In comparison with polypectomy, colorectal resection is associated with improved survival for patients diagnosed with malignant polyps.

Abstract

Patients diagnosed with a malignant polyp generally have favourable overall survival (OS) and cancer-specific survival (CSS). However, it is unclear how choice in management for malignant polyps may affect survival. Data from the Queensland Oncology Repository was analysed to derive a population wide assessment of the impact of management strategy on OS and CSS for patients diagnosed with malignant polyps. Log-rank testing, Kaplan-Meier and Cox-regression models were performed. Patients were matched using propensity score and Mahalanobis distance matching. A total of 1,646 patients were included with 240 deaths and 52 colorectal cancer related deaths until censor date. Following propensity score and Mahalanobis distance matching of patients undergoing polypectomy alone versus colorectal resection, there was no significant difference in the age groups (<60 years of age or ≥60 years of age), American Society of Anesthesiology score, comorbidity count or Association of ColoProctology of Great Britain and Ireland risk category. However, of note Log-rank testing demonstrated a significant difference in OS (p < 0.001) and CSS (p=0.0061) between management strategies. Multivariable Cox-regression models in matched and un-matched patient cohorts demonstrated significantly lower hazards of death for OS with resection (p < 0.001). However, CSS was no longer significantly different between management groups in multivariable Cox-regression analysis (p=0.073). Patients who underwent colorectal resection had significantly improved OS and CSS compared with polypectomy alone. Improved OS was furthermore seen on multivariable analysis, and in matched cohorts. Future research should investigate why this unexpected finding may be the case and whether updates to guidelines should be considered.