A Study Comparing Cancer Imaging Approaches in People With Lobular Breast Cancer

This study is comparing different cancer imaging approaches (such as different types of PET and CT scans) for people with metastatic lobular breast cancer — a specific subtype of breast cancer — to see which methods best detect the spread of cancer throughout the body. **You may be eligible if...** - You are an adult (18+) with confirmed metastatic invasive lobular breast cancer (ILC) - Your cancer is estrogen receptor positive (ER+) and HER2 negative - You have a good performance status (ECOG 0–2) and a life expectancy of at least 12 months - You have received up to 2 prior lines of treatment for metastatic disease **You may NOT be eligible if...** - Your estrogen receptor expression is very low (less than 10%) - You have recently been on certain estrogen-blocking drugs without a proper washout period - You are pregnant or breastfeeding - You have another serious life-threatening illness Talk to your doctor to see if this trial is right for you.