Prognostic relevance of primary tumor location in stage III and II colon cancer: Experience at University Hospital Ramon y Cajal (HURyC) Madrid.

Abstract

703 Background: Primary tumor location of colon cancer (CC) is emerging as an important prognostic factor owing to distinct biological features. However, this factor still does not represent a prognostic parameter when deciding for adyuvant or palliative chemotherapy. In a meta-analysis of 66 studies including patients with all stages of disease, left-sided primary tumor location was associated with a significantly reduced risk of death and this was independent of other prognostic factors. Methods: We retrospectively included patients with stage II and III CC that underwent surgical resection between 2009 and 2014 HURyC. We performed a multivariate Cox model analysis to estimate if tumor location is an independent prognostic factor for overall survival (OS). The model was further adjusted by including the following confounders: ECOG-PS, number of removed nodes ( < 12 or ≥ 12), perforation, grade, use of adyuvant chemotherapy and age. A covariate was considered a confounder factor if the difference between the adjusted and unadjusted coefficient of chemotherapy varied > 10%. Stata 13.1 was used to analyze the data. Results: 564 patients were identified (267 left sided and 297 right sided). The median follow-up of the entire cohort was 49 months. Globally, right sided CC was not significantly associated with better DFS or OS in comparison with left sided CC (HR: 0.74, p: 0.128; HR: 0.94, p: 0.75, respectively). By stages, stage II right sided CC seemed to show better DFS (HR: 0.45, p: 0.02), although no significant differences were found in OS (HR: 1.004, p: 0.98). Stage III right sided CC was not significantly associated with better DFS or OS in comparison with left sided CC (HR: 0.87, p: 0.585; HR: 0.66, p: 0.19, respectively). Conclusions: The multivariate analysis did not show significant differences in terms of prognostic relevance of primary tumor location in the adyuvant setting.