The standard definition of triple-negative breast cancer (TNBC), says Lee Schwartzberg, MD, is disease with <1% estrogen receptor (ER) or progesterone receptor (PR) expression and those who are HER2-negative. In many situations, Schwartzberg advises that patients with very low levels of ER expression should be treated as if they have triple-negative disease, since a response to endocrine is unlikely.

The current standard of care for metastatic TNBC is chemotherapy, Richard Finn, MD, explains. The optimal classes of chemotherapy agents in this setting, says Schwartzberg, are taxanes and anthracyclines. There are varying standards for dosing and administration, depending on region and institution.

Although she utilizes nab-paclitaxel in her practice, Ruth O’Regan, MD, does not administer it preferentially following a head-to-head study showing that it was not superior to weekly paclitaxel. She adds that for a patient who has an allergic reaction to paclitaxel, nab-paclitaxel is a good alternative.

A subanalysis of the GeparSepto study presented at the 2014 SABCS meeting suggested that neoadjuvant nab-paclitaxel could be superior to standard paclitaxel in patients with breast cancer. In those with TNBC, the pCR rate was 48.2% in the nab-paclitaxel group compared with 25.7% for conventional paclitaxel (P <.001).