Diagnostic Performance of [18F]alf-Thretide PET/CT in Patients with Newly Diagnosed Prostate Cancer Using Histopathology As Reference Standard

This study aimed to assess the diagnostic value of [F-18]AlF-thretide PET/CT in patients with newly diagnosed prostate cancer (PCa). Methods: In total, 49 patients with biopsy-proven PCa were enrolled in this prospective study. All patients underwent [F-18]AlF-thretide PET/CT, and the scoring system of the PRIMARY trial was used for PET image analysis. The dosimetry evaluation of [F-18]AlF-thretide was performed on 3 patients. Pathologic examination was used as the reference standard to evaluate the location, number, size, and Gleason score of tumors, for comparison with the [F-18]AlF-thretide PET/CT results. PSMA expression was evaluated by immunohistochemical staining. Results: All patients tolerated the [F-18]AlF-thretide PET/CT well. The total effective dose of [F-18]AlF-thretide was 1.16E-02 mSv/MBq. For patient-based analysis of intraprostatic tumors, 46 of 49 (93.9%) patients showed pathologic uptake on [F-18]AlF-thretide PET/CT. For lesion-based analysis of intraprostatic tumors, the sensitivity and positive predictive value for [F-18]AlF-thretide PET/CT were 58.2% and 90.5%, respectively. Delayed images can detect more lesions than standard images (n = 57 vs. 49, P = 0.005), and the SUVmax and tumor-to-background ratio of the former were higher than those of the latter (SUVmax: 14.5 +/- 16.7 vs. 11.4 +/- 13.6, P < 0.001; tumor-to-background ratio: 37.1 +/- 42.3 vs. 23.1 +/- 27.4, P < 0.001). The receiver-operating-characteristic curve analysis showed that the areas under the curve for PRIMARY score-predicted true-positive and false-positive lesions were significantly higher than those for the SUVmax of standard images (P = 0.015) and seemed higher than those for the SUVmax of delayed images (P = 0.257). [F-18]AlF-thretide PET/CT showed a higher detection rate than multiparametric MRI for all intraprostatic foci (53.5% vs. 40.8%, P = 0.012) and clinically significant PCa (75.0% vs. 61.4%, P = 0.031). Conclusion: [F-18]AlF-thretide PET/CT showed high diagnostic value for patients with primary PCa and can be used as an excellent imaging modality for preoperative evaluation of PCa patients.