Factors affecting treatment decisions for endoscopically resected low- and high-risk malignant colorectal polyps in a screening setting

Introduction: The European Guidelines for colorectal cancer screening of 2006 state that only high-risk endoscopically resected malignant colorectal polyps (MCPs), defined as poor/no differentiation or positive resection margins or lymphovascular invasion, require colonic resection. Methods: A multicentre series of 954 patients with screen-detected MCP (northern Italy, 2005–2016, age 50–69) was studied to identify (1) the factors affecting the choice of colonic resection, and (2) the factors associated with deviation from the European Guidelines for low- and high-risk patients. Data analysis was based on multilevel logistic regression models. Results: Five hundred sixty-four (59.1 %) patients underwent colonic resection. The factors significantly associated with surgical referral included: distal and rectal versus proximal tumour site (inverse association); sessile and flat versus pedunculated morphology (direct association); tumour size (direct); moderate/poor versus good differentiation (direct); adenocarcinoma of not otherwise specified type versus adenocarcinoma with a residual adenoma component (direct); positive versus negative resection margins (direct); lymphovascular invasion (direct); and high-grade versus low-grade/absent tumour budding (direct). In low-risk MCPs, tumour budding encouraged strongly the decision for surgery. In high-risk MCPs, a distal/rectal tumour site encouraged the follow-up option. Conclusion: The identification of factors associated with treatment choices other than those currently recommended may help prioritise the clinical questions in the development of future guidelines.