Chemopreventive Effects of Anastrozole in a Premenopausal Breast Cancer Model

Abstract

Background: Monotherapy with aromatase inhibitors has no established role in premenopausal breast cancer in women and is an area of future exploration. Materials and Methods: In this study, chemopreventive effects of anastrozole in the model of N-methyl-N-nitrosourea-induced premenopausal mammary carcinogenesis in female rats were evaluated. Anastrozole was dietarily administered at two concentrations: 0.05 mg/kg (ANA 0.05) and 0.5 mg/kg (ANA 0.5). Basic parameters of experimental carcinogenesis and side-effects on selected organs after anastrozole treatment in animals were assessed. Results: In the ANA 0.5 group, anastrozole suppressed tumor incidence by 40% (p<0.05) and tumor frequency by 57% (p<0.01), as well as lengthening the latency period by 10 days (p=0.084) compared to control animals. Adverse effects of anastrozole on the genital system (uterus and vagina) and lipid and bone metabolism in rats were not found. Anastrozole did not alter serum concentrations of estradiol, testosterone or dehydroepiandrosterone in animals. An increase in the body weight gain of rats in the ANA 0.5 group compared with the controls (p<0.01) was observed. Conclusion: This study is the first about the antineoplastic effects of anastrozole in a model of premenopausal mammary carcinogenesis in female rats.