Adenocarcinoma/genetics; Adenocarcinoma/mortality; Biomarkers, Tumor/analysis; Colonic Neoplasms/genetics; Colonic Neoplasms/mortality; Thymidylate Synthase/metabolism; Adenocarcinoma/pathology; Adenocarcinoma/rehabilitation; Aged; Base Sequence; Chemotherapy, Adjuvant; Cohort Studies; Colectomy/methods; Colonic Neoplasms/pathology; Colonic Neoplasms/therapy; Combined Modality Therapy; Female; Humans; Male; Middle Aged; Molecular Sequence Data; Multivariate Analysis; Neoplasm Staging; Polymerase Chain Reaction; Polymorphism, Genetic; Prognosis; Proportional Hazards Models; Risk Assessment; Sensitivity and Specificity; Statistics, Nonparametric; Survival Analysis; Thymidylate Synthase/genetics; Treatment Outcome