To determine the diagnostic accuracy of Bone Scan at different PSA levels for detecting skeletal metastases in men with biochemical recurrence of prostate cancer.
We conducted a retrospective review of the statewide RIS-PACS to identify 251 men with biochemical recurrence who underwent both a Bone Scan and Ga68 PSMA PET/CT (within 2 months of each other) between September 2019 and December 2022 at a single institution. The Ga68 PSMA PET/CT report was considered to be the reference standard.
The median age was 72 years (IQR 67-76) with a median PSA level of 1 ng/ml (IQR 0.25-2.8). Using Ga68 PSMA PET/CT as the reference standard, 68/251 patients (25%) were positive for osseus metastases. Overall sensitivity and specificity of Bone Scan was 51% (95% CI 40-64%) and 99% (95% CI 98-100%) respectively. Using PSA banding, a PSA threshold of 20 ng/ml provided the greatest discriminatory benefit with sensitivity of the Bone Scan below the threshold being 46% (95% CI 33-59%) and above the threshold being 89% (95% CI 68-100%). Specificity remained consistently high both below and above this threshold.
Bone Scan provides greater diagnostic accuracy for detecting skeletal metastases in biochemical recurrence when the PSA level is above 20 ng/ml. This knowledge is valuable in optimising imaging algorithms in biochemical recurrence, particularly in regions where PSMA PET/CT is less readily available or affordable.
Journal of medical imaging and radiation sciences. 2024 Jan 11 [Epub ahead of print]
Karan B Singh, Kevin I London, Veronica C K Wong, Robert Mansberg
Department of Nuclear Medicine, The Children's Hospital at Westmead, Westmead, NSW 2145, Australia. Electronic address: ., Department of Nuclear Medicine, The Children's Hospital at Westmead, Westmead, NSW 2145, Australia; Discipline of Medical Imaging Science, Faculty of Medicine and Health, The University of Sydney, Camperdown, NSW 2050, Australia., Department of Nuclear Medicine & PET, Nepean Hospital, Kingswood, NSW 2747, Australia.