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.