The association between tumour sidedness, clinicopathological characteristics and outcomes in patients undergoing curative resection for colon cancer.

Abstract

148 Background: Right-sided colon cancer is associated with worse outcomes than left-sided disease, likely due to an association between tumour/host factors and tumour sidedness. The present study analyses the association between tumour sidedness, clinicopathological features and common mutations to better understand this discrepancy in outcomes. Methods: The association between tumour sidedness, clinicopathological characteristics and survival was examined within a cohort of patients undergoing curative surgery for TNM I-III colon cancer. Results: 3,419 patients were identified. 54% of cases were right-sided and associated with worse 3-year OS/CSS. On multivariate analysis for clinical factors: sex (OR 0.63), Systemic Inflammatory Grade (SIG), anaemia and differentiation (OR 0.80/0.31/0.57) were associated with T3 cancer sidedness and: sex, anaemia and differentiation (OR 0.61/0.46/0.57) were associated with T4 cancer sidedness. On further MVA including mutational factors anaemia/BRAF status remained significant in T3/T4 cancer respectively (OR 0.08/0.09). BRAF mutant status was associated with SIG in all patients/T3 disease (p=0.046/0.016). Conclusions: Worse outcomes seen in right-sided colon cancer are likely explained predominantly by factors including tumour stage, SIG, anaemia and BRAF mutational status. BRAF mutations are associated with the Systemic Inflammatory Response and further research is required to better understand this relationship taking into the tumour microenvironment, microsatellite instability.[Table: see text]