Association of primary tumor location with prognosis in postoperative colorectal cancer patients

Objective To investigate the association of primary tumor location with clinical pathologic features and prognosis in postoperative colorectal cancer patients. Methods Patients with stage I~III colorectal cancer treated in the First Hospital of China Medical University from September 2000 to April 2016 were collected, and the relationship between primary tumor location and clinical pathological features was analyzed. The effect of primary tumor location on the prognosis was also investigated. Results In total, 1 345 patients with colorectal cancer were grouped according to primary tumor location: the rectum, left-sided, and right-sided colon group. The primary tumor location was associated with gender ( (χ2=10.943; P=0.004), histological grade (χ2=12.402; P=0.015), pathological T stage (χ2=49.794; P<0.001) and TNM stage (χ2=30.102; P<0.001) . Survival analysis showed no significant difference in three groups (χ2=4.806; P=0.09). Cox univariate analysis did not show any correlation between primary tumor location and survival (χ2=2.938; P=0.088) , but showed a significant correlation between positive lymph nodes、TNM stage and prognosis (χ2=39.739, χ2=23.872; P<0.001). Multivariable analyses showed a significant correlation between positive lymph nodes and survival (95%CI: 1.210~2.317; P=0.002). Conclusion In postoperative colorectal cancer, different primary tumor location correlated with different clinical pathological characteristics. There was no relationship between primary tumor location and prognosis. Number of positive lymph nodes was an independent prognostic factor for survival. Key words: Colorectal neoplasms; Prognosis; Primary tumor location; Clinicopathological characteristics