Endocrine therapy for breast cancer is one of the important tools in the treatment of breast cancer. It is popular among patients and physicians because of its therapeutic efficacy, long duration of efficacy, ease of administration, and low adverse effects. Endocrine therapy for breast cancer has been around for more than 100 years, and there are many topics in this field that are still troubling us, some of which have been definitely concluded and some of which still need to be further researched and explored. Now we are going to discuss the areas of concern of endocrine therapy for breast cancer in stages, which I will keep updating. The first topic of discussion: Am I menopausal? Whether or not menopause affects endocrine therapy decisions for breast patients, and menopause does not mean the cessation of menstruation. According to the Breast NCCN guidelines and the Chinese Breast Cancer Clinical Practice Guidelines, menopausal status in breast cancer is interpreted as follows: The definition of menopause varies from one breast cancer clinical trial to another. Menopause is usually the permanent termination of menstruation physiologically or the permanent loss of estrogen synthesis by the ovaries due to breast cancer treatment. The following criteria can be referred to: 1. post bilateral oophorectomy; 2. age >= 60 years; 3. age < 60 years and menopause without chemotherapy and treatment with tamoxifen, toremifene and ovarian function suppression for more than 1 year, while blood FSH and estradiol levels are in the postmenopausal range, while menopause in those who are taking tamoxifen, toremifene and age < 60 years, must be tested continuously Blood FSH and estradiol levels are in the postmenopausal range. It is also important to note that: 1. Women who are receiving LH-RH agonists or antagonists cannot be determined to be menopausal; 2. In women who were not menopausal prior to adjuvant chemotherapy, menopause cannot be used as a basis for determining menopause because the patient's ovarian function may still be normal or reversible despite cessation of ovulation or absence of menstruation after chemotherapy; 3. In women with chemotherapy-induced menopause, if aromatase inhibitors are considered as endocrine therapy, then effective ovarian suppression (complete bilateral ovariectomy or pharmacological suppression) needs to be considered, or continuous multiple monitoring of FSH and/estradiol levels to confirm that the patient is in a postmenopausal state. Endocrine treatment of breast cancer with AI inhibitors requires confirmation of the patient's menopausal status. For patients younger than 60 years of age, especially younger than 50 years of age, endocrine therapy requires serial testing of FSH and estradiol. It is best to confirm the menopausal status with a physician who specializes in breast cancer oncology for more professional guidance.