Triple-negative breast cancer: role of specific chemotherapy agents

Cytotoxic chemotherapy remains the mainstay of treatment for triple-negative breast cancer (TNBC) despite the promise of new targeted and biologic agents. Many studies have shown significant benefit of chemotherapy in the neoadjuvant, adjuvant, and metastatic treatment of TNBC. Neoadjuvant chemotherapy studies have consistently reported higher response rates in TNBC than non-TNBC, and pathologic complete response has been shown to predict improved long-term outcomes for TNBC. Although the specific adjuvant regimens that may be most effective for TNBC are still being determined, third-generation chemotherapy regimens using dose dense or metronomic polychemotherapy are among the most effective tools presently available. The role of specific chemotherapy agents in the treatment of TNBC remains incompletely defined and warrants careful review to ensure that the most effective therapy is delivered while minimizing unnecessary toxicity. Platinum agents have seen renewed interest in TNBC based on a growing body of preclinical and clinical data suggesting encouraging activity. Taxanes and anthracyclines are active in TNBC and remain important agents but have not shown specific benefit over non-TNBC. Capecitabine has limited reported data in TNBC, but some reports suggest differential activity in TNBC compared with hormone receptor-positive breast cancer. TNBC is itself a heterogeneous group in which subgroups such as BRCA1 mutation carriers may have particular sensitivity to platinum agents and relatively less sensitivity to taxanes. Therefore, the identification of additional molecular biomarkers to predict response to specific chemotherapy is required to further improve treatment strategies with the current menu of chemotherapy options and future combinations with targeted therapies.