Systemic Therapy for Recurrent Metastatic TNBC

Joyce O’Shaughnessy, MD:In metastatic triple-negative breast cancer we often utilize cytotoxic chemotherapy agents that we had used in the adjuvant or neoadjuvant curative setting. The most common example of this would be a taxane. Patients often receive paclitaxel in the neoadjuvant or adjuvant setting. In the 20% to 25% of women who develop recurrent metastatic triple-negative breast cancer, taxanes are very commonly utilized and are effective agents. As long as a woman’s breast cancer didn’t recur within a year of finishing her adjuvant or neoadjuvant therapy, it’s very likely that she’ll benefit again from a taxane in the metastatic setting. Patients whose disease recurs very quickly after neoadjuvant or adjuvant chemotherapy tend to have chemotherapy-refractory disease and don’t really benefit from chemotherapy. Another example is platinum agents. Carboplatin and cisplatin are used in the metastatic setting, but we use carboplatin quite a bit in the preoperative or adjuvant setting, or in the curative setting for metastatic triple-negative breast cancer. We also utilize it in the metastatic setting. So it’s something that you definitely can use provided enough time has gone by—from finishing the adjuvant or neoadjuvant therapy to the development of metastatic disease.

In triple-negative breast cancer, it’s a situation where you either cure it or you’re going to have multi-drug resistant disease. We utilize 3, 4, or 5 chemotherapy agents in the curative settings these days for triple-negative breast cancer. If metastatic disease recurs despite that therapy, you will have drug-resistant clones. The patient can still go on to benefit from cytotoxic therapy, but we will not be able to cure them in the metastatic setting because of the development of drug-resistant clones. So with triple-negative breast cancer, you either cure it in the beginning, or, unfortunately, you will have a difficult problem in the metastatic setting with multiple cells that are resistant to the prior chemotherapy.

Transcript edited for clarity.