How would you treat HR positive, HER2 positive metastatic breast cancer in patients with a borderline or poor performance status?   

For HR positive, HER2 positive metastatic breast cancer in this patient, I would favor a combination with endocrine therapy + trastuzumab, not chemotherapy plus trastuzumab. This combination has been shown to be more effective versus endocrine therapy alone (Huober et al., PMID 21862331) and is incl...