My first Diagnosis was May 2018 as Stage 4 Metastatic Breast Cancer spread to bones. I started taking Tamoxifen only in July of 2018 since I am pre menopausal. They give this first as long as it shows signs its working. Last week I had a Petscan that showed NO metabolic cancer was remaining in my body.( Just the old scars or lesions on the bone , but they are dead) A bone biopsy a month beforehand had showed dead cancer and viable bone, so they ordered the PET scan. The bone mets were moderate throughout the upper half of my body and the breast cancer itself was fairly large. I can not find anyone else discussing this. I thought Metastatic Cancer could be slowed or slightly reversed, This was killed off. The doctor is very confused how a front line drug could do this in a short amount of time. Has anyone else encountered this with Tamoxifen.