Phase II study of docetaxel and S-1 (DS) as neoadjuvant chemotherapy for clinical stage III resectable gastric cancer.

Background: We conducted a phase II trial to evaluate the efficacy and safety of preoperative chemotherapy with docetaxel (DTX) plus S-1 for resectable advanced gastric cancer.

Patients And Methods: A total of 47 patients from 14 centers were centrally registered. Patients received DTX (35 mg/m(2)) on days 1 and 15, and daily oral administration of S-1 (80 mg/m(2)/day) for days 1-14 every 4 weeks for two courses, followed by gastrectomy with D2 lymphadenectomy. The primary endpoint was pathological response rate (pRR). This study was registered in the UMIN clinical trial registry (UMIN000000875).

Results: The primary endpoint pRR was 47 % (90 % confidence interval (CI), 34-60 %; p < 0.0001). The response rate to preoperative chemotherapy using Response Evaluation Criteria in Solid Tumors (RECIST) was 34 %. Forty-six patients (98 %) underwent surgery, and curative resection was performed in 44 patients. Thirty-seven patients completed the protocol treatment. The most common toxicities of neoadjuvant chemotherapy were grade 3/4 neutropenia (42 %), febrile neutropenia (4 %), grade 2 anorexia (21 %), and fatigue (15 %). Treatment-related death and operative mortality was not observed in this study.

Conclusions: The combination of docetaxel and S-1 was well tolerated. This is promising as a preoperative chemotherapy regimen for patients with potentially resectable advanced gastric cancer.