I am certainly no doctor, but it could be a difference between pre and post menopausal women. "Tamoxifen use may be extended to 10 years based on new data demonstrating additional benefit. Women taking tamoxifen should be informed about the risks of endometrial proliferation, endometrial hyperplasia, endometrial cancer, and uterine sarcomas, and any abnormal vaginal bleeding, bloody vaginal discharge, staining, or spotting should be investigated. Postmenopausal women taking tamoxifen should be closely monitored for symptoms of endometrial hyperplasia or cancer." (ACOG Number 601 (Replaces Committee Opinion Number 336, June 2006. Reaffirmed 2020) unable to enter link)
I am not thrilled with AI's because of their effect on bones and heart. I have osteopenia and high cholesterol and do not want to take other meds to counter side effects. There has to be a better way...eventually.