Genetic testing in families with hereditary colorectal cancer in British Columbia and Yukon: a retrospective cross-sectional analysis

Expanding access to genetic testing for pancreatic cancer

Among individuals with pancreatic ductal adenocarcinoma (PDAC) 5-10% have a pathogenic germline variant (PGV) in a PDAC susceptibility gene. Guidelines recommend genetic testing among all individuals with PDAC. Additionally, at-risk relatives of PDAC patients benefit from their own genetic education, risk assessment, and testing. Multigene panel testing (MGPT) can identify individuals with inherited cancer risk who can benefit from early cancer surveillance and risk reduction strategies. This manuscript discusses various healthcare delivery models for MGPT including traditional in-person genetic counseling, novel integrated in-person infrastructures, telemedicine genetics care via telephone- or video-visits and direct-to-consumer testing. Barriers and facilitators to care on the individual, provider, and system level are also outlined including specific considerations for historically marginalized communities.

Province-Wide Ascertainment of Lynch Syndrome in Manitoba

BACKGROUND & AIMS

We describe the experience of Lynch syndrome (LS) diagnosis in the province of Manitoba, Canada, over the past 20 years.

METHODS

We performed a retrospective review of charts from the provincial Genetics Clinic from January 1, 2000, to May 31, 2023. We extracted data on individuals identified to carry a germline pathogenic or likely pathogenic LS gene variant, the mode of ascertainment, family history, and cascade genetic testing (CGT). Data were stratified and compared before and after the year of implementation (October 2013) of the provincial LS screening program (LSSP) and ascertainment by the LSSP vs clinic referrals (CRs).

RESULTS

Between 2014 and 2021, 50 of 101 (49.5%) index cases were identified by the LSSP compared with 51 of 101 (50.5%) from CRs. The proportion of PMS2 variants was 34% (17 of 50) for LSSP index cases compared with 21.6% (11 of 51) for CRs from 2014 to 2021 (P < .001). Among CRs from 2014 to 2021, 24 of 51 (47.1%) families met the Amsterdam criteria, compared with 11 of 50 (22.0%) for the LSSP (P = .01). CGT occurred among 46.8% (95 of 203; average, 1.9 relatives/index) of first-degree relatives of CR index cases vs 36.5% (84 of 230; average, 1.7 relatives/index) of first-degree relatives of LSSP index cases (P = .03). Daughters were most likely to undergo CGT.

CONCLUSIONS

A tumor screening program is more effective at detecting individuals with lower penetrant gene variants and families who do not meet traditional family history-based criteria. Cascade genetic testing is higher among clinic referrals compared with the screening program. These findings suggest a complementary role of these 2 ascertainment methods for Lynch syndrome.

Young-onset colorectal cancer

In the past decades the incidence of colorectal cancer (CRC) in people under the age of 50 years has increased, which is referred to as early-onset CRC or young-onset CRC (YO-CRC). YO-CRC is expected to account for 11% of colon cancers and 23% of rectal cancers by 2030. This trend is observed in different parts of the world and in both men and women. In 20% of patients with YO-CRC, a hereditary cancer syndrome is found as the underlying cause; however, in the majority of patients no genetic predisposition is present. Beginning in the 1950s, major changes in lifestyle such as antibiotic use, low physical activity and obesity have affected the gut microbiome and may be an important factor in YO-CRC development. Owing to a lack of screening, patients with YO-CRC are often diagnosed with advanced-stage disease. Long-term treatment-related complications should be taken into account in these younger patients, making the more traditional sequential approaches of drug therapy not always the most appropriate option. To better understand the underlying mechanism and define relationships between environmental factors and YO-CRC development, long-term prospective studies are needed with lifestyle data collected from childhood.

Cascade Testing for Hereditary Cancer Syndromes: Should We Move Toward Direct Relative Contact? A Systematic Review and Meta-Analysis

PURPOSE

Evidence-based guidelines recommend cascade genetic counseling and testing for hereditary cancer syndromes, providing relatives the opportunity for early detection and prevention of cancer. The current standard is for patients to contact and encourage relatives (patient-mediated contact) to undergo counseling and testing. Direct relative contact by the medical team or testing laboratory has shown promise but is complicated by privacy laws and lack of infrastructure. We sought to compare outcomes associated with patient-mediated and direct relative contact for hereditary cancer cascade genetic counseling and testing in the first meta-analysis on this topic.

MATERIALS AND METHODS

We conducted a systematic review and meta-analysis in accordance with Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines (PROSPERO No.: CRD42020134276). We searched key electronic databases to identify studies evaluating hereditary cancer cascade testing. Eligible trials were subjected to meta-analysis.

RESULTS

Eighty-seven studies met inclusion criteria. Among relatives included in the meta-analysis, 48% (95% CI, 38 to 58) underwent cascade genetic counseling and 41% (95% CI, 34 to 48) cascade genetic testing. Compared with the patient-mediated approach, direct relative contact resulted in significantly higher uptake of genetic counseling for all relatives (63% [95% CI, 49 to 75] v 35% [95% CI, 24 to 48]) and genetic testing for first-degree relatives (62% [95% CI, 49 to 73] v 40% [95% CI, 32 to 48]). Methods of direct contact included telephone calls, letters, and e-mails; respective rates of genetic testing completion were 61% (95% CI, 51 to 70), 48% (95% CI, 37 to 59), and 48% (95% CI, 45 to 50).

