Current treatment options in triple negative breast cancer

Triple negative breast cancer (TNBC) refers to a subgroup of breast carcinomas that do not express the estrogen receptor, progesterone receptor, or human epidermal growth factor receptor type 2. This heterogeneous group of tumors has significant overlap with both basal-like tumors (defined through gene expression array) and BRCA1 mutation-associated tumors. Due to a lack of well defined clinical targets, chemotherapy is the standard of care treatment for TNBC. When compared with other breast cancer subtypes, TNBC exhibits at least equivalent, or often superior sensitivity to chemotherapy. However, despite this increased chemosensitivity, TNBC has a worse clinical outcome than other breast cancer subtypes. This has led to the investigation of DNA damaging chemotherapy agents, including platinum drugs, angiogenesis inhibitors, poly(ADP-ribose) polymerase inhibitors, novel microtubule inhibitors, and other targeted therapies in an effort to improve the outcome for patients with these high-risk tumors. Treatment decisions for patients with TNBC should be based on the best currently available evidence, which consists mainly of retrospective and prospective subgroup analyses and phase II prospective data. This review summarizes data from select neoadjuvant, adjuvant, and metastatic chemotherapy clinical trials which included analyses of treatment effects and outcomes in TNBC and/or basal-like breast cancer.