Diagnosis of colorectal cancer by measurement of tumor markers

: In Japan, carcinoembryonic antigen (CEA), carbohydrate antigen 19-9 (CA19-9), and serum p53 antibody have been used as a tumor marker for colorectal cancer. Preoperative CEA value is a prognostic factor. For the patients with stage II and stage III, the measurement of CEA is recommended every three months for three years. During the therapy of the recurrent, the measurement of CEA is recommended before treatment and every 1-3 month. CA19-9 is not suggested as an effective tumor marker because of insufficient evidence. The measurement of serum p53 antibody may be effective for detecting early colorectal cancer, because the positive rate of serum p53 antibody in the patients with stage I was higher than that of CEA and CA19-9.