Detection of HER2-Positive Metastases in Patients with HER2-Negative Primary Breast Cancer Using ⁸⁹Zr-Trastuzumab PET/CT

In this proof-of-concept study, we demonstrated that ⁸⁹Zr-trastuzmab PET/CT detects unsuspected HER2-positive metastases in patients with HER2-negative primary breast cancer. Although these are only initial results in a small sample, they are a proof of the concept that HER2-targeted imaging can identify additional candidates for HER2-targeted therapy. More specific HER2-targeted agents will be needed for clinical use.