First Clinical Experience of 68Ga-FAPI PET/CT in Tertiary Cancer Center: Identifying Pearls and Pitfalls.

Background/

Objectives

Over the past four years, 68Ga-fibroblast activation protein inhibitor (FAPI) positron emission tomography/computed tomography (PET/CT) has been established at a tertiary cancer care facility in Jordan. This retrospective study aims to explore tracer uptake metrics across various epithelial neoplasms, identify diagnostic pitfalls associated with 68Ga-FAPI PET/CT, and evaluate the influence of 68Ga-FAPI PET/CT staging results on changes in therapeutic intent compared to gold standard molecular imaging modalities.

Methods

A total of 48 patients with biopsy-confirmed solid tumors underwent 77 68Ga-FAPI PET/CT examinations for molecular imaging assessment, encompassing neoplasms originating from the gastrointestinal tract, head and neck, hepatobiliary system, pancreas, breast, and lung.

Results

Notably, pancreaticobiliary tumors exhibited the highest tracer uptake, with mean maximum standardized uptake values (SUVmax) and tumor-to-background ratios (TBR) surpassing 10. A comparative sub-analysis of 68Ga-FAPI PET metrics in 20 treatment-naïve patients revealed a significant correlation between 68Ga-FAPI uptake metrics and tumor grade (Spearman's rho 0.83; p = 0.00001). Importantly, the results from 68Ga-FAPI PET/CT influenced treatment decisions in 35.5% of the cases, primarily resulting in an escalation of management plans. A total of 220 diagnostic challenges were identified across 88.3% of the scans, predominantly within the musculoskeletal system, attributed to degenerative changes (99 observations).

Conclusions

This comprehensive analysis highlights the potential significance of 68Ga-FAPI PET/CT in oncological imaging and treatment strategy, while also emphasizing the necessity for meticulous interpretation to mitigate diagnostic challenges.