What systemic therapy would you offer to a postmenopausal patient with an unresectable local recurrence of HER2+/ER weakly + IDC?

For local recurrences, in general I think about 4 situations based on whether it is resectable or not and whether it is during or soon after adjuvant therapy or not. In this case, we have an unresectable local recurrence during adjuvant therapy within a year after surgery, since it is during adjuvant trastuzumab. Therefore, systemic therapy is needed and a change in therapy is needed.

In line with NCCN guidelines, I would biopsy the recurrence and recheck the markers to ensure it is still HER2 p...