The impact of FAPI PET on staging and management in patients with digestive system tumors: a systematic review and meta-analysis

Introduction

The incidence of digestive system tumors has been increasing worldwide recently, accounting for nearly a quarter of global cancer incidence according to GLOBOCAN 2022 (1). Among all cancer types, the mortality of colorectal tumors ranks second, followed by liver cancer (1,2). These statistics highlight the high global burden of digestive system tumors.

Accurate diagnosis, staging, and response assessment are critical for management of patients with digestive system tumors. Recently, fibroblast-activated protein (FAP) overexpressed in more than 90% of epithelial tumors has been established as a promising target for cancer theranostics (3,4). FAP-targeted positron emission tomography (PET) imaging has exhibited remarkable diagnostic performance in primary and metastatic lesions of digestive system tumors, including gastric cancer, pancreatic cancer, and colorectal cancer, further bringing added value for cancer management (5-7). Compared to guideline-compatible imaging, this new modality brought significant staging and management changes in a substantial portion of patients with digestive system tumors, although current guidelines do not recommend the routine use of FAP inhibitor (FAPI) PET for these patients (8-12). Given that the clinical benefit of FAPI PET has not been comprehensively assessed, we performed a systematic review and meta-analysis to evaluate the impact of FAPI PET on staging and management in patients with digestive system tumors. We present this article in accordance with the PRISMA reporting checklist (13) (available at https://qims.amegroups.com/article/view/10.21037/qims-2025-1196/rc).

Methods

This systematic review and meta-analysis was registered to the International Prospective Register of Systematic Reviews network (registration number CRD42024563064).

Search strategy

A systematic search was conducted in PubMed, EMBASE, MEDLINE, and SCOPUS databases from inception to May 31^st, 2024, using the following strategy: (“malignancy” OR “tumor*” OR “cancer*” OR “carcinoma*” OR “neoplasm*” OR “neoplasia*”) AND (“digestive system” OR “digestive tract” OR “alimentary system” OR “biliary tract” OR “bile duct” OR “gastrointestinal” OR “gastric” OR “stomach” OR “esophageal” OR “esophagus” OR “esophageal squamous cell carcinoma” OR “Intestinal” OR “Intestines” OR “colorectal” OR “Liver” OR “Hepatic” OR “Hepatocellular” OR “liver cell adenoma*” OR “Pancreatic” OR “Pancreas” OR “Peritoneal” OR “cholangiocarcinoma” OR “bile duct” OR “biliary tract” OR “appendix” OR “appendiceal”) AND (“FAP” OR “fibroblast activation protein”) AND (“PET” OR “Positron Emission Computed Tomography”).

Selection process

Our search was limited to English publications, and included studies should follow the patient-index test-comparison-outcome-study design (PICOS) criteria: patients with digestive system tumors (esophageal cancer, gastric cancer, colorectal cancer, pancreatic cancer, hepatic cancer, appendiceal cancer, and biliary tract cancer); FAPI PET or PET/CT or PET/magnetic resonance imaging (MRI) as the index test; conventional imaging (CI) modalities as the comparison; the proportions of patients who had staging and/or management changes after FAPI PET as the outcome, and study design mainly including original peer-review articles. Studies with less than 10 patients or without sufficient information for the proportions of staging and/or management changes were excluded. Reviews, case reports, guidelines, editorials, book chapter and conference abstracts were also excluded. In cases where the populations of multiple studies overlapped, the representative study with the largest sample was considered in quantitative synthesis. Two authors independently reviewed the articles based on the inclusion and exclusion criteria, with disagreement dissolved through discussion with a third reviewer.

