⁶⁸Ga-PSMA-HBED-CC Uptake in Cervical, Celiac, and Sacral Ganglia as an Important Pitfall in Prostate Cancer PET Imaging

Abstract

The study aims to investigate the presence of physiologic prostate-specific membrane antigen (Ga-PSMA)-ligand uptake on PET in cervical, celiac, and sacral ganglia of the sympathetic trunk as a pitfall for lymph node metastases in prostate cancer imaging. Four hundred seven patients who underwent Glu-NH-CO-NH-Lys radiolabeled withGa-gallium -bis[2-hydroxy-5-(carboxyethyl)benzyl]ethylenediamine--diacetic acid (Ga-PSMA-HBED-CC) PET (combined with a diagnostic CT) were retrospectively analyzed. The number of Ga-PSMA PET-positive cervical, celiac, and sacral ganglia was determined, and the configuration and SUV of each ganglion were measured. In addition, the configuration and SUV of adjacent lymph node metastases in the respective region (cervical, celiac, or sacral) were determined. Ga-PSMA-ligand uptake above background was detected in 401 (98.5%) patients in any peripheral ganglia, in 369 (92%) patients in cervical ganglia, in 363 (89%) patients in celiac ganglia, and in 183 (46%) patients in sacral ganglia. TheGa-PSMA-ligand uptake was highest in celiac (mean SUV, 2.9 ± 0.8 vs. cervical mean SUV, 2.4 ± 0.6) and sacral (mean SUV 1.7 ± 0.5; both < 0.0001) ganglia. Intraindividually there was a statistically significant but weak to moderate correlation between the Ga-PSMA-ligand uptake in cervical versus celiac ganglia ( = 0.34, < 0.0001), cervical versus sacral ( = 0.52, < 0.0001), and celiac versus sacral ( = 0.16, < 0.05). The Ga-PSMA-ligand uptake was significantly more intense in adjacent lymph node metastases than the respective ganglia (cervical: 18.0 ± 16.2 vs. 2.4 ± 0.6, < 0.0001; celiac: 13.5 ± 12.3 vs. 2.9 ± 0