Are aromatase inhibitors effective in endometriosis treatment?

INTRODUCTION: Current therapies for endometriosis cannot completely cure the disease, and patients present with high recurrence rates. Novel medical approaches are, therefore, needed. AREAS COVERED: In endometriosis, aromatase was long thought to be involved in the in situ formation of estrogens, leading to a positive feedback loop favoring estrogens, themselves inducing prostaglandin production and inflammation. This hypothesis led to aromatase inhibitors (AIs) being proposed as the new medical therapy for endometriosis, as reported in all the studies reviewed here. Recent findings nevertheless indicate that aromatase may be less implicated in endometriosis than previously postulated. More than 10 years after the first successful treatment of a rare and severe case of postmenopausal endometriosis with an AI, there are only three small randomized controlled trials in the literature. EXPERT OPINION: Until recently, AIs were thought to be an alternative to current medical therapies for endometriosis. However, recent findings question their real utility in clinical practice in the context of this disease. Because there is no strong evidence of their efficacy or benefit compared to other molecules in existing clinical trials, AIs need to be investigated further in well-designed studies to confirm/disprove their hypothetical impact on endometriotic lesions.