S-1/docetaxel compared with the other standard S-1 based regimens as a first-line chemotherapy for patients with advanced gastric cancer.

Abstract

e15173 Background: S-1 monotherapy or S-1/CDDP have remained important as a standard chemotherapy regimen for patients with advanced gastric cancer (AGC), based on the randomized phase III trials. Although S-1/docetaxel has been reported highly active and well tolerated for AGC by many researchers, it could not show the superiority compared with S-1 monotherapy in the recent international randomized trial. We have also demonstrated that it might be effective for patients with Stage III AGC in both preoperative and postoperative adjuvant setting. The aim of this study was to evaluate efficacy, toxicity and validity of S-1/docetaxel retrospectively, compared with the standard regimens. Methods: We conducted a retrospective review of the data of 89 patients with AGC who received chemotherapy who were given S-1-containing regimens as the first line chemotherapy; 15 patients treated with S-1 monotherapy, 21 with S-1/CDDP, and 53 with S-1/docetaxel. The objective response, adverse event (AE), progression-free survival (PFS), and overall survival (OS) were compared between the three groups. Results: The overall response rates (ORRs) were obtained 6.7%, 38.1% and 30.2% for S-1 monotherapy, S-1/CDDP, and S-1/docetaxel, respectively. The incidence of AEs was more frequent in S-1 based combined treatments than in the S-1 monotherapy, however there was no significant difference in the severe AEs between each group. Survival data showed that the PFSs were 121 days, 199 days and 178 days, respectively, and there was the significant difference between S-1 monotherapy and S-1/docetaxel (p<0.05). The overall survival showed that the MSTs were not significantly different. The conversion rate to the subsequent treatments following S-1 monotherapy was higher than the other treatments. Conclusions: S-1/docetaxel was active and well tolerated for the patients with ARGC as the first line. Although the Japanese guideline for treatment of gastric cancer recommends S-1 monotherapy or S-1/CDDP as the standard regimens, docetaxel could be applied for patients with AGC in case of CDDP-resistant or –naïve patients.