Improved Efficacy by Addition of Protein-bound Polysaccharide K to Adjuvant Chemotherapy for Advanced Gastric Cancer

Aim: To evaluate the efficacy of protein-bound polysaccharide K (PSK) added to S-1 adjuvant chemotherapy for treatment of advanced gastric cancer. Patients and Methods: We retrospectively examined clinicopathological and recurrence-free survival (RFS) data for 136 patients with stage II or III advanced gastric cancer who underwent S-1 adjuvant chemotherapy with or without PSK. Results: Among 13 clinicopathological factors, non-T4 stage (odds ratio (OR)=0.61; 95% confidence interval (CI)=0.41-0.89; p<0.01), N0-1 (OR=0.65; 95% CI=0.43-0.95; p=0.03) and number of treatment cycles >= 7 (OR=0.37; 95% CI=0.200.67; p<0.01) were significant independent factors for better RFS. The number of treatment cycles of S-1 plus PSK was significantly higher than that of S-1 alone (p<0.01). Conclusion: S-1 adjuvant chemotherapy combined with PSK may reduce recurrence by prolonging the treatment cycles in patients with advanced non-T4 or N0-1 gastric cancer.