PT  - JOURNAL ARTICLE
AU  - Koerber, Stefan A.
AU  - Staudinger, Fabian
AU  - Kratochwil, Clemens
AU  - Adeberg, Sebastian
AU  - Haefner, Matthias F.
AU  - Ungerechts, Guy
AU  - Rathke, Hendrik
AU  - Winter, Erik
AU  - Lindner, Thomas
AU  - Syed, Mustafa
AU  - Bhatti, Irfan A.
AU  - Herfarth, Klaus
AU  - Choyke, Peter L.
AU  - Jaeger, Dirk
AU  - Haberkorn, Uwe
AU  - Debus, Juergen
AU  - Giesel, Frederik L.
TI  - The role of FAPI-PET/CT for patients with malignancies of the lower gastrointestinal tract – first clinical experience
AID  - 10.2967/jnumed.119.237016
DP  - 2020 Feb 01
TA  - Journal of Nuclear Medicine
PG  - jnumed.119.237016
4099  - http://jnm.snmjournals.org/content/early/2020/02/13/jnumed.119.237016.short
4100  - http://jnm.snmjournals.org/content/early/2020/02/13/jnumed.119.237016.full
AB  - For oncological management or radiotherapy planning, reliable staging tools are essential. Recent development of quinoline-based ligands targeting cancer-associated fibroblasts demonstrated promising preclinical and clinical results. The current study aimed to evaluate the role of fibroblast activation protein inhibitors (FAPI)-positron-emission tomography (PET)/computed tomography (CT) for primary malignancies located within the lower gastrointestinal tract (LGT) as a very first clinical analysis. Methods: 68Ga-FAPI-PET/CT was performed in a cohort of 22 patients with LGT including 15 patients with metastatic disease, 1 patient with suspected local relapse and 6 treatment-naïve patients. 68Ga-FAPI-04 and 68Ga-FAPI-46 uptake was quantified by standardized uptake values (SUV)max and (SUV)mean. After comparison with standard imaging, changes in tumor stage/ localization and (radio)oncological management were recorded. Results: The highest uptake of FAPI tracer was observed in liver metastases and anal cancer with a SUVmax of 9.1 and 13.9, respectively. Due to a low background activity in normal tissue, there was a high tumor-to-background ratio of more than 3 in most lesions. In treatment-naïve patients, TNM was changed in 50% while for patients with metastases new findings occurred in 47%. In total, FAPI-imaging caused a high, medium and low change of (radio)oncological management in 19%, 33% and 29%, respectively. For almost every patient undergoing irradiation, target volume delineation was improved by 68Ga-FAPI-PET/CT. Conclusion: The present study demonstrated that both primary and metastatic LGT were reliably detected by 68Ga-FAPI-PET/CT leading to relevant changes in TNM status and (radio)oncological management. 68Ga-FAPI-PET/CT seems to be a highly promising imaging agent for the diagnosis and management of LGT, potentially opening new applications for tumor (re-)staging.