine whether patients with MMR-deficient tumors had been referred for Genetic assessment and what proportion of patients and first-degree relatives accepted an appointment and genetic testing. We performed logistic regression analysis to identify predictors of testing.

RESULTS

We identified 3,146 colorectal adenocarcinoma specimens (biopsies and surgical resections) from 1,692 unique individuals (mean age 68.66 years, male 57%). Of those aged 70 years or younger (n = 936), 89.4% received MMR-IHC screening. Individual pathologists (categorized by the highest, average, and lowest screening rates) were the biggest predictors of MMR-IHC screening on multivariable analysis (highest vs lowest: odds ratio 17.5, 95% confidence interval 6.05-50.67). While only 53.4% (n = 31) of 58 screen-positive cases were referred by pathologists for genetic assessment, other clinicians referred an additional 22.4% (n = 13), resulting in 75.8% overall referral rate of screen-positive cases. Thirteen (1.4%) patients (1.1%, aged 70 years or younger) were confirmed to experience Lynch syndrome through germline testing, and 8 first-degree relatives (an average of 1.6 per patient) underwent cascade genetic testing.

DISCUSSION

The first Canadian Lynch syndrome screening program has achieved high rates of reflex testing.

Lynch Syndrome: From Carcinogenesis to Prevention Interventions

Simple Summary

Promoting proper preventive interventions to reduce morbidity and mortality is one of the most important challenges pertaining to inherited conditions. Lynch syndrome (LS) is an inherited disorder that predisposes to several kinds of tumor and is responsible for a relevant proportion of human colorectal and endometrial cancers. Recent knowledge has allowed for a better understanding of the genetic cause, pathogenesis, underlying immunological mechanisms, epidemiological distribution, and prevalence of this disease. This opens up unpredictable perspectives of translating such knowledge into validated programs for prevention and surveillance, in order to reduce the health impact of this disease through medical interventions before cancer development. In our review, we summarize the updated guidelines of the screening, surveillance, and risk-reducing strategies for LS patients. Moreover, we present novel opportunities in the treatment and prevention of LS patients through harnessing the immune system using immunocheckpoint inhibitors and vaccines.

Abstract

Lynch syndrome (LS) is the most common inherited disorder responsible for an increased risk of developing cancers at different sites, most frequently in the gastrointestinal and genitourinary tracts, caused by a germline pathogenic variant affecting the DNA mismatch repair system. Surveillance and risk-reducing procedures are currently available and warranted for LS patients, depending on underlying germline mutation, and are focused on relevant targets for early cancer diagnosis or primary prevention. Although pharmacological approaches for preventing LS-associated cancer development were started many years ago, to date, aspirin remains the most studied drug intervention and the only one suggested by the main surveillance guidelines, despite the conflicting findings. Furthermore, we also note that remarkable advances in anticancer drug discovery have given a significant boost to the application of novel immunological strategies such as immunocheckpoint inhibitors and vaccines, not only for cancer treatment, but also in a preventive setting. In this review, we outline the clinical, biologic, genetic, and morphological features of LS as well as the recent three-pathways carcinogenesis model. Furthermore, we provide an update on the dedicated screening, surveillance, and risk-reducing strategies for LS patients and describe emerging opportunities of harnessing the immune system.

Worldwide prevalence of Lynch syndrome in patients with colorectal cancer: Systematic review and meta-analysis

PURPOSE

Lynch syndrome (LS) is the most common hereditary colorectal cancer (CRC) syndrome, with an estimated prevalence of 2% to 3% of CRC. A prevalence study is needed to provide accurate estimates of the true prevalence of LS.

METHODS

MEDLINE (Ovid), Embase, and Web of Science were searched. Prevalence was calculated by random effects meta-analysis models. I² score was used to assess heterogeneity across studies. Meta-regression was performed for between-study variance.

