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J Nucl Med. 2019 Jun;60(6):801-805. doi: 10.2967/jnumed.119.227967. Epub 2019 Apr 6.

68Ga-FAPI PET/CT: Tracer Uptake in 28 Different Kinds of Cancer.

Author information

1
Department of Nuclear Medicine, University Hospital Heidelberg, Heidelberg, Germany clemens.kratochwil@med.uni-heidelberg.de.
2
Department of Nuclear Medicine, University Hospital Heidelberg, Heidelberg, Germany.
3
Translational Lung Research Center Heidelberg, German Center for Lung Research, Heidelberg, Germany.
4
Clinical Cooperation Unit Nuclear Medicine, German Cancer Research Center, Heidelberg, Germany.
5
Department of Radiation Oncology, University Hospital Heidelberg, Heidelberg, Germany.
6
Heidelberg Institute for Radiation Oncology, Heidelberg, Germany.
7
Department of Surgery, Thoraxklinik at University Hospital Heidelberg, Heidelberg, Germany.
8
Department of Otorhinolaryngology, Head and Neck Surgery, University Hospital Heidelberg, Heidelberg, Germany.
9
Department Obstetrics and Gynecology, University Hospital Heidelberg, Heidelberg, Germany.
10
Department Obstetrics and Gynecology, University Hospital Mannheim, Mannheim, Germany.
11
Department of Surgery, University Hospital Heidelberg, Heidelberg, Germany.
12
Department of Diagnostic and Interventional Radiology, University Hospital Heidelberg, Heidelberg, Germany.
13
Department of Medical Oncology and Internal Medicine VI, National Center for Tumor Diseases, University Hospital Heidelberg, Germany.
14
Clinical Cooperation Unit Applied Tumor Immunity, German Cancer Research Center, Heidelberg, Germany; and.
15
Clinical Cooperation Unit Radiation Oncology, German Cancer Research Center, Heidelberg, Germany.

Abstract

The recent development of quinoline-based PET tracers that act as fibroblast-activation-protein inhibitors (FAPIs) demonstrated promising preclinical and clinical results. FAP is overexpressed by cancer-associated fibroblasts of several tumor entities. Here, we quantify the tumor uptake on 68Ga-FAPI PET/CT of various primary and metastatic tumors to identify the most promising indications for future application. Methods: 68Ga-FAPI PET/CT scans were requested by various referring physicians according to individual clinical indications that were considered insufficiently covered by 18F-FDG PET/CT or other imaging modalities. All PET/CT was performed 1 h after injection of 122-312 MBq of 68Ga-FAPI-04. We retrospectively identified 80 patients with histopathologically proven primary tumors or metastases or radiologically unequivocal metastatic lesions of histologically proven primary tumors. Tumor uptake was quantified by SUVmax and SUVmean (60% isocontour). Results: Eighty patients with 28 different tumor entities (54 primary tumors and 229 metastases) were evaluated. The highest average SUVmax (>12) was found in sarcoma, esophageal, breast, cholangiocarcinoma, and lung cancer. The lowest 68Ga-FAPI uptake (average SUVmax < 6) was observed in pheochromocytoma, renal cell, differentiated thyroid, adenoid cystic, and gastric cancer. The average SUVmax of hepatocellular, colorectal, head-neck, ovarian, pancreatic, and prostate cancer was intermediate (SUV 6-12). SUV varied across and within all tumor entities. Because of low background in muscle and blood pool (SUVmax < 2), the tumor-to-background contrast ratios were more than 3-fold in the intermediate and more than 6-fold in the high-intensity uptake group. Conclusion: Several highly prevalent cancers presented with remarkably high uptake and image contrast on 68Ga-FAPI PET/CT. The high and rather selective tumor uptake may open up new applications for noninvasive tumor characterization, staging examinations, or radioligand therapy.

KEYWORDS:

FAPI; PET/CT; breast cancer; colorectal cancer; lung cancer

PMID:
30954939
DOI:
10.2967/jnumed.119.227967

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