The investigators hypothesize differentiation of Peripheral Immune Cells(PIC) would result in resistance of chemotherapy and tumor local of metastatic recurrence.
The primary endpoint of this study is Disease Free Survival and the secondary endpoint is 5-year Overall Survival.
5ml peripheral blood will be sorted and counted through flow cytometry at the point of before primary treatment(surgery for colon cancers, neoadjuvant therapy for rectal cancers) , before the first chemotherapy postoperatively and 1 month after last chemotherapy.
Patients will be followed up with 3 monthly assessments in the first two years and 6 monthly assessments in the rest three years. Stratification factors include age , BMI , gender , tumor location , rectal or colon cancer stage,the chemotherapy (FOLFOX, XELOX, DeGramont or Capecitabine ),laparoscopic or laprotomy, anastomosis, concomitant medications and complications.
