Li B, Shen S, You S, et al. - Researchers sought to determine the potential advantage of more than 4 courses of S1 [an oral 5-fluorouracil prodrug that consists of tegafur, gimeracil and oteracil in a 1:0.4:1 M concentration ratio] adjuvant chemotherapy for patients with pancreatic ductal adenocarcinoma (PDAC) post-surgery. They retrospectively acquired data from consecutive patients who received S-1 adjuvant chemotherapy after curative pancreatectomy between January 2016 and December 2018. There were 99 and 64 patients in the four-courses and > 4 courses cohorts, respectively. The identified independent prognostic factors included TNM stage, duration of S-1 administration and tumor grade. Under the condition of patients’ survival time beyond 8 months, significantly prolonged overall survival was noted among patients in > 4 courses cohort vs that of 4 courses cohort, particularly for patients in TNM stageII. Findings revealed that prognosis of patients with PDAC resection was beneficially influenced by prolonged duration of S-1 intake.