Colorectal Adenoma Cohort

This is an ambidirectional cohort study aiming to develop and validate a risk prediction model for colorectal adenoma recurrence and progression. The study will enroll patients aged 18-75 years who undergo colorectal adenoma resection at the Second Affiliated Hospital of Zhejiang University School of Medicine. A retrospective cohort will include patients treated in the past 10 years with available endoscopic, pathologic, and routine laboratory data. A prospective cohort will be enrolled from the date of ethical approval until December 31, 2030, with collection of epidemiological questionnaire data, lifestyle information, blood and tissue biospecimens, and follow-up outcomes. The primary outcome is adenoma recurrence, with secondary outcomes including advanced adenoma and colorectal cancer. Based on a target of 1,083 evaluable participants (325 events) to ensure adequate model development, and accounting for 15% loss to follow-up, the total planned enrollment is 1,280 participants. The study will validate existing risk models based on traditional adenoma characteristics and establish a novel model incorporating lifestyle factors and systemic inflammatory markers to improve risk stratification and guide surveillance strategies.