GNRH1 and breast cancer: Among the patients, 295 were excluded from the study for the following reasons: 275 patients had insufficient hormone records, 12 patients received GnRH agonist administration after breast cancer diagnosis, 48 patients received bilateral oophorectomy or hysterectomy, 12 patients lack information on their menstruation status, and 27 patients failed to follow-up (several patients were excluded for two or more of the aforementioned reasons).