Efficacy of S-1 in patients with capecitabine-resistant breast cancer-Japan Breast Cancer Research Network (JBCRN) 04-1 trial.

ABSTRACT

BACKGROUND: S-1 is an orally administered fluorinated pyrimidine with high activity in metastatic breast carcinoma (MBC) and in chemotherapy-pretreated metastatic breast carcinoma. PATIENTS AND METHODS: Forty patients with MBC who did not respond to capecitabine-based chemo-therapy and then received S-1 were identified from our data base of records between 2006 and 2008. The clinico-pathological data and outcomes of these patients were then reviewed. RESULTS: The overall response rate was 27.8%. The median survival was 19.2 months, and the median time to disease progression was 6.2 months. The most common treatment-related adverse events (all grades) were hand-foot syndrome (15%), nausea (15%), vomiting (7.5%), disorder of taste (7.5%), and diarrhea (5%). However, the majority were mild to moderate in intensity, and only one patient experienced grade 3 (according to the National Cancer Institute of Canada Common Toxicity criteria) adverse events. Myelosuppression and alopecia were rare, and there were no reported treatment-related deaths. CONCLUSION: The results of the current study demonstrate that S-1 is an effective and well-tolerated treatment in patients with capecitabine-resistant MBC. In addition, it is a convenient, orally administered drug, which makes it an attractive agent for use in outpatient treatment.