RESULTS

A total of 51 studies were included in this review. The overall pooled yield of LS screening was 2.2% based on all methods of detection. Studies performing germline tests on all participants with CRC reported higher prevalence (5.1%) as opposed to studies only performing germline tests on participants with tumors with mismatch repair deficiency (1.6%) or microsatellite instability (1.1%). Selected cohorts of CRC had a higher prevalence of germline LS diagnoses.

CONCLUSION

LS prevalence across multiple ethnic, geographic, and clinical populations is remarkably similar. Universal germline testing of patients presenting with cancer identifies that most CRCs are attributed to LS. Young patients presenting with CRC and those who fulfill criteria for a familial risk provide the highest returns for LS identification. Our study supports the universal germline CRC screening for LS.

Identifying patients with Lynch syndrome using a universal tumor screening program in an integrated healthcare system

INTRODUCTION

Lynch syndrome (LS) is associated with an increased risk of colorectal (CRC) and endometrial (EC) cancers. Universal tumor screening (UTS) of all individuals diagnosed with CRC and EC is recommended to increase identification of LS. Kaiser Permanente Northwest (KPNW) implemented a UTS program for LS among individuals newly diagnosed with CRC in January 2016 and EC in November 2016. UTS at KPNW begins with immunohistochemistry (IHC) of tumor tissue to determine loss of mismatch repair proteins associated with LS (MLH1, MSH2, MSH6, and PMS2)., IHC showing loss of MLH1 is followed by reflex testing (automatic testing) to detect the presence of the BRAF V600E variant (in cases of CRC) and MLH1 promoter hypermethylation to rule out likely sporadic cases.

MATERIALS AND METHODS

Individuals newly diagnosed with CRC and EC were identified between the initiation of the respective UTS programs and July 2018. Electronic medical records were reviewed to extract patient data related to UTS, including IHC and reflex testing results, date of referrals to the genetics department, and results of germline genetic testing for LS.

RESULTS

313 out of 362 individuals diagnosed with CRC and 61 out of 64 individuals diagnosed with EC who were eligible were screened by IHC for LS. Most (47/52 or 90%, including 46/49 CRC and 1/3 EC) individuals that were not screened by IHC only had a biopsy sample available. Fourteen individuals (3.7% overall, including 13/313 CRC and 1/61 EC) received an abnormal result after reflex testing and were referred for genetic counseling. Of these, 10 individuals (71% overall, including 9/13 CRC and 1/1 EC) underwent germline genetic testing for LS. Five individuals diagnosed with CRC were found to have pathogenic variants. in PMS2 (n = 3), MLH1 (n = 1), and MSH6 (n = 1). No pathogenic variants were identified in individuals diagnosed with EC.

CONCLUSIONS

UTS identified individuals at risk for LS. Most individuals who screened positive for LS had follow-up germline genetic testing for LS. The consistent use of biopsy samples is an opportunity to improve UTS.

Identification of Lynch syndrome-associated DNA mismatch repair-deficient bladder cancer in a Japanese hospital-based population

BACKGROUND

The prevalence of Lynch syndrome (LS)-associated DNA mismatch repair (MMR)-deficient bladder cancer (BC) has scarcely been investigated.

METHODS

Immunohistochemistry for four MMR proteins (MLH1, MSH2, MSH6, and PMS2) was performed in formalin-fixed paraffin-embedded (FFPE) sections prepared from the resected specimens of 618 consecutive newly diagnosed BC cases. Genetic/epigenetic analyses were performed in patients displaying the loss of any MMR proteins in the tumor.

RESULTS

Of the 618 patients, 9 (1.5%) showed the loss of MMR protein expression via immunohistochemistry; specifically, 3, 3, 2, and 1 patients displayed the loss of MLH1/PMS2, PMS2, MSH6, and MSH2/MSH6, respectively. All nine patients were male with a median age of 68 years (63-79 years). One had been previously diagnosed as having LS with an MSH2 variant. Genetic testing demonstrated the presence of a pathogenic PMS2 variant (n = 1), a variant of uncertain significance in MSH2 (n = 1), and no pathogenic germline variants of the MMR genes (n = 1). One patient with MSH6-deficient BC did not complete the genetic testing because of severe degradation of DNA extracted from the FFPE specimen, but the patient was strongly suspected to have LS because of their history of colon cancer and MSH6-deficient upper urinary tract cancer. There remained a possibility that the remaining four patients who refused genetic testing had LS.

