Aromatase Inhibitors: Are There Differences Between Steroidal and Nonsteroidal Aromatase Inhibitors and Do They Matter?

Disclosure: W.R.M. discloses that this article discusses letrozole (Novartis), anastrozole (AstraZeneca), and exemestane (Pfizer) for validation of mechanism of action. He has also been on the advisory board for Pfizer and received speaker’s honoraria. J.B. has received honoraria and research funding from Pfizer (exemestane). A.M.H.B. has received honoraria and research support from AstraZeneca (anastrozole research). R.W.B. discloses that this article discusses exemestane (Pfizer), anastrozole (AstraZeneca), and letrozole (Novartis) for use in breast cancer therapy. He also received an honorarium for participating in an expert panel meeting from Pfizer/CC Ford Healthcare. E.d.S. is an employee and has stock options in Pfizer (exemestane). P.E.L. has received speaker’s honoraria from Novartis, AstraZeneca, and Pfizer. A.L. discloses no conflict of interest. N.M. discloses that the article discusses exemestane (Pfizer), anastrozole (AstraZeneca), and letrozole (Novartis) for breast cancer treatment, and he has been on an advisory board and received honoraria from Pfizer (exemestane). T.M. has research funding from Novartis (letrozole) and has received a consulting fee from Pfizer (exemestane). H.S. has research funding and has received an honorarium from Pfizer (exemestane). P.E.G. discloses that this article discusses letrozole (Novartis), anastrozole (AstraZeneca), and exemestane (Pfizer) for validation of mechanism of action. He also discloses that the article discusses aromatase inhibitors for prevention (Novartis, AstraZeneca, Pfizer), and that he has received speaker’s honoraria from Novartis, AstraZeneca, and Pfizer. The content of this manuscript has been reviewed by independent peer reviewers to ensure that it is balanced, objective, and free from any commercial bias; they have disclosed no financial relationships relevant to this content.