Conventional imaging techniques are inadequate for lymph node staging in prostate cancer (PC). This study aims to assess the accuracy of 68Ga-PSMA positron emission tomography/computed tomography (PET/CT) for lymph node (LN) staging in intermediate and high-risk PC.
From April to October 2015, 30 patients with intermediate (n=3) or high-risk (n=27) PC were prospectively enrolled. Patients underwent preoperative 68Ga-PSMA PET/CT. Both visual and semi quantitative analysis was undertaken. Subsequently, all patients underwent a radical prostatectomy with an extended pelvic lymph node dissection (eLND). Sensitivity, specificity, positive and negative predictive value (PPV and NPV) for LN status of 68Ga-PSMA were calculated using histopathology as reference.
Eleven patients (37%) had lymph node metastases (LNMs), 26 LNMs were identified in the 11 patients. On a patient analysis, 68Ga-PSMA PET/CT has a sensitivity of 64% for the detection of LNMs, specificity was 95%, PPV was 88%, and NPV was 82%. In total, 180 LN fields were analyzed. For the LN-region-based analysis, the sensitivity of 68Ga-PSMA PET/CT for detection of LNMs was 56%, specificity was 98%, PPV was 90% and NPV was 94%. Mean size of missed LNMs was 2.7mm. Receiver operating characteristic (ROC) analysis demonstrated high accuracy of SUV max for the detection of LNMs, AUC 0.915 (95%CI 0.847-0.983); optimum SUV max was 2.0.
In patients with intermediate to high-risk PC, 68Ga-PSMA PET/CT has a high specificity and a moderate sensitivity for LNM detection. 68Ga-PSMA PET/CT has the potential to replace current imaging for LN staging of patients with PC scheduled for radical prostatectomy. This article is protected by copyright. All rights reserved.
BJU international. 2016 May 21 [Epub ahead of print]
Pim J van Leeuwen, Louise Emmett, Bao Ho, Warick Delprado, Francis Ting, Quoc Nguyen, Phillip Stricker
St Vincent's Prostate Cancer Centre, St Vincent's Clinic, Sydney, Australia., Department of Diagnostic Imaging, St Vincent's Public Hospital, Sydney, Australia., Department of Diagnostic Imaging, St Vincent's Public Hospital, Sydney, Australia., University of Notre Dame, Darlinghurst, New South Wales, Australia., St Vincent's Prostate Cancer Centre, St Vincent's Clinic, Sydney, Australia., Australian Prostate Cancer Research Centre - New South Wales, The Garvan Institute of Medical Research / The Kinghorn Cancer Centre, Sydney, Australia., St Vincent's Prostate Cancer Centre, St Vincent's Clinic, Sydney, Australia.