The role of [68 Ga]Ga-FAPI-04 PET/CT in renal cell carcinoma: a preliminary study

• Published in: European journal of nuclear medicine and molecular imaging Vol. 51; no. 3; pp. 852 - 861
• Main Authors: Civan, Caner, Kuyumcu, Serkan, Has Simsek, Duygu, Sanli, Oner, Isik, Emine Goknur, Ozkan, Zeynep Gozde, Hurdogan, Ozge, Sanli, Yasemin
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer Berlin Heidelberg 01-02-2024; Springer Nature B.V
• Subjects: Cardiology; Computed tomography; Imaging; Kidney cancer; Lesions; Lungs; Lymph nodes; Malignancy; Medicine; Medicine & Public Health; Metastases; Nuclear Medicine; Oncology; Original Article; Orthopedics; Positron emission; Positron emission tomography; Radiology; Renal cell carcinoma; Tumors; RCC; FAPI; Renal cell carcinoma; PET/CT
• ISSN: 1619-7070; 1619-7089
• DOI: 10.1007/s00259-023-06461-4

Purpose
We aimed to investigate the role of [
68
 Ga]Ga-FAPI-04 PET/CT and uptake patterns of primary and metastatic lesions in patients with renal cell carcinoma (RCC).
Methods
Twenty patients with a suspicious lesion considered primary renal malignancy or a history of RCC were included in our study. Two patients were excluded from further analyses due to other confirmed malignancies. Six patients were newly diagnosed, while the indication of 12 patients was restaging. All patients underwent [
68
 Ga]Ga-FAPI-04 and [
18
F]F-FDG PET/CT. SUVmax and tumor-to-background ratio (TBR) of primary (
n
 = 7) and local recurrent lesions (
n
 = 6) and lymph node (
n
 = 26), lung (
n
 = 32), bone (
n
 = 5), and other metastases (
n
 = 14) were compared between the two tracers.
Results
We detected 90 lesions in 18 patients with varying FAPI and FDG uptake values on both PET/CT. The median TBR of FAPI-PET/CT of all lesions was higher than TBR of FDG-PET/CT with statistically significance (5.6 vs. 2.1,
p
 < 0.001). In primary and recurrent lesions, the median SUVmax, TBR, and tumor volume on FAPI-PET/CT were higher than FDG-PET/CT. The median SUVmax of lung lesions on FAPI-PET/CT was statistical significantly higher than FDG-SUVmax (3.8 vs. 1.8,
p
 = 0.02). The median of FAPI-SUVmax on primary lesions was lower in the early stage based on TNM compared to the advanced stage. FAPI-SUVmax in 49% of all lesions were SUVmax ≥ 6, and 13% were SUVmax ≥ 10. In patient-based analyses, seven patients (39%) had at least one lesion with FAPI-SUVmax ≥ 10; 12 patients (67%) had at least one lesion with FAPI-SUVmax ≥ 6.
Conclusion
This study showed the potential utility of [68 Ga]Ga-FAPI-04 PET/CT showing promising results in RCC. We have presumed that FAPI-PET/CT may be performed for complementary imaging modality providing prognosis and possibility of theranostic application in selected patients.