Universal tumor screening for Lynch syndrome: health-care providers' perspectives

Routine informed consent for mismatch repair testing in endometrial cancers: Review and ethical analysis

OBJECTIVE

To review available data regarding consent for tumor testing for mismatch repair (MMR), and to make recommendation for ethical best practices based on synthesis of contemporary data and ethical principles.

METHODS

PubMed and CINAHL databases were searched through September 2021; articles reporting on consent for MMR tumor testing for patients at risk for Lynch Syndrome were abstracted. Additional articles were identified through review of references. Key data and ethical principles were extracted, summarized, and analyzed in the context of contemporary clinical practice.

RESULTS

16 articles met inclusion criteria for this review, none of which specifically related to MMR testing for endometrial cancers. All but two studies were published prior to the approval of pembrolizumab for treatment of MMR-deficient tumors. Scant available data suggest that routine consent prior to tumor testing is uncommon; however, several decision aids improved patient knowledge and satisfaction prior to deciding whether to proceed with tumor testing. Previous ethical analyses invoke clinical utility, potential germline implications, and logistical factors in making recommendations regarding consent practices. These analyses varied in their final recommendations; however, all had significant deficits in their arguments related to contemporary clinical care for patients with endometrial cancer.

CONCLUSION

Current data are needed to assess the impact of potential consent strategies for tumor testing. Based on available data, and consistent with contemporary ethical best practices, we recommend that planned MMR testing of endometrial cancers be discussed routinely with patients verbally or in surgical consent documents.

OUP accepted manuscript

Background

We explored health professionals’ views on the utility of circulating tumor DNA (ctDNA) testing in hereditary cancer syndrome (HCS) management.

Materials and Methods

A qualitative interpretive description study was conducted, using semi-structured interviews with professionals across Canada. Thematic analysis employing constant comparison was used for analysis. 2 investigators coded each transcript. Differences were reconciled through discussion and the codebook was modified as new codes and themes emerged from the data.

Results

Thirty-five professionals participated and included genetic counselors (n = 12), geneticists (n = 9), oncologists (n = 4), family doctors (n = 3), lab directors and scientists (n = 3), a health-system decision maker, a surgeon, a pathologist, and a nurse. Professionals described ctDNA as “transformative” and a “game-changer”. However, they were divided on its use in HCS management, with some being optimistic (optimists) while others were hesitant (pessimists). Differences were driven by views on 3 factors: (1) clinical utility, (2) ctDNA’s role in cancer screening, and (3) ctDNA’s invasiveness. Optimists anticipated ctDNA testing would have clinical utility for HCS patients, its role would be akin to a diagnostic test and would be less invasive than standard screening (eg imaging). Pessimistic participants felt ctDNA testing would add limited utility; it would effectively be another screening test in the pathway, likely triggering additional investigations downstream, thereby increasing invasiveness.

Conclusions

Providers anticipated ctDNA testing will transform early cancer detection for HCS families. However, the contrasting positions on ctDNA’s role in the care pathway raise potential practice variations, highlighting a need to develop evidence to support clinical implementation and guidelines to standardize adoption.

When guidelines face reality - Lynch syndrome screening in the setting of public health system in a developing country

Lynch syndrome (LS) is the most common cause of hereditary colorectal cancer (CRC); however, it is still underrecognized and underdiagnosed. While international guidelines gravitate towards universal screening, the underuse of screening methods has been reported in real-world scenarios. This study aims to evaluate screening for LS among patients diagnosed with CRC in a public cancer center in Brazil and evaluate access to genetic counseling and testing for abnormal screens. For that purpose, all patients with CRC registered in our institution from July 2012 to December 2018 had their charts reviewed. Demographic and clinical characteristics were noted, as well as immunohistochemistry and microsatellite instability analysis results, when available. After applying exclusion criteria, a total of 1234 charts were reviewed. Among these, 257 patients were screened for LS, making up a 20.8% screening rate; when considering Jerusalem criteria, screening rate was 24.5%; for Bethesda criteria, it was 35.1%. Almost 80% of patients fulfilling Amsterdam criteria I/II were screened. There were 64 abnormal screens, from which 40 (62.5%) underwent genetic counseling and 12 (18.7%) underwent genetic testing. We concluded that overall screening rates for LS among CRC patients in a public cancer center in Brazil are low, and still very guided by stringent clinical criteria. Referral to genetic counseling and access to testing is limited, calling the whole process into question. Public policies aiming to raise awareness on hereditary cancer and include genetic testing in the public health system could help improve this scenario.

