Immunotherapy and combined assay of serum levels of carcinoembryonic antigen and acute-phase reactants

Abstract

 Our previous studies have revealed that gastric and esophageal cancer patients with abnormal sialic acid levels had a better response than those with normal levels if they received polysaccharide K (PSK), a nonspecific immunomodulator. Serum levels of carcinoembryonic antigen (CEA) and acute-phase reactants (APR) such as immunosuppressive acidic protein, acid-soluble glycoproteins, α1-antichymotrypsin, and sialic acid were analyzed in 872 gastric cancer patients who had undergone resection from March 1979 to September 1993 at the Department of Surgery of Tokai University. The patients were categorized into four groups according to the preoperative serum levels: group A had normal levels of both CEA and APR, group B had abnormal CEA and normal APR levels, group C had a normal CEA level and normal levels of one or more APR, and group D had abnormal levels of both CEA and of one or more APR. Patients in group D who received PSK showed significantly better survival than those without PSK (29.3% versus 6.9%; log-rank test, P = 0.0015; Breslow test, P = 0.0042). CEA-positive patients receiving PSK therapy exhibited a significantly better survival rate than those without PSK (38.1% versus 18.6%; log-rank test, P = 0.0136; Breslow test, P = 0.0125). Cox’s regression analysis showed that PSK therapy was significantly related to survival in group D, but not in the other groups. We conclude that the combined assay of tumor-associated factors (such as CEA) and various nonspecific reactants to the presence of cancer (such as immunosuppressive acidic protein, α1-antichymotrypsin, acid-soluble glycoproteins and sialic acid) provides a good set of preoperative indicators on which to base the selection of treatment for individual gastric cancer patients.