Data collection and quality assessment

Two reviewers identically extracted data and conducted quality assessment, with disagreement dissolved through discussion with a third reviewer. Extracted data included: author(s), publication year, country, patient population (gender, year, sample size, tumor type, clinical indication and clinical stage information), study design (prospective or retrospective, multicenter or single-center), details of FAPI PET (radiotracer, injection dose, vendor) and CI modalities [e.g., CT, MRI, contrast enhanced (CE)-CT], interval between FAPI PET and CI modalities, blinded interpretation, proportions of patients who had staging change as a result of FAPI PET, proportions of patients who had management change due to FAPI PET results, the management modification details, and the reference standard. Staging change was defined as the American Joint Committee on Cancer (AJCC) TNM/BCLC stage change (e.g., IIA to IIB, III to IV) for initial staging and exchange between recurrence/metastasis and non-recurrence/metastasis status for restaging. Minor management change was defined as modifications within already prescribed treatment type and major change was classified as alteration of management type or management intent. For studies that contained various malignancies, we only extracted data from patients with digestive system tumors if possible. Quality assessment was performed using the revised Quality Assessment of Diagnostic Accuracy Studies-2 (QUADAS-2) and QUADAS-comparative (QUADAS-C) criteria. The evaluation focused on four key domains: (I) patient selection; (II) index test; (III) reference standard; and (IV) flow and timing. For each domain except flow and timing, which does not assess applicability concerns, both risk of bias and applicability concerns were evaluated and categorized as high, low, or unclear. For comparative diagnostic accuracy assessments, the QUADAS-2 evaluation was supplemented with additional bias risk questions from QUADAS-C, a tool specifically designed for comparative test accuracy studies (14,15).

Data synthesis and analysis

Freeman-Turkey transformation was used to stabilize the variance from small studies for the proportion of staging/management change. I² statistics were used to assess heterogeneity. If I² is greater than 50%, a random-effect model is used, otherwise a fixed-effect model. Sub-group analyses were performed to explore the potential explanation for heterogeneity: study design (prospective or retrospective), country (Germany or China), study population size (≤40 or >40) and clinical setting (initial staging, restaging, or mixed). Sankey diagrams were generated to clarify the staging and management changes before and after performing FAPI PET. Publication bias assessment is performed using the Egger’s test, and P<0.05 indicated significant difference. If the number of studies included in the final model was more than five, a funnel plot was drawn. All analyses were performed in R software (version 4.4.0).

Results

Literature search

A total of 2,923 studies were identified thorough a systemic search on EMBASE, MEDLINE, Scopus, and PubMed (Figure 1), consisting of 725 duplicates. Most of records were excluded based on the title and abstract (n=2,113), and the remaining 85 potentially eligible records were reviewed through the full text. After full-text review, 72 studies were excluded because of the following reasons: sample size less than 10 (n=7), no comparisons with CI modalities (n=58), no results of staging and management changes (n=5), and evaluating the combination impact of ¹⁸F-FDG PET and FAPI PET rather than the sole impact of FAPI PET (n=2). Finally, 13 studies were included for systematic review, of which seven studies focused on evaluating staging change (8,16-21). Regarding management change, three retrospective studies from the same institute may have overlapped populations, thus we only included the study with the most representative data in the quantitative synthesis (17,22,23). Finally, 11 studies were included in meta-analysis for management change (8,16,18-21,23-27).

Figure 1 The flowchart of study selection process. CI, conventional imaging; FAPI, fibroblast-activated protein inhibitor; FDG, fluorodeoxyglucose; PET, positron emission tomography.

Characteristics of included studies

General characteristics of included studies and patient characteristics are presented in Table 1. These 13 single-center studies enrolling 544 patients were conducted from 2020 to 2024, including four prospective and nine retrospective studies. Six studies were conducted in Germany, and seven in China. Types of malignancies included gastric cancer, colon cancer, rectal cancer, appendiceal cancer, pancreatic cancer, bile duct cancer, and hepatic cancer, of which pancreatic cancer accounted for the largest proportion. FAP-targeted radiotracers included ⁶⁸Ga-FAPI-04, ⁶⁸Ga-FAPI-46, ⁶⁸Ga-FAPI-02, ⁶⁸Ga-FAPI-74, and ¹⁸F-FAPI-42. Other detailed information is shown in the Tables S1,S2.

