Retrospective analysis of clinical results and predictors of response in chemo-naive patients with advanced gastric cancer treated with S-1, an oral fluoropyrimidine derivative, as single-agent chemotherapy.

BACKGROUND

Despite the fact that there are only a few reports of phase II studies, S-1 is widely used in single-agent or combination therapies for patients with advanced gastric cancer in Japan. We retrospectively analyzed the effectiveness of S-1 as single-agent chemotherapy for patients with advanced gastric cancer.

METHODS

A total of 119 patients with advanced or recurrent gastric cancer were treated with S-1 as first-line monochemotherapy from September 1999 to March 2003 at the National Cancer Center Hospital. S-1 was administered orally twice daily, at a standard dose of 80 mg/m2 per day for 28 days, followed by a 14-day rest.

RESULTS

One hundred and eleven patients were analyzed retrospectively. The overall response rate was 26.1% (29/111; 95% confidence interval [CI], 17.8% to 34.1%). Median time to progression and median overall survival were 141 days (95% CI, 108 to 175 days) and 378 days (95% CI, 310 to 447 days), respectively. The response rate of ascites, according to the Japanese classification of gastric carcinoma, was 36.8% (14/38; 95% CI, 25.4% to 56.6%). Among all of the pretreatment variables examined, hemoglobin level and the presence of lymph node metastasis were related to the response.

CONCLUSION

Single-agent chemotherapy of S-1 for chemo-naive patients with advanced gastric cancer was modestly effective and well-tolerated in the outpatient setting.