Clinicopathological Factors in Colorectal Cancer

Clinicopathological features studied included the following 13 factors: sex, age at surgery, tumor location, tumor size, histology, lymphovascular invasion, lymph node metastasis, number of lymph nodes retrieval, surgical procedure, postoperative complications, postoperative adjuvant chemotherapy, preoperative serum carbohydrate antigen 19-9 (CA19-9) level and carcinoembryonic antigen (CEA) level.
All the patients underwent curative colonectomy plus complete mesocolic excision and lymph node dissection. The tumors were staged according to the eighth edition of the UICC TNM classification system. Tumors were classified into two groups based on WHO two-tier classification of histology grade: low grade and high grade. The indications of postoperative adjuvant chemotherapy included stage III patients and stage II patients with high risk factors for recurrence, such as poor histological differentiation, lymphovascular invasion, perineural invasion, preoperative bowel obstruction, and less than 12 lymph nodes examined, etc. However, whether the patients eventually received postoperative adjuvant chemotherapy was based on the patient's willingness, age, comorbid underlying diseases, physical status and pathological stages.