Quality assessment

The risk of bias and applicability assessment are presented in Table 2. In the patient selection domain, four studies were judged as high risk of bias because these studies enrolled patients who underwent FAPI PET to address inconclusive findings on CI modalities (16,17,22,23). This selection bias may overestimate the impact of FAPI PET on staging and management changes. Eight studies were considered unclear risk of bias because of uncertainty about consecutive enrollment (8,18-21,24,26,27). In the index test domain, one study was estimated at high risk of bias based on QUADAS-C. In that study, CE-CT or CT imaging was employed to provide anatomical information to differentiate distal obstructive pancreatitis when interpreting PET/CT (25). In the reference standard domain, MDT or the combination of histology and follow-up was used as the reference standard in nine studies, which might result in high risk of bias because the results of index tests may be part of MDT (16,18-21,24-27). Four studies had unclear risk of bias due to limited information in the reference standard (8,17,22,23). In the flow and timing domain, no studies were considered at high risk of bias for both QUADAS-2 and QUADAS-C. Several studies had unclear risk of bias due to insufficient information in the flow and timing domains (8,16,17,19-23). As for the concern of applicability, patient selection for four studies was regarded as of high concern because these patients had inconclusive findings on CI modalities (16,17,22,23). Other included studies were judged to have low applicability concerns.

Impact of FAPI-PET on staging

According to our definition, seven studies with 274 patients reporting the impact of FAPI PET on tumor staging were included (8,16-21). The proportion of staging change ranged from 10% to 34%. Overall, the pooled proportion of staging change was 26% [95% confidence interval (95% CI): 21–32%] with a moderate heterogeneity (I²=36%) (Figure 2). Among these changes, upstage and downstage proportions were 94.6% (70/74) and 5.4% (4/74), respectively. Based on CI modalities, there were 3.6% (3/83) patients with stage 0, 10.8% (9/83) with stage I, 18.1% (15/83) with stage II, 13.3% (11/83) with stage III, 44.6 % (37/83) with stage IV, and 9.6% (8/83) without stage information in initial staging group. Figure 3 shows the details of the staging changes. For those patients staged as IV, FAPI PET did not alter the stage although it detected additional lesions, whereas in patients staged as 0-III, the pooled change proportion was 40% (95% CI: 8–76%; I²=93%). In fact, the high proportion of patients with stage IV may have led to an underestimation of FAPI PET impact. In the restaging group, the pooled proportion of staging change was 30% (95% CI: 22–31%; I²=0%). Sub-group analyses were performed to explore the heterogeneity (Table 3), however, no significant factors were found (P>0.05). In addition, as revealed by the Egger’s test, no publication bias was present (P=0.1476, Figure S1).

Figure 2 The pooled proportion of staging change before and after performing FAPI PET in patients with digestive system tumors. 95% CI, 95% confidence interval; FAPI, fibroblast-activated protein inhibitor; PET, positron emission tomography.

Figure 3 Sankey diagrams of staging change before (left) and after (right) FAPI PET in patients with digestive system tumors in the clinical setting of initial staging. This Sankey diagram only includes patients staged as 0–III by CI modalities. CI, conventional imaging; FAPI, fibroblast-activated protein inhibitor; PET, positron emission tomography.

Impact of FAPI-PET on patient management

A total of 11 studies with 492 patients depicted the impact of FAPI-PET on patient management (8,16,18-21,23-27). In individual studies, the proportion of management modifications ranged from 0% to 50%, producing a pooled proportion of 21% (95% CI: 12–31%) with a high heterogeneity (I²=82%) (Figure 4). Of these modifications, major change accounted for 34.9% (45/129), minor change for 41.9% (54/129), and unknown change for 23.3% (30/129). Further analysis showed most patients (28/45) experienced major change because of new lesions or additional lesions identified, one because of less disease extent found, three because of primary tumor detected, while reasons were not provided for 13 patients. For example, eight patients who were originally scheduled for surgery canceled it because of newly identified metastases (18,21,25). Initially planned active surveillance was changed to more aggressive management in six patients (18,20,24). Similarly, local treatment was changed to systemic therapy in two patients, and four patients avoided unnecessary systemic treatment because of FAPI-detected extensive metastatic diseases (16,25). In terms of minor change, six patients experienced minor change because of additional lesions detected, two because of less disease extent found, and reasons for the remaining 46 patients were not revealed. Management modification details are depicted in Sankey plot (Figure S2). Sub-group analyses indicated no significant factors of the heterogeneity (P>0.05) during pooling proportions of management change (Table 3) and the publication bias was also not observed (P=0.2451) (Figure S3).

Figure 4 The pooled proportion of management change before and after performing FAPI PET in patients with digestive system tumor. 95% CI, 95% confidence interval; FAPI, fibroblast-activated protein inhibitor; PET, positron emission tomography.

