Application Of The ¹⁸F-PSMA PET/CT SUVmax In Detection Of Prostate Cancer And Bone Metastasis

Purposes1.To evaluate the correlation between the maximal standardized uptake value（SUVmax）of prostate cancer lesions and the malignant degree of cancer.2.To analyze the application value of the ¹⁸F-PSMA PET/CT in the detection of bone metastases of prostate cancer by comparing the efficacy of the the ¹⁸F-PSMA PET/CT and the whole-body bone scintigraphy.MethodsThe clinical data of 74 newly diagnosed patients with prostate cancer who received the ¹⁸F-PSMA PET/CT and the whole-body bone scintigraphy in the hospital from June 2018 to September 2022 were retrospectively analyzed.Based on D’Amico risk stratification,patients were divided into low-risk,medium-risk,and high-risk groups.The SUVmax values were compared among the three groups.Associations of the SUVmax values with age,prostate-specific antigen（PSA）,prostate volume,TNM stage,Gleason score,and ISUP grading group were evaluated.Thirty-eight of the 74 patients underwent radical prostatectomy.The correlations of the SUVmax values with neuroinvasion and positive tumor margins in these patients were analyzed.According to the results of the Best Valuable Comparator（BVC）,the patients were divided into bone metastasis group and no bone metastasis group.The sensitivity,specificity,positive predictive value and negative predictive value of ¹⁸F-PSMA PET/CT and the whole-body bone scintigraphy in the diagnosis of prostate cancer with bone metastasis were calculated,respectively.The Area Under Curve（AUC）values of the Receiveroperating Characteristic Curve（ROC）were calculated to compare the differences in detection efficiency between the two tests.The bone metastases found on ¹⁸F-PSMA PET/CT and the whole-body bone imaging were graded using Soloway bone metastasis grading method.Paired sample Wilcoxon rank sum test was used to compare the differences between levels.Results1.Analysis of variance and Least Significant Difference method（LSD method）showed that the SUVmax value of the high-risk group was significantly higher than that of the intermediate-risk group and low-risk group（P=0.005）.The SUVmax values were strongly correlated with Gleason score（r=0.800,P<0.001）,ISUP grade grouping（r=0.789,P<0.001）,T stage（r=0.873,P<0.001）,and M stage（r=0.792,P<0.001）.The SUVmax values were moderately correlated with N stage（r=0.662,P<0.001）,nerve invasion（r=0.437,P=0.006）,and negative and positive incisal margin（r=0.404,P=0.013）.The SUVmax values were weakly correlated with PSA（r=0.320,P=0.040）.The SUVmax values was not correlated with age or prostate volume（P=>0.04）.2.Among 74 patients with prostate cancer,44 patients（59.46%）were clinically diagnosed without bone metastases and 30 patients（40.54%）with bone metastases.The sensitivity,specificity,positive predictive value and negative predictive value of the 18 FPSMA PET/CT in the diagnosis of bone metastasis of prostate cancer were 100%（95%CI: 89.4%-100.0%）,97.62%（95%CI: 87.4%-99.9%）,97.06% and 100%,respectively.The sensitivity,specificity,positive predictive value and negative predictive value of the whole-body bone scintigraphy in the diagnosis of bone metastasis of prostate cancer were 87.88%（95%CI: 71.8%⁹6.6%）,92.86%（95%CI: 80.5%⁹8.5%）,90.63% and 90.70% respectively.The AUC values of the ¹⁸F-PSMA PET/CT and the whole-body bone scintigraphy for the diagnosis of bone metastasis were 1.000（95%CI: 1.000¹.000）and 0.913（95%CI: 0.835⁰.991）,respectively,with a statistically significant difference（P < 0.001）.The paired sample Wilcoxon rank sum test was performed after grading of bone metastases detected by both tests,and the difference was statistically significant（Z=-3.276,P=0.001）.Conclusions1.The SUVmax is significantly correlated with the staging of prostate cancer,which can effectively evaluate the malignancy of prostate cancer and guide clinical decision-making.It has high clinical application value.2.Compared with conventional whole-body bone imaging,the ¹⁸F-PSMA PET/CT is more effective in detecting bone metastases.The lesions detected by the ¹⁸F-PSMA PET/CT are more accurate and reliable,which can provide more accurate information for clinical diagnosis and treatment.