Do you routinely check hormone levels to confirm postmenopausal status before adding aromatase inhibitors to OFS in premenopausal women with early breast cancer?

I avoid the issue by taking a sequential approach. I typically start premenopausal women on tamoxifen, then add OFS 4-6w later depending on their tolerance of tamoxifen, and then change to an AI after another 6-12 weeks.

It is easy to underestimate the severity of side effects that many premenopausal women experience from OFS and tamoxifen/AIs and I have found that this gradual approach tends to be more tolerable and is more likely to be adhered to than going all in from the beginning. I have al...

I check hormone levels to confirm the efficacy of ovarian suppression – but not specifically prior to adding an aromatase inhibitor. For example, in the TREND trial, it took a median of 14 days to achieve estradiol <2.7 pg/mL, and all patients achieved optimal ovarian suppression by the end of the first cycle – so most patients starting both concurrently wouldn’t be an issue.

For patients who are starting GnRH agonist therapy, I routinely check hormone levels to confirm ovarian suppression before adding an aromatase inhibitor. A small proportion of patients do not achieve suppression of ovarian function (Bellet et al., PMID 26729437), although the clinical implications of this lack of suppression aren't fully understood.

For those who have chemotherapy-induced amenorrhea, I also routinely check hormone levels to confirm ovarian suppression before starting an aromatase...