Discussion

The current study has demonstrated that the pooled proportions of staging and management changes using FAPI PET in patients with digestive system tumors were 26% (95% CI: 21–32%) and 21% (95% CI: 12–31%), respectively. Given that accurate staging is critical for appropriate patient management, the findings on FAPI PET have a considerable impact, such as the intent transfer from curation to palliation, or from active surveillance to treatment implementation, and adjustment in already prescribed treatment type. Applying FAPI PET allows to timely modify the management plan to avoid unnecessary adverse effects and maximize the treatment benefit. Accumulating evidence has demonstrated that FAPI PET has high staging accuracy, especially excellent sensitivity in evaluating patients with digestive system tumors (28-30). To our knowledge, this was the first meta-analysis to evaluate the impact of FAPI PET on staging and management in patients with digestive system tumors.

As is well-known, low physiological uptake and high lesion uptake of FAPI PET render a high-contrast imaging, leading to favorable diagnostic capacity of abdominal lesions, especially peritoneal and hepatic lesions (5,31). It compensates for the limitations of CI modalities, particularly in patients with digestive system tumors. In the study of Kosmala et al., all three patients with pancreatic cancer or liver cancer had changed stage due to only FAPI-identified liver and/or peritoneal metastases (8). Similarly, in the study of Qin et al. involving gastric cancers, the reasons for changed stage in nearly two thirds (24/37) of patients were additional liver and/or peritoneal metastases detected by FAPI (18). Of note, the definitions of staging change were inconsistent among studies. In the study of Koerber et al., any additional lesions were regarded as staging change, thus producing a higher change proportion of 42% across digestive system tumors. In fact, for patients with confirmed focal lymph node metastasis or initial stage IV disease, detecting an additional lymph node or other metastatic lesions may not alter the stage, respectively (23). To better reflect the clinical guidance role of FAPI PET, we used the change proportion of TNM stage, rather than the detection rate of additional lesions in this meta-analysis.

The findings detected by FAPI PET influencing TNM stage also had a direct impact on subsequent management, as exemplified by the shift from local to systemic therapy upon confirmation of distant metastasis in initial staging group. Also, in restaging group, confirmation of recurrence or progression by FAPI PET necessitated management plan revisions. However, certain cases highlighted nuanced differences between staging and management changes. Locating the unknown primary site in patients with metastatic lesions guided treatment options without altering the stage (8,20). For some cancers, the same treatment plan is appropriate for different stages. For example, for patients with gastric cancer staged as IIB or III, perioperative chemotherapy and surgery are suitable treatment strategies (12). In the field of radiation oncology, due to reduced interobserver variability, FAPI PET has exhibited great potential in radiation treatment planning, especially dose modifications and target volume delineation, particularly in esophageal cancers and pancreatic cancers (22,32). Most published studies focused on simulation comparisons rather than real-world practice, highlighting the need for more prospective, randomized studies to comprehensively assess the impact of FAPI PET on radiation oncology (32). Overall, FAPI PET has exhibited great potential in staging and management in patients with digestive system tumors.

High heterogeneity was present across studies in both staging and management change analyses. Although the sub-group analyses did not identify any significant factors, the primary cancer type was a potential variable affecting heterogeneity. As reported, the diagnostic efficacy of FAPI-PET varied among different digestive system tumors, which might affect the subsequent staging and management (33,34). The study design was also a potential factor. In some retrospective studies, FAPI PET was conducted to confirm suspected or inconclusive lesions on CI modalities, leading to underestimation of the pooled proportions. Also, the uncertainty of consecutive enrollment in retrospective studies led to challenges for ensuring that the sample represented the target population and for minimizing bias. Besides, stage status was a potential factor although we did not further perform sub-group analysis stratified by stage status because of limited known information. Regarding the impact on staging change, more than one third of patients were staged as IV by CI modalities in the initial staging group. In the study of Röhrich et al., nearly half (10/19) patients had additional lesions by FAPI PET, however only five of these patients (5/19) had TNM stage change. The remaining five patients with additional lesions demonstrated the absence of staging change, mainly due to their pre-existing distant metastases (17). In fact, for these patients, FAPI PET did not alter the stage although it detected more lesions, whereas in patients staged as 0–III, FAPI PET brought a substantial value with a pooled change proportion of 40% (95% CI: 8–76%). Meanwhile, for patients with extensive recurrences or metastases, most available therapies may have been performed before FAPI-PET. Thus, in such clinical settings, there may be no more options for management change despite the depiction of new lesions (26,35).

