68Ga-FAPI PET/CT Detected Non–PSMA/FDG-Avid Primary Tumor in De Novo Metastatic Prostate Cancer

Abstract

68Ga-labeled PET tracer targeting PSMA is a promising diagnostic approach for staging and restating of prostate cancer (PCa), but cases with clinically relevant PCa and false-negative PSMA PET/CT have been reported. In this case, we reported 68Ga-PSMA, 18F-FDG, and 68Ga-FAPI PET/CT findings in a 65-year-old man with de novo metastatic PCa. 68Ga-FAPI PET/CT detected non–PSMA/FDG-avid primary PCa, consisting with multiparametric MRI findings. The subsequent histopathologic examination confirmed a Gleason 4 + 5 PCa. This case highlighted that 68Ga-FAPI PET/CT may be a useful imaging modality for primary PCa detection and localization.

Fibroblast Activation Protein Inhibitor (FAPI)-Based Theranostics—Where We Are at and Where We Are Heading: A Systematic Review

“…Lung fibrosis and interstitial lung disease are a challenge, as they may be comparable to tumor lesion uptake, although later imaging shows faster washout from the scarred lung than the lung tumor [ 42 ]. To this date there is no literature that focuses primarily on FAPI-PET/CT for prostate cancer, aside from case reports of FAPI-positive scans that were negative on PSMA scans [ 43 , 44 ]. Breast cancer might also get good use out of FAPI.…”

Preliminary Findings of the Role of FAPi in Prostate Cancer Theranostics

“…In a case report, Pang et al [ 27 ] described [ 68 Ga]Ga-PSMA, [ 18 F]FDG and [ 68 Ga]Ga-DOTA-FAPi-04 PET/CT findings in a 65-year-old man with de novo mPCa and a PSA level > 60 ng/mL. [ 68 Ga]Ga-PSMA PET/CT revealed osteogenic bony destruction with intense uptake throughout the skeleton, which suggested widespread metastatic bone lesions in the absence of any abnormal [ 68 Ga]Ga-PSMA uptake in the prostate gland.…”

Visualization of Intermetastatic Heterogeneity in Mixed Neuroendocrine Carcinoma–Acinar Adenocarcinoma of the Prostate by 68Ga-PSMA, 68Ga-FAPI, and 18F-FDG PET/CT

“…2 Considering the possibility of a heterogeneous loss of PSMA expression in neuroendocrine prostate cancer, 3-5 68 Ga-FAPI and 18 F-FDG may be complementary to PSMA PET/CT in tumor staging. [6][7][8] In addition, the multitracer strategy may allow noninvasive characterization of intermetastatic heterogeneity in neuroendocrine prostate cancer.…”

“…Mixed neuroendocrine adenocarcinoma–acinar adenocarcinoma is an uncommon type of neuroendocrine prostate cancer, 1 representing <2% of all prostate malignancies at diagnosis 2 . Considering the possibility of a heterogeneous loss of PSMA expression in neuroendocrine prostate cancer, 3–5 68 Ga-FAPI and 18 F-FDG may be complementary to PSMA PET/CT in tumor staging 6–8 . In addition, the multitracer strategy may allow noninvasive characterization of intermetastatic heterogeneity in neuroendocrine prostate cancer.…”