How would you treat a patient with a known history of ER/PR 90% and HER2 negative who develops skeletal metastatic disease on adjuvant endocrine therapy but now ER is only 2% and is PR and HER2 negative?

While I sometimes question results of receptors obtained from decalcified bone biopsies, this patient's clinical history (high risk by Mammoprint despite strongly positive hormone receptors, early disease recurrence) suggests that the behavior of her cancer is being determined by a hormone therapy-r...