Possible predictive markers of immunotherapy in esophageal cancer: retrospective analysis of a randomized study. The Cooperative Study Group for Esophageal Cancer in Japan.

The aim of this report is to evaluate retrospectively the data from a prospective randomized study of 158 esophageal cancer patients who actually completed therapy with protein-bound polysaccharide P (PSK) and the 5-year survivals with and without raised alpha 1-antichymotrypsin and sialic acid levels to determine the value of these parameters in predicting effectiveness of immunotherapy. There was a significant difference in survival between the patients with and without PSK therapy. The survival of the radiochemotherapy plus PSK group treated for > 3 months was significantly better than that of the radiochemotherapy group. Among the patients with abnormal levels of alpha 1-antichymotrypsin and sialic acid, those who received PSK may have a significantly better survival than those without PSK. These results indicate that the preoperative serum levels of alpha 1-antichymotrypsin and sialic acid may possibly predict the effectiveness of immunotherapy using PSK.