Complexity of the response evaluation during primary systemic therapy of breast cancer.

e12010 Background: We analyzed the accuracy of different response evaluation score systems in a group of breast cancer patients treated with primary systemic therapy (PST). The score systems tested were based on the metabolical, morphological and proliferation markers of tumor response. Methods: We report on 42 patients in whom staging FDG-PET/CTs were carried out before and after the PST. Maximal SUVs (Standardized Uptake Values) and morphological changes were evaluated in the primary tumor (PT) and axillary lymph node (AL) region. Ki-67 labeling indexes (LI) were measured in the core-biopsies and surgical specimens. Response scoring was performed with the Chevallier and Sataloff (pathological), WHO and RECIST (morphological), EORTC and PERCIST (metabolical) systems and a Ki-67 LI score. Results: The SUVmax and size decreased significantly in the PTs (p<0.001;<0.001) and in the ALs (p<0.001;=0.027). Ki-67 LI decrease was significant (p=0.001). Significant differences were detected between the complete re...