Prognostic factors of non‐metastatic right colon adenocarcinoma: A multicentre retrospective analysis from the ATCCR database

Abstract Background Right‐sided colon cancer (RSCC) exhibits distinct characteristics, yet specific prognostic determinants remain insufficiently defined. This multicentre retrospective study evaluated clinicopathological and surgical factors influencing survival in a real‐world cohort undergoing curative resection for non‐metastatic RSCC. Methods We analysed 800 adults undergoing curative‐intent resection for non‐metastatic RSCC across 28 centres (2018–2024). The primary outcome was 3‐year overall survival (OS). Multivariate Cox model identified prognostic factors. An exploratory, post hoc subgroup analysis evaluated the impact of complete mesocolic excision (CME) on OS, stratified by tumour anatomical subsite. Results The mean age was 62.8 years, and 24% required emergency surgery. CME was performed in 57.1% of patients, with baseline characteristics reflecting significant real‐world selection bias against CME in complex clinical presentations. At 3 years (OS: 86%), multivariate analysis identified age (HR 1.071, 95% CI: 1.023–1.122, p = 0.004) and adjacent organ invasion (HR 3.642, 95% CI: 1.360–9.750, p = 0.010) as independent mortality predictors. Unadjusted post hoc analysis suggested CME was associated with improved OS for ascending colon and hepatic flexure tumours ( p = 0.003). Conclusion Although CME showed an exploratory site‐specific survival advantage, the critical lack of molecular profiling (MSI, RAS, BRAF) prevents adjustment for major biological confounders. Consequently, these findings are strictly hypothesis‐generating, highlighting real‐world surgical bias and require prospective multi‐institutional validation before altering standard practice.