68Ga-PSMA-11 PET has the potential to improve patient selection for extended pelvic lymph node dissection in intermediate to high-risk prostate cancer

• Published in: European journal of nuclear medicine and molecular imaging 2020, Vol.47 (1), p.147-159
• Main Authors: Ferraro, Daniela A., Muehlematter, Urs J., Garcia Schüler, Helena I., Rupp, Niels J., Huellner, Martin, Messerli, Michael, Rüschoff, Jan Hendrik, ter Voert, Edwin E. G. W., Hermanns, Thomas, Burger, Irene A.
• Format: Article
• Language: English
• Subjects: Biopsy; Cancer surgery; Cardiology; Complications; Dissection; Health risks; Imaging; Lymph nodes; Lymphatic system; Medicine; Medicine & Public Health; Metastases; Metastasis; Nomograms; Nuclear Medicine; Oncology; Oncology – Genitourinary; Original Article; Orthopedics; Parameters; Patients; Positron emission; Positron emission tomography; Prostate cancer; Prostatectomy; Radiology; Regression analysis; Regression models; Risk; Risk assessment; Sensitivity analysis; Tomography; Tumors
• ISSN: 1619-7070; 1619-7089
• DOI: 10.1007/s00259-019-04511-4

Introduction Radical prostatectomy with extended pelvic lymph node dissection (ePLND) is a curative treatment option for patients with clinically significant localised prostate cancer. The decision to perform an ePLND can be challenging because the overall incidence of lymph node metastasis is relatively low and ePLND is not free of complications. Using current clinical nomograms to identify patients with nodal involvement, approximately 75–85% of ePLNDs performed are negative. The aim of this study was to assess the added value of 68 Ga-PSMA-11 PET in predicting lymph node metastasis in men with intermediate- or high-risk prostate cancer. Methods 68 Ga-PSMA-11 PET scans of 60 patients undergoing radical prostatectomy with ePLND were reviewed for qualitative (visual) assessment of suspicious nodes and assessment of quantitative parameters of the primary tumour in the prostate (SUV max , total activity (PSMA total ) and PSMA positive volume (PSMA vol )). Ability of quantitative PET parameters to predict nodal metastasis was assessed with receiver operating characteristics (ROC) analysis. A multivariable logistic regression model combining PSA, Gleason score, visual nodal status on PET and primary tumour PSMA total was built. Net benefit at each risk threshold was compared with five nomograms: MSKCC nomogram, Yale formula, Roach formula, Winter nomogram and Partin tables (2016). Results Overall, pathology of ePLND specimens revealed 31 pelvic metastatic lymph nodes in 12 patients. 68 Ga-PSMA-11 PET visual analysis correctly detected suspicious nodes in 7 patients, yielding a sensitivity of 58% and a specificity of 98%. The area under the ROC curve for primary tumour SUV max was 0.70, for PSMA total 0.76 and for PSMA vol 0.75. The optimal cut-off for nodal involvement was PSMA total > 49.1. The PET model including PSA, Gleason score and quantitative PET parameters had a persistently higher net benefit compared with all clinical nomograms. Conclusion Our model combining PSA, Gleason score and visual lymph node analysis on 68 Ga-PSMA-11 PET with PSMA total of the primary tumour showed a tendency to improve patient selection for ePLND over the currently used clinical nomograms. Although this result has to be validated, 68 Ga-PSMA-11 PET showed the potential to reduce unnecessary surgical procedures in patients with intermediate- or high-risk prostate cancer.