Detection of recurrent prostate cancer lesions before salvage lymphadenectomy is more accurate with (68)Ga-PSMA-HBED-CC than with (18)F-Fluoroethylcholine PET/CT.

AIM - [(68)Ga]PSMA-HBED-CC ((68)Ga-PSMA) is a novel and promising tracer for highly sensitive combined integrated positron emission tomography and X-ray computed tomography (PET/CT) diagnosis of recurrent prostate cancer (PCA).

Our aim was to assess the sensitivity, specificity, positive and negative predictive value (PPV/NPV), and accuracy per lesion, as well as the positive predictive value per patient of (68)Ga-PSMA PET/CT using post-lymphadenectomy histology as a standard, and to compare these values to those obtained in a patient collective scanned using (18)F-Fluoroethylcholine ((18)FEC) PET/CT.

METHODS - Thirty eight patients had (18)FEC and 28 patients had (68)Ga-PSMA. We performed a pelvic and/or retroperitoneal lymphadenectomy, if necessary supplemented by resection of locally recurrent lesions in accordance with imaging results.

RESULTS - In 30/38 (18)FEC and 23/28 (68)Ga-PSMA patients ≥1 focus of PCA was identified in postsurgical histology, leading to a per-patient PPV of 78.9 % for (18)FEC and 82.1 % for (68)Ga-PSMA. In (18)FEC and (68)Ga-PSMA patients, a total of 378 and 308 lymph nodes and local lesions were removed, respectively. For (18)FEC and (68)for Ga-PSMA, the respective sensitivity (95 % confidence interval) was 71.2 % (64.5-79.6 %) and 86.9 % (75.8-94.2 %), specificity was 86.9 % (82.3-90.6 % ) and 93.1 % (89.2-95.9 %), PPV was 67.3 % (57.7-75.9 %) and 75.7 % (64.0-98.5 %), NPV was 88.8 % (84.4-92.3 %) and 96.6 % (93.5-98.5 %), and accuracy was 82.5 % (78.3-86.8 %) and 91.9 % (88.7 %-95.1 %).

CONCLUSIONS - In the present series Ga-PSMA PET/CT shows a better performance than FEC PET/CT with a significantly higher NPV and accuracy for the detection of locoregional recurrent and/or metastatic lesions prior to salvage lymphadenectomy.

European journal of nuclear medicine and molecular imaging. 2016 Mar 19 [Epub ahead of print]

David Pfister, Daniel Porres, Axel Heidenreich, Isabel Heidegger, Ruth Knuechel, Florian Steib, Florian F Behrendt, Frederik A Verburg

Department of Urology, RWTH University Hospital Aachen, Aachen, Germany.  Department of Urology, RWTH University Hospital Aachen, Aachen, Germany., Department of Urology, RWTH University Hospital Aachen, Aachen, Germany., Department of Urology, RWTH University Hospital Aachen, Aachen, Germany., Department of Pathology, RWTH University Hospital Aachen, Aachen, Germany., Department of Pathology, RWTH University Hospital Aachen, Aachen, Germany., Department of Nuclear Medicine, RWTH University Hospital Aachen, Aachen, Germany., Department of Nuclear Medicine, RWTH University Hospital Aachen, Aachen, Germany.