RADIomics to Predict HER2 Status And T-DXd Efficacy in Metastatic Breast Cancer: the RADIOSPHER2 Study

This is a data analysis study using imaging (CT and PET scans) to build a model that can predict whether a metastatic breast cancer tumor is HER2-positive and whether a targeted drug called T-DXd will work for that patient. **You may be eligible if:** - You have metastatic breast cancer - You had a biopsy from the liver, lung, lining of the chest, or bone in the metastatic setting, done between January 2005 and January 2024 - You have CT or PET-FDG scan images taken within 3 months before your biopsy or before your last treatment was stopped **You may NOT be eligible if:** - You do not have the required imaging available - Your HER2 status is unknown - Your biopsy was taken from a lymph node, soft tissue, or another organ not listed (liver, lung, pleura, or bone) Talk to your doctor to see if this trial is right for you.