Relatives from Hereditary Breast and Ovarian Cancer and Lynch Syndrome Families Forgoing Genetic Testing: Findings from the Swiss CASCADE Cohort

Streamlined Genetic Education and Cascade Testing in Men from Hereditary Breast Ovarian Cancer Families: A Randomized Trial

INTRODUCTION

When a pathogenic BRCA1 or BRCA2 mutation is identified in a family, cascade genetic testing of family members is recommended since the results may inform screening or treatment decisions in men and women. However, rates of cascade testing are low, and men are considerably less likely than women to pursue cascade testing. To facilitate cascade testing in men, we designed a Web-based genetic education tool that addressed barriers to cascade testing, was individually tailored, delivered proactively, and could be used in lieu of pretest genetic counseling to streamline the cascade testing process.

METHODS

We randomized 63 untested men from hereditary cancer families to Web-based genetic education (WGE) versus enhanced usual care (EUC). WGE participants were provided access to a genetic education website after which they could accept or decline genetic testing or opt for pretest genetic counseling. EUC participants received an informational brochure and a letter informing them of their eligibility for genetic testing and recommending they schedule genetic counseling. The primary outcome was the uptake of genetic testing.

RESULTS

Men in the WGE group were more likely to complete genetic counseling and/or genetic testing (43% vs. 12.1%; χ2 [n = 63, df = 1] = 7.77, p = 0.005). WGE participants were also more likely to complete genetic testing compared to men in the EUC group (30% vs. 9.1%; χ2 [n = 63, df = 1] = 4.46, p = 0.03).

CONCLUSION

This preliminary trial suggests that a streamlined approach to genetic testing using proactively delivered genetic education may reduce barriers to cascade testing for at-risk men, leading to increased uptake. These results should be interpreted cautiously given the select sample and high rate of non-response.

Lynch syndrome in Mexican-Mestizo families: Genotype, phenotypes, and challenges in cascade testing among relatives at risk

Lynch syndrome (LS) is the most frequent cancer predisposition syndrome affecting the colon and rectum. A pathogenic variant (PV) disrupting one of the mismatch repair (MMR) genes is responsible for the disease. The spectrum of tumors in LS is heterogeneous and includes cancer of the colon and rectum (CRC), endometrium, ovaries, stomach, small bowel, urinary tract, bladder, pancreas, and skin. Knowledge of the phenotypic variation of patients with LS, the type and frequency of PVs, and cascade testing studies in the Latin American population is limited. The present study aims to recognize the PVs in MMR genes, describe the phenotype in Mexican-Mestizo patients and their relatives, and identify the acceptance rate of cascade testing of relatives at risk. We included 40 carriers of a MMR gene PV and 142 relatives that developed a LS-related neoplasm. Patients' clinical data, number, and type of malignancies were obtained from their medical records. Amsterdam I-II, Bethesda criteria, and PREMM5® predictive model score were estimated. Available immunohistochemistry (IHC) reports were analyzed. Relatives at risk were determined from index cases pedigrees. The distribution of MMR gene mutations among 40 probands was: MLH1 (67.5 %), MSH2 (22.5 %), MSH6 (7.5 %), and PMS2 (2.5 %). Out of the 182 LS cases, 58 % exhibited the LS phenotype before age 50. The most common tumor was CRC, followed by endometrial cancer in women and gastric cancer in males. We found a 90.0 % concordance between the IHC and germline PV. The most frequent PV in our sample was MLH1 c.676C > T, occurring in 1/6 index cases. All probands disclosed their molecular test result to their family. Out of the 451 asymptomatic relatives at risk, 28.2 % underwent germline testing. Our results highlight the importance of conducting germline genetic studies in LS since it allows the establishment of appropriate cancer screening, risk-reducing measures, and genetic cascade testing among relatives at risk. Interestingly, we observed a significantly higher prevalence of the c.676C > T variant in MLH1, probably a singular characteristic of the Mexican-Mestizo population. New strategies to facilitate accurate communication between index cases and relatives should be implemented to improve the cascade testing acceptance rate.