Overall, our findings indicate that the clinical utility of FAPI PET is strongly influenced by disease stage. Patients with stage 0–III disease derived the greatest benefit, as FAPI PET-guided staging changes frequently led to meaningful management modifications, whereas patients with stage IV disease often exhibited detection of additional lesions that did not translate into actionable therapeutic changes. This implies that FAPI PET may be most appropriately prioritized in earlier-stage disease, where treatment decisions critically depend on precise staging. Compared with FDG PET or conventional CT, which has limited sensitivity for subtle peritoneal deposits and small hepatic lesions, FAPI PET offers higher sensitivity and enables earlier, more accurate lesion detection. Its high lesion-to-background contrast further supports its use in cases with equivocal or inconclusive findings on standard imaging. Notably, FAPI PET appears to offer the greatest incremental value in pancreatic and cholangiocarcinoma, where it consistently outperforms CI modalities in identifying lymph node involvement and distant metastases, particularly hepatic metastases (36). In radiation oncology, FAPI PET can serve as a valuable adjunct to resolve ambiguities and inconsistencies in target volume delineation inherent to CI modalities. However, caution is warranted when interpreting FAPI PET scans in the post-radiation setting, as treatment-related fibrosis and scarring may yield false-positive signals (37). Collectively, these attributes underscore the potential of FAPI PET to enhance diagnostic accuracy and inform clinical decision-making, supporting its integration into diagnostic algorithms and future guideline development—especially in clinical scenarios where precise staging directly shapes therapeutic strategy.

There are some limitations in our study. First, more than half studies included in this systematic review and meta-analysis were retrospective. FAPI PET may be conducted to confirm suspected or inconclusive lesions on CI modalities, which might overestimate the pooled proportions. Second, since there was a substantial heterogeneity regarding proportions of staging and management changes, the pooled estimates need to be interpreted with caution in specific clinical scenarios. Third, in some studies, the reference standard involved the results of FAPI PET and CI modalities, potentially leading to the inaccurate estimation of FAPI PET performance. Fourth, studies included in this meta-analysis encompassed various digestive system tumors, therefore, the pooled estimates could not represent the impact on each type of tumors individually. Additionally, with the relatively limited sample size, we were unable to perform more detailed sub-group analyses, such as stratification by stage status or by tumor type.

Conclusions

FAPI PET has a significant impact on staging and management in patients with digestive system tumors. Due to the limited disclosure of details regarding staging and management changes in current studies, further well-designed prospective studies with larger sample sizes and more details are warranted.

Acknowledgments

None.

Footnote

Reporting Checklist: The authors have completed the PRISMA reporting checklist. Available at https://qims.amegroups.com/article/view/10.21037/qims-2025-1196/rc

Funding: This work was supported by the National Natural Science Foundation of China (grant No. 82202211).

Conflicts of Interest: All authors have completed the ICMJE uniform disclosure form (available at https://qims.amegroups.com/article/view/10.21037/qims-2025-1196/coif). The authors have no conflicts of interest to declare.

Ethical Statement: The authors are accountable for all aspects of the work in ensuring that questions related to the accuracy or integrity of any part of the work are appropriately investigated and resolved.

Open Access Statement: This is an Open Access article distributed in accordance with the Creative Commons Attribution-NonCommercial-NoDerivs 4.0 International License (CC BY-NC-ND 4.0), which permits the non-commercial replication and distribution of the article with the strict proviso that no changes or edits are made and the original work is properly cited (including links to both the formal publication through the relevant DOI and the license). See: https://creativecommons.org/licenses/by-nc-nd/4.0/.

