The growth of estrogen receptor-positive breast cancer cells is mainly dependent on estrogen. In premenopausal women, estrogen is mainly derived from the ovary; in postmenopausal women, estrogen is mainly derived from peripheral tissues such as fat, muscle and liver, and the androgen is converted into estrogen by aromatase. Therefore, by inhibiting the aromatase, the level of estrogen in the body can be lowered to achieve a therapeutic effect.
The first-generation aromatase inhibitors have been eliminated because of their side effects and inconvenient use. The second-generation aromatase inhibitors have less side effects, but their efficacy is not superior to tamoxifen (tamoxifen). It is no longer used; third-generation aromatase inhibitors, such as letrozole, anastrozole, and exemestane, which have been gradually developed in recent years, are highly selective because they can inhibit aromatase. Strong, while the side effects are also significantly reduced.
Oral aromatase inhibitors have relatively low toxic side effects and are tolerated by most patients. The main side effects of long-term use of aromatase inhibitors are osteoporosis and dyslipidemia. Postmenopausal women have an increased risk of cardiovascular disease due to decreased estrogen levels after ovarian dysfunction, and breast cancer patients have further reduced estrogen and drug-related side effects such as dyslipidemia due to endocrine therapy-related drugs. The risk of vascular disease is further increased. Therefore, in the course of medication, attention should be paid to the management of dyslipidemia and the reduction of cardiovascular events.