Diagnostic Accuracy of 18F-PSMA-1007 PET/CT Imaging for Lymph Node Staging of Prostate Carcinoma in Primary and Biochemical Recurrence.

Katharina Sprute,Markus Hohenfellner,Constantin Schwab,Isabel Rauscher,Manuel Meneses,Vasko Kramer,Camilo Sandoval,Norio Nonomura,Jun Hatazawa,Stefan A Koerber,Tadashi Watabe,Kambiz Rahbar,Sadahiro Naka,Uwe Haberkorn,Viktoria Schütz,Frederik L Giesel,Clemens Kratochwil,Horacio Amaral,Michael Schaefers,Jürgen Debus ,M Eiber ,Wolfgang Weber ,Cristian Soza‐Ried ,Ramón Fernández-Guerra Fernández ,P L Choyke ,Mamoru Uemura ,Tim Holland‐Letz

doi:10.2967/jnumed.120.246363

Abstract

Prostate-specific membrane antigen (PSMA)–ligand PET/CT is performed on patients with prostate cancer to stage the disease initially or to identify sites of recurrence after definitive therapy. On the basis of clinical results, 18F-PSMA-1007 is a promising PSMA PET tracer, but detailed histologic confirmation has been lacking. Methods: Ninety-six patients with prostate cancer underwent 18F-PSMA-1007 PET/CT followed by either radical prostatectomy with lymphadenectomy or salvage lymphadenectomy. The histologic findings of PSMA PET–positive nodes were analyzed retrospectively. A lesion-based and patient-based analysis was performed comparing all positive lesions and only lesions larger than 3 mm on histopathology. Results: Of the patients, 90.6% received 18F-PSMA-1007 PET/CT for staging before the primary treatment, whereas 9.4% underwent imaging for biochemical recurrence. In 34.4% of the cohort, positive lymph nodes were present on imaging. In total, 1,746 lymph nodes were dissected in 96 patients. 18F-PSMA-1007 PET had a lesion-based sensitivity of 81.7%, a specificity of 99.6%, a positive predictive value of 92.4%, and a negative predictive value of 98.9% for detecting positive lymph nodes larger than 3 mm. In the analysis of all malignant nodes regardless of size, the overall sensitivity, specificity, positive predictive value, and negative predictive value on lesion-based analysis were 71.2%, 99.5%, 91.3%, and 97.9%, respectively. The patient-based analysis showed a sensitivity of 85.9% and a specificity of 99.5% for lymph nodes larger than 3 mm. Conclusion: 18F-PSMA-1007 PET/CT reliably detects malignant lymph nodes and has an exceptional specificity of more than 99% for nodal metastases.

Highlights

Prostate cancer is one of the most common diagnosed cancers worldwide and the number of newly diagnosed patients is increasing commensurate with an aging population [1] PSMA-ligand PET/CT is increasingly used in the initial staging of high-risk tumors and to identify sites of recurrence
Materials and Methods Study design and patient population We identified patients who underwent 18F-PSMA-1007-PET/CT imaging followed by surgery with histopathological evaluation of surgical specimens from the databases of five institutions
A total number of 92 positive lymph nodes were detected in the 18F-PSMA-1007-PET/CT

Summary

Introduction

Prostate cancer is one of the most common diagnosed cancers worldwide and the number of newly diagnosed patients is increasing commensurate with an aging population [1] PSMA-ligand PET/CT is increasingly used in the initial staging of high-risk tumors and to identify sites of recurrence. In a recent study involving 8 patients with 18F-PSMA-1007 imaging and histopathology, a sensitivity of 94.7% was reported in patients undergoing radical prostatectomy and extended lymphadenectomy [8]. A different study of 10 patients with 18F-PSMA-1007 reported a sensitivity of 71%, specificity of 81%, a PPV of 83%, and a NPV of 68% with an accuracy of 75% for total agreement [9]. The aim of this retrospective, multicenter study is to determine the diagnostic accuracy of 18FPSMA-1007-PET/CT-imaging for N-staging of prostate cancer initially and the assessment of nodal recurrence using histopathology as the gold standard

Methods

Results

Conclusion