Comparison of 68Ga-PSMA PET/CT and 18F-FDG PET/CT for preoperative TNM staging of patients with prostate cancer / 中华核医学与分子影像杂志

ABSTRACT

Objective:To compare the diagnostic efficacy of 68Ga-prostate specific membrane antigen (PSMA)-11 PET/CT and 18F-fluorodeoxyglucose (FDG) PET/CT in TNM staging before radical prostatectomy. Methods:From July 2018 to December 2019, a total of 67 patients ((67.5±6.8) years) with prostate cancer diagnosed pathologically by radical surgery in Renji Hospital, School of Medicine, Shanghai Jiao Tong University were retrospectively enrolled. All patients underwent 68Ga-PSMA-11 PET/CT and 18F-FDG PET/CT whole-body scans before surgery. Results of PET/CT were compared with pathological diagnosis after surgery to compare the diagnostic efficiencies of 68Ga-PSMA-11 PET/CT and 18F-FDG PET/CT for preoperative TNM staging ( χ2 test). The differences of the maximum standardized uptake value (SUV max) in primary lesions between 2 imaging methods were compared by Mann-Whitney U test. Patients were divided into low-risk, intermediate-risk and high-risk for stratified analysis. Results:Among 67 patients, 9 were with low-risk, 19 were with intermediate-risk, 39 were with high-risk. For T staging, 59 (88.06%, 59/67) patients showed positive results by 68Ga-PSMA-11 PET/CT imaging, with median SUV max of 13.80(7.30, 22.40) for 67 patients; 31(46.27%, 31/67) patients showed positive results in 18F-FDG PET/CT imaging, with median SUV max of 4.00(3.10, 5.60) ( U=62, P<0.05). Stratifed analysis showed that the detection rate of 68Ga-PSMA-11 PET/CT was higher than that of 18F-FDG PET/CT in intermediate-risk patients (17/19 vs 6/19; χ2=4.920, P<0.05). Among 67 patients, 10 were diagnosed as N1 stage based on the pathological results. The sensitivities, specificities, accuracies, positive predictive values and negative predictive values of 68Ga-PSMA-11 PET/CT and 18F-FDG PET/CT for detecting positive regional lymph nodes were 6/10, 87.72%(50/57), 83.58%(56/67), 6/13, 92.59%(50/54) and 4/10, 89.47%(51/57), 82.09%(55/67), 4/10, 89.47%(51/57), respectively. 68Ga-PSMA-11 PET/CT detected 15 patients (22.39%, 15/67) with M1 stage, and 18F-FDG PET/CT identified 9 patients (13.43%, 9/67; χ2=35.436, P<0.05). Conclusions:As for T staging, the detection rate of 68Ga-PSMA-11 PET/CT in the intermediate-risk group is better than 18F-FDG PET/CT. In N and M staging, the detection rates of 68Ga-PSMA-11 PET/CT are higher than those of 18F-FDG PET/CT.