GNRH1 and breast cancer: Common adverse events after GnRH agonists plus endocrine therapy in premenopausal women with HR+ breast cancer include hot flushes, nasopharyngitis, headache, back pain, insomnia, and musculoskeletal stiffness (Kurebayashi et al., 2017; Masuda et al., 2011; Noguchi et al., 2016).