Diagnostic performance of 68Ga-PSMA PET/CT in the detection of prostate cancer prior to initial biopsy: comparison with cancer-predicting nomograms
To assess the diagnostic performance of 68Ga-PSMA PET/CT for detecting suspected prostate cancer (PCa) and to compare it with that of two cancer-predicting nomograms.
We performed a retrospective analysis of 146 consecutive patients with suspected PCa based on symptoms or elevated total prostate-specific antigen (tPSA) levels who underwent 68Ga-PSMA PET/CT and histopathologic examinations from April 2017 to April 2018 in a large tertiary care hospital in China. The 68Ga-PSMA PET/CT results (PCa or benignancy) were evaluated by two experienced nuclear medicine specialists. The risk of positive PCa was evaluated using ERSPC and PCPT nomograms. The diagnostic performances of 68Ga-PSMA PET/CT and that of the two nomograms were compared via receiver operating characteristic (ROC) curve analysis, decision curve analysis, and logistic regression.
A total of 58 patients with tPSA of 0.4–50 ng/ml were included in the final analysis; PCa diagnosis was confirmed in 37 patients and excluded in 21 patients. ROC analysis showed that the sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of 68Ga-PSMA PET/CT were 91.67, 81.82, 89.19, and 85.71%, respectively, in per-patient analyses. 68Ga-PSMA PET/CT exhibited a higher AUC (0.867) than those of ERSPC-RC3 (0.855) and PCPT-RC (0.770). The net benefit of 68Ga-PSMA PET/CT was greatest for patients within threshold probabilities of 15–90%. Among the 58 patients, 11 (19%) biopsies suggested by ERSPC-RC3 were unnecessary and could have been avoided if judged by the 68Ga-PSMA PET/CT results. Multivariate analysis revealed that the maximum standardised uptake value (SUVmax) and prostate volume were significant predictive factors for positive PCa results.
In suspected PCa patients with tPSA of 0.4–50 ng/ml, 68Ga-PSMA PET/CT outperformed the nomograms in predicting cancer and reducing unnecessary biopsies. In addition, the risk of PCa was positively correlated with a higher SUVmax and lower prostate volume, which could help clinicians in making preliminary estimates of individual cancer risk, monitoring 68Ga-PSMA PET/CT false-positive results and making biopsy decisions in daily medical practice.
Keywords68Ga-PSMA PET/CT Prostate cancer Biopsy Nomogram Multivariate analysis Decision curve analysis
This study was funded by the National Natural Science Foundation of China (grant nos. 81372771, 81772734, 81871379, 816771713), the Shaanxi Science and Technology Co-ordination and Innovation Project (grant no. 2016KTCQ03–09), the National Key R&D Program of China (grant no. 2016YFC0103804), the Natural Science Foundation of Shaanxi Province (grant no. 2018SF-228, 2018PT-08), and the International Cooperation Program of Xijing Hospital (grant no. XJZT15G01).
Compliance with ethical standards
Conflict of interest
The authors declare that they have no conflict of interest.
All of the procedures performed in studies involving human participants were in accordance with the ethical standards of the institutional and/or national research committees and with the 1964 Declaration of Helsinki and its later amendments or comparable ethical standards. For this study type, formal consent is not required.
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