FITting Non-invasive Tests in Lynch Syndrome Surveillance

Inclusion Criteria: * Have a diagnosis of LS with a confirmed pathogenic variant in MLH1, MSH2, MSH6, PMS2 or EPCAM genes. * Aged 20 - 80 years (for those with pathogenic variants in MLH1, MSH2, and EPCAM) * Aged 30 - 80 years (for those with pathogenic variants in PMS2 or MSH6). * Have an upcoming standard of care (SOC) colonoscopy appointment in line with standard LS surveillance guidelines (NCCN). * Patients with previous colon surgery who still have 20cm or more of colon remaining * Patients who are diagnosed with advanced neoplasia (e.g., advanced adenomas or cancers) and have NOT had endoscopic or surgical resection * Willing to sign informed consent, collect stools samples and complete surveys Exclusion Criteria: * Individuals who have not proceeded with genetic testing and therefore are not known to have LS, despite family history and/or criteria for testing. * Individuals who have previously undergone a subtotal or total colectomy. * Newly diagnosed Lynch Syndrome patients \< 20 years old with a pathogenic variant in MLH1, MSH2 or EPCAM, MSH6 or PMS2. * Newly diagnosed Lynch Syndrome patients \< 30 years old with a pathogenic variant in MSH6 or PMS2. * Individuals who are pregnant. * Individuals with inflammatory bowel disease or active malignancy. * Individuals not willing or able to sign informed consent.