Randomized study of orally administered fluorinated pyrimidines (capecitabine versus S-1) in women with metastatic or recurrent breast cancer: Japan Breast Cancer Research Network 05 Trial.

Purpose Capecitabine and S-1 are orally administered fluorinated pyrimidines with high-level activity against metastatic breast cancer (MBC). This randomized, multicenter, phase II study compared the activities and safeties of the oral fluoropyrimidines, capecitabine and S-1, in breast cancer patients.