Confirmed three-year RFS and OS of the randomized trial of adjuvant S-1 versus S-1 plus docetaxel after curative resection of pStage III gastric cancer (JACCRO GC-07).

Abstract

159 Background: JACCRO GC-07 is a randomized controlled trial to explore postoperative S-1/docetaxel compared to S-1 alone after D2 gastrectomy for pStage III gastric cancer (GC) patients. The second interim analysis demonstrated that the significant improvement of RFS was obtained by S-1/docetaxel compared to S-1 alone. The study was terminated by the recommendation of independent data and safety monitoring committee and the results were reported at ASCO 2018 and published in the Journal of Clinical Oncology (Yoshida K et al. 2019; 37:1296-1304). As 3 years have passed after completion of the enrollment, preplanned analysis was performed with the updated information of the patients. Methods: Patients with pStage III GC were randomly assigned to receive either S-1/docetaxel (S-1 80-120mg/body on days 1-14 with a 7-day rest followed by docetaxel 40mg/m2 on day 1 and S-1 80-120mg/body on days 1-14 every 21 days for 6 cycles followed by S-1 80-120mg/body on days 1-28 every 42 days for 4 cycles) or S-1 (80-120mg/body on days 1-28 every 42 days for 8 cycles) after D2 gastrectomy. Block randomization was performed by a central interactive computerized system stratified by the stage (IIIA, IIIB, IIIC) and histological type (differentiated or undifferentiated). The sample size of 1,100 was necessary to detect a 7% increase in the 3-year RFS. The primary endpoint was 3y RFS and the secondary endpoints were OS, TTF and safety. Results: In the present analysis, 400 recurrences and 324 deaths were confirmed among 912 patients during the median follow-up period of 42.5 months (0.3-85.16). The 3y RFS of 67.7% in the S-1/docetaxel group was significantly superior to 57.4% in the S-1 group (HR 0.715, 95% CI: 0.587-0.871, p = 0.0008) and the 3y OS was 77.7% in the S-1/docetaxel group and that of S-1 group was 71.2%, respectively (HR 0.742, 95% CI: 0.596-0.925, p = 0.0076), confirming the significant improving effect on the survival of the patient. Conclusions: Adjuvant S-1 plus docetaxel is recommended for patients with pStage III gastric cancer who underwent D2 gastrectomy without neoadjuvant chemotherapy. Clinical trial information: UMIN 000010337.