References

1. Bray F, Laversanne M, Sung H, Ferlay J, Siegel RL, Soerjomataram I, Jemal A. Global cancer statistics 2022: GLOBOCAN estimates of incidence and mortality worldwide for 36 cancers in 185 countries. CA Cancer J Clin 2024;74:229-63. [Crossref] [PubMed]
2. Siegel RL, Miller KD, Wagle NS, Jemal A. Cancer statistics, 2023. CA Cancer J Clin 2023;73:17-48. [Crossref] [PubMed]
3. Nurmik M, Ullmann P, Rodriguez F, Haan S, Letellier E. In search of definitions: Cancer-associated fibroblasts and their markers. Int J Cancer 2020;146:895-905. [Crossref] [PubMed]
4. Zhao L, Chen J, Pang Y, Fu K, Shang Q, Wu H, Sun L, Lin Q, Chen H. Fibroblast activation protein-based theranostics in cancer research: A state-of-the-art review. Theranostics 2022;12:1557-69. [Crossref] [PubMed]
5. Pang Y, Zhao L, Luo Z, Hao B, Wu H, Lin Q, Sun L, Chen H. Comparison of (68)Ga-FAPI and (18)F-FDG Uptake in Gastric, Duodenal, and Colorectal Cancers. Radiology 2021;298:393-402. [Crossref] [PubMed]
6. Lan L, Zhang S, Xu T, Liu H, Wang W, Feng Y, Wang L, Chen Y, Qiu L. Prospective Comparison of (68)Ga-FAPI versus (18)F-FDG PET/CT for Tumor Staging in Biliary Tract Cancers. Radiology 2022;304:648-57. [Crossref] [PubMed]
7. Mori Y, Dendl K, Cardinale J, Kratochwil C, Giesel FL, Haberkorn U. FAPI PET: Fibroblast Activation Protein Inhibitor Use in Oncologic and Nononcologic Disease. Radiology 2023;306:e220749. [Crossref] [PubMed]
8. Kosmala A, Serfling SE, Schlötelburg W, Lindner T, Michalski K, Schirbel A, Higuchi T, Hartrampf PE, Buck AK, Weich A, Werner RA. Impact of 68 Ga-FAPI-04 PET/CT on Staging and Therapeutic Management in Patients With Digestive System Tumors. Clin Nucl Med 2023;48:35-42. [Crossref] [PubMed]
9. Caruso D, Polici M, Bellini D, Laghi A. ESR Essentials: Imaging in colorectal cancer-practice recommendations by ESGAR. Eur Radiol 2024;34:5903-10. [Crossref] [PubMed]
10. Vogel A, Bridgewater J, Edeline J, Kelley RK, Klümpen HJ, Malka D, Primrose JN, Rimassa L, Stenzinger A, Valle JW, Ducreux MESMO Guidelines Committee. Electronic address: clinicalguidelines@esmo. Biliary tract cancer: ESMO Clinical Practice Guideline for diagnosis, treatment and follow-up. Ann Oncol 2023;34:127-40. [Crossref] [PubMed]
11. Obermannová R, Alsina M, Cervantes A, Leong T, Lordick F, Nilsson M, van Grieken NCT, Vogel A, Smyth ECESMO Guidelines Committee. Electronic address: clinicalguidelines@esmo. Oesophageal cancer: ESMO Clinical Practice Guideline for diagnosis, treatment and follow-up. Ann Oncol 2022;33:992-1004. [Crossref] [PubMed]
12. Ajani JA, D'Amico TA, Bentrem DJ, Chao J, Cooke D, Corvera C, et al. Gastric Cancer, Version 2.2022, NCCN Clinical Practice Guidelines in Oncology. J Natl Compr Canc Netw 2022;20:167-92. [Crossref] [PubMed]
13. Page MJ, McKenzie JE, Bossuyt PM, Boutron I, Hoffmann TC, Mulrow CD, et al. The PRISMA 2020 statement: an updated guideline for reporting systematic reviews. BMJ 2021;372: [Crossref] [PubMed]
14. Whiting PF, Rutjes AW, Westwood ME, Mallett S, Deeks JJ, Reitsma JB, Leeflang MM, Sterne JA, Bossuyt PM. QUADAS-2 Group. QUADAS-2: a revised tool for the quality assessment of diagnostic accuracy studies. Ann Intern Med 2011;155:529-36. [Crossref] [PubMed]
