How accurate is 68Gallium-prostate specific membrane antigen positron emission tomography / computed tomography (68Ga-PSMA PET/CT) on primary lymph node staging before radical prostatectomy in intermediate and high risk prostate cancer? A study of patient- and lymph node- based analyses

• Published in: Urologic oncology 2022-01, Vol.40 (1), p.6.e1-6.e9
• Main Authors: Erdem, Selcuk, Simsek, Duygu Has, Degirmenci, Enes, Aydin, Resat, Bagbudar, Sidar, Ozluk, Yasemin, Sanli, Yasemin, Sanli, Oner, Ozcan, Faruk
• Format: Article
• Language: English
• Subjects: 68Gallium-prostate specific membrane antigen positron emission tomography / computed tomography (68Ga-PSMA PET/CT); Intermediate-high risk prostate cancer; Lymph node staging; Radical prostatectomy
• ISSN: 1078-1439; 1873-2496
• DOI: 10.1016/j.urolonc.2021.07.006

•Intermediate to high risk prostate cancer needs accurate primary lymph node staging•PSMA PET/CT is promising diagnostic modality on prostate cancer staging•The accuracy of PSMA PET/CT on primary lymph node staging is moderate to high•High specificity and high NPV found in intermediate to high risk prostate cancer•Moderate sensitivity and moderate PPV need to be improved Gallium-68 (68Ga)-Prostate Membrane Specific Antigen Positron Emission Tomography/Computed Tomography (68Ga-PSMA PET/CT) is an emerging diagnostic modality which is gaining importance in individualized prostate cancer (PCa) management era. This study aimed to investigate the diagnostic accuracy of 68Ga-PSMA PET/CT on primary LN staging before radical prostatectomy (RP) in intermediate and high risk PCa. The retrospectively documented 49 patients with intermediate and high risk non-metastatic PCa who had 68Ga-PSMA PET/CT before RP were enrolled into this study. The histopathology of dissected LNs was used as reference standard to evaluate the accuracy of 68Ga-PSMA PET/CT on primary LN staging, both in per-patient (n = 49) and in per-node (n = 454) analyses. The diagnostic accuracy was investigated using sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV), and by area under the curve (AUC) provided using receiver operating curve (ROC) analysis. Median age was 64 (48-79) years and, median and mean PSA values were 10 (1.31–138) ng/ml and 16.2 (±19.8) ng/ml, respectively. 22 (44.9%) and 27 (55.1%) of patients had intermediate and high risk PCa, respectively. A total of 5 (10.2%) patients had histopathologically proven LN metastasis and 3 (60%) of them was detected in 68Ga-PSMA PET/CT. In per patient analysis, the sensitivity, specifity, PPV and NPV of 68Ga-PSMA PET/CT on primary LN staging were 0.60, 0.96, 0.60 and 0.96, respectively. Among overall 454 LNs, 16 (3.5 %) of them were reported as metastatic in histopathology and, 13 (2.9%) of these metastatic LNs were detected in 68Ga-PSMA PET/CT. In per-node analysis, the sensitivity, specificity, PPV and NPV of 68Ga-PSMA PET/CT on primary LN staging were 0.82, 0.99, 0.87 and 0.99, respectively. The ROC analyses found AUCs for primary LN staging as 0.777 (95%CI:0.508–1.0) in per patient analysis and, as 0.904 (95%CI:0.790 – 1.0) in per node analysis, respectively. The use of 68Ga-PSMA PET/CT has promising diagnostic accuracy on primary LN staging before RP in intermediate and high risk PCa. However, the ef