Published in:
01-11-2019 | Gastrectomy | Original Article
Delay in initiation of postoperative adjuvant chemotherapy with S-1 monotherapy and prognosis for gastric cancer patients: analysis of a multi-institutional dataset
Published in: Gastric Cancer | Issue 6/2019
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Background
This study aimed to evaluate whether the timing of initiating postoperative chemotherapy with S-1 monotherapy affects gastric cancer patients’ prognosis.
Methods
A multi-institution dataset identified patients with pStage II or III gastric cancer who received S-1 monotherapy for over 6 months after curative resection between 2010 and 2014. Patients were divided into three groups based on the timing of S-1 monotherapy initiation. Prognostic factors for relapse-free survival (RFS) were investigated.
Results
We classified 401 patients into groups as follows: S-1 administered within 6 weeks (n = 247), between 6 and 8 weeks (n = 95), and after 8 weeks (n = 59). The RFS times were not significantly different in the within 6 weeks group and the between 6 and 8 weeks group, but the after 8 weeks group had a shorter RFS time compared with the other two groups (within 6 weeks group vs. after 8 weeks group; P = 0.0044). By disease stage, this trend was the same. The multivariable analysis showed that a larger tumor size (≥ 50 mm), pStage III, and the after 8 weeks group were independent prognostic factors for RFS (after 8 weeks group: hazard ratio, 2.05; P = 0.0069). The prevalence of hematogenous metastasis as the initial recurrence site increased by delayed initiation of S-1. A forest plot revealed that delayed administration after 8 weeks was associated with a greater risk of recurrence in most subgroups.
Conclusions
Postoperative chemotherapy with S-1 monotherapy for gastric cancer is recommended to begin within 8 weeks after surgery.