CONCLUSIONS

The prevalence of LS-associated MMR-deficient BC was estimated to be 0.6-1.1% among unselected BC cases.

Comparison of universal screening in major lynch-associated tumors: a systematic review of literature

Lynch syndrome (LS) is associated with an increased lifetime risk of several cancers including colorectal (CRC), endometrial (EC), ovarian (OC), urinary (UT) and sebaceous tumors (ST). The benefit for universal screening in CRC and EC is well known. However, this benefit in other major lynch-associated tumors is unclear. We performed a systematic review of all published articles in the MEDLINE database between 2005 to 2017 to identify studies performing universal screening for LS in unselected CRC, EC, OC, UT and ST. All cases with MSI-H (instability in two or more markers) or missing one or more proteins on IHC testing were considered screening positive. Cases with MLH1 promoter hypermethylation or BRAF mutation positive were considered to have somatic mutations. A total of 3788 articles were identified in MEDLINE yielding 129 study arms from 113 studies. The overall pooled yield of universal LS screening and germline mismatch gene mutation was significantly different across the major LS-associated tumors (Mann Whitney test, p < 0.001). The pooled screening yield was highest in ST [52.5% (355/676), 95% CI 48.74-56.26%] followed by EC [22.65% (1142/5041), 95% CI 21.54-23.86%], CRC [11.9% (5649/47,545), 95% CI 11.61-12.19%], OC [11.29% (320/2833), 95% CI 10.13-12.47%] and UT [11.2% (31/276), 95% CI 7.48-14.92%]. ST also had the highest pooled germline positivity for mismatch repair gene mutation [18.8%, 33/176, 95%CI 13.03-24.57], followed by EC [2.6% (97/3765), 95% CI 2.09-3.11], CRC [1.8% (682/37,220), 95% CI 1.66-1.94%], UT [1.8%(3/164), 95% CI - 0.24-3.83%] and OC [0.83%(25/2983), 95% CI 0.48-1.12%]. LS screening in EC yielded significantly higher somatic mutations compared to CRC [pooled percentage 16.94% [(538/3176), 95%CI 15.60-18.20%] vs. 5.23% [(1639/26,152), 95% CI 4.93-5.47%], Mann Whitney test, p < 0.0001. Universal LS testing should be routinely performed in OC, UT and STs in addition to CRC and EC. Our findings also support consideration for IHC and somatic mutation testing before germline testing in EC due to higher prevalence of somatic mutations as well as germline testing in all patients with ST. Our results have implications for future design of LS screening programs and further studies are needed to assess the cost effectiveness and burden on genetic counselling services with expanded universal testing for LS.

Lynch Syndrome: Its Impact on Urothelial Carcinoma

Lynch syndrome, known as hereditary nonpolyposis colorectal cancer (HNPCC), is an autosomal-dominant familial cancer syndrome with an increased risk for urothelial cancer (UC). Mismatch repair (MMR) deficiency, due to pathogenic variants in MLH1, MSH2, MSH6, and PMS2, and microsatellite instability, are known for development of Lynch syndrome (LS) associated carcinogenesis. UC is the third most common cancer type in LS-associated tumors. The diversity of germline variants in the affected MMR genes and their following subsequent function loss might be responsible for the variation in cancer risk, suggesting an increased risk of developing UC in MSH2 mutation carriers. In this review, we will focus on LS-associated UC of the upper urinary tract (UUT) and bladder, their germline profiles, and outcomes compared to sporadic UC, the impact of genetic testing, as well as urological follow-up strategies in LS. In addition, we present a case of metastatic LS-associated UC of the UUT and bladder, achieving complete response during checkpoint inhibition since more than 2 years.