Cascade testing in Italian Hereditary Breast Ovarian Cancer families: a missed opportunity for cancer prevention?

Healthy carriers of BRCA1/2 pathogenic variants (PVs) may benefit from risk-reducing measures of proven efficacy. The main approach to identify these individuals is cascade testing, and strategies to support this complex process are under investigation. In Italy, cascade testing has received little attention; therefore, we analyzed the uptake and characteristics of BRCA1/2 cascade testing in families diagnosed with HBOC between 2017 and 2019 at two Italian genetics centers. All blood relatives aged 18 years or older at September 2022 and who could be involved in the first step of cascade testing (i.e., all the living relatives closest to the proband) were included. In addition to first-degree relatives, individuals who were second-, third- or fourth-degree relatives were included if the closest relative(s) was/were deceased. Overall, 213 families were included (103, Genoa; 110, Bologna). Most probands were women affected by breast and/or ovarian cancer (86.4%, Genoa; 84.5%, Bologna), and the branch segregating the PV was known/suspected in 62% of families (62.1%, Genoa; 60.9%, Bologna). Overall, the uptake of cascade testing was 22.8% (25.8%, Genoa; 19.9%, Bologna; OR = 0.59: 95%CI 0.43-0.82). It was strongly associated with female gender (OR = 3.31, 95%CI 2.38-4.59), age ≤ 70 years (< 30 years OR = 3.48, 95%CI 1.85-6.56; 30-70 years OR = 3.08, 95%CI 2.01-4.71), first-degree relationship with the proband (OR = 16.61, 95%CI 10.50-26.28) and segregation of the PV in both the maternal (OR = 2.54, 95%CI 1.72-3.75) and the paternal branch (OR = 4.62, 95%CI 3.09-6.91). These real-world data may be important to inform the design and implementation of strategies aimed at improving the uptake of HBOC cascade testing in Italy.

Modes of responsibility in disclosing cancer genetic test results to relatives: An analysis of Swiss and Korean narrative data

OBJECTIVE

We examined how responsibility (the "duty to inform relatives about genetic testing results") is understood and enacted among Swiss and Korean women carrying BRCA1 or BRCA2 pathogenic variants.

METHODS

In-depth interviews and/or focus groups with 46 Swiss and 22 Korean carriers were conducted, using an identical interview guide. Data were analyzed inductively and translated into English for cross-country comparisons.

RESULTS

We identified five modes of responsibility in both samples: Persuader, Enabler, Relayer, Delayer, and Decliner. The Enabler and Relayer modes were the most common in both countries. They followed the rational imperative of health and norms of competence and self-determination, respectively. The Relayer mode transmitted information without trying to influence relatives' decisions. The Delayer and Decliner modes withheld information, deeming it the best way to safeguard the family during that specific moment of its trajectory. Responsibility to disclose testing results was influenced by culturally diverging conceptions of the family unit and socio-contextual norms.

CONCLUSION

Responsibility primarily reflects the imperative of health prevention; findings demonstrate various interpretations, including the sense of family caring achieved through controlled disclosure of genetic information.

PRACTICE IMPLICATIONS

Findings offer healthcare providers socio-anthropological insights to assist probands navigate the disclosure of genetic information within their families.

TRIAL REGISTRATION NUMBER

NCT04214210 (registered Nov 2, 2020), KCT 0005643 (registered Nov 23, 2020).

