The consensus points to the importance of adjuvant endocrine therapy for patients with hormone receptor (HR)-positive luminal A and luminal B breast cancers to reduce the risk of recurrence and prolong survival. Endocrine therapy for breast cancer has a history of more than 100 years and is one of the important methods of systemic treatment for breast cancer. 1.What are the commonly used endocrine therapy drugs for breast cancer? Endocrine therapy for premenopausal women includes selective estrogen receptor modulators (tamoxifen or toremifene); luteinizing hormone-releasing hormone (LH) agonists (goserelin and leuprolide acetate); surgical or radiotherapy oophorectomy; progesterone (progesterone); androgens (methyltestosterone); and high-dose estrogen (ethinyl estradiol). Endocrine therapy for postmenopausal women includes non-steroidal aromatase inhibitors (AI, anastrozole and letrozole); steroidal aromatase inhibitors (exemestane); serum estrogen receptor modulators (tamoxifen or toremifene), ER downregulators (fluvastatin), progestins (megestrol acetate), androgens (fluoxymesterone) and high-dose estrogens (ethinyl estradiol). 2. Time frame of endocrine therapy, 5 years or 10 years? For hormone receptor positive patients, the choice of early adjuvant therapy and the need to extend the course of treatment to 10 years?The data from the ATLAS and aTTom studies have given a positive answer to clinical practice. The trials have all confirmed that 10 years of tamoxifen (TAM) treatment reduces breast cancer recurrence and mortality rates. As a result, the National Comprehensive Cancer Network (NCCN) 2014 clinical practice guidelines for breast cancer, among others, have been modified accordingly, stating that the time frame for tamoxifen treatment can be extended from 5 to 10 years for some patients. The MA17 trial, a study of 5 years of TAM treatment followed by 5 years of sequential letrozole, showed that subsequent adjuvant endocrine therapy with AI was effective in some patients; subgroup analysis showed that those who were premenopausal at diagnosis but reached menopause after TAM treatment benefited more significantly from subsequent intensive adjuvant therapy with letrozole than those who were postmenopausal at diagnosis. In view of these results, premenopausal hormone receptor (HR)-positive patients who are still in premenopausal status after 5 years of TAM therapy may choose to continue TAM therapy up to 10 years; if they are already in postmenopausal status, they may choose to continue AI therapy for 5 years. 3. Should premenopausal patients with HR-positive early breast cancer undergo ovarian function suppression (OFS) and should aromatase inhibitors be added? In the 2015 St. Gallen Consensus Expert Poll, most experts supported the addition of OFS for patients <35 years old, patients with ≥4 lymph nodes, and for patients who are still premenopausal after chemotherapy and grade III patients, 60-80% of experts supported the choice of OFS. In postmenopausal patients with hormone receptor-positive breast cancer, the choice of endocrine therapy is AI. Currently, several large-scale multicenter clinical trials, including ATAC, BIG1-98 and IES031, have reached a consensus that aromatase inhibitors are safer and more effective than tamoxifen for postmenopausal patients with ER-positive breast cancer. The consensus has been that aromatase inhibitors are safer and more effective than tamoxifen in postmenopausal ER-positive breast cancer. In patients treated with aromatase inhibitors, it is important to monitor bone mineral density; if osteoporosis develops, calcium and vitamin D supplements should be given, with the addition of bisphosphonates and denosumab if necessary. for patients with premenopausal diagnosis of breast cancer, postmenopausal (physiologic or chemotherapeutic effects) use of aromatase inhibitors remains beneficial. 5. Which treatment option is preferred if endocrine therapy is given to postmenopausal patients with recurrent metastatic HR+ after adjuvant therapy? In the treatment of advanced postmenopausal patients, patients with recurrence and metastasis after adjuvant therapy with TAM have the option to switch to AI, but for patients with recurrence and metastasis after using AI in adjuvant therapy, what should be the choice of advanced endocrine therapy?The GlobalConfirm study confirmed that in postmenopausal HR-positive breast cancer patients treated with endocrine therapy, the efficacy of fulvestrant 500 mg was superior to In 2014, the ChinaConfirm study reported in SABCS reconfirmed the efficacy of second-line treatment with fulvestrant 500 mg over 250 mg in the Chinese population, and a subgroup analysis showed that in patients with recurrent metastases after AI treatment, patients in the fulvestrant 500 mg group had a 1-fold longer progression-free survival (PFS) than those in the 250 mg group. (5, 8 months vs. 2, 9 months, HR=0, 65), suggesting that the selection of fulvestrant 500 mg may increase the clinical benefit for patients who failed AI therapy. 6. Is everolimus an ideal choice after AI treatment failure? Resistance to endocrine therapy in hormone receptor-positive patients sometimes occurs. One mechanism of resistance is activation of the mammalian target of rapamycin (mTOR) signal transduction pathway. The phase III clinical trial (BOLERO-2) targeted postmenopausal hormone receptor-positive advanced progressive or recurrent breast cancer with exemestane with or without the mTOR inhibitor everolimus. The final results after 18 months of follow-up showed that everolimus combined with exemestane had a significantly longer median PFS compared to exemestane alone, 11,0 months and 4,1 months, respectively. The new NCCN guidelines state that the evidence for BOLERO-2 is compelling enough to consider the addition of everolimus in exemestane patients who meet the BOLERO-2 enrollment criteria.