Impact of routine mismatch repair screening on genetic counseling and surgical management in colorectal cancer patients

BACKGROUND

Mismatch repair (MMR) deficiency in colorectal cancer (CRC) should prompt consideration of genetic counseling (GC) as a Lynch syndrome (LS) diagnosis may have several implications for the patient and family. The study aims were to examine how routine MMR testing influences the rate of GC and surgical resection extent.

METHODS

A single-institution retrospective review was performed on CRC specimens (including colonoscopic biopsies) routinely screened for MMR deficiency from 2012 to 2018. MLH1-deficient cancers with mutated BRAF or MLH1-promoter hypermethylation were excluded.

RESULTS

MMR deficiency was identified in 295 of 1139 CRC specimens. After exclusions, 57 patients remained. Forty-two patients (74%) were identified preoperatively, and 35 (83%) were referred to GC: 16 were seen preoperatively, 9 postoperatively. Eight patients were diagnosed with Lynch syndrome (LS) preoperatively: 2 had no resection, 2 underwent segmental resection and 4 underwent extended resection.

CONCLUSIONS

Most MMR-deficient patients were identified and referred to GC preoperatively, though not all were seen. Of the preoperatively diagnosed LS patients, half underwent extended resection. Barriers to GC and decision-making around resection extent bears further study.

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.

Frequency and coexistence of KRAS, NRAS, BRAF and PIK3CA mutations and occurrence of MMR deficiency in Danish colorectal cancer patients

The MAPK signalling genes KRAS, NRAS and BRAF and the PIK3CA gene are routinely investigated for mutations in the diagnostic routine of colorectal cancer. Few studies have reported co-existing mutations in these genes with clinical relevance, while some have been previously regarded as mutually exclusive. We set to investigate the frequency and co-occurrent mutations in these targets, and the occurrence of mismatch repair deficiency (dMMR) in a large cohort of Danish colorectal cancers. 1000 colorectal tumours were sequenced as part of our diagnostic workflow for KRAS, NRAS, BRAF and PIK3CA mutations using next-generation sequencing (NGS) and analysed by immunohistochemistry (IHC) for loss of the MMR proteins, MLH1, PMS2, MSH2 and MSH6. Co-existing mutations in 12 patients (1.2%) occurred as multiple mutations in the same gene or spread across several genes (KRAS, NRAS and/or BRAF). The frequency of single mutations in the genes occurred with a frequency similar to previously reported, except for a higher frequency of BRAF mutations (18.0%). We found dMMR in 14.6% of the cases with a majority lacking expression of both MLH1 and PMS2. BRAF mutations were only present in dMMR cases involving MLH1 and/or PMS2. Our findings suggest that co-existing mutations occur, except for the hotspot BRAF V600E, which is mutually exclusive with KRAS/NRAS mutations. Therefore, instead of single gene alterations from the MAPK signalling, assessing co-occurrence of mutations within one or more of those genes should also be accounted. This may impact future oncological treatments and should be considered in the diagnostic workflow.

Worldwide variation in lynch syndrome screening: case for universal screening in low colorectal cancer prevalence areas

To perform a systematic assessment of universal Lynch syndrome (LS) screening yield in colorectal cancer (CRC) patients around the world. Universal screening for LS is recommended in all CRC patients. However, the variation in yield of LS screening in the setting of significant global variation in CRC prevalence is unknown. A systematic review of articles in the MEDLINE database was performed to identify studies performing universal screening for LS. All cases with microsatellite instability (MSI-H) or missing one or more proteins on immunohistochemistry (IHC) were considered screening positive. The overall pooled yield of universal LS screening in 97 study arms from 89 identified studies was 11.9% (5649/47545) and the overall pooled percentage of confirmed LS patients was 1.8% (682/37220). LS screening positivity varied significantly based on geographic region (Kruskal Wallis test, p < 0.001) and reported 5-year CRC prevalence in the country (Fisher's exact, p < 0.001). Significant inverse correlation was found between LS screening positivity and 5-year CRC prevalence (Pearson correlation, r =  - 0.56, p < 0.001). The overall yield of LS screening was 15.00% (382/2553) and rate of confirmed LS was 7.7% (113/1475) in LS screening done in patients ≤ 50 years (16 studies). There is significant geographic variation in LS screening positivity with higher yield in countries with lower prevalence of CRC. Our results highlight the importance of universal LS screening in younger patients and low CRC prevalence countries.

