S514 A Model to Predict Colon Adenomas in Lynch Syndrome Patients

Introduction: Patients with Lynch syndrome have an elevated risk for colon cancer and are recommended to have a colonoscopy every one to 3 years. Colonoscopy is performed to identify and remove precancerous polyps (adenomas) to prevent colon cancer. Many Lynch syndrome patients are unable to undergo frequent colonoscopy, and some are diagnosed with colon cancer even with frequent colonoscopy. Targeting colonoscopy to Lynch syndrome patients at highest risk for adenoma development would allow for more efficient use of resources and improved cancer prevention. There has been little research on risk factors for adenoma development in Lynch syndrome patients. Methods: This prospective cohort study collected on individuals with Lynch syndrome having colonoscopy at Mayo Clinic from 2009-2025. Results: The study dataset included information from 142 individuals with Lynch syndrome who had 475 colonoscopies. Older age, a history of prior colon adenomas and no previous colonoscopy at our center predicted finding an adenoma on colonoscopy. A 5 tier Lynch syndrome adenoma prediction score (LS-APS) was developed incorporating these factors. LS-APS scoring and corresponding adenoma detection rates were 0%-15.95%, 1%-23.2%, 3%-29.2%, 4%-46.1%, and 5%-58.8%. The LS-APS score was a median of 3 for adenoma-positive colonoscopies and 2 for adenoma-negative colonoscopies (P < 0.001). Conclusion: The LS-APS is a simple prediction score based on age and history of prior adenoma can identify LS patients more likely to develop adenomas. Further validation in large, multicenter datasets is needed.