Objective:

To compare the value of

18

F-prostate-specific membrane antigen (PSMA)-1007 positron emission tomography (PET)/computed tomography (CT) and multiparametric magnetic resonance imaging (mpMRI) images for the diagnosis of primary prostate cancer (PCa) using prostate puncture pathology as gold standard and to evaluate the value of maximum standard uptake value (SUV

max

) in predicting the benignity and malignancy of primary prostate foci and the risk stratification of PCa.

Methods:

From September 2019 to December 2022

fifty-six patients with suspected PCa who underwent

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F-PSMA-1007 PET/CT at the Fudan University Shanghai Cancer Center were retrospectively recruited. Forty-eight of these patients also underwent mpMRI. The prostate was divided into four segments

the left and right central glands and the left and right peripheral zones

corresponding to the pathological findings of the prostate puncture. Differences in detection rates between groups were compared using the

2

test or Fis

hers exact test and sensitivity

specificity

positive predictive value and negative predictive value were calculated for the diagnosis of PCa. Spearman rank correlation analysis was used to determine the correlation between prostate-specific antigen (PSA)

the Gleason score (GS) and SUV

max

. Differences in SUV

max

were analyzed by the Mann-Whitney

U

test. The area under curve (AUC) was calculated using the receiver operating characteristic (ROC) curve to derive the optimal diagnostic threshold for SUV

max

.

Results:

About 57.1% (32/56) patients had confirmed PCa by puncture pathology and 42.9% (24/56) patients were benign. There were 10 benign patients with prostate inflammation. PSA and SUV

max

were significantly higher in PCa patients than in benign patients (

P

=0.002

P

＜0.001). The ROC curve for predicting the benignity or malignancy of the primary prostate foci by SUV

max

was constructed based on the results of segmental lesion detection

with an AUC of 0.93. When SUV

max

=9.45 was used as the optimal diagnostic threshold

the sensitivity and specificity were 82.0% and 89.6%

respectively. Based on segment analysis

there was no significant difference in detection rate (80.7%

vs

77.1%

P

=0.568) between

18

F-PSMA PET/CT and mpMRI. More segmental lesions were detected with the combination of

18

F-PSMA-1007 PET/CT and mpMRI (84.3%

70/83)

but there was no significant difference in detection rate compared to

18

F-PSMA-1007 PET/CT alone and mpMRI alone (

P

=0.540

P

=0.238

respectively). SUV

max

was significantly higher in segments with prostate inflammation than in those with benign prostate tissue (

P

=0.007). Based on patient analysis

the sensitivity

accuracy and negative predictive value of

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F-PSMA-1007 PET/CT for detecting primary prostate cancer were slightly higher than that of mpMRI (78.1%

vs

76.7%

73.2%

vs

72.9%

69.6%

vs

63.2%

respectively). In terms of detection of regional lymph nodes and bone metastases

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F-PSMA-1007 were higher than mpMRI. The SUV

max

of PCa primary foci was positively correlated with both PSA (

r

=0.467

P

=0.008) and GS (

r

=0.571

P

＜0.001). The detection rate of PCa was 100% when SUV

max

18.00. SUV

max

=22.40 was identified by ROC curve (AUC=0.79) as the optimal diagnostic threshold to distinguish between high and low-moderate risk of PCa

with corresponding sensitivity and specificity of 62.7% and 100.0%

respectively.

Conclusion:

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F-PSMA-1007 PET/CT had better diagnostic efficacy in detecting PCa primary foci and improved the detection of tumor extent in combination with mpMRI. Thesemi-quantitative index SUV

max

had promising predictive value for the identification of benign or malignant primary prostate foci and for risk stratification of PCa.