Multicenter cohort study of early FDG-PET for estimating outcomes after initial treatment for metastatic breast cancer

Optimizing treatment decisions in metastatic breast cancer (mBC) can alleviated patients’ burden and improve quality of life. The IMPACT-MBC cohort study, at four centers in The Netherlands, evaluated clinical utility of early metabolic change on FDG-PET for improving outcome estimation compared with standard diagnostic evaluation in patients with newly diagnosed mBC. The analysis included 200 patients. Baseline asscessment included metastasis biopsy procedure and FDG-PET and CT imaging. Early FDG-PET was performed after 2 weeks of treatment, and CT response evaluation after 8 weeks. Patients without disease progression on early FDG-PET had better median progression-free survival and overall survival than patients with disease progression on early FDG-PET. Among patients without progression on CT after 8 weeks, those with progression on early FDG-PET had a median overall survival of 22.3 months, whereas patients without progression on both CT and early FDG-PET had a median overall survival of 50.1 months. The authors conclude that early FDG-PET imaging may improve outcome estimation in newly diagnosed mBC compared to standard CT alone.