TTP2.04 Unravelling the Genetic Enigma of Lynch Syndrome: An Audit of Practice in a District General Hospital

Aim Lynch syndrome, caused by germline mutations in DNA mismatch repair (MMR) genes, is the most common hereditary cause of colorectal cancer (CRC) in the UK, contributing to approximately 1,100 new cases annually. This autosomal dominant condition necessitates timely genetic testing and surveillance. This study aimed to assess adherence to NICE guidelines in the Lynch syndrome testing pathway for CRC in our department. Methods A retrospective review of newly diagnosed CRC cases from January 2022 to December 2023 was conducted using the hospital’s electronic database. Focus was placed on identifying MMR deficiency in histology reports and documentation in MDT outcome proformas, followed by an analysis of genetic testing referrals for MMR-deficient cases per NICE guidelines. Results Out of 193 diagnosed CRC cases, 17 (8.8%) exhibited deficient MMR (dMMR). Genetic testing revealed 14 cases with MLH1 mutations and 3 with mutations in non-MLH1 genes. Genetic testing referrals were made for 5 dMMR cases, resulting in 2 somatic variations, 2 with no variants, and 1 missed referral. The missed referral was promptly addressed with follow-up testing. Conclusion Lynch syndrome requires lifelong surveillance and genetic counseling. This study underscores the importance of adhering to NICE guidelines to ensure timely genetic testing and appropriate referrals. An interprofessional approach, including Surgical and medical oncology, gastroenterology, genetic counselors, and specialist nurses, is essential for comprehensive patient care. Education and collaboration among healthcare professionals are key to improving Lynch syndrome management as guidelines evolve.