The evolving role of capecitabine in breast cancer

Breast cancer is the most common cancer and the second greatest cause of cancer-related death among women in the United States. Capecitabine is a selectively tumor-activated fluoropyrimidine carbamate that is converted to 5-fluorouracil by the sequential activity of these enzymes, the final of which is thymidine phosphorylase, which is overexpressed in many human cancers. Capecitabine as a single agent and in combination with other drugs is efficacious in previously treated and untreated metastatic breast cancer (MBC). The integration of capecitabine, either as a single agent or in combination with docetaxel, into adjuvant breast cancer therapy is justified due to its high antitumor activity in previously treated and untreated MBC, its tolerability, lack of cross-resistance with the anthracyclines and taxanes, and because combined docetaxel/capecitabine improves the overall survival of patients with MBC. Capecitabine is being evaluated as preoperative therapy in patients with operable breast cancer, as adjuvant therapy in patients with high-risk node-negative or node-positive disease, and as oral single-agent therapy in women > or = 65 years of age. This article is an overview of published studies of capecitabine in MBC and the studies that are planned or have been proposed to evaluate capecitabine as adjuvant therapy for breast cancer.