NCT05898854

[68Ga]Ga-FAPI PET/CT in Gastric and Gastroesophageal Junctional Cancer

[68Ga]Ga-FAPI PET/CT: The Dagnostic Accuracy for Primary Staging and Re-staging After Chemotherapy in Patients With Gastric and Gastro-esophageal Junctional Cancer

• Status: Completed
• Phase: Phase 2
• Study type: Interventional
• Enrollment: 20 (actual)
• Sponsor: Aalborg University Hospital · Academic / Other
• Sex: All
• Age: 18 Years
• Healthy volunteers: Not accepted

Summary

Twenty (n=20) patients with gastric cancer or gastro-esophageal junctional cancer will undergo FAPI PET/CTs in addition to routing diagnostic workup (including FDG PET/CT) at primary staging and restaging. The FAPI PET/CT results will be compared to conventional imaging (including FDG PET/CT) using histopathology as reference standard, and the diagnostic accuracy will be determined. FAP-immunohistochemistry will be conducted in surgical specimens. FAPI PET/CT's impact on patient management and the prognostic value of FAPI PET/CT will be evaluated.

Detailed description

A new and promising PET-tracer in oncology has been developed; Gallium-68 labelled fibroblast activation protein inhibitor (FAPI). In general, FAPI PET/CT delivers increased sensitivity compared to 18F-Fluorodeoxyglucose (FDG) PET/CT in cancer types of mesenchymal origin (i.e., sarcomas), and in cancers characterized by a large proportion of stromal cells such as gastric and pancreatic cancers. It is currently debated whether FAPI PET/CT will take over FDG PET/CTs well-established role in oncological PET/CT, but more studies are needed to evaluate the diagnostic accuracy. The clinical interest in FAPI extends beyond the use as a diagnostic tool, as the 68Ga-isotope can be replaced by a β-emitting isotope, e.g., 177-Lu or 90-Y, enabling radionuclide therapy of FAPI-avid cancers. In recent comparative studies of FDG- and FAPI PET/CT, all primary tumors of the stomach were detected on FAPI PET, whereas the reported detection rate on FDG PET ranged from 40% to 86%. Regarding metastases, FAPI PET/CT showed comparable or better detection rate for regional lymph nodes, but outperformed FDG PET/CT in the detection of peritoneal and other distant metastases. Re-staging with FAPI PET after chemotherapy has been attempted in only a handful of patients and seems feasible. Even though the results of FAPI PET/CT compared to conventional imaging seem convincing, there are several limitations and therefore FAPI PET/CT is not yet implemented in cancer diagnostics. The investigators are conducting a prospective explorative study complying with the Standard for Reporting Diagnostic Accuracy (STARD) criteria where 20 patients with gastric cancer or gastro-eophageal junctional cancer are recruited. Study subject will undergo FAPI PET/CT at primary staging (before treatment, i.e., neoadjuvant chemotherapy or surgery) and at restaging (after neoadjuvant chemotherapy - before surgery) in addition to routing diagnostic workup (including FDG PET/CT). The FAPI PET/CT will be blinded and the choice of treatment will not be influence by the FAPI PET/CT results'. The additional scans will not interfere with or delay routine diagnostic workup or treatment. The FAPI PET/CTs (at primary staging and restaging) will be compared to the corresponding FDG PET/CTs, and histopathology of biopsied material and surgical specimens will serve as reference standard. FAPI PET/CTs before and after neoadjuvant chemotherapy will be assessed and compared to the FDG PET/CTs. FAP-immunohistochemistry will be conducted in surgical specimens. A tentative retrospective Multi-Disciplinary Team conference (MDT) will be arranged where treating clinicans are presented the FAPI PET/CT, and potential changes in patient management will be evaluated. This tentative MDT will not influence patient management. Follow up will be conducted for 10 years to evaluate the prognostic value of FAPI PET/CT.

Conditions

• Gastric Cancer
• Gastro Esophageal Junctional Cancer
• Cancer

Interventions

Type	Name	Description
DRUG	68Ga-FAPi-46	Gastric or gatro-esophageal junction cancer patients undergo 68Ga-FAPi-46 PET/CT at primary staging and at restaging

Timeline

• Start date: 2024-02-15
• Primary completion: 2025-12-18
• Completion: 2025-12-18
• First posted: 2023-06-12
• Last updated: 2025-12-30

Locations

1 site across 1 country: Denmark