When aromatase inhibitors are used to treat breast cancer, it is important to note that adjuvant endocrine therapy in patients with early breast cancer is her first choice. There are a number of evidences suggesting that prolonging the quality of the content will further benefit patients, but prolonged The optimal time has not yet been determined. A randomized clinical trial was conducted from 2012 to 2018. A systematic review was conducted to extend the duration of adjuvant endocrine therapy regardless of overall survival, but prolonged AR (aromatase inhibitor) compared with placebo. The treatment of breast cancer recurrence, and the risk of symmetrical breast cancer is significantly reduced, aromatase inhibitors are divided into two major categories of steroids and lung steroids, non-steroidal anastrozole and letrozole, The steroidal drug is exemestane. The most common side effects are calcium loss, osteoporosis, severe fractures, bone-related events, joint pain, muscle pain, dyslipidemia, and increased risk of the cardiovascular system. There are also hot reactions such as hot flashes, vaginal dryness, etc. Therefore, adverse reactions to endocrine drugs during this treatment should be taken seriously.