Abstract
PurposeWe aimed to evaluate the value of [68 Ga]Ga-DOTA-FAPI-04 PET/CT for the diagnosis of recurrent soft tissue sarcoma (STS), compared with [18F]FDG PET/CT.MethodsA total of 45 patients (21 females and 24 males; median age, 46 years; range, 18–71 years) with 13 subtypes of STS underwent [18F]FDG and [68 Ga]Ga-DOTA-FAPI-04 PET/CT examination within 1 week for assessment local relapse or distant metastasis. Positive lesions on PET/CT images were verified by biopsy or 3-month follow-up. Wilcoxon matched-pairs signed-rank test was used to compare the semiquantitative values (SUVmax and TBR) of [18F]FDG and [68 Ga]Ga-DOTA-FAPI-04 in tumor lesions, and McNemar test was applied to test for differences of both tracers.ResultsAmong the 45 patients, 282 local relapses and distant metastases were identified. Compared to [18F]FDG, [68 Ga]Ga-DOTA-FAPI-04 PET/CT detected more lesions (275 vs. 186) and outperformed in sensitivity, specificity, PPV, NPV, and accuracy for the diagnosis of recurrent lesions (P < 0.001). [68 Ga]Ga-DOTA-FAPI-04 demonstrated significantly higher values of SUVmax and TBR than [18F]FDG PET/CT in liposarcoma (P = 0.011 and P < 0.001, respectively), malignant solitary fibrous tumor (MSFT) (P < 0.001 and P < 0.001, respectively), and interdigitating dendritic cell sarcoma (IDCS) (P < 0.001and P < 0.001, respectively). While mean SUVmax and TBR presented favorable uptake of [18F]FDG over [68 Ga]Ga-DOTA-FAPI-04 in undifferentiated pleomorphic sarcoma (UPS) (P = 0.003 and P < 0.001, respectively) and rhabdomyosarcoma (RMS) (P < 0.001 and P < 0.001, respectively).Conclusion[68 Ga]Ga-DOTA-FAPI-04 PET/CT is a promising new imaging modality for recurrent surveillance of STS, and compares favorably with [18F]FDG for identifying recurrent lesions of liposarcoma, MSFT, and IDCS.
Highlights
Soft tissue sarcomas (STS) are rare and heterogeneous tumors, which contain more than 50 different histologic subtypes according to the World Health Organization (WHO)1 3 Vol.:(0123456789)European Journal of Nuclear Medicine and Molecular Imaging classification [1]
In this study, we aimed to investigate the potential usefulness of [68 Ga]Ga-DOTA-fibroblast activation protein inhibitor (FAPI)-04 PET/Computed tomography (CT) for the diagnosis of recurrent lesions in patients with STS, compared with [18F]FDG positron emission tomography/computed tomography (PET/CT)
All patients were diagnosed with STS and got radical treatment before PET/CT scans
Summary
Soft tissue sarcomas (STS) are rare and heterogeneous tumors, which contain more than 50 different histologic subtypes according to the World Health Organization (WHO)1 3 Vol.:(0123456789)European Journal of Nuclear Medicine and Molecular Imaging classification [1]. Optimal imaging of STS is crucial for accurately restaging and detecting local relapse and/or distant metastasis as early and as completely as possible. Computed tomography (CT) and magnetic resonance imaging (MRI) serve as the routine means for local relapsed surveillance. For detecting distant metastasis, [18F]-fluorodeoxyglucose ([18F]FDG) positron emission tomography/computed tomography (PET/CT) shows higher sensitivity and accuracy [4]. [18F]FDG PET/CT is useful for initial staging and restaging, evaluation of treatment response, and predicting treatment efficacy and clinical outcome for STS [5]. Due to lack of sensitivity among some subtypes of sarcomas, low-grade sarcomas, [18F]FDG PET/CT is not generally recommended for the management of sarcomas [6,7,8]
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