[(68)Ga]Ga-DOTA-FAPI-04 PET/CT in the evaluation of gastric cancer: comparison with [(18)F]FDG PET/CT.

This study aimed to compare the performance of [68Ga]Ga-DOTA-FAPI-04 and [18F]FDG PET/CT in the evaluation of primary and metastatic lesions of gastric cancer. Fifty-six patients with histologically proven gastric carcinomas were enrolled in this study, including 45 patients for staging and 11 patients for restaging after surgery. Each patient underwent both [18F]FDG and [68Ga]Ga-DOTA-FAPI-04 PET/CT within 1 week. The activity of tracer accumulation in lesions was assessed by maximum standardized uptake value (SUVmax) and TBR (lesions SUVmax/ascending aorta SUVmean). Histological workup served as a standard of reference. If tissue diagnosis was not applicable, the follow-up data including the results of laboratory tests and medical imaging could also serve as a reference. [68Ga]Ga-DOTA-FAPI-04 PET/CT was comparable to [18F]FDG on detecting primary tumors and lymph node (LN) metastases, whereas [68Ga]Ga-DOTA-FAPI-04 outperformed [18F]FDG in detecting peritoneal (159 vs. 47, P < 0.001) and bone metastases (64 vs. 55, P = 0.003) by the lesion-based analysis. [68Ga]Ga-DOTA-FAPI-04 showed higher SUVmax (10.3 vs. 8.1, P = 0.004) and TBR (11.6 vs. 5.8, P < 0.001) in primary tumor, and higher TBR in LN involvement (8.0 vs. 3.7, P < 0.001) and peritoneal metastases (8.1 vs. 3.2, P < 0.001), compared with [18F]FDG PET/CT. The specificity and positive predictive value of [68 Ga]Ga-DOTA-FAPI-04 were significantly higher than that of [18F]FDG (100.0% vs. 97.7%, P < 0.001; 100.0% vs. 57.1%, P = 0.001) in determining the LN status. [68Ga]Ga-DOTA-FAPI-04 was comparable to [18F]FDG in evaluating N-staging (47.1% vs. 23.5%, P = 0.282). [68Ga]Ga-DOTA-FAPI-04 PET/CT detected more positive recurrent lesions in all restaging patients and showed clearer tumor delineation. Two patients underwent follow-up [68Ga]Ga-DOTA-FAPI-04 PET/CT scans after chemotherapy, which both showed remission. [68Ga]Ga-DOTA-FAPI-04 PET/CT can better evaluate primary gastric cancer and metastatic lesions in the peritoneum, abdominal LNs, and bone. Furthermore, [68Ga]Ga-DOTA-FAPI-04 PET/CT provided more information for patients with recurrent disease and had the potential in monitoring response to treatment.

Lin R ，Lin Z ，Chen Z ，Zheng S ，Zhang J ，Zang J ，Miao W ... -  《-》

(68)Ga-DOTA-FAPI-04 PET/MR in the Evaluation of Gastric Carcinomas: Comparison with (18)F-FDG PET/CT.

We sought to evaluate the performance of 68Ga-DOTA-FAPI-04 ( 68 Ga-FAPI) PET/MR for the diagnosis of primary tumor and metastatic lesions in patients with gastric carcinomas and to compare the results with those of 18F-FDG PET/CT. Methods: Twenty patients with histologically proven gastric carcinomas were recruited, and each patient underwent both 18F-FDG PET/CT and 68 Ga-FAPI PET/MR. A visual scoring system was established to compare the detectability of primary tumors and metastases in different organs or regions (the peritoneum, abdominal lymph nodes, supradiaphragmatic lymph nodes, liver, ovary, bone, and other tissues). The original SUVmax and normalized SUVmax (calculated by dividing a lesion's original SUVmax with the SUVmean of the descending aorta) of selected lesions on both 18F-FDG PET/CT and 68Ga-FAPI PET/MR were measured. Original/normalized SUVmax-FAPI and SUVmax-FDG were compared for patient-based (including a single lesion with the highest activity uptake in each organ/region) and lesion-based (including all lesions [≤5] or the 5 lesions with highest activity [>5]) analyses, respectively. Results: The 20 recruited patients (median age: 56.0 y; range: 29-70 y) included 9 men and 11 women, 14 patients for initial staging and 6 for recurrence detection. 68Ga-FAPI PET was superior to 18F-FDG PET for primary tumor detection (100.00% [14/14] vs. 71.43% [10/14]; P = 0.034), and the former had higher tracer uptake levels (P < 0.05). 68Ga-FAPI PET was superior to 18F-FDG PET in both patient-based and lesion-based evaluation except for the metastatic lesions in supradiaphragmatic lymph nodes and ovaries. Additionally, multiple sequences of MR images were beneficial for the interpretation of hepatic metastases in 3 patients, uterine and rectal metastases in 1 patient, ovarian lesions in 7 patients, and osseous metastases in 2 patients. Conclusion:68Ga-FAPI PET/MR outperformed 18F-FDG PET/CT in visualizing the primary and most metastatic lesions of gastric cancer and might be a promising method, with the potential of replacing 18F-FDG PET/CT.

