Ga-68-PSMA PET/CT in the evaluation of locally advanced and metastatic breast cancer, a single center experience

Current research indicates that prostate-specific membrane antigen (PSMA) is related to angiogenesis of many solid tumors including breast cancer (BC), our objective is evaluating PSMA expression in primary tumor and metastatic BC by Positron emission tomography/computed tomography (PET/CT). In this retrospective study twenty-one patients with BC included all molecular subtypes, was evaluated with F-18-FDG-PET/CT imaging as stratification and Ga-68-PSMA-PET/CT. Primary sites of BC was identifying in all patients with F-18-FDG-PET/CT. We identified lymph node metastases in 17 patients (81%) and metastatic disease in 15 patients (71%). A total 127 lesions were detected by F-18-FDG-PET/CT, 30 of which were in the breast, 31 axillary lymph-node metastases, 25 mediastinal lymph-node metastases, 15 distant non-bone metastases and 26 bone metastases. Ga-68-PSMA-11-PET/CT showed lower detection-rate (DRs) than did F-18-FDG-PET/CT in all patients with LUM-A and LUM-B HER2. All F-18-FDG PET/CT positive lesions in patients TPN (local, lymph nodes, and metastatic lesions) showed Ga-68-PSMA-PET/CT uptake (P<0.05). Sensitivities and specificities of 99.2% and 93.6% for F-18-FDG-PET/CT and for Ga-68-PSMA-11-PET/CT of 84% and 91.8% (P<0.05). Accuracy measured as AUC was 0.86-0.95 in F-18-FDG-PET/CT and 0.74-0.94 for Ga-68-PSMA-PET/CT (P<0.05). In Patient-Based analysis we found that patients triple-negative subtype (TPN) evaluated with Ga-68-PSMA-PET/CT identified a higher number of positive patients than did LUM A. We conclude that a significate DRs to imaging with Ga-68-PSMA-PET/CT in the staging of locally advanced and metastatic BC with high rates in patients TPN, LUM B HER2(+) and HER2 overexpression. We believe that concept of theranostics it may be considered as a potential diagnostic and therapeutic target.