Effect of S-1 on survival outcomes in 838 patients with advanced pancreatic cancer: A 7-year multicenter observational cohort study in Taiwan

Objective: Studies have rarely explored the efficacy of S-1 in treating advanced pancreatic cancer outside Japan. This study compared the survival outcomes of patients with advanced pancreatic cancer treated with S-1 with the survival outcomes of those without S-1 treatment before and after S-1 reimbursement was introduced in Taiwan in June of 2014. Method: We retrospectively analyzed 838 patients with locally advanced or metastatic pancreatic cancer who underwent palliative chemotherapy from 2010 to 2016 at 4 institutes in Taiwan. For survival analysis, patients were categorized into two groups according to whether they received S-1 treatment as palliative chemotherapy after diagnosis: (a) S-1-treated (n = 335) and (b) non-S-1-treated (n = 503) groups. Results: The median overall survival was longer in the S-1-treated group than in the non-S-1-treated group (10.7 vs 6.0 mo, P < 0.001). Subgroup survival analyses showed that the S-1-treated group had more favorable outcomes than the non-S-1-treated group in terms of stage III (19.6 vs 10.1 mo, P < 0.001) and stage IV (8.5 vs 5.3 mo, P < 0.001) disease. The disease control rates were 43.6% and 32.8% (P < 0.001) in patients treated with and without S-1 in the first-line setting, respectively. In multivariate analysis, exposure to S-1 treatment was an independent prognosticator for survival. Conclusion: Our results support the clinical use of S-1 as the treatment of choice for patients with locally advanced or metastatic pancreatic cancer, particularly in resource-limited situations.