Evaluating the impact of universal Lynch syndrome screening in a publicly funded healthcare system

PURPOSE

Referrals for Lynch syndrome (LS) assessment have traditionally been based on personal and family medical history. The introduction of universal screening practices has allowed for referrals based on immunohistochemistry tests for mismatch repair (MMR) protein expression. This study aims to characterize the effect of universal screening in a publicly funded healthcare system with comparison to patients referred by traditional criteria, from January 2012 to March 2017.

METHODS

Patient files from the time of initiation of universal screening from 2012 to 2017 were reviewed. Patients were sorted into two groups: (a) universally screened and (b) referred by traditional methods. Mutation detection rates, analysis of traditional testing criteria met, and cascade carrier testing were evaluated.

RESULTS

The mutation detection rate of the universal screening group was higher than the traditionally referred group (45/228 (19.7%) vs 50/390 (12.5%), P = .05), though each were able to identify unique patients. An analysis of testing criteria met by each patient showed that half of referred patients from the universal screening group could not meet any traditional testing criteria.

CONCLUSION

The implementation of universal screening in a publicly funded system will increase efficiency in detecting patients with LS. The resources available for genetic testing and counseling may be more limited in public systems, thus inclusion of secondary screening with BRAF and MLH1 promoter hypermethylation testing is key to further optimizing efficiency.

Understanding implementation success: protocol for an in-depth, mixed-methods process evaluation of a cluster randomised controlled trial testing methods to improve detection of Lynch syndrome in Australian hospitals

INTRODUCTION

In multisite intervention trials, implementation success often varies widely across settings. Process evaluations are crucial to interpreting trial outcomes and understanding contextual factors and causal chains necessary for successful implementation. Lynch syndrome is a hereditary cancer predisposition conferring an increased risk of colorectal, endometrial and other cancer types. Despite systematic screening protocols to identify Lynch syndrome, the condition remains largely underdiagnosed. The Hide and Seek Project ('HaSP') is a cluster randomised controlled trial determining the effectiveness of two approaches to improving Lynch syndrome detection at eight Australian hospital networks. To enhance widespread implementation of optimal Lynch syndrome identification, there is a need to understand not only what works, but also why, in what contexts, and at what costs. Here we describe an in-depth investigation of factors influencing successful implementation of procedures evaluated in the HaSP trial.

METHODS AND ANALYSIS

A mixed-methods, theory-driven process evaluation will be undertaken in parallel to the HaSP trial. Data will include: interviews of Implementation Leads and Lynch syndrome stakeholders, pre-post implementation questionnaires, audio analysis of meetings and focus groups, observation of multidisciplinary team meetings, fidelity checklists and project log analysis. Results will be triangulated and coded, drawing on the Theoretical Domains Framework, Consolidated Framework for Implementation Research and Proctor's implementation outcomes.

ETHICS AND DISSEMINATION

Use of a theory-based process evaluation will enhance interpretation and generalisability of HaSP trial findings, and contribute to the implementation research field by furthering understanding of the conditions necessary for implementation success. Ethical approval has been granted and results will be disseminated via publications in peer-reviewed journals and conference presentations. At trial completion, key findings will be fed back to sites to enable refinement of intervention strategies, both in the context of Lynch syndrome and for the possible generalisability of intervention components in other genetic and broader clinical specialties.

HASP TRIAL REGISTRATION NUMBER

Australian New Zealand Clinical Trials Registry (Identifier: ACTRN12618001072202). Registered 27 June 2018. http://www.ANZCTR.org.au/ACTRN12618001072202.aspx.

