157 Background: The aim of this phase I study is to confirm the dose of cisplatin as adjuvant combination chemotherapy with S-1 in gastric cancer patients in an outpatient setting. Methods: The first course was initiated with S-1 monotherapy on days 1-28. From the second to sixth course, S-1 was administered on days 1-28 and cisplatin was added on days 1, 15, and 29. Dose level of cisplatin was escalated as follows: 20 mg/m2 (level 1); 25 mg/m2 (level 2); 30 mg/m2 (level 3). Results: Between Sep. 2010 and Feb. 2014, 13 patients were entered into this study. The median age was 65 years. All patients had a performance status of 0. Final stages were: Stage IIIA, 4; Stage IIIB, 8; and Stage IIIC, 1. The first three patients enrolled at level 1 and none of the three patients experienced Dose-limiting toxicity (DLT). However, one patient at level 2 could not complete administration of cisplatin. Therefore, an additional three patients were entered into level 2. Since these patients did not experience any severe adverse events, level 2 was completed. The first patient enrolled at level 3 had experienced leukocytopenia and elevated bilirubin. These toxicities did not resolve to the level of the starting criteria for the next course within 21 days. In the next patient, the third course could not be started within 21 days because of fatigue and anorexia. Based on these results, the Maximum Tolerated Dose and Recommended Dose were confirmed as level 3 and level 2, respectively. The DLT was >21-day delay of starting the next course. Three patients at level 1 completed combination adjuvant chemotherapy between the second and sixth course based on the protocol. During these treatments, no grade >2 hematological or non-hematological toxicities were experienced. At level 2, two out of six patients completed 5 courses of combination chemotherapy without experiencing severe adverse events. Three out of six patients at level 2 had received 4 courses of combination chemotherapy. Conclusions: Although further clinical trials are recommended to evaluate efficacy, this combination S-1 plus cisplatin regimen is expected to become a standard adjuvant treatment for gastric cancer in the outpatient setting. Clinical trial information: 601995.
Combination chemotherapy with S-1 plus cisplatin for gastric cancer that recurs after adjuvant chemotherapy with S-1: multi-institutional retrospective analysis
