Non-18F-FDG-Avid Intrahepatic Metastasis of Breast Cancer Revealed by 68Ga-FAPI PET/CT

Significantly Higher 68 Ga-FAPI Than 18 F-FDG Uptake by Hidradenocarcinoma of Head and Neck on PET/CT

ABSTRACT

Hidradenocarcinoma is quite rare in clinical practice. Herein, we describe the 68 Ga-FAPI and 18 F-FDG PET/CT findings of hidradenocarcinoma of the head and neck in a 75-year-old man. In the present case, the primary tumor and secondary lesions showed intense accumulation of 68 Ga-FAPI but only slight 18 F-FDG uptake. This case demonstrates that 68 Ga-FAPI PET/CT might be used as a helpful tool for evaluating hidradenocarcinoma.

PET/CT with Fibroblast Activation Protein Inhibitors in Breast Cancer: Diagnostic and Theranostic Application-A Literature Review

Growing studies have recently reported on the promising application of radiolabeled-fibroblast activation protein inhibitors (FAPIs) as diagnostic and therapeutic agents in various oncological populations. To exclusively evaluate the current evidence on the diagnostic and therapeutic role of FAPI radiotracers in patients with breast cancer (BC), a narrative review of the available literature was performed. A search algorithm from PubMed/MEDLINE, based on the combination of "PET" OR "positron emission tomography" and "FAPI" and "cancer", with a last update in February 2022, was applied. From 233 identified articles, 33 studies conducted in BC patients and with available data on PET imaging or radiolabeled-FAPI therapy were finally considered, for a total of 191 patients. Despite some clinical and methodological heterogeneity among the reviewed articles, ⁶⁸Ga-FAPI PET/CT emerges as a valuable diagnostic tool in BC patients both at staging and restaging, also demonstrating several technical advantages and an overall better performance than ¹⁸F-FDG, especially in histotypes with well-known low ¹⁸F-FDG avidity. Moreover, although with still limited clinical evidence in BC, radiolabeled FAPIs emerge as promising therapeutic agents in a theranostic perspective, increasing the possibility of more personalized treatments. From these results, future research directions on FAPI radiotracers application in BC patients are suggested.

68Ga-FAPI-04 PET/CT Versus 18F-FDG PET/CT in the Detection of Malignant Gastrointestinal Stromal Tumor

ABSTRACT

A 65-year-old man presented with abdominal bloating for approximately 4 weeks. After CT imaging, it was diagnosed as gastric carcinoma with hepatic metastasis. 68Ga-FAPI-04 PET/CT revealed much higher tumor-to-background contrast and more metastatic lesions compared with 18F-FDG PET/CT in this case. Following gastroscopy and pathological examination, the final diagnosis was malignant gastrointestinal stromal tumor. This case demonstrated that 68Ga-FAPI-04 PET/CT was more sensitive than 18F-FDG PET/CT for detecting primary and metastatic lesions in malignant gastrointestinal stromal tumor.