Selection and Validation of an SUV <sub>max</sub> Cutoff Value to Discriminate Prostate Cancer From Benign Prostate Hypertrophy by <sup>68</sup>Ga-PSMA PET/CT: A Real-World Study

Abstract

Background: The aims of the present study were to perform immunohistochemistry (IHC)-based validation of prostate-specific membrane antigen (PSMA) expression measured by 68Ga-PSMA PET/CT and to select and validate a maximum standardized uptake value (SUVmax) cutoff to discriminate prostate cancer (PC) from benign prostate hypertrophy (BPH). Methods: A retrospective analysis based on symptoms and elevated total prostate-specific antigen (tPSA) was performed to assess 102 patients with suspected PC in a large tertiary care hospital in China who underwent 68Ga-PSMA-11 PET/CT. A volume of interest (VOI) was selected according to the highest uptake of 68Ga-PSMA to generate an SUVmax and was subsequently evaluated. The 68Ga-PSMA PET/CT results were compared with the histopathological results. Receiver operating characteristic (ROC) curve analysis was used to generate an SUVmax cutoff value for discrimination between PC and BPH. External validation was performed prospectively in 113 patients with suspected PC. Results: In accordance with the PSMA IHC staining results, PC patients had higher SUVmax values than BPH patients. There was a strongly positive correlation between the SUVmax and PSMA expression ( r s =0.734, P 4.70 in the validation group was 84.96%. Conclusion: The 68Ga-PSMA PET/CT SUVmax is strongly positively correlated with PSMA expression, as validated by IHC. We selected and validated the best SUVmax cutoff value (4.70) for discriminating PC from BPH with high accuracy. Funding Statement: This work was supported by the National Natural Science Foundation of China (grant numbers 81772734, 81971646, 91959208 and 81871379). Declaration of Interests: The authors declare that they have no conflict of interest. Ethics Approval Statement: This retrospective chart review study involving human participants was performed in accordance with the ethical standards of the institutional and national research committee and with the Declaration of Helsinki. The Ethics Committee of the Fourth Military Medical University approved the study protocol and all patients provided written informed consent for retrospective use of their data.