Prevalence of Lynch syndrome among patients with upper urinary tract carcinoma in a Japanese hospital-based population

BACKGROUND

The prevalence of Lynch syndrome and the use of universal tumor screening to identify Lynch syndrome among unselected patients with upper urinary tract urothelial carcinoma, which is associated with Lynch syndrome, have not been closely investigated yet.

METHODS

A total of 166 tumors from 164 upper urinary tract urothelial carcinoma patients were tested for microsatellite instability and expression of mismatch repair proteins (MLH1, MHS2, MSH6 and PMS2) by immunohistochemistry. Genetic testing was performed for patients suspected of having Lynch syndrome. Clinicopathological factors, including familial and personal cancer history associated with mismatch repair deficiency, were evaluated.

RESULTS

The frequency of high-level microsatellite instability and loss of at least one mismatch repair protein was 2.4% (4/164); the microsatellite instability and immunohistochemistry results showed complete concordance. Of these four patients, three were genetically proven to have Lynch syndrome, while the remaining one was highly suggestive for Lynch syndrome based on their personal cancer history. Univariate analysis showed that age<70 years (P = 0.04), ureter as the tumor location (P = 0.052), previous history/synchronous diagnosis of colorectal cancer (P < 0.01) and fulfillment of the criteria per the revised Bethesda guideline (P < 0.01) tended to be or were significantly associated with high-level microsatellite instability/mismatch repair loss.

CONCLUSIONS

The prevalence of Lynch syndrome among unselected upper urinary tract urothelial carcinoma patients was at least 1.8% in our study population. The screening efficacies of the microsatellite instability test and immunohistochemistry appear equivalent. Universal tumor screening may be a valid approach; however, selective screening methods that consider factors associated with mismatch repair loss/high-level microsatellite instability tumors require further investigation.

Colorectal cancer in adolescents and young adults: Defining a growing threat

Colorectal cancer (CRC) incidence is rising among adolescents and young adults (AYAs), with the greatest increase occurring in distal colon and rectal cancers. Reasons for this striking trend are not well understood. Genetically linked cases of CRC occur in the context of familial conditions such as Lynch Syndrome, but most AYA cases of CRC are sporadic. Unique biology is suggested, yet limited information is available regarding the molecular underpinnings of CRC in this age group. Young patients are more likely to experience delays in diagnosis and to present with advanced-stage disease; yet, prognosis by stage is comparable between younger and older adults. Treatment paradigms are based on evidence reflecting the older adult population. Given the concerning rise in CRC rates among AYAs, there is urgent need for further research into the role of screening from a younger age, biology of disease, and optimal therapies in this age group.

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.

Experience of the implementation and outcomes of universal testing for Lynch syndrome in the United Kingdom

AIM

Colorectal cancer (CRC) is diagnosed in approximately 45 000 people annually in the UK, and it is estimated that Lynch syndrome (LS) accounts for 3.1% of these cases. In February 2017, National Institute for Health and Care Excellence (NICE guideline DG27 recommended universal testing of new cases of CRC for mismatch repair (MMR) status. The aim of this study was to implement universal testing for LS in CRC patients in a secondary care setting.

METHOD

We prospectively collected data on consecutive newly diagnosed CRC patients at our centre from November 2016 to August 2018, including evidence of MMR status determined by immunohistochemistry. We recorded clinicopathological data including age at diagnosis, stage, tumour site, reported histological findings and MMR tumour status. Statistical analysis was performed using the chi-square test and the two-tailed t-test for binary and continuous variables, respectively.

RESULTS

A cohort of 203 consecutive patients were diagnosed with CRC during this period. Universal MMR testing was performed for the 198 CRC patients in whom a diagnosis of adenocarcinoma was confirmed, with colonoscopic biopsy used as the source material in 68.6% of cases. Twenty-three CRCs (11.6%) were MMR deficient (dMMR). Most dMMR CRCs (21/23) were early stage tumours (Dukes A or B, P = 0.002). In 39 Dukes B CRCs in patients under 70 years of age, the result of MMR testing influenced decision-making about personalized treatment with 5-fluorouracil based chemotherapy.

