Cancer screening behaviors and risk perceptions among family members of colorectal cancer patients with unexplained mismatch repair deficiency

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.

Population genomic screening: Ethical considerations to guide age at implementation

Currently, most genetic testing involves next generation sequencing or panel testing, indicating future population-based screening will involve simultaneous testing for multiple disease risks (called here “panel testing”). Genomic screening typically focuses on single or groups of related disorders, with little utilization of panel testing. Furthermore, the optimal age for test ordering is rarely addressed in terms of whether it should coincide with the age of majority (18 years old) or after the age of majority (26 years old). We conducted an ethical analysis utilizing a hypothetical “narrow” panel test comprised of the CDC Tier 1 Genomic Applications: Familial Hypercholesterolemia (FH), increases individuals’ cardiovascular risk due to elevated low-density lipoprotein (LDL) cholesterol levels; Hereditary Breast and Ovarian Cancer (HBOC), increases lifetime risk of developing cancer; and Lynch Syndrome (LS), increases lifetime risk of developing colorectal cancer. We conducted a utilitarian analysis, on the assumption that health systems seek to maximize utility for patients. Screening at the “age of majority” is preferred for FH due to lowering FH patients’ cholesterol levels via statins providing high lifetime benefits and low risks. Screening “after the age of majority” is preferred for HBOC and LS due to availability of effective surveillance, the recommendation for screening activities to begin at age 26, and prophylactic interventions connected to surveillance. We also utilized a supplemental principlist-based approach that identified relevant concerns and trade-offs. Consideration of clinical, non-clinical, and family planning implications suggests narrow panel testing would be best deployed after 26 (rather than at 18) years of age.

Heterogeneity in the psychosocial and behavioral responses associated with a diagnosis of suspected Lynch syndrome in women with endometrial cancer

Background

A suspected Lynch syndrome (SLS) diagnosis is made when a tumor exhibits DNA mismatch repair deficiency but cannot be definitively assigned to an inherited or non-inherited etiology. This diagnosis poses challenges for healthcare professionals, patients, and their families in managing future cancer risks and clinical care.

Methods

This qualitative study aimed to explore the psychosocial and behavioral responses of endometrial cancer (EC) patients receiving a SLS diagnosis (EC-SLS). Semi-structured telephone interviews were conducted with 15 EC-SLS women, transcribed, and thematically analyzed.

Results

Most who interpreted their result as negative for Lynch syndrome (LS) believed they were at population-level risk of cancer and felt happy and relieved. Many participants who interpreted their result as inconclusive/not definitive for LS were confused about their cancer risk and experienced negative emotions of anger and frustration. Despite variation in colorectal cancer screening recommendations reported by participants, most adhered to the advice given. Almost all participants communicated their genetic test result to immediate family members; however, communication of family cancer risk management advice was more limited due to most participants reporting not receiving family screening advice. A family history of cancer and a professional healthcare background influenced participants’ engagement in regular cancer screening.

Conclusion

These findings highlight variability in the psychosocial and behavioral responses associated with EC-SLS, providing insight into how healthcare professionals can optimally manage and support such individuals.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13053-022-00233-1.

Universal Immunohistochemistry for Lynch Syndrome: A Systematic Review and Meta-analysis of 58,580 Colorectal Carcinomas

BACKGROUND & AIMS

Lynch syndrome is a form of hereditary colorectal cancer (CRC) caused by pathogenic germline variants (PV) in DNA mismatch repair (MMR) genes. Currently, many Western countries perform universal immunohistochemistry testing on CRC to increase the identification of Lynch syndrome patients and their relatives. For a clear understanding of health benefits and costs, data on its outcomes are required: proportions of Lynch syndrome, sporadic MMR-deficient (MMRd) cases, and unexplained MMRd cases.

METHODS

Ovid Medline, Embase, and Cochrane CENTRAL were searched for studies reporting on universal MMR immunohistochemistry, followed by MMR germline analysis, until March 20, 2020. Proportions were calculated, subgroup analyses were performed based on age and diagnostics used, and random effects meta-analyses were conducted. Quality was assessed using the Joanna Briggs Critical Appraisal Tool for Prevalence Studies.

RESULTS

Of 2723 identified articles, 56 studies covering 58,580 CRCs were included. In 6.22% (95% CI, 5.08%-7.61%; I² = 96%) MMRd was identified. MMR germline PV was present in 2.00% (95% CI, 1.59%-2.50%; I² = 92%), ranging from 1.80% to 7.27% based on completeness of diagnostics and age restriction. Immunohistochemistry outcomes were missing in 11.81%, and germline testing was performed in 76.30% of eligible patients. In 7 studies, including 6848 CRCs completing all diagnostic stages, germline PV and biallelic somatic MMR inactivation were found in 3.01% and 1.75%, respectively; 0.61% remained unexplained MMRd.

