Will you continue anti-estrogen therapy in the setting of initiation of TDM-1 for patients with metastatic ER+/HER2+ breast cancer?

The answer to this question has not been well studied, but the registration trials that led to the approval of T-DM1 (EMILIA and TH3RESA) did not use T-DM1 with concurrent hormonal therapy. Historically, we have avoided combining chemotherapy with hormonal therapy for breast cancer. This was in part...