CONCLUSION

Our results demonstrate that universal testing of all new cases of CRC for features suggestive of LS is feasible and effective in the UK. Our data also indicate the importance of genetic testing and personalized oncological care.

Low Referral Rate for Genetic Testing in Racially and Ethnically Diverse Patients Despite Universal Colorectal Cancer Screening

BACKGROUND & AIMS

Guidelines recommend that all colorectal tumors be assessed for mismatch repair deficiency, which could increase identification of patients with Lynch syndrome. This is of particular importance for minority populations, in whom hereditary syndromes are under diagnosed. We compared rates and outcomes of testing all tumor samples (universal testing) collected from a racially and ethnically diverse population for features of Lynch syndrome.

METHODS

We performed a retrospective analysis of colorectal tumors tested from 2012 through 2016 at 4 academic centers. Tumor samples were collected from 767 patients with colorectal cancer (52% non-Hispanic white [NHW], 26% African American, and 17% Hispanic patients). We assessed rates of tumor testing, recommendations for genetic evaluation, rates of attending a genetic evaluation, and performance of germline testing overall and by race/ethnicity. We performed univariate and multivariate regression analyses.

RESULTS

Overall, 92% of colorectal tumors were analyzed for mismatch repair deficiency without significant differences among races/ethnicities. However, minority patients were significantly less likely to be referred for genetic evaluation (21.2% for NHW patients vs 16.9% for African American patients and 10.9% for Hispanic patients; P = .02). Rates of genetic testing were also lower among minority patients (10.7% for NHW patients vs 6.0% for AA patients and 3.1% for Hispanic patients; P < .01). On multivariate analysis, African American race, older age, and medical center were independently associated with lack of referral for genetic evaluation and genetic testing.

CONCLUSION

In a retrospective analysis, we found that despite similar rates of colorectal tumor analysis, minority patients are less likely to be recommended for genetic evaluation or to undergo germline testing for Lynch syndrome. Improvements in institutional practices in follow up after tumor testing could reduce barriers to diagnosis of Lynch diagnosis in minorities.

Next-Generation Service Delivery: A Scoping Review of Patient Outcomes Associated with Alternative Models of Genetic Counseling and Genetic Testing for Hereditary Cancer

The combination of increased referral for genetic testing and the current shortage of genetic counselors has necessitated the development and implementation of alternative models of genetic counseling and testing for hereditary cancer assessment. The purpose of this scoping review is to provide an overview of the patient outcomes that are associated with alternative models of genetic testing and genetic counseling for hereditary cancer, including germline-only and tumor testing models. Seven databases were searched, selecting studies that were: (1) full-text articles published ≥2007 or conference abstracts published ≥2015, and (2) assessing patient outcomes of an alternative model of genetic counseling or testing. A total of 79 publications were included for review and synthesis. Data-charting was completed using a data-charting form that was developed by the study team for this review. Seven alternative models were identified, including four models that involved a genetic counselor: telephone, telegenic, group, and embedded genetic counseling models; and three models that did not: mainstreaming, direct, and tumor-first genetic testing models. Overall, these models may be an acceptable alternative to traditional models on knowledge, patient satisfaction, psychosocial measures, and the uptake of genetic testing; however, particular populations may be better served by traditional in-person genetic counseling. As precision medicine initiatives continue to advance, institutions should consider the implementation of new models of genetic service delivery, utilizing a model that will best serve the needs of their unique patient populations.

