Toremifene, a selective estrogen receptor modulator, is commonly used in China for premenopausal breast cancer patients. This real-world study aimed to compare patient-reported outcome (PRO) and survival between toremifene and aromatase inhibitor (AI) plus ovarian function suppression (OFS) in patients with moderate-/high-risk premenopausal hormone receptor (HR)-positive breast cancer. The primary endpoint was PROs, assessed using SF-36 and EQ-5D-5L questionnaires between January and March 2023. A total of 392 patients were included, with 171 receiving toremifene and 221 receiving AI. The toremifene group showed significantly higher scores in the role physical (