Efficacy of S-1 in second-line chemotherapy after nab-paclitaxel plus gemcitabine for patients with advanced pancreatic cancer

Abstract

Background: Second-line (2 L) chemotherapy is important for improved survival. However, the efficacy of S-1 after nab-paclitaxel plus gemcitabine (AG) for advanced pancreatic cancer (APC) remains unclear. Aim: We retrospectively investigated the clinical impact of S-1 after AG. Methods and results: From January 2015 to July 2018, 37 patients with APC underwent AG as first-line chemotherapy at our institute. Of these patients, 14 (38%) underwent S-1 as 2 L chemotherapy after AG (S-1 group), five (14%) received another agent after AG, and 18 (49%) underwent no 2 L chemotherapy (best supportive care [BSC] group). The clinical features were retrospectively compared between the S-1 and BSC groups. Prognostic factors for residual survival (RS) were analyzed using a Cox proportional hazards model. The induction rate of 2 L chemotherapy was 51%, and most patients received S-1 monotherapy (74%). The disease control rate and progression-free survival duration were 57.1% and 2.8 months, respectively. The median RS duration in the S-1 and BSC groups was 5.2 and 2.4 months, respectively; this difference was statistically significant (hazard ratio, 0.33; P =.005). The median overall survival duration in the S-1 and BSC groups was 12.3 and 5.0 months, respectively; this difference was also statistically significant (hazard ratio, 0.26; P =.001). The efficacy of S-1 in 2L chemotherapy for RS was identified in the multivariate analysis, as was age (<65 vs ≥65 y) and the presence of liver metastasis. Conclusion: The antitumor activity of S-1 was retained after AG, and the induction of S-1 after AG might improve the prognosis of patients with APC.