A Multi-site, Open, Perspective Study of Prognostic Value and Benefit From Chemotherapy of Stage II Colon Cancer Based on a 6 microRNA Stratified Tool

Investigators randomly assign patients to be assessed by classical pathological features(control group) or the miRNA tool(experimental group). Pathological features include poorly differentiated histology(exclusive of those cancers that are MSI-H),lymphatic/vascular invasion,bowel obstruction and <12 lymph nodes examined.MicroRNA tool contains miRNA of miR-21、miR-20a-5p、miR-103a-3p、miR-106b-5p、miR-143-5p and miR-215. Investigators evaluate these miRNA status of surgical specimens using qRT-PCR and calculate their risk score(risk score =(0.108×status of miR-21-5p)+(0.086×status of miR-20a-5p)+(0.240×status of miR-103a-3p)+(0.095×status of miR-106b-5p)-(0.238×status of miR-143-5p)-(0.237×status of miR-215),low expression status equals 0 and high expression status equals 1). Investigators defined high risk patient if had any pathological features in control group or the score larger than 1 in the experimental group ,the others as low risk patient.The high risk group should receive adjuvant chemotherapy while the low risk group deserve observation. Primary endpoint is the disease free survival and overall survival.