A phase I study of docetaxel/oxaliplatin/S-1 (DOS) combination neoadjuvant chemotherapy for patients with locally advanced adenocarcinoma of the esophagogastric junction.

BACKGROUND: The optimal dose of each drug used in the docetaxel, oxaliplatin, and S-1 (DOS) chemotherapy remains to be clarified for the Japanese population. The purpose of this study was to determine a recommended dose for a combination neoadjuvant DOS chemotherapy for Japanese patients with locally advanced adenocarcinoma of the esophagogastric junction (AEG). METHODS: Patients with cT3 or more advanced AEG without distant metastasis were eligible for this study. The planned dosages of docetaxel (mg/m2, day 1), oxaliplatin (mg/m2, day 1), and S-1 (mg/day, days 1-14) were: 50/100/80-120 at level 1, and 60/100/80-120 at level 2, respectively. The treatment cycle was repeated every 3 weeks, and patients were assessed for response to the treatment after 2 and 3 cycles. This study was registered in the UMIN Clinical Trial Registry (UMIN 000022210). RESULTS: We enrolled 12 patients with locally advanced AEG in this study. At dose level 1, one of the six patients experienced dose-limiting toxicity (DLT) of grade 3 diarrhea and grade 3 febrile neutropenia. Two of the next six patients also experienced DLT of need for more than 2-week delay of the start of the second cycle due to adverse events at dose level 2. Based on these results, level 2 was considered the recommended dose for this regimen. CONCLUSION: Recommended doses of docetaxel (mg/m2), oxaliplatin (mg/m2), and S-1 (mg/day) were 60/100/80-120. This chemotherapy scheme showed good preliminary efficacy with acceptable toxicity warranting a further phase II trial to investigate the efficacy of this regimen.