Does a proactive procedure lead to a higher uptake of predictive testing in families with a pathogenic BRCA1/BRCA2 variant? A family cancer clinic evaluation

The uptake of genetic counseling and predictive genetic testing by family members at risk for hereditary tumor syndromes is generally below 50%. To address this issue, a new guideline was introduced in the Netherlands in 2019 that aims to improve the sharing of information within families. In addition to cascade screening supported by follow-up telephone calls with the proband, municipal records were accessed to allow the geneticist to contact at-risk family members directly. We evaluated this procedure in 32 families with a (likely) pathogenic germline BRCA1/BRCA2 variant diagnosed at our hospital between May 1, 2020, and July 31, 2021, comparing current uptake with outcomes achieved for 33 families diagnosed in 2014. Fifteen months after diagnostic testing of the proband, the uptake was 43% (120/277), comparable to the 44% (87/200) registered previously. Among a subgroup of women at 50% risk aged 25-75 years, 71% (47/66) were tested, comparable to an earlier uptake of 69% (59/86). Of the 34 at-risk relatives we contacted directly, 17 (50%) underwent predictive testing. In conclusion, we found no evidence that the new procedure leads to a substantially increased uptake. Future research should be primarily aimed at understanding intrafamilial communication barriers.

Only 32.3% of Breast Cancer Families with Pathogenic Variants in Cancer Genes Utilized Cascade Genetic Testing

BACKGROUND

Hereditary cancer predisposition syndromes are responsible for approximately 5-10% of all diagnosed cancer cases. In order to identify individuals at risk in a cost-efficient manner, family members of individuals carrying pathogenic alterations are tested only for the specific variant that was identified in their carrier relative. The purpose of this study was to investigate the clinical use and implementation of cascade family testing (CFT) in families of breast cancer patients with pathogenic/likely pathogenic variants (PVs/LPVs) in cancer-related predisposition genes.

METHODS

Germline sequencing was carried out with NGS technology using a 52-gene panel, and cascade testing was performed by Sanger sequencing or MLPA.

RESULTS

In a cohort of 1785 breast cancer patients (families), 20.3% were found to have PVs/LPVs. Specifically, 52.2%, 25.1%, and 22.7% of patients had positive findings in high-, intermediate-, and low-penetrance breast cancer susceptibility genes, respectively. Although CFT was recommended to all families, only 117 families (32.3%) agreed to proceed with genetic testing. Among the first-degree relatives who underwent CFT, 70.3% were female, and 108 of 121 (89.3%) were cancer free. Additionally, 42.7%, 36.7%, and 20.6% were offspring, siblings, and parents of the subject, respectively. Our data suggest that CFT was mostly undertaken (104/117, 88.8%) in families with positive findings in high-risk genes.

CONCLUSIONS

Cascade family testing can be a powerful tool for primary cancer prevention by identifying at-risk family members. It is of utmost importance to implement genetic counseling approaches leading to increased awareness and communication of genetic testing results.

Special Issue: "Genetic Counseling and Genetic Testing in Precision Medicine"

Progress in genomic technologies has spurred innovation in healthcare and medicine, contributing to improved health and well-being [...].

Privacy and utility of genetic testing in families with hereditary cancer syndromes living in three countries: the international cascade genetic screening experience

Background: Hereditary breast and ovarian cancer and Lynch syndrome are associated with increased lifetime risk for common cancers. Offering cascade genetic testing to cancer-free relatives of individuals with HBOC or LS is a public health intervention for cancer prevention. Yet, little is known about the utility and value of information gained from cascade testing. This paper discusses ELSI encountered during the implementation of cascade testing in three countries with national healthcare systems: Switzerland, Korea, and Israel. Methods: A workshop presented at the 5th International ELSI Congress discussed implementation of cascade testing in the three countries based on exchange of data and experiences from the international CASCADE cohort. Results: Analyses focused on models of accessing genetic services (clinic-based versus population-based screening), and models of initiating cascade testing (patient-mediated dissemination versus provider-mediated dissemination of testing results to relatives). The legal framework of each country, organization of the healthcare system, and socio-cultural norms determined the utility and value of genetic information gained from cascade testing. Conclusion: The juxtaposition of individual versus public health interests generates significant ELSI controversies associated with cascade testing, which compromise access to genetic services and the utility and value of genetic information, despite national healthcare/universal coverage.