Prospective comparison of 68Ga-PSMA PET/CT, 18F-sodium fluoride PET/CT and diffusion weighted-MRI at for the detection of bone metastases in biochemically recurrent prostate cancer

To prospectively compare diagnostic accuracies for detection of bone metastases by 68Ga-PSMA PET/CT, 18F-NaF PET/CT and diffusion-weighted MRI (DW600-MRI) in prostate cancer (PCa) patients with biochemical recurrence (BCR).

Sixty-eight PCa patients with BCR participated in this prospective study. The patients underwent 68Ga-PSMA PET/CT, a 18F-NaF PET/CT and a DW600-MRI (performed in accordance with European Society of Urogenital Radiology guidelines, with b values of 0 and 600 s/mm2). Bone lesions were categorized using a three-point scale (benign, malignant or equivocal for metastases) and a dichotomous scale (benign or metastatic) for each imaging modality by at least two experienced observers. A best valuable comparator was defined for each patient based on study-specific imaging, at least 12 months of clinical follow-up and any imaging prior to the study and during follow-up. Diagnostic performance was assessed using a sensitivity analysis where equivocal lesions were handled as non-metastatic and then as metastatic.

Ten of the 68 patients were diagnosed with bone metastases. On a patient level, sensitivity, specificity and the area under the curve (AUC) by receiver operating characteristic analysis were, respectively, 0.80, 0.98-1.00 and 0.89-0.90 for 68Ga-PSMA PET/CT (n = 68 patients); 0.90, 0.90-0.98 and 0.90-0.94 for 18NaF PET/CT (n = 67 patients); and 0.25-0.38, 0.87-0.92 and 0.59-0.62 for DW600-MRI (n = 60 patients). The diagnostic performance of DW600-MRI was significantly lower than that of 68Ga-PSMA PET/CT and 18NaF PET/CT for diagnosing bone metastases (p < 0.01), and no significant difference in the AUC was seen between 68Ga-PSMA PET/CT and 18NaF PET/CT (p = 0.65).

68Ga-PSMA PET/CT and 18F-NaF PET/CT showed comparable and high diagnostic accuracies for detecting bone metastases in PCa patients with BCR. Both methods performed significantly better than DW600-MRI, which was inadequate for diagnosing bone metastases when conducted in accordance with European Society of Urogenital Radiology guidelines.

European journal of nuclear medicine and molecular imaging. 2018 Jun 06 [Epub ahead of print]

Helle D Zacho, Julie B Nielsen, Ali Afshar-Oromieh, Uwe Haberkorn, Nandita deSouza, Katja De Paepe, Katja Dettmann, Niels C Langkilde, Christian Haarmark, Rune V Fisker, Dennis T Arp, Jesper Carl, Jørgen B Jensen, Lars J Petersen

Department of Nuclear Medicine and Clinical Cancer Research Center, Aalborg University Hospital, Hobrovej 18-22, Postboks 365, DK-9100, Aalborg, Denmark. ., Department of Nuclear Medicine and Clinical Cancer Research Center, Aalborg University Hospital, Hobrovej 18-22, Postboks 365, DK-9100, Aalborg, Denmark., Department of Nuclear Medicine, University Hospital Heidelberg, Heidelberg, Germany., The Institute of Cancer Research and Royal Marsden NHS Foundation Trust, London, UK., Department of Urology, Regional Hospital West Jutland, Holstebro, Denmark., Department of Urology, Aalborg University Hospital, Aalborg, Denmark., Department of Clinical Physiology and Nuclear Medicine, Herlev and Gentofte Hospital, Herlev, Denmark., Department of Medical Physics, Oncology Department, Aalborg University Hospital, Aalborg, Denmark., Department of Oncology, Naestved Sygehus, Zealand University Hospital, Roskilde, Denmark.