Arantzazu Martínez Barquín García
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Olga Martinez Saez
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Juan José Serrano Domingo
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Roberto Martín Huertas
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Maria Villamayor Delgado
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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.
Prognostic value of primary tumor location in stage III colon cancer is associated with RAS and BRAF mutational status.
