Hormonal changes with anastrozole treatment in breast cancer

Abstract

e12026 Background: Aromatase inhibitors are a class of drugs that inhibit tumor growth in hormone receptor positive breast cancer, in postmenopausal women. They inhibit the conversion of androgens to estrogens. Both clinical benefit and side effects are believed to be due to alterations in blood hormonal levels. Methods: Clinical charts of postmenopausal women with estrogen receptor positive breast cancer, receiving anastrozole 1 mg daily, were reviewed to determine the clinical side effects and blood hormonal changes during treatments, at a community oncology practice. Hormonal levels measured were serum testosterone, serum estrogens and prolactin levels. Results: There were 31 postmenopausal women age 52–73 (median 62) years, receiving anastrozole 1 mg daily. Duration of treatment was 8 to 42 (median 24) months. Clinical side effects noted were joint pains in 4 patients; mild to moderate hot flashes in 4; temporary nausea lasting for 1 week in 3; and vaginal dryness in 2 patients. Serum estrogen levels dropped by 20% in 10 patients from baseline but remained within normal range (14–103 pg/mL), there were no changes in serum testosterone (range 14–76 ng/mL) or prolactin (2.8–29 ng/ml) levels. 2 out of 4 patients with joint pains had testosterone levels in upper range, and remained unchanged during treatments. Conclusions: Anastrozole 1 mg daily is well tolerated in clinical practice, in terms of side effects and does not cause significant blood hormonal changes. No significant financial relationships to disclose.