S501 Adenoma History Correlated With Higher Risk of New and More Advanced Adenoma Findings

Introduction: Colorectal cancer (CRC) is one of the major causes of cancer-related mortality. Different recommendations are in place for post-screening surveillance of patients with and without findings at index colonoscopy. This analysis aims to quantify the association between adenoma history and demographic and new adenoma finding risk in a multi-center clinical study. Methods: Patients included were collected as part of a multi-center study from Spain and the USA 2018-2024. The collection included patients from average risk screening colonoscopy (either first time colonoscopy or consecutive one after previously negative screening with any modality, including fecal immunochemical test screening) or surveillance colonoscopy program. A total of 8,114 patients with no adenoma history and 534 patients with adenoma history were included for analysis. Different demographic, such as age, gender and study country and post-colonoscopy histopathology parameters such as adenoma total findings, average size, cumulative size and dysplasia, were evaluated between adenoma history “yes“ and adenoma history “no“ groups. Odds ratios (ORs) were calculated, and statistical significance was assessed using the Mann-Whitney U test with a threshold of P < 0.05. Results: Adenoma history “yes” patients were more at risk of having any new adenoma finding (OR = 1.46, 95% confidence interval [CI], 1.22-1.74), while advanced adenoma risk was higher (OR = 1.42, 95% CI, 0.84-2.4) in age group >65 than adenoma history “no” (OR = 0.98, 95% CI, 0.82-1.16). Patients with adenoma history “yes” had higher risk of having new adenoma findings (OR = 1.33, 95% 1.06-1.66). Neither patient gender nor study country was associated with an increased risk for having findings during the colonoscopy for patients with or without adenoma history, as observed though non-significant OR P-values. Conclusion: Patients with a previous history of adenomas are at higher risk of new and multiple adenoma findings, underscoring the importance of continued surveillance colonoscopy in this group. Risk stratification strategies may benefit from incorporating additional factors such as age. Further analysis will follow, aiming to link genetic and epigenetic markers to the risk characteristics and more detailed analysis of patient adenoma history to better estimate personal risk.