Initial clinical experience using ⁶⁸Ga-FAPI-46 PET/CT for detecting various cancer types

Area of Science:

• Nuclear Medicine
• Oncology
• Radiochemistry

Background:

• ⁶⁸Ga-FAPI PET/CT offers high intra-tumoral tracer uptake and low background, enabling clear visualization of cancer microenvironment lesions.
• ⁶⁸Ga-FAPI-46 is a novel tracer being compared against established methods for cancer assessment.

Purpose of the Study:

• To compare the diagnostic efficacy of novel ⁶⁸Ga-FAPI-46 PET/CT with routine ¹⁸F-FDG PET/CT and other tracers (⁶⁸Ga-DOTATATE, ⁶⁸Ga-Pentixafor) in various cancers.
• To evaluate the suitability of ⁶⁸Ga-FAPI-46 for detecting cancer recurrence and metastasis.

Main Methods:

• Retrospective analysis of 11 patients with histopathologically confirmed cancers including adenocarcinoma, MTC, PTC, cervical, gastric, GBM, colon, Ewing's sarcoma, and breast cancer.
• PET/CT scans were performed using ¹⁸F-FDG, ⁶⁸Ga-FAPI, ⁶⁸Ga-DOTATATE, and ⁶⁸Ga-Pentixafor.
• Image analysis included visual evaluation for cancer detection and semi-quantitative analysis using SUVmax and TBR for recurrence and metastasis.

Main Results:

• ⁶⁸Ga-FAPI-46 detected more metastases (lymph nodes, liver, bone) than ¹⁸F-FDG.
• Significantly higher SUVmax and TBR values for lymph node and bone metastases were observed with ⁶⁸Ga-FAPI-46 compared to ¹⁸F-FDG.
• ⁶⁸Ga-FAPI-46 demonstrated a significantly higher TBR than ¹⁸F-FDG for liver metastases, though SUVmax was comparable.

Conclusions:

• ⁶⁸Ga-FAPI PET/CT generally outperforms ¹⁸F-FDG PET/CT for breast, gastrointestinal, gynecological, PTC, and MTC.
• ⁶⁸Ga-FAPI PET/CT is not suitable for evaluating GBM and Ewing sarcoma.
• Larger clinical trials are necessary to validate the preliminary findings on ⁶⁸Ga-FAPI-46 efficacy.