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.

Exploring the role of a multidisciplinary hereditary gynecologic oncology clinic in epithelial ovarian cancer risk-reducing surgical decision-making practices: A mixed-methods study.

Individuals that have gynecologic reproductive organs with pathogenic variants in BRCA1 or BRCA2 ("BRCA-positive") have an increased risk of developing high-grade serous ovarian cancer (HGSOC). The majority of HGSOC develops in the fallopian tubes and later spreads to the ovaries and peritoneal cavity. Therefore, risk-reducing salpingo-oophorectomy (RRSO) is recommended for those who are BRCA-positive to preventatively remove their ovaries and fallopian tubes. The Hereditary Gynecology Clinic (HGC) is a provincial program in Winnipeg, Canada, that specifically targets care to the unique needs of such individuals through an interdisciplinary team of gynecological oncologists, menopause specialists, and registered nurses. A mixed-methods study design was used to explore the decision-making processes of these BRCA-positive individuals who have been recommended (or who completed) RRSO and experiences with healthcare providers at the HGC influenced this decision. Individuals who are BRCA-positive without a previous diagnosis of HGSOC and who had previously received genetic counselling were recruited from the HGC and the provincial cancer genetics program (Shared Health Program of Genetics & Metabolism). Forty-three people completed a survey and 15 participated in an in-depth interview about their experiences and decisions surrounding RRSO. Surveys were analyzed to compare scores on validated scales related to decision-making and cancer-related worry. Qualitative interviews were transcribed, coded, and analyzed using interpretive description. Participants described the complex decisions faced by those who are BRCA-positive, which are intertwined with life experiences and circumstances including age, marital status, and family disease history. Participants interpreted their HGSOC risk through a personalized "lens" of contextual factors that impacted perceptions about the practical and emotional implications of RRSO and the need for surgery. Mean scores on validated scales evaluating the HGC's impact on decisional outcomes and preparedness for decision-making about RRSO were not significant, indicating that the HGC played a supportive role, rather than helping with decision-making itself. Therefore, we present a novel framework that consolidates the various influences on decision-making and connects them to the psychological and practical implications of RRSO in the context of the HGC. Strategies for improving support, decisional outcomes, and the overall experiences of individuals who are BRCA-positive attending the HGC are also described.

Referral, Genetic Counselling, and BRCA Testing in the Manitoba High-Grade Serous Ovarian Cancer Population, 2004-2019.

(1) Background: The primary objective of this study was to examine the rate of genetic referral, BRCA testing, and BRCA positivity amongst all patients with high-grade serous ovarian cancers (HGSOC) from 2004-2019. The secondary objective was to analyze secondary factors that may affect the rates of referral and testing. (2) Methods: This population-based cohort study included all women diagnosed with HGSOC using the Manitoba Cancer Registry, CervixCheck registry, Medical Claims database at Manitoba Health, the Hospital Discharge abstract, the Population Registry, and Winnipeg Regional Health Authority genetics data. Data were examined for three different time cohorts (2004-2013, 2014-2016; 2017-2019) correlating to practice pattern changes. (3) Results: A total of 944 patients were diagnosed with HGSOC. The rate of genetic referrals changed over the three timeframes (20.0% → 56.7% → 36.6%) and rate of genetic testing increased over the entire timeframe. Factors found to increase rates of referral and testing included age, histology, history of oral contraceptive use, and family history of ovarian cancer. Prior health care utilization indicators did not affect genetic referral or testing. (4) Conclusion: The rate of genetic referral (2004-2016) and BRCA1/2 testing (2004-2019) for patients with a diagnosis of HGSOC increased over time. A minority of patients received a consultation for genetics counselling, and even fewer received testing for a BRCA1/2. Without a genetic result, it is difficult for clinicians to inform treatment decisions. Additional efforts are needed to increase genetics consultation and testing for Manitoban patients with HGSOC. Effects of routine tumour testing on rates of genetic referral will have to be examined in future studies.

DICER1 mutations in familial multinodular goiter with and without ovarian Sertoli-Leydig cell tumors.

CONTEXT: Nontoxic multinodular goiter (MNG) is frequently observed in the general population, but little is known about the underlying genetic susceptibility to this disease. Familial cases of MNG have been reported, and published reports describe 5 families that also contain at least 1 individual with a Sertoli-Leydig cell tumor of the ovary (SLCT). Germline mutations in DICER1, a gene that codes for an RNase III endoribonuclease, have been identified in families affected by pleuropulmonary blastoma (PPB), some of whom include cases of MNG and gonadal tumors such as SLCTs. OBJECTIVE: To determine whether familial MNG with or without SLCT in the absence of PPB was associated with mutations in DICER1. DESIGN, SETTING, AND PATIENTS: From September 2009 to September 2010, we screened 53 individuals from 2 MNG and 3 MNG/SLCT families at McGill University for mutations in DICER1. We investigated blood lymphocytes and MNG and SLCT tissue from family members for loss of the wild-type DICER1 allele (loss of heterozygosity), DICER1 expression, and microRNA (miRNA) dysregulation. MAIN OUTCOME MEASURE: Detection of germline DICER1 gene mutations in familial MNG with and without SLCT. RESULTS: We identified and characterized germline DICER1 mutations in 37 individuals from 5 families. Two mutations were predicted to be protein truncating, 2 resulted in in-frame deletions, and 1 was a missense mutation. Molecular analysis of the 3 SLCTs showed no loss of heterozygosity of DICER1, and immunohistochemical analysis in 2 samples showed strong expression of DICER1 in Sertoli cells but weak staining of Leydig cells. miRNA profiling of RNA from lymphoblastoid cell lines from both affected and unaffected members of the familial MNG cases revealed miRNA perturbations in DICER1 mutation carriers. CONCLUSIONS: DICER1 mutations are associated with both familial MNG and MNG with SLCT, independent of PPB. These germline DICER1 mutations are associated with dysregulation of miRNA expression patterns.