Efficacy of chemotherapy for patients with gastric cancer with early recurrence during or after adjuvant chemotherapy with S-1 alone: a multicenter retrospective study.

This study aimed to survey the efficacy of chemotherapy regimens in the real world setting and explore the most promising regimen for patients experiencing early recurrence for gastric cancer. We retrospectively reviewed the clinical course of 207 patients with gastric cancer, who developed early recurrence during or within 6 months after completing S-1 adjuvant therapy at 19 Japanese institutions between 2012 and 2016. The treatment regimens after recurrence were fluoropyrimidines plus platinum-based regimens (FP) in 91 (44%) patients, paclitaxel-based regimens (PTX) in 102 (49%), and irinotecan-based regimens (IRI) in 14 (7%). The overall response and disease control rates were 28.7% and 54.1%. Median progression-free survival (PFS) and overall survival (OS) were 5.1 and 12.9 months, respectively. In the FP, PTX, and IRI regimens, the median PFS and OS were 5.9, 4.1, 4.1 months and 12.8, 12.9, and 11.8 months, respectively. The combination of PTX and ramucirumab showed survival comparable to capecitabine plus platinum. Multivariate analyses for OS showed that recurrence during adjuvant chemotherapy and undifferentiated histological type were independent poor prognostic factors. Although the prognosis of patients with early recurrence even with adjuvant S-1 was poor, PTX plus ramucirumab therapy could be a potential treatment option.