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

Am J Nucl Med Mol Imaging. 2020 Jun 15;10(3):135-142. eCollection 2020.

Abstract

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 18F-FDG-PET/CT imaging as stratification and 68Ga-PSMA-PET/CT. Primary sites of BC was identifying in all patients with 18F-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 18F-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. 68Ga-PSMA-11-PET/CT showed lower detection-rate (DRs) than did 18F-FDG-PET/CT in all patients with LUM-A and LUM-B HER2. All 18F-FDG PET/CT positive lesions in patients TPN (local, lymph nodes, and metastatic lesions) showed 68Ga-PSMA-PET/CT uptake (P<0.05). Sensitivities and specificities of 99.2% and 93.6% for 18F-FDG-PET/CT and for 68Ga-PSMA-11-PET/CT of 84% and 91.8% (P<0.05). Accuracy measured as AUC was 0.86-0.95 in 18F-FDG-PET/CT and 0.74-0.94 for 68Ga-PSMA-PET/CT (P<0.05). In Patient-Based analysis we found that patients triple-negative subtype (TPN) evaluated with 68Ga-PSMA-PET/CT identified a higher number of positive patients than did LUM A. We conclude that a significate DRs to imaging with 68Ga-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.

Keywords: 68Ga-PSMA; breast cancer; positron emission tomography computed tomography; theranostics.