This retrospective analysis aimed to evaluate the diagnostic performance of 18F-flotufolastat PET/MRI for the detection of clinically significant prostate cancer (csPCa). The primary objective of the study was to assess the proportion of patients for whom a prostate biopsy could be safely circumvented by combining the Prostate Imaging Reporting and Data System (PI-RADS) from multiparametric MRI and quantitative data from PET. Methods: This study included 79 patients with suspicion of csPCa based on elevated prostate-specific antigen (>4 ng/mL) who underwent 18F-flotufolastat PET/MRI before biopsy or surgical resection of the prostate. Analytic methods included receiver operating characteristic analysis, logistic regression, and threshold-based evaluation of PI-RADS and of SUVmax Imaging findings were compared against histopathology. Results: csPCa (International Society of Urological Pathology grade group ≥ 2) was confirmed in 42 patients, whereas histopathology excluded csPCa in 37 patients. The combination of PI-RADS and SUVmax resulted in an area under the curve (AUC) of 87.1%, outperforming PI-RADS alone (AUC of 75.2%) and SUVmax alone (AUC of 80.7); however, differences were not statistically significant. A PI-RADS score of at least 3 and 18F-flotufolastat PET showed comparable sensitivity (0.90 vs. 0.91) and specificity (0.42 vs. 0.32) in the detection of csPCa, when applying a low SUVmax threshold (>4.5). Using a high SUVmax threshold (>10.0) increased the specificity of 18F-flotufolastat PET to 100%. Furthermore, combined PET/MRI increased the number of patients for whom csPCa can be reliably diagnosed to 28%, as well as increasing to 29% the number of patients for whom csPCa can be ruled out with a very high degree of certainty. Conclusion: This retrospective analysis suggests that prostate-specific membrane antigen PET/MRI can stratify patients with suspected prostate cancer into 3 groups: one with a very high likelihood of csPCa who may undergo definitive therapy without biopsy, one with a very low risk for csPCa who may not require biopsy, and an indeterminate group who still need biopsy. Overall, in our cohort, prostate biopsy would have been avoided in 57% of patients. Therefore, there is an urgent need for prospective studies on prostate-specific membrane antigen PET/MRI to reduce the number of unnecessary biopsies in men with suspected prostate cancer.
Journal of nuclear medicine : official publication, Society of Nuclear Medicine. 2026 Jul 02 [Epub ahead of print]
Türkay Hekimsoy, Andreas P Sauter, Robert Tauber, Thomas Horn, Matthias Jahnen, Fabian Horné, Julian Q Petzold, Daniel Sasse, Isabel Rauscher, Matthias Eiber, Wolfgang A Weber, Bernd M Erber
Department of Nuclear Medicine, School of Medicine and Health, TUM Klinikum, Technical University of Munich, Munich, Germany., Department of Diagnostic and Interventional Radiology, School of Medicine and Health, TUM Klinikum, Technical University of Munich, Munich, Germany; and., Department of Urology, School of Medicine and Health, TUM Klinikum, Technical University of Munich, Munich, Germany., Department of Nuclear Medicine, School of Medicine and Health, TUM Klinikum, Technical University of Munich, Munich, Germany; .