15. Yang B, Mallett S, Takwoingi Y, Davenport CF, Hyde CJ, Whiting PF, et al. QUADAS-C: A Tool for Assessing Risk of Bias in Comparative Diagnostic Accuracy Studies. Ann Intern Med 2021;174:1592-9. [Crossref] [PubMed]
16. Guo W, Pang Y, Yao L, Zhao L, Fan C, Ke J, Guo P, Hao B, Fu H, Xie C, Lin Q, Wu H, Sun L, Chen H. Imaging fibroblast activation protein in liver cancer: a single-center post hoc retrospective analysis to compare [68Ga]Ga-FAPI-04 PET/CT versus MRI and [18F]-FDG PET/CT. Eur J Nucl Med Mol Imaging 2021;48:1604-17.
17. Röhrich M, Naumann P, Giesel FL, Choyke PL, Staudinger F, Wefers A, Liew DP, Kratochwil C, Rathke H, Liermann J, Herfarth K, Jäger D, Debus J, Haberkorn U, Lang M, Koerber SA. Impact of (68)Ga-FAPI PET/CT Imaging on the Therapeutic Management of Primary and Recurrent Pancreatic Ductal Adenocarcinomas. J Nucl Med 2021;62:779-86. [Crossref] [PubMed]
18. Qin C, Song Y, Gai Y, Ruan W, Liu Q, Liu F, Zheng D, Zhang P, Liu H, Zhang T, Tao K, Lan X. Gallium-68-labeled fibroblast activation protein inhibitor PET in gastrointestinal cancer: insights into diagnosis and management. Eur J Nucl Med Mol Imaging 2022;49:4228-40. [Crossref] [PubMed]
19. Pang Y, Zhao L, Shang Q, Meng T, Zhao L, Feng L, Wang S, Guo P, Wu X, Lin Q, Wu H, Huang W, Sun L, Chen H. Positron emission tomography and computed tomography with [68Ga]Ga-fibroblast activation protein inhibitors improves tumor detection and staging in patients with pancreatic cancer. Eur J Nucl Med Mol Imaging 2022;49:1322-37.
20. Li C, Tian Y, Chen J, Jiang Y, Xue Z, Xing D, Wen B, He Y. Usefulness of [68Ga]FAPI-04 and [18F]FDG PET/CT for the detection of primary tumour and metastatic lesions in gastrointestinal carcinoma: a comparative study. Eur Radiol 2023;33:2779-91.
21. Jinghua L, Kui X, Deliang G, Bo L, Qian Z, Haitao W, Yaqun J, Dongde W, Xigang X, Ping J, Shengli T, Zhiyong Y, Yueming H, Zhonglin Z, Yong H, Yufeng Y. Clinical prospective study of Gallium 68 ((68)Ga)-labeled fibroblast-activation protein inhibitor PET/CT in the diagnosis of biliary tract carcinoma. Eur J Nucl Med Mol Imaging 2023;50:2152-66. [Crossref] [PubMed]
22. Koerber SA, Staudinger F, Kratochwil C, Adeberg S, Haefner MF, Ungerechts G, Rathke H, Winter E, Lindner T, Syed M, Bhatti IA, Herfarth K, Choyke PL, Jaeger D, Haberkorn U, Debus J, Giesel FL. The Role of (68)Ga-FAPI PET/CT for Patients with Malignancies of the Lower Gastrointestinal Tract: First Clinical Experience. J Nucl Med 2020;61:1331-6. [Crossref] [PubMed]
23. Koerber SA, Röhrich M, Walkenbach L, Liermann J, Choyke PL, Fink C, Schroeter C, Spektor AM, Herfarth K, Walle T, Calais J, Kauczor HU, Jaeger D, Debus J, Haberkorn U, Giesel FL. Impact of (68)Ga-FAPI PET/CT on Staging and Oncologic Management in a Cohort of 226 Patients with Various Cancers. J Nucl Med 2023;64:1712-20. [Crossref] [PubMed]
24. Kessler L, Hirmas N, Pabst KM, Hamacher R, Ferdinandus J, Schaarschmidt BM, Milosevic A, Nader M, Umutlu L, Uhl W, Reinacher-Schick A, Lugnier C, Witte D, Niedergethmann M, Herrmann K, Fendler WP, Siveke JT. (68)Ga-Labeled Fibroblast Activation Protein Inhibitor ((68)Ga-FAPI) PET for Pancreatic Adenocarcinoma: Data from the (68)Ga-FAPI PET Observational Trial. J Nucl Med 2023;64:1910-7. [Crossref] [PubMed]
