Clinical Value of 68 Ga-DOTA-Bombesin PET/CT Compared With 18 F-FDG PET/CT in the Staging of Breast Cancer.

Abstract

To prospectively evaluate the diagnostic performance of 68 Ga-DOTA-Bombesin PET/CT compared with 18 F-FDG PET/CT in breast cancer (BC), emphasizing its utility across molecular subtypes and nodal staging. Twenty-four patients with biopsy-proven BC who underwent both 68 Ga-DOTA-Bombesin and 18 F-FDG PET/CT were included. Imaging findings were analyzed on a per-lesion and per-patient basis for primary tumor detection, axillary lymph-node involvement, and distant metastases. Quantitative parameters (SUVmax, MTV, and tumor-to-background ratios) were compared across histopathologic and receptor subgroups, with histopathology as the reference standard. 68 Ga-DOTA-Bombesin visualized 92.3% of primary tumors, achieving comparable sensitivity to 18 F-FDG (84.6%) but higher specificity in nodal staging (100% vs. 53.8%). Bombesin uptake correlated strongly with estrogen receptor positivity and a lower Ki-67 index ( P <0.05). In a limited number of patients with distant metastases (n=4), FDG appeared to detect hepatic and pulmonary lesions, whereas Bombesin identified additional osseous and peritoneal lesions. Physiological uptake was lower in the liver and bone marrow but higher in the blood pool for Bombesin. Emerging antagonist data indicate further improvements in tumor-to-background ratios and potential theranostic applications. 68 Ga-DOTA-Bombesin PET/CT provides a receptor-specific imaging approach in BC, showing complementary strengths to 18 F-FDG, particularly in hormone-receptor-positive and low-proliferation tumors. Its superior nodal specificity and theranostic potential support further evaluation of GRPR-targeted imaging and therapy in personalized BC management.