Qin C ，Shao F ，Gai Y ，Liu Q ，Ruan W ，Liu F ，Hu F ，Lan X ... -  《-》

Superiority of [(68)Ga]Ga-FAPI-04/[(18)F]FAPI-42 PET/CT to [(18)F]FDG PET/CT in delineating the primary tumor and peritoneal metastasis in initial gastric cancer.

This study aimed to compare [68Ga]Ga-FAPI-04/[18F]FAPI-42 PET/CT with [18F]FDG PET/CT in the evaluation of initial gastric cancer. We retrospectively compared [68Ga]Ga-FAPI-04/[18F]FAPI-42 PET/CT with [18F]FDG PET/CT in patients with initial gastric cancer from September 2020 to March 2021. Lesion detectability and the uptake of lesions quantified by the maximum standardized uptake value (SUVmax) and target-to-background ratio (TBR) were compared between the two modalities using the Wilcoxon signed-rank test, Mann-Whitney U test, and McNemar's chi-square test. A total of 61 patients (37 males, aged 23-81 years) were included, of which 22 underwent radical gastrectomy. For primary lesions, higher uptake of [68Ga]Ga-FAPI-04/[18F]FAPI-42 was observed compared to [18F]FDG (median SUVmax, 14.60 vs 4.35, p < 0.001), resulting in higher positive detection using [68Ga]Ga-FAPI-04/[18F]FAPI-42 PET/CT than [18F]FDG PET/CT (95.1% vs 73.8%, p < 0.001), particularly for tumors with signet-ring cell carcinoma (SRCC) (96.4% vs 57.1%, p < 0.001). [68Ga]Ga-FAPI-04/[18F]FAPI-42 PET/CT detected more positive lymph nodes than [18F]FDG PET/CT (637 vs 407). However, both modalities underestimated N staging compared to pathological N staging. [68Ga]Ga-FAPI-04/[18F]FAPI-42 PET/CT showed a higher sensitivity (92.3% vs 53.8%, p = 0.002) and peritoneal cancer index score (18 vs 3, p < 0.001) in peritoneum metastasis and other suspect metastases compared to [18F]FDG PET/CT. Our findings indicate that [68Ga]Ga-FAPI-04/[18F]FAPI-42 PET/CT outperformed [18F]FDG PET/CT in the evaluation of primary tumors with SRCC and peritoneum metastasis in initial gastric cancer. However, no clinically useful improvement was seen in N staging. • The uptake of [68Ga]Ga-FAPI-04/[18F]FAPI-42 in primary tumor and metastasis was intensely higher than that of [18F]FDG (p < 0.001) in 61 patients with initial gastric cancer. • [68Ga]Ga-FAPI-04/[18F]FAPI-42 PET/CT had a higher sensitivity detection in primary tumors (95.1% vs 73.8%, p < 0.001) and peritoneal metastases (92.3% vs 53.8%, p = 0.002) than [18F]FDG PET/CT. • [68Ga]Ga-FAPI-04/[18F]FAPI-42 PET/CT depicted more positive lymph nodes than [18F]FDG PET/CT (637 vs 407); however, both underestimated N staging compared to pathological N staging.

Fu L ，Huang S ，Wu H ，Dong Y ，Xie F ，Wu R ，Zhou K ，Tang G ，Zhou W ... -  《-》

Comparison of [(68) Ga]Ga-DOTA-FAPI-04 PET/CT and [(18)F]FDG PET/CT in colorectal cancer.