CONCLUSION

Most relatives at risk for hereditary cancer do not undergo cascade genetic counseling and testing, forgoing potentially life-saving medical interventions. Compared with patient-mediated contact, direct relative contact increased rates of cascade genetic counseling and testing, arguing for a shift in the care delivery paradigm, to be confirmed by randomized controlled trials.

Intention to Inform Relatives, Rates of Cascade Testing, and Preference for Patient-Mediated Communication in Families Concerned with Hereditary Breast and Ovarian Cancer and Lynch Syndrome: The Swiss CASCADE Cohort

Cascade screening for Tier 1 cancer genetic conditions is a significant public health intervention because it identifies untested relatives of individuals known to carry pathogenic variants associated with hereditary breast and ovarian cancer (HBOC) and Lynch syndrome (LS). The Swiss CASCADE is a family-based, open-ended cohort, including carriers of HBOC- and LS-associated pathogenic variants and their relatives. This paper describes rates of cascade screening in relatives from HBOC- and LS- harboring families, examines carriers' preferences for communication of testing results, and describes theory-based predictors of intention to invite relatives to a cascade screening program. Information has been provided by 304 index cases and 115 relatives recruited from September 2017 to December 2021. On average, 10 relatives per index case were potentially eligible for cascade screening. Approximately 65% of respondents wanted to invite relatives to the cohort, and approximately 50% indicated a preference for patient-mediated communication of testing results, possibly with the assistance of digital technology. Intention to invite relatives was higher for first- compared to second- and third-degree relatives, but was not different between syndromes or based on relatives' gender. The family environment and carrying pathogenic variants predicts intention to invite relatives. Information helps optimize delivery of tailored genetic services.

Awareness regarding early treatment and related factors in first-degree relatives of patients with hereditary colorectal cancer

BACKGROUND

First-degree relatives of patients with hereditary colorectal cancer are a population at high risk for colorectal cancer, but most of them lack correct health knowledge and screening behaviors. Therefore, raising the awareness of early detection, early diagnosis, and early treatment among this population is particularly important in preventing and treating tumors and improving prognosis.

AIM

To analyze the awareness regarding early treatment and related factors in first-degree relatives of patients with hereditary colorectal cancer.

METHODS

A cross-sectional survey method was used to select 200 first-degree relatives of hereditary colorectal cancer patients who were hospitalized at our hospital from June 2017 to March 2021 as the research subjects. A self-made general information questionnaire was used to collect the basic information of the subjects. An awareness questionnaire was used to identify the risk factors that might affect the awareness regarding early treatment of tumors in the first-degree relatives of hereditary colorectal cancer patients through single-factor and multi-factor analyses.

RESULTS

A total of 200 questionnaires were issued, and 196 valid questionnaires were returned, with an effective recovery rate of 98.00%; 127 of the 196 first-degree relatives chose active treatment, accounting for 64.80%, and 50 chose not to actively treat, accounting for 25.51%. The main reasons for active treatment included economic reasons, fear of pain caused by treatment, and time reasons, accounting for 72.00%, 42.00%, and 34.00%, respectively. Non-conditional logistic regression analysis demonstrated that education level (junior high school and below), marital status (unmarried), family per capita monthly income (< 3000 yuan), medical insurance (new rural cooperative medical care/no medical insurance), no commercial medical insurance, number of blood relatives suffering from colorectal cancer (< 4 people), and cognitive level (low recognition) were risk factors affecting the awareness regarding early treatment of tumors in first-degree relatives (odds ratio > 1, P < 0.05).

CONCLUSION

Awareness regarding early treatment needs to be improved among first-degree relatives of hereditary colorectal cancer patients. Factors such as low education, unmarried status, low family monthly income, and no commercial medical insurance may reduce the awareness of early treatment. Therefore, intervention measures should be formulated according to risk factors to enhance the awareness of early treatment.

Patient ethnicity and cascade genetic testing: a descriptive study of a publicly funded hereditary cancer program

Cascade genetic testing for hereditary cancer is highly accurate and cost-effective for identifying individuals at high risk for cancer; however, not all eligible people utilize this service. While sociodemographic factors related to the uptake of cascade genetic testing, such as age and sex, have been fairly well described in the literature, there is limited data available regarding patient ethnicity. We analyzed four years of testing data for this factor, as well as sex, age and genes tested. The patients were seen by the Hereditary Cancer Program of BC Cancer, which serves the entire population of British Columbia and Yukon, Canada. Patient ethnicity was compared to the 2016 Census data from the same region. Fisher's exact test was conducted to explore the cascade genetic testing uptakes. Chi-square test was used to compare the major ethnicity groups to Census data. There was significant variability in the uptake of cascade genetic testing in the three largest population groups (p < 0.05), with individuals of European ethnic origin overrepresented, individuals of Asian ethnic origin modestly underrepresented, and individuals of North American Indigenous origin considerably underrepresented for cascade genetic testing. The proportions represented compared to those expected from census data were significantly different for these three largest groups (p < 0.01). The majority of cascade genetic tests were for BRCA1/BRCA2 (58.8%), followed by 16.9% for Lynch syndrome genes. Most patients were female (70%), and the mean age of patients was 49 years old. This study provides further insight into uptake of cascade genetic testing by patient ethnicity. Examining patient ethnicity and cascade genetic testing rates helps to identify underserved populations. Our analysis highlights significant underrepresentation of North American Indigenous individuals for hereditary cancer cascade genetic testing, and helps recognize the need for development of culturally-safe alternatives to outreach and service promotion.