[Oncological outcomes analysis of colorectal cancer with unfavorable histological features]

Objective: To explore the effect of unfavorable histological features on the clinical outcomes of patients receiving radical resection of colorectal cancer. Methods: A retrospective analysis of patients with colorectal cancer who received radical surgery between January 2013 and December 2015 at Department of General Surgery, Peking Union Medical College Hospital was performed. The impact of unfavorable histological features on the oncological outcomes of patients with lymph node-negative colorectal cancer were analyzed.A total of 167 patients were enrolled, including 98 males and 69 females with age of (63.6±11.6) years. Observation indicators included age, T stage, lymphovascular invasion, perineural invasion, tumor deposits, number of lymph node dissection, degree of differentiation, tissue type, and circumferential margin. Univariate analysis was performed with χ(2) test and multivariate analysis was performed with Cox regression model. Results: Univariate analysis showed that positive circumferential margins (CRM), tumor deposits and age were associated with disease free survival (DFS) rate; positive CRM, age, tumor deposits, and lymph nodes dissection less than 12 were significantly associated with overall survival (OS) rate (all P<0.05). Multivariate analysis showed that over 70 years of age (HR=1.053, 95% CI: 1.013 to 1.095, P=0.009), poorly differentiated adenocarcinoma (HR=7.572, 95%CI: 1.815 to 31.587, P=0.005), tumor deposits (HR=4.711, 95% CI: 1.809 to 12.264, P=0.002), mucinous adenocarcinoma (HR=3.063, 95% CI: 1.003 to 9.354, P=0.049), lymphovascular invasion (HR=2.885, 95% CI: 1.062 to 7.832, P=0.038), and nerve infiltration (HR=6.610, 95% CI: 1.037 to 42.122, P=0.046) were adverse prognostic factors of DFS rate; poorly differentiated adenocarcinoma (HR=12.200, 95% CI: 1.985 to 74.972, P=0.007), tumor nodules (HR=5.379, 95% CI: 1.636 to 17.685, P=0.006), over 70 years of age (HR=1.062, 95% CI: 1.013 to 1.114, P=0.013), and perineural invasion (HR=8.043, 95% CI: 1.026 to 63.055, P=0.047) were adverse prognostic factors of OS rate. There was no significant difference in the 3-year DFS rate and 3-year OS rate between T1-2 group and T3-4 group (P>0.05). Conclusion: Over 70 years of age, poorly differentiated adenocarcinoma, mucinous adenocarcinoma, tumor nodules, lymphovascular invasion, and perineural invasion are independent adverse prognostic factors of lymph node-negative colorectal cancer.