Prognostic Significance of Tumor Location in Oncologic Outcome of Colon Cancer

Background: A growing amount of data has indicated the possibility that tumor location may play a prognostic role in colon cancer. We set out to investigate the relationship between the location of colon cancer (right-sided vs. left-sided) and the patient’s oncologic outcome. Methods: This retrospective cohort study included 654 colon cancer patients treated and followed up at Namazi and Faghihi hospitals in Shiraz and Imam Reza Hospital in Mashhad, Iran, between 2005 and 2014. The Cox regression multivariate analysis model was used to determine the most important independent predictors of oncologic outcomes. We analyzed the prognostic impact of the primary tumor location and other clinical, pathological, and treatment-related factors.Results: In the univariate analysis, the prognostic factors for disease-free survival (DFS) were the primary tumor stage (P 0.001), node stage (P 0.001), tumor grade (P=0.013), surgical margin status (P=0.001), lymphovascular invasion (LVI) (P 0.001), and perineural invasion (PNI) (P 0.001). Additionally, the prognostic factors for overall survival (OS) were the primary tumor stage (P 0.001), node stage (P 0.001), tumor grade (P=0.036), LVI ( 0.001), PNI (P 0.001), and the mucinous type (P=0.042). In the multivariate analysis, LVI, T3-4 lesions, tumor grade II-III, and an advanced disease stage remained independent prognostic factors for DFS and OS. However, the colon cancer location was not a prognostic factor regarding DFS or OS. Conclusion: Our study indicates that the tumor location is not a significant prognostic factor for DFS and OS in colon cancer patients.