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.

An Integrative DNA Sequencing and Methylation Panel to Assess Mismatch Repair Deficiency

Clinical testing for mismatch repair (MMR) deficiency often entails serial testing of tumor and constitutional DNA using multiple assays. To minimize cost and specimen requirements of MMR testing, we developed an integrated targeted sequencing protocol (termed MultiMMR) that tests for promoter methylation, mutations, copy number alterations, copy neutral loss of heterozygosity, and microsatellite instability from a single aliquot of DNA. Hybrid capture of DNA-sequencing libraries constructed with methylated adapters was performed on 142 samples (60 tumors and 82 constitutional samples) from 82 patients with MMR-associated colorectal, endometrial, and brain cancers as well as a synthetic DNA mix with 11 known mutations. The captured material was split to enable parallel bisulfite and conventional sequence analysis. The panel targeted microsatellite regions and 13 genes associated with MMR, hypermutation, and hereditary colorectal cancer. MultiMMR recapitulated clinical testing results in 23 of 24 cases, was able to explain MMR loss in an additional 29 of 48 patients with incomplete or inconclusive testing, and identified all 11 MMR variants within the synthetic DNA mix. Promoter methylation and microsatellite instability analysis found 95% and 97% concordance with clinical testing, respectively. We report the feasibility for amalgamation of the current stepwise and complex clinical testing workflow into an integrated test for hereditary and somatic causes of MMR deficiency.

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.

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.

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.

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.

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.

Barriers to Lynch Syndrome Testing and Preoperative Result Availability in Early-onset Colorectal Cancer: A National Physician Survey Study

Objective

Although widely recommended, Lynch syndrome (LS) testing with tumor microsatellite instability (MSI) and/or immunohistochemistry (IHC) is infrequently performed in early-onset colorectal cancer (CRC), and CRC generally. Reasons are poorly understood. Hence, we conducted a national survey focusing on gastroenterologists, as they are frequently first to diagnose CRC, assessing testing barriers and which specialist is felt responsible for ordering MSI/IHC. Additionally, we assessed factors influencing timing of MSI/IHC ordering; testing on colonoscopy biopsy, opposed to post-operative surgical specimens, assists decisions on preoperative germline genetic testing and extent of colonic resection (ECR).

Methods

A 21-question web-based survey was distributed through an American College of Gastroenterology email listing.

Results

In total 509 completed the survey. 442 confirmed gastroenterologists were analyzed. Only 33.4% felt gastroenterologists were responsible for MSI/IHC ordering; pathologists were believed most responsible (38.6%). Cost, unfamiliarity interpreting results and unavailable genetic counseling most commonly prevented routine ordering (33.3%, 29.2%, 24.9%, respectively). In multivariable analysis, non-academic and rural settings were associated with cost and genetic counseling barriers. Only 46.1% felt MSI/IHC should always be performed on colonoscopy biopsy. Guideline familiarity predicted whether respondents felt surgical resection should be delayed until results returned given potential effect on ECR decisions.

Conclusion

Inconsistencies in who is felt should order MSI/IHC may lead to diffusion of responsibility, preventing consistent testing, including preoperatively. Assuring institutional universal testing protocols are in place, with focus on timing of testing, can optimize care. Strategies addressing cost barriers and genomic service availability in rural and non-academic settings can enhance testing. Greater emphasis on guideline familiarity is required.