A randomized controlled study on immunotherapy for gastric cancer assigned according to CEA and acute-phase reactants levels

To determine whether preoperative levels of carcinoembryonic antigen (CEA) and acute-phase reactants (APR), such as immunosuppressive acidic protein (IAP), α 1-antichymotrypsin (ACT), acid-soluble glycoproteins (ASP), and sialic acid, before immunotherapy using protein-bound polysaccharide K (PSK) can predict the clinical outcome in patients with gastric cancer. Seven hundred and twelve patients were enrolled in the study from February 1987 to November 1989 at 16 institutions throughout Japan. All patients were followed over a period of 5 years. Among the 712 patients, 694 (97.5%) eligible patients with biopsy-proven gastric adenocarcinoma underwent gastrectomy and were randomly assigned to receive supportive therapy as follows: gastrectomy alone, gastrectomy plus PSK, gastrectomy plus chemotherapy (CT), and gastrectomy+CT+PSK. The 5-year follow up rate was 94.5%. There was a significant difference in survival between patients receiving gastrectomy with or without PSK who showed abnormal serum levels of CEA (log-rank test, P=0.0175), and both CEA and APR (log-rank test, P=0.0431), and between those receiving PSK and not receiving PSK in those with parameter point 3 (log-rank test, P=0.0404). These results indicate that PSK therapy has a beneficial effect in gastric cancer patients with high levels of CEA and APR.