Abstract:

Ovarian function suppression (OFS) has been used in the treatment of breast cancer for decades. Early adjuvant treatment studies have confirmed that the application of OFS alone can reduce the recurrence risk of breast cancer patients under the age of 50 and improve their survival. With the emergence of new evidence-based medical data, the Breast Cancer Professional Committee of the China Anti-Cancer Association convened domestic clinical experts in the field of breast cancer treatment, who jointly discussed and formulated the "Chinese Consensus of Ovarian Function Suppression in Early Breast Cancer (2021 edition) " on the basis of the 2018 edition. Consensus suggests that gonadotropin-releasing hormone agonist (GnRHa) should be the first choice of OFS for premenopausal hormone receptor-positive (HR positive) early breast cancer. Medium- and high-risk premenopausal HR positive breast cancer patients are recommended for endocrine therapy including OFS; low-risk patients are recommended for selective estrogen receptor modulator (SERM) monotherapy; premenopausal patients who use aromatase inhibitor (AI) instead of SERM need to receive OFS at the same time. For the medium- and high-risk patients with premenopausal HR positive early breast cancer, or the medium/high-risk patients analyzed by subpopulation treatment effect pattern plot (STEPP), the combination of OFS and AI is recommended, and the combination of OFS and SERM is also an alternative choice. For patients with contraindications or at risk of contraindications to SERM, OFS combined with AI is recommended. The adjuvant endocrine therapy should be decided based on the status of ovarian function before adjuvant chemotherapy. If ovarian function protection is considered, GnRHa plus chemotherapy is recommended, which does not affect the survival benefits. If not, it is recommended that GnRHa can be used sequentially after chemotherapy. It is recommended that patients with confirmed ovarian function status after chemotherapy should not use GnRHa. The GnRHa adjuvant endocrine therapy should be used for 5 years. After 5 years, it is recommended to continue endocrine therapy combined with OFS for 5 years or 5 years of SERM therapy if the patients are still premenopausal and well tolerated. For low-risk patients who choose OFS instead of chemotherapy, OFS combined with endocrine therapy can be considered for 2 years. Full communication with patients based on adverse events of the OFS is needed before decision making. The sound management of adverse events will effectively relieve symptoms and increase the treatment compliance. For patients with OFS, it is not recommended to monitor estrogen levels routinely during the treatment and make decisions according to the test. However, when incomplete ovarian function suppression is suspected (including changes in usage such as unskilled injection, replacement of dosage forms, or indications of ovarian function recovery, such as menstrual recovery and/or the fluctuating perimenopausal symptoms), estrogen testing can be performed. For premenopausal patients, no matter HRs are positive or negative, it is recommended to use ovarian function suppression drugs before and during (neo)adjuvant chemotherapy to protect ovarian function and reduce the risk of ovarian function failure and impaired fertility. It is recommended to start using GnRHa 2 weeks before chemotherapy, once every 28 days, until 2 weeks after the last dose of chemotherapy.In addition, the consensus suggests that premenopausal patients with sufficient OFS should be included in the clinical trials so as to investigate the impact of HR positive breast cancer drugs on tumor biological characteristics and long-term quality of life.

Key words: Breast cancer, Ovarian function suppression, Endocrine therapy, Expert consensus