Sweden Cancerome Analysis Network - Breast Recurrence (SCAN-B-rec)

This trial is collecting blood samples and health data from patients with advanced breast cancer to study cancer genetics and how tumors change over time, which could help improve future treatment strategies. **You may be eligible if...** - You have been diagnosed with advanced breast cancer, including locally advanced disease that cannot be surgically removed, or cancer that has spread to other organs (Stage IV) - You are 18 years or older - Your overall health is reasonably good (ECOG performance status 0–2) - Your cancer is detectable by physical exam or imaging **You may NOT be eligible if...** - Your cancer is early-stage and has not spread - You are in very poor health (ECOG performance status 3 or above) - You have no assessable or measurable disease - You have had imaging more than 6 weeks before enrollment without a recent update Talk to your doctor to see if this trial is right for you.