25. Ding J, Qiu J, Hao Z, Huang H, Liu Q, Liu W, Ren C, Hacker M, Zhang T, Wu W, Li X, Huo L. Comparing the clinical value of baseline [68 Ga]Ga-FAPI-04 PET/CT and [18F]F-FDG PET/CT in pancreatic ductal adenocarcinoma: additional prognostic value of the distal pancreatitis. Eur J Nucl Med Mol Imaging 2023;50:4036-50.
26. Pabst KM, Trajkovic-Arsic M, Cheung PFY, Ballke S, Steiger K, Bartel T, Schaarschmidt BM, Milosevic A, Seifert R, Nader M, Kessler L, Siveke JT, Lueckerath K, Kasper S, Herrmann K, Hirmas N, Schmidt HH, Hamacher R, Fendler WP. Superior Tumor Detection for (68)Ga-FAPI-46 Versus (18)F-FDG PET/CT and Conventional CT in Patients with Cholangiocarcinoma. J Nucl Med 2023;64:1049-55. [Crossref] [PubMed]
27. Dong Y, Huang S, Wu H, Cao M, Huang Y, Tang G, Zhou W. Superiority of (18)F-FAPI-42 PET/CT in the detection of primary tumor and management of appendiceal neoplasm to (18)F-FDG PET/CT and CE-CT. Cancer Imaging 2024;24:58. [Crossref] [PubMed]
28. Huang D, Wu J, Zhong H, Li Y, Han Y, He Y, Chen Y, Lin S, Pang H. [68Ga]Ga-FAPI PET for the evaluation of digestive system tumors: systematic review and meta-analysis. Eur J Nucl Med Mol Imaging 2023;50:908-20.
29. Xu W, Cai J, Peng T, Meng T, Pang Y, Sun L, Wu H, Zhang J, Chen X, Chen H. Fibroblast Activation Protein-Targeted PET/CT with (18)F-Fibroblast Activation Protein Inhibitor-74 for Evaluation of Gastrointestinal Cancer: Comparison with (18)F-FDG PET/CT. J Nucl Med 2024;65:40-51. [Crossref] [PubMed]
30. Prashanth A, Kumar Ravichander S, Eswaran P, Kalyan S, Maheswari Babu S. Diagnostic performance of Ga-68 FAPI 04 PET/CT in colorectal malignancies. Nucl Med Commun 2023;44:276-83. [Crossref] [PubMed]
31. Zhao L, Pang Y, Luo Z, Fu K, Yang T, Zhao L, Sun L, Wu H, Lin Q, Chen H. Role of [(68)Ga]Ga-DOTA-FAPI-04 PET/CT in the evaluation of peritoneal carcinomatosis and comparison with [(18)F]-FDG PET/CT. Eur J Nucl Med Mol Imaging 2021;48:1944-55.
32. Koerber SA. Radiation Therapy Planning Using Fibroblast Activation Protein Inhibitor. PET Clin 2023;18:369-80. [Crossref] [PubMed]
33. Cheng Z, Wang S, Xu S, Du B, Li X, Li Y. FAPI PET/CT in Diagnostic and Treatment Management of Colorectal Cancer: Review of Current Research Status. J Clin Med 2023;12:577. [Crossref] [PubMed]
34. Evangelista L, Frantellizzi V, Schillaci O, Filippi L. Radiolabeled FAPI in pancreatic cancer: can it be an additional value in the management of patients? Expert Rev Anticancer Ther 2023;23:745-52. [Crossref] [PubMed]
35. Banales JM, Marin JJG, Lamarca A, Rodrigues PM, Khan SA, Roberts LR, et al. Cholangiocarcinoma 2020: the next horizon in mechanisms and management. Nat Rev Gastroenterol Hepatol 2020;17:557-88. [Crossref] [PubMed]
36. Pabst KM, Fendler WP, Jochheim LS, Herrmann K. The Value of FAPI PET/CT in Cholangiocarcinoma and Pancreatic Cancer: An Update. Semin Nucl Med 2025;55:701-9. [Crossref] [PubMed]
37. Guberina N, Kessler L, Pottgen C, Guberina M, Metzenmacher M, Herrmann K, Mucha M, Rischpler C, Indenkampen F, Siveke JT, Treckmann J, Umutlu L, Kasper S, Fendler WP, Stuschke M. [(68)Ga]FAPI-PET/CT for radiation therapy planning in biliary tract, pancreatic ductal adeno-, and adenoidcystic carcinomas. Sci Rep 2022;12:16261.