In this study, we aimed to evaluate the diagnostic sensitivity of [68 Ga]Ga-DOTA-FAPI-04 PET/CT in the evaluation of primary or recurrent tumor, and nodal, peritoneal, and distant organ metastases in patients with newly diagnosed or relapsed colorectal cancer (CRC) in comparison with [18F]FDG PET/CT. Thirty-nine patients with histopathologically confirmed primary or relapsed CRC were included in our study. All patients underwent both [18F]FDG and [68 Ga]Ga-DOTA-FAPI-04 PET/CT imaging in the same week. Primary lesions, lymph nodes, and metastatic lesions were recorded on both scans. SUVmax and background values were measured from the primary and metastatic lesions; tumor-to-background ratio (TBR) was calculated and compared. The results of the operation were compared with PET findings in patients who underwent surgical treatment without neoadjuvant chemotherapy (NAC). The sensitivity and specificity of [68 Ga]Ga-DOTA-FAPI-04 PET/CT in the evaluation of primary tumors were 100%, while the sensitivity of [18F]FDG PET/CT was 100% and its specificity was 85.3%. When evaluated with surgical results in the detection of lymph nodes, [68 Ga]Ga-DOTA-FAPI-04 PET/CT had a sensitivity of 90% and a specificity of 100%, whereas [18F]FDG PET/CT had a sensitivity of 80% and a specificity of 81.8%. The sensitivity and specificity of [68 Ga]Ga-DOTA-FAPI PET/CT for peritoneal implants were 100%, and the sensitivity of [18F]FDG PET/CT was 55%. The SUVmax of primary lesions was higher with [18F]FDG (p < 0.001), while TBR was higher in [68 Ga]Ga-DOTA-FAPI PET/CT than [18F]FDG PET/CT (p: 0.008). SUVmax and TBR of the lymph nodes were significantly higher in [68 Ga]Ga-DOTA-FAPI PET/CT than [18F]FDG PET/CT (p < 0.001 for both). [68 Ga]Ga-DOTA-FAPI-04 PET/CT achieved much higher sensitivity and specificity in the detection of primary lesions, and especially the lymph nodes and peritoneal metastases, suggesting that it can be employed in the assessment of primary tumor and metastases in patients with CRC in routine clinical practice.

Kömek H ，Can C ，Kaplan İ ，Gündoğan C ，Kepenek F ，Karaoglan H ，Demirkıran A ，Ebinç S ，Güzel Y ，Gündeş E ... -  《-》

Head-to-head comparison of [(68)Ga]Ga-DOTA-FAPI-04 and [(18)F]FDG PET/CT for the evaluation of tonsil cancer and lymph node metastases: a single-centre retrospective study.

This study aimed to compare the diagnostic value of [68 Ga]Ga-DOTA-FAPI-04 and [18F]FDG PET/CT imaging for primary lesions and metastatic lymph nodes in patients with tonsil cancer. Twenty-one tonsil cancer patients who underwent [68 Ga]Ga-DOTA-FAPI-04 and [18F]FDG PET/CT scans within two weeks in our centre were retrospectively enrolled. The maximum standardized uptake value (SUVmax) and tumor-to-background ratio (TBR) of the two tracers were compared by using the Mann‒Whitney U test. In addition, the sensitivity, specificity, and accuracy of the two methods for diagnosing metastatic lymph nodes were analysed. In detecting primary lesions, the efficiency was higher for [68 Ga]Ga-DOTA-FAPI-04 PET/CT (20/22) than for [18F]FDG PET/CT (9/22). Although [68 Ga]Ga-DOTA-FAPI-04 uptake (SUVmax, 5.03 ± 4.06) was lower than [18F]FDG uptake (SUVmax, 7.90 ± 4.84, P = 0.006), [68 Ga]Ga-DOTA-FAPI-04 improved the distinction between the primary tumor and contralateral normal tonsillar tissue. The TBR was significantly higher for [68 Ga]Ga-DOTA-FAPI-04 PET/CT (3.19 ± 2.06) than for [18F]FDG PET/CT (1.89 ± 1.80) (p < 0.001). In lymph node analysis, SUVmax and TBR were not significantly different between [68 Ga]Ga-DOTA-FAPI-04 and [18F]FDG PET/CT (7.67 ± 5.88 vs. 8.36 ± 6.15, P = 0.498 and 5.56 ± 4.02 vs. 4.26 ± 3.16, P = 0.123, respectively). The specificity and accuracy of [68 Ga]Ga-DOTA-FAPI-04 PET/CT were higher than those of [18F]FDG PET/CT in diagnosing metastatic cervical lymph nodes (all P < 0.05). The availability of [68 Ga]Ga-DOTA-FAPI-04 complements the diagnostic results of [18F]FDG by improving the detection rate of primary lesions and the diagnostic accuracy of cervical metastatic lymph nodes in tonsil cancer compared to [18F]FDG.

Ji M ，Ma G ，Liu C ，Gu B ，Du X ，Ou X ，Xu X ，Song S ，Yang Z ... -  《-》