Long-Acting Luteinizing Hormone-Releasing Hormone Agonist for Ovarian Hyperstimulation Induced by Tamoxifen for Breast Cancer.

Tamoxifen treatment for breast cancer may induce ovarian cysts and supraphysiological levels of serum estrogen. We report successful management with luteinizing hormone-releasing hormone (LHRH) agonist of ovarian hyperstimulation induced by tamoxifen. A 49-year-old woman was operated on for invasive ductal carcinoma of the right breast. She received breast irradiation and adjuvant tamoxifen therapy. After 2 years, she had a cystic ovarian mass, and her serum concentration of estradiol was 1280 pg/mL. She was treated with an injection of 11.25 mg leuprolide acetate, a long-acting LHRH agonist, without abandoning tamoxifen therapy. The levels of estradiol decreased to <10 pg/mL and the cystic mass disappeared 2 months later. Three-month depot treatment with LHRH agonists can be useful for patients receiving tamoxifen for breast cancer who have ovarian cysts and supraphysiological levels of estrogen.