A Phase II Study of S-1 Monotherapy as a First-line Combination Therapy of S-1 Plus Cisplatin as a Second-line Therapy, and Weekly Paclitaxel Monotherapy as a Third-line Therapy in Patients with Advanced Gastric Carcinoma: A Second Report

Background: We have previousy reported on a Phase II study of S-1 monotherapy as a first line, combination therapy of S-1 plus cisplatin as a second line, and weekly paclitaxel monotherapy as a third line therapy in patients with advanced gastric carcinomas. The median survival time (MST) of patients over the whole course of treatment was not previously calculated because 12 out of 19 patients had not yet succumbed. Since then, we have calculated the MST for this study and herein report our findings. Patients and Methods: Between 2002 and 2005, 19 patients were enrolled in this study. Chemotherapy consisted of either 60 mg/m(2) of S-1 for 4 weeks at 6-week intervals, a combination of 60 mg/m(2) S-1 for 3 weeks and 60 mg/m(2) cisplatin on day 8 at 5-week intervals, or 60 mg/m(2) paclitaxel at days 1, 8, and 15, at 4-week intervals. The regimens were repeated until the occurrence of unacceptable toxicities, disease progression, or patient noncompliance. The primary end point was the overall survival. Results: The median survival time was 774 days. The response rates were 33.3% (3/9), 12.5% (1/8), and 0% (0/4) after the first, second, and third line chemotherapies, respectively. The major adverse hematological toxicity was leukopenia, which reached grades 3-4 in all lines of chemotherapy investigated. In addition, the major adverse non-hematological toxicity was anorexia, which reached grade 3-4 in second line chemotherapy, and no deaths were attributable to the adverse effects of the drugs. Conclusion: This sequential therapy was an effective treatment for advanced gastric cancer with acceptable toxic side-effects. We considered this therapy to be effective because of the smooth transition to the next regimen.