Prospective Observational Study on Outcome of High-precision Hypo-fractionated Radiotherapy in Metastatic Breast Cancer (PRECISE-M)

This is an observational study (no experimental treatment is given) tracking the real-world outcomes of metastatic breast cancer patients who are receiving high-precision radiation therapy. The aim is to better understand how this type of radiation works in patients whose cancer has spread. **You may be eligible if...** - You have breast cancer that has spread to other parts of the body (metastatic) - You are receiving or planning to receive precision radiation therapy (IMRT, SBRT, or proton therapy) - You are willing and able to follow the study protocol **You may NOT be eligible if...** - You are unable to follow the study protocol Talk to your doctor to see if this trial is right for you.