Phosphorylation meets DNA mismatch repair

DNA mismatch repair (MMR) is a highly conserved process and ensures the removal of mispaired DNA bases and insertion-deletion loops right after replication. For this, a MutSα or MutSβ protein complex recognizes the DNA damage, MutLα nicks the erroneous strand, exonuclease 1 removes the wrong nucleotides, DNA polymerase δ refills the gap and DNA ligase I joins the fragments to seal the nicks and complete the repair process. The failure to accomplish these functions is associated with higher mutation rates and may lead to cancer, which highlights the importance of MMR by the maintenance of genomic stability. The post-replicative MMR implies that involved proteins are regulated at several levels, including posttranslational modifications (PTMs). Phosphorylation is one of the most common and major PTMs. Suitable with its regulatory force phosphorylation was shown to influence MMR factors thereby adjusting eukaryotic MMR activity. In this review, we summarized the current knowledge of the role of phosphorylation of MMR process involved proteins and their functional relevance.

High-risk family colorectal cancer screening service in Ireland: Critical review of clinical outcomes

BACKGROUND

We present the 15-year experience of a family colorectal cancer screening service in Ireland with emphasis on real life experience and outcomes.

METHODS

Questionnaires were used to assess family cancer history and assign patients to risk categories; 'Moderate Risk', HNPCC, (suspected) genetic syndrome (non-HNPCC), 'Low Risk'. Screening was by full colonoscopy. We report neoplastic yield, examining effect of risk category, age, gender, and index colonoscopy findings.

RESULTS

Between 1998 and 2013, 2242 individuals were referred; 57.3% female, 42.7% male, median age 46 years (range9-85yrs). Median follow up time was 7.9yrs (range 0.5-15.3yrs). Follow up data after exclusion (non-compliance, known CRC) was available in 1496 (66.7%): 'Moderate risk' 785 (52.5%), HNPCC 256 (17.1%), (suspected) genetic syndrome (non-HNPCC) 85 (5.7%), 'Low Risk' 370 (24.7%). Screening was performed in 1025(68.5%) patients; colonoscopy data available for 993 (96.9%); total 1914 colonoscopies. At index colonoscopy, 178 (18.0%) patients had adenomas; 56 (5.5%) advanced adenoma. During the entire study period, 240 (24.2%) had an adenoma; 69 (7.0%) advanced adenoma. Cancers were diagnosed on screening in 2 patients. Older age and male gender were associated with higher adenoma detection rate; p<0.001, p=0.01, respectively. Risk category did not affect adenoma yield. Adenoma and advanced adenoma detection at index colonoscopy were associated with detection of same at follow up screening; p<0.001.

CONCLUSION

Male gender and age (>50) were the core identifiable risk factors for neoplasia at screening colonoscopy in this family screening setting. Our results would support less intensive surveillance in younger patients (<50), particularly where index colonoscopy is normal.

Screening for mismatch repair deficiency in colorectal cancer: data from three academic medical centers

Reflex immunohistochemistry (rIHC) for mismatch repair (MMR) protein expression can be used as a screening tool to detect Lynch Syndrome (LS). Increasingly the mismatch repair-deficient (dMMR) phenotype has therapeutic implications. We investigated the pattern and consequence of testing for dMMR in three Irish Cancer Centres (CCs). CRC databases were analyzed from January 2005-December 2013. CC1 performs IHC upon physician request, CC2 implemented rIHC in November 2008, and CC3 has been performing rIHC since 2004. The number of eligible patients referred to clinical genetic services (CGS), and the number of LS patients per center was determined. 3906 patients were included over a 9-year period. dMMR CRCs were found in 32/153 (21%) of patients at CC1 and 55/536 (10%) at CC2, accounting for 3% and 5% of the CRC population, respectively. At CC3, 182/1737 patients (10%) had dMMR CRCs (P < 0.001). Additional testing for the BRAF V600E mutation, was performed in 49 patients at CC3 prior to CGS referral, of which 29 were positive and considered sporadic CRC. Referrals to CGS were made in 66%, 33%, and 30% of eligible patients at CC1, CC2, and CC3, respectively. LS accounted for CRC in eight patients (0.8%) at CC1, eight patients (0.7%) at CC2, and 20 patients (1.2%) at CC3. Cascade testing of patients with dMMR CRC was not completed in 56%. Universal screening increases the detection of dMMR tumors and LS kindreds. Successful implementation of this approach requires adequate resources for appropriate downstream management of these patients.