Objective: Knowledge of the menopause status of a woman with breast cancer is important for good clinical practice. Long-lasting amenorrhea is frequent in this population, often for reasons other than definitive menopause. Antiestrogens like tamoxifen or oral aromatase inhibitors (AIs) may reactivate the ovary causing vaginal bleeding, menstruation, pregnancy, and unopposed endometrial stimulation. In contrast to tamoxifen, AIs are not active against breast cancer in the presence of functional ovaries. Antimüllerian hormone (AMH) is a potential marker of residual ovarian function that can predict not only the onset of menopause but also chemotherapy-induced amenorrhea (CIA) and fertility. We assess the value of AMH in women who recovered from CIA on an AI.
Methods: This is a series of six women with clinical and biochemical evidence of ovarian recovery during AI treatment. All six were premenopausal at breast cancer diagnosis and developed CIA. AMH, follicle-stimulating hormone, and estradiol levels were measured when patients developed clinical signs of ovarian recovery and/or when a gynecological procedure showed evidence of this.
Results: In all six AI-treated women, AMH levels were undetectable despite clinical, biochemical, or pathological evidence of ovarian reactivation after a long period of amenorrhea and sensitive biochemical markers indicating definitive menopause status.
Conclusions: Repeated biochemical monitoring of ovarian function remains important in women with breast cancer undergoing AI treatment because ovarian function can recover, AIs are not active with functional ovaries, and amenorrhea does not, by itself, confirm definitive menopause. Undetectable AMH levels do not exclude residual ovarian function in women with breast cancer on an AI.