Prognostic significance of ⁶⁸ Ga-FAPI PET/CT in patients with bone metastases in various cancers

Area of Science:

• Nuclear Medicine
• Oncology
• Radiomics

Background:

• Bone metastases significantly impact cancer patient prognosis and treatment strategies.
• Accurate detection and characterization of bone lesions are crucial for staging and management.
• Comparing the efficacy of novel PET tracers like 68Ga-FAPI with established tracers like 18F-FDG in bone metastases is essential.

Purpose of the Study:

• To compare the performance of 68Ga-FAPI PET/CT and 18F-FDG PET/CT in detecting bone metastases across various cancer types.
• To evaluate the prognostic significance of the maximum standardized uptake value (SUVmax) from 68Ga-FAPI PET/CT in bone lesions for overall survival (OS).

Main Methods:

• Retrospective analysis of 75 cancer patients with bone metastases who underwent both 68Ga-FAPI PET/CT and 18F-FDG PET/CT within one week.
• Comparison of lesion detection rates and SUVmax values between the two imaging modalities.
• Statistical analysis to determine the correlation between bone lesion SUVmax and overall survival.

Main Results:

• 68Ga-FAPI PET/CT detected significantly more bone lesions (median 4 vs. 2) compared to 18F-FDG PET/CT (p=0.014), particularly sclerotic lesions (p=0.001).
• Bone lesions showed higher median SUVmax values on 68Ga-FAPI PET/CT (7.8) than on 18F-FDG PET/CT (5.9).
• Higher 68Ga-FAPI SUVmax in bone lesions was significantly associated with poorer overall survival (p<0.001), whereas 18F-FDG SUVmax did not show this correlation (p=0.079).

Conclusions:

• 68Ga-FAPI PET/CT offers superior detection of bone metastases and higher lesion uptake compared to 18F-FDG PET/CT in diverse cancer types.
• The SUVmax of 68Ga-FAPI bone lesions is a significant independent prognostic factor for overall survival, irrespective of cancer subtype.
• 68Ga-FAPI PET/CT holds promise for improved staging and prognostication of bone metastases in cancer patients.