CT-guided biopsy of 18F-piflufolastat radiotracer avid lesions in osseous metastatic prostate disease: Initial experience, technical factors and biopsy yield

Abstract

Objectives

To evaluate the yield of CT-guided biopsy of 18F-piflufolastat PET avid osseous lesions in suspected prostate metastases.

Methods

Retrospective review of computed tomography guided biopsies targeting 18F-piflufolastat avid lesions on PET/CT or PET/MR performed between 2022 and 2024. Demographics, image modality, biopsy system, number of cores, lesion location, lean body mass corrected SUV (SUL) and pathology were recorded. Biopsied lesions were compared to the PROMISE (prostate cancer molecular imaging standardized evaluation) scoring system, version 2.

Results

Eighteen patients were included, average age 68.7 years. Lesions were defined as: ≥ 50 % sclerotic (n = 10), <50 % sclerotic (n = 7), occult (n = 0), and lytic (n = 1). A technically successful pathologic diagnosis was made in 94 % of biopsies (n = 17). Histopathological diagnosis included: metastatic prostate adenocarcinoma (n = 12), benign with fibrotic/densely sclerotic bone or normocellular bone marrow (n = 5), and metastatic non-small cell lung carcinoma (n = 1). The median SUL on PET for all patients was 7.9 (IQR 13.3), 2.6 (0.3) for benign biopsies, and 8.8 (12.5) for malignant biopsies. Major identifiable differences between biopsies yielding a metastatic versus benign diagnosis included: higher SUL (p-value = 0.03), target lesion volume (p-value = 0.01), and higher incidence of sclerotic lesions (p value = 0.003); however, multivariate analysis did not find these to be statistically significant predictors (p-value >0.05). The prostate cancer lesion biopsy positive group had significantly higher PROMISE scores than the negative group (p = 0.03).

Conclusion

CT-guided biopsy of bone lesions demonstrating avidity for 18F-piflufolastat can be performed with a high diagnostic yield.