CONCLUSIONS

Age, completeness, and type of diagnostics affect the percentage of MMR PV and unexplained MMRd percentages. Complete diagnostics explain almost all MMRd CRCs, reducing the amount of subsequent multigene panel testing. This contributes to optimizing testing and surveillance in MMRd CRC patients and relatives.

"Left in limbo": Exploring how patients with colorectal cancer interpret and respond to a suspected Lynch syndrome diagnosis

Background

A diagnosis of suspected Lynch syndrome (SLS) is given when a tumour displays characteristics consistent with Lynch syndrome (LS), but no germline pathogenic variant is identified. This inconclusive diagnosis results in uncertainty around appropriate cancer risk management. This qualitative study explored how patients with CRC interpret and respond to an SLS diagnosis.

Methods

Semi-structured telephone interviews were conducted with 15 patients with CRC who received an SLS diagnosis, recruited from cancer genetics services across Australia. Interviews were transcribed verbatim and analysed using thematic analysis. Participant responses were compared with appointment summary letters from cancer genetics services.

Results

Participants’ interpretations of genetic test results were found to vary widely. While this variation often aligned with variation in interpretations by cancer genetics services, participants also had difficulties with the complexity and recall of genetic test results. Participants had a range of psychological responses to the uncertainty that their results presented, from relief to disappointment and doubt. Cancer risk perceptions also varied widely, with participants’ interpretations of their genetic test results just one of several influencing factors. Despite this variability, almost all participants adhered to cancer risk management advice, although different participants received different advice. All participants also communicated any cancer risk management advice to first-degree relatives, motivated by protecting them, but information communicated was not always consistent with advice received.

Conclusions

Our study findings highlight the variability in patients’ interpretations of their diagnosis, cancer risk management and family communication when a diagnosis of SLS is received, and provide novel insights into how healthcare professionals can better support patients with SLS.

"The effects of cancer on a family are way beyond the person who's had it": The experience and effect of a familial cancer diagnosis on the health behaviours of family members

PURPOSE

People who are first-degree relatives of cancer patients are at an increased risk of developing cancer themselves. Despite this, relatives of cancer patients do not always make beneficial changes to their health behaviours. This study aimed to answer the following questions: (1) do the health behaviours of people who are first-degree relatives of cancer survivors change following cancer diagnosis, and if so, how, and why, (2) what motivations/barriers exist for first-degree relatives when seeking to engage with health promoting behaviours, and (3) what do first-degree relatives believe healthcare organisations can do to improve uptake of healthy lifestyle changes.

METHOD

Nine biological first-degree relatives of cancer survivors living in Ireland (6 children, 2 siblings, 1 parent) participated in semi-structured interviews which were later thematically analysed.

RESULTS

Findings revealed four superordinate themes: Being Conscious/Aware, Limited Lifestyle Changes, Psychosocial Consequences of Experience, and Unmet Needs, with each of these themes having two to three subordinate themes. Patient and public involvement emphasised Unmet Needs, including needs for information and family support, as the theme that was most reflective of participants' lived experience.

CONCLUSIONS

Results suggest that while family members tend not to change their lifestyle behaviours following cancer diagnosis, they do seem to make changes to their medical behaviours. Additionally, they can be negatively impacted by the experience in several other ways. Identifying means of support will allow relatives to cope better post diagnosis.

Patients with unexplained mismatch repair deficiency are interested in updated genetic testing

Background

Individuals who have colorectal or endometrial cancers displaying loss of immunohistochemical staining of one or more mismatch repair proteins without an identifiable causative germline pathogenic variant have unexplained mismatch repair deficiency (UMMRD). Comprehensive germline genetic testing for Lynch syndrome (LS) includes sequencing and deletion/duplication analysis of MLH1, MSH2, MSH6, and PMS2, deletion analysis of EPCAM, and MSH2 inversion analysis. Updated genetic testing to include elements of comprehensive LS testing not previously completed could further clarify LS status in individuals with UMMRD, allowing for tailored screening guidelines for affected individuals and their family members. However, patient understanding of the potential impact of updated genetic testing for LS is unclear. This study aimed to evaluate the interest in and perceived impact of updated genetic testing among individuals with UMMRD at a tertiary academic center.

Methods

A survey evaluating interest in and perceived impact of updated genetic testing was mailed to 98 potential participants. Electronic health record review was completed for all individuals meeting eligibility criteria. Thirty-one individuals responded to the survey.

Results

Results indicate this population is highly interested in updated genetic testing with the perceived impact being primarily for family members to have appropriate genetic testing and screening. Electronic health record review indicates that clinicians have an evolving understanding of causes of UMMRD, representing a potential change in assessment of cancer risk.

Conclusions

Updated risk assessment and genetic counseling with a discussion of the benefits and limitations of germline and somatic genetic testing, is essential as the understanding of UMMRD and genetic testing recommendations for this population evolve.