Aromatase inhibitors and ER positive breast cancer

Happy Monday everyone!

Why are aromatase inhibitors effective in post menopausal women who have breast cancer and why not in women who are premenopausal?

I was asked this question during rounds.

Before menopause, ovarian aromatase is responsible for the majority of circulating estrogen and is exquisitely sensitive to changes in luteinising hormone (LH). Following menopause, aromatase in fat and muscle may be responsible for much of the circulating estrogen.

In premenopausal women, AIs have a limited ability to reduce circulating estrogen. Unlike postmenopausal women, premenopausal women have a large amount of aromatase substrate present in the ovary.

The exquisite sensitivity of the ovarian aromatase promoter to gonadotrophins, which increase dramatically after AI administration, makes AIs less effective in inhibiting ovarian estrogen production. Thus, AIs are generally not given to premenopausal women for breast cancer treatment.

If it is administered, it is given with the addition of a medication to suppress the rise in gonadotrophins and subsequent increase in hormone levels.

That's all!
It's been a crazy month but I'm back to blogging. Yaay! (:
-IkaN