Delay in initiation of postoperative adjuvant chemotherapy with S-1 monotherapy and prognosis for gastric cancer patients: analysis of a multi-institutional dataset

Abstract

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.Publisher's Note Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

Multi‐institutional analysis of the prognostic significance of postoperative complications after curative resection for gastric cancer

“…To our knowledge, convincing data consistent with these findings have not been published subsequent to the implementation of standardization of postoperative adjuvant chemotherapy in Japan. We recently reported that delayed initiation of S‐1 is associated with worse prognosis . Moreover, the importance of the duration of administration is demonstrated by the OPAS‐1 trial .…”

“…We recently reported that delayed initiation of S-1 is associated with worse prognosis. 30 Moreover, the importance of the duration of administration is demonstrated by the OPAS-1 trial. 31 Our data suggest that postoperative complications confer a negative effect on prognosis through interference with adjuvant treatment.…”

Propensity-score-matched analysis of a multi-institutional dataset to compare postoperative complications between Billroth I and Roux-en-Y reconstructions after distal gastrectomy

“…linear and circular staplers) and laparoscopic surgery allow surgeons to select reconstruction methods with their discretion. In addition, worse perioperative course, more postoperative complications, and delayed postoperative adjuvant chemotherapy lead to worse prognosis in patients with gastric cancer [14][15][16][17]. Therefore, the clinical importance of preventing postoperative complications is increasing, and it is worthwhile to re-evaluate the differences in postoperative complications by reconstruction method after distal gastrectomy.…”

Prognostic effect of postoperative duration until adjuvant chemotherapy and cumulative S-1 dose in gastric cancer

“…PDAC has been reported to be an independent prognostic factor in other types of cancer, with various cutoff values suggested, including 12 weeks [10] and 8 weeks in colon cancer [15][16][17] and 13 weeks (91 days) in breast cancer [18]. With regard to gastric cancer, various cut-off values of PDAC have been reported as prognostic factors, ranging from 4 to 8 weeks [12,16,[19][20][21]. Our PDAC cut-off value of 7 weeks could also be a candidate indicator.…”