SENSITIVITY OF MONOCLONAL-ANTIBODIES TO CARCINOEMBRYONIC ANTIGEN, TISSUE POLYPEPTIDE ANTIGEN, ALPHA-FETOPROTEIN, CARBOHYDRATE ANTIGEN-50, AND CARBOHYDRATE ANTIGEN-19-9 IN THE DIAGNOSIS OF COLORECTAL ADENOCARCINOMA

PURPOSE: This study was designed to establish the sensitivity of monoc lonal antibodies to carcinoembryonic antigen (CEA), alphafetoprotein ( AFP), tissue polypeptide antigen (TPA), carbohydrate antigen 50 (CA 50 ), and carbohydrate antigen 19-9 (CA 19-9) and the efficacy of the joi nt determination of several tumor markers, as well as the dynamics of postoperative normalization of each marker in the absence of recurrenc e. MATERIALS AND METHODS: A prospective study was carried out in 100 p atients subjected to surgical resection of colon adenocarcinoma. Serum concentrations of these markers were determined the day before surger y and seven days, two months, and six months after surgery. RESULTS: T he results demonstrate that sensitivity increased as the disease sprea d and that CA 19-9 was the most sensitive tumor marker. The rate of fa lse negatives was 40 percent for Dukes Stage A lesions, 19 percent for Dukes Stage B, 7 percent for Dukes Stage C, and 0 percent for Dukes S tage D. Determination of two markers (CA 19-9 and CEA) provided the gr eatest sensitivity in Stages A and D tumors (60 percent and 100 percen t, respectively); the incidence did not change when measurements of ot her antigens were associated. For Stages B and C, determination of at least three markers was necessary, the association of CEA, TPA, and CA 19-9 being that which showed the greatest sensitivity, 78 percent and 91 percent, respectively. CONCLUSIONS: It would be advisable to inclu de monoclonal antibody determination of CEA, TPA, and CA 19-9 in the d iagnosis of adenocarcinoma, despite the fact that ultimate sensitivity will depend on the degree of tumor extension or on the presence of me tastasis.