ObjectiveTo investigate the impact of primary tumor site on prognosis of colorectal cancer after radical resection in different stages.MethodsFour hundreds and twenty patients with colorectal cancer in our hospital from Jan. 2008 to Dec. 2016 were selected as study subjects, all patients were confirmed by pathology. According to the location of colorectal cancer, the patients were divided into rectum group (n=220), left colon group (n=105) and right colon group (n=95). The difference of clinicopathological features of patients with different group were compared. The risk factors affecting the prognosis of colorectal cancer patients were analyzed by single factor and multi factor unconditional Cox regression analysis, and the survival curve was drawn by Kaplan-Meier method, and the difference test was carried out by log-rank method.ResultsThere were no significant differences between the three groups in age, BMI, smoking history, alcohol history, family history, vascular tumor thrombus, N staging, tumor diameter, nerve invasion and cancer nodule (P>0.05). There were significant differences in sex, pathological type, anterior intestinal obstruction, TNM staging, T staging and M staging (P<0.05). The results of single factor Cox regression analysis showed that sex, pathological type, anterior intestinal obstruction, TNM staging, T staging, M staging, primary tumor site, nerve invasion and cancer nodule were the risk factors for the prognosis of the patients (P<0.05). Multivariate Cox regression analysis showed that TNM staging, location of primary tumor and nerve invasion were risk factors affecting prognosis of patients (P<0.05). The total 5-year survival rate of the rectal group was 80.45% (177/220), the total 5-year survival rate of the left hemicolon group was 67.62% (71/105), and the total 5-year survival rate of the right hemicolon group was 68.42% (65/95). The survival curves of Kaplan-Meier showed that the difference between the three groups was statistically significant (P<0.05).ConclusonsThe 5-year survival rate of patients with rectal cancer is significantly higher than that of patients with left colon cancer and right colon cancer. For patients with different stage of colorectal cancer after radical resection, the prognosis of colorectal cancer can be predicted by the location of primary tumor.