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

Aim [Ga-68]PSMA-HBED-CC (Ga-68-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 Ga-68-PSMA PET/CT using post-lymphadenectomy histology as a standard, and to compare these values to those obtained in a patient collective scanned using F-18-Fluoroethylcholine ((FEC)-F-18) PET/CT. Methods Thirty eight patients had (FEC)-F-18 and 28 patients had Ga-68-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 (FEC)-F-18 and 23/28 Ga-68-PSMA patients a parts per thousand yen1 focus of PCA was identified in postsurgical histology, leading to a per-patient PPV of 78.9 % for (FEC)-F-18 and 82.1 % for Ga-68-PSMA. In (FEC)-F-18 and Ga-68-PSMA patients, a total of 378 and 308 lymph nodes and local lesions were removed, respectively. For (FEC)-F-18 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 %). Conclusion 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.