How would you treat a premenopausal patient with ER/PR+, Her2 (-) metastatic breast cancer patient who progresses on tamoxifen?

I would give her maintenance fulvestrant high dose with palbociclib given she had progressed on tamoxifen (so combination anastrozole and fulvestrant maintenance will not be an ideal choice). While neither S0226 (first-line and few with acquired or innate resistance) and Paloma 3 (second line or first-line aquired endocrine-resistance setting) tested maintenance, it will be reasonable to extrapolate from Paloma-3 PFS and QOL benefit. You could also give her ovarian suppression if she is still pr...

I would favor combining ovarian function suppression with an AI and a cdk 4/6 inhibitor (palbociclib or ribociclib, whichever is the least expensive - abemaciclib is not yet approved in this setting though likely will be soon based on data from MONARCH-3 presented at ESMO). While there are no randomized clinical trial data that demonstrate the benefit of 'maintenance' endocrine therapy after a response to chemotherapy in patients with ER+/HER2- metastatic disease, administration of this treatmen...

Ovarian suppression plus an AI +/- a CDK 4/6 inhibitor depending on disease pace and prior endocrine sensitivity. Generally, unless rendered postmenopausal, there is a limited role for fulvestrant and it should be avoided in premenopausal women.

Although S0226 showed an effect for combined fulvestrant+Anastrozole vs Anastrozole alone, this effect was associated with a significant and contiuously lower anastrozole levels on PK testing in the combination arm, and thus most likely S0226 is more of a...