[The Clinical Role of the Neutrophil/Lymphocyte Ratio in Patients with Advanced Gastric Cancer Treated with Protein-Bound Polysaccharide K and Chemotherapy].

This study aimed to evaluate the efficacy of protein-bound polysaccharide K (PSK)-containing chemotherapy in patients with unresectable advanced or recurrent gastric cancer (AGC). We retrospectively analyzed 190 patients with AGC who received systemic chemotherapy including 69 patients who were treated with a PSK-containing regimen. Using propensity score matching, we obtained 62 matched patients in the S-1 and S-1 plus PSK groups for outcomes analysis. There was a tendency for overall survival to be higher in the S-1 plus PSK group than in the S-1 alone group. In particular, there was a tendency for overall survival in the S-1 plus PSK group to be higher in patients with a neutrophil/lymphocyte ratio (NLR)<2.2 than in patients with a NLR<2.2. There was a tendency for fewer changes in the NLR after the beginning of treatment in the S-1 plus PSK group than in the S-1 alone group. PSK-containing chemotherapy may contribute to improved treatment outcomes of AGC patients. In particular, it may be effective in patients with a high NLR. Further investigations, including a prospective randomized controlled trial, are expected to verify the mechanisms of interaction between cancer cells and the immunoreaction.