Head-to-head evaluation of [18F]FDG and [68 Ga]Ga-DOTA-FAPI-04 PET/CT in recurrent soft tissue sarcoma

Abstract

Purpose We 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. Methods A 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. Results Among 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.

Comparison of the Detection Performance Between FAP and FDG PET/CT in Various Cancers

“…However, the difference in detection between FAP and FDG could not be certain in sarcoma. 43,46 Because of the difference in radiotracer mechanisms between FAP and FDG, the detection ability of malignant lesions is different in PET imaging. 52,53 In the TME, the tumor lesion actually accounts for less than 10% of the cancer tissue, and the stroma accounts for all parts, as approximately the tumor lesion exceeding 1 to 2 mm in size requires the formation of a supporting stroma.…”

“…In 20 of all included studies, the radiotracer activities administered intravenously to the patients are shown, depending on the body weight, which ranges from 2.59 to 5.55 MBq/kg for FDG and from 1.85 to 3.7 MBq/kg for FAP. 22,25,28,[30][31][32][33][35][36][37][38][39][40][41]44,[47][48][49][50][51] However, the mean of the median and mean radiotracer activities administered intravenously to the patients were 147.69 MBq (range, 111-259 MBq) for FAP in 9 of the included studies 23,24,26,27,29,34,43,45,46 and 271 MBq (range, 214-316 MBq) for FDG radiotracers in 6 of the studies 23,24,26,29,43,46 (Supplement Table 1, Supplemental Digital Content, http://links.lww.com/CNM/A392).…”

“…BC, breast cancer; DR, detection rate; FAP, fibroblast activation protein; GC, gastric cancer; GIS, gastrointestinal system cancer; HCC, hepatocellular carcinoma; HN, head and neck cancer; ICC, intrahepatic cholangiocarcinoma; LC, lung cancer; My_Sarcoma, myeloma and sarcoma; RR, relative risk. P < 0.0001) 22,27,28,31,[33][34][35]40,[42][43][44][45][48][49][50][51] (Fig. 2), as well as those for LN metastasis per patient and per lesion were, respectively, 1.13 (95% CI, 1.03-1.24; P = 0.007) 23,28,29,39,40,42,44,47,[49][50][51] and 1.12 (95% CI, 1.10-1.15; P < 0.0001) 22,27,28,30,31,[33][34][35]40,[42][43][44][45][48][49][50][51] (Fig.…”

Performance and Prospects of [68Ga]Ga-FAPI PET/CT Scans in Lung Cancer

“…Imaging of FAP-expression by [ 68 Ga]Ga-FAPI PET/CT could provide insight in tumor characteristics because FAP-expression in adult normal tissue is low and generally undetectable. [ 68 Ga]Ga-FAPI PET/CT can, therefore, be used in the diagnosis and staging of cancer [ 15 , 16 , 17 , 18 , 19 , 20 , 21 ]. In the upcoming paragraphs, the available evidence on the use of [ 68 Ga]Ga-FAPI PET/CT for diagnosis and staging of lung cancer is presented.…”

“…In several studies, [ 68 Ga]Ga-FAPI PET imaging has demonstrated an equal or better performance compared to [ 18 F]FDG for the detection of tumors and metastatic lesions. It is also used as a complement to [ 18 F]FDG to improve tumor-delineation for planned surgery or radiotherapy [ 15 , 16 , 17 , 18 , 19 , 20 , 21 ].…”