Comparison of 68Ga-DOTA-FAPI and 18FDG PET/CT imaging modalities in the detection of liver metastases in patients with gastrointestinal system cancer

Abstract

We aimed to compare the diagnostic performance of PET/CT imaging performed with 68Ga-DOTA-FAPI and 18FDG in detection of liver metastases in patients with gastrointestinal system (GIS) cancer. MethodsA total of 31 patients who underwent 68 Ga-DOTA-FAPI and 18 F-FDG PET/CT examinations and diagnosed with GIS cancer (15 colorectal, 9 pancreas, 4 stomach and 3 other cancers) were included in the study. The presence of liver metastasis was decided based on histopathologic diagnosis, PET/CT, other radiologic examinations or tumor biomarker ndings, and both PET/CT imaging ndings were compared on the patient and lesion basis. ResultsOf the 31 patients, 28 were found as true positive with 68 Ga-DOTA-FAPI-PET/CT and 17 with 18 FDG-PET/CT. Of the 98 metastatic liver lesions determined according to our diagnostic criteria, 92 were found as true positive lesions with 68 Ga-DOTA-FAPI-PET/CT and 65 with 18 FDG-PET/CT. There was a statistically signi cant difference between both imaging modalities in the patient and lesion based comparisons (p<0.05).When semiquantitative values (SUVmax, mlr) obtained from the lesions were compared between the two imaging methods, mlr values showed statistically signi cant difference in all tumor subgroups (p<0.05). ConclusionIt was concluded that 68 Ga-DOTA-FAPI-PET/CT was superior over 18 FDG-PET/CT in detection of liver metastases of GIS cancers and it can be a complementary method especially in negative cases with 18 FDG-PET/CT.

Head-to-Head Comparison of Fibroblast Activation Protein Inhibitors (FAPI) Radiotracers versus [18F]F-FDG in Oncology: A Systematic Review

“…No additional studies were found screening the references of the selected articles. Finally, 26 articles (925 patients) including data on the comparison between radiolabeled FAPI and [ 18 F]F-FDG as PET radiotracers in oncology were included in the systematic review [ 10 , 11 , 12 , 13 , 14 , 15 , 16 , 17 , 18 , 19 , 20 , 21 , 22 , 23 , 24 , 25 , 26 , 27 , 28 , 29 , 30 , 31 , 32 , 33 , 34 , 35 ]. The characteristics of the studies selected for the systematic review are presented in Table 1 , Table 2 , Table 3 .…”

“…Through the comprehensive computer literature search, 26 full-text articles including data on the head-to-head comparison of radiolabeled FAPI and [ 18 F]F-FDG in cancer patients were selected ( Table 1 ) [ 10 , 11 , 12 , 13 , 14 , 15 , 16 , 17 , 18 , 19 , 20 , 21 , 22 , 23 , 24 , 25 , 26 , 27 , 28 , 29 , 30 , 31 , 32 , 33 , 34 , 35 ]. All the selected articles were published in the last two years.…”

“…Regarding the normal tissue biodistribution of radiolabeled FAPI in comparison to [ 18 F]F-FDG, all the included studies showed a lower radiolabeled FAPI uptake in the normal brain, liver, and oral mucosa, compared to [ 18 F]F-FDG [ 10 , 11 , 12 , 13 , 14 , 15 , 16 , 17 , 18 , 19 , 20 , 21 , 22 , 23 , 24 , 25 , 26 , 27 , 28 , 29 , 30 , 31 , 32 , 33 , 34 , 35 ].…”

“…Overall, taking into account the radiotracer uptake and TBR values, compared to [ 18 F]F-FDG PET, an equal or higher detection of primary tumors and/or metastatic lesions was usually demonstrated by using radiolabeled FAPI PET [ 10 , 11 , 12 , 13 , 14 , 15 , 16 , 17 , 18 , 19 , 20 , 21 , 22 , 23 , 24 , 25 , 26 , 27 , 28 , 29 , 30 , 31 , 32 , 33 , 34 , 35 ]. In particular, the cancer entities with better detection rate of tumor lesions by using radiolabeled FAPI PET compared to [ 18 F]F-FDG PET were gastrointestinal tumors, liver tumors, breast cancer and nasopharyngeal carcinoma.…”

“…About the normal tissue biodistribution of radiolabeled FAPI in comparison to [ 18 F]F-FDG, all the included studies showed a lower radiolabeled FAPI uptake in the normal brain, liver, and oral mucosa, compared to [ 18 F]F-FDG. Therefore, this is the rationale for the better detection of primary or metastatic lesions in these organs [ 10 , 11 , 12 , 13 , 14 , 15 , 16 , 17 , 18 , 19 , 20 , 21 , 22 , 23 , 24 , 25 , 26 , 27 , 28 , 29 , 30 , 31 , 32 , 33 , 34 , 35 ]. As radiolabeled FAPI seems to present lower background activity, compared to [ 18 F]F-FDG, considering the equal or higher uptake in tumoral lesions, this may finally result in a sharper contrast [ 10 , 11 , 12 , 13 , 14 , 15 , 16 , 17 , 18 , 19 , 20 , 21 , 22 , 23 , 24 , 25 , 26 , 27 , 28 , 29 , 30 , 31 , 32 , 33 , 34 , 35 ].…”