Diagnosis and management of Lynch syndrome

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.

Experiences of patients and family members with follow-up care, information needs and provider support after identification of Lynch Syndrome

BACKGROUND

Lynch Syndrome is among the most common hereditary cancer syndromes and requires ongoing cancer surveillance, repeated screenings and potential risk-reducing surgeries. Despite the importance of continued surveillance, there is limited understanding of patient experiences after initial testing and counseling, the barriers or facilitators they experience adhering to recommendations, and how they want to receive information over time.

METHODS

A cross-sectional, observational study was conducted among 127 probands and family members who had received genetic testing for Lynch Syndrome. We conducted semi-structured interviews to determine proband and family member experiences after receiving genetic testing results including their surveillance and screening practices, information needs, and interactions with health care providers. Both closed-ended and open-ended data were collected and analyzed.

RESULTS

Both probands (96.9%) and family members (76.8%) received recommendations for follow-up screening and all probands (100%) and most family members (98.2%) who tested positive had completed at least one screening. Facilitators to screening included receiving screening procedure reminders and the ease of making screening and surveillance appointments. Insurance coverage to pay for screenings was a frequent concern especially for those under 50 years of age. Participants commented that their primary care providers were often not knowledgeable about Lynch Syndrome and surveillance recommendations; this presented a hardship in navigating ongoing surveillance and updated information. Participants preferred information from a knowledgeable health care provider or a trusted internet source over social media or support groups.

CONCLUSIONS

Probands and family members receiving genetic testing for Lynch Syndrome generally adhered to initial screening and surveillance recommendations. However, factors such as insurance coverage and difficulty finding a knowledgeable healthcare provider presented barriers to receiving recommended follow-up care. There is an opportunity to improve care through better transitions in care, procedures to keep primary care providers informed of surveillance guidelines, and practices so that patients receive reminders and facilitated appointment setting for ongoing screening and surveillance at the time they are due.

"Lynch Syndrome"-From Healer to a Vulnerable Patient: A Transformative Odyssey

Lynch syndrome, an autosomal dominant genetic disorder, increases the risk of certain cancers, notably colorectal cancer. Early genetic testing and surveillance can significantly reduce associated morbidity and mortality. However, young patients face significant challenges navigating the healthcare system, with the psychological impact often neglected. Coping with the hereditary condition and elevated cancer risk can lead to distress, anxiety, and depression. Healthcare providers tend to focus on physical aspects, disregarding psychological well-being, leading to reduced treatment compliance and satisfaction. This case highlights the need for multidisciplinary teams and mental health support, emphasizing patient-centered care and support systems within the healthcare system.

Lynch Syndrome Genetics and Clinical Implications

Lynch syndrome (LS) is one of the most prevalent hereditary cancer syndromes in humans and accounts for some 3% of unselected patients with colorectal or endometrial cancer and 10%-15% of those with DNA mismatch repair-deficient tumors. Previous studies have established the genetic basis of LS predisposition, but there have been significant advances recently in the understanding of the molecular pathogenesis of LS tumors, which has important implications in clinical management. At the same time, immunotherapy has revolutionized the treatment of advanced cancers with DNA mismatch repair defects. We aim to review the recent progress in the LS field and discuss how the accumulating epidemiologic, clinical, and molecular information has contributed to a more accurate and complete picture of LS, resulting in genotype- and immunologic subtype-specific strategies for surveillance, cancer prevention, and treatment.

A Focused Clinical Review of Lynch Syndrome

Lynch syndrome (LS) is an autosomal dominant condition that increases an individual's risk of a constellation of cancers. LS is defined when an individual has inherited pathogenic variants in the mismatch repair genes. Currently, most people with LS are undiagnosed. Early detection of LS is vital as those with LS can be enrolled in cancer reduction strategies through chemoprophylaxis, risk reducing surgery and cancer surveillance. However, these interventions are often invasive and require refinement. Furthermore, not all LS associated cancers are currently amenable to surveillance. Historically only those with a strong family history suggestive of LS were offered testing; this has proved far too restrictive. New criteria for testing have recently been introduced including the universal screening for LS in associated cancers. This has increased the number of people being diagnosed with LS but has also brought about unique challenges such as when to consent for germline testing and questions over how and who should carry out the consent. The results of germline testing for LS can be complicated and the diagnostic pathway is not always clear. Furthermore, by testing only those with cancer for LS we fail to identify these individuals before they develop potentially fatal pathology. This review will outline these challenges and explore solutions. Furthermore, we consider the potential future of LS care and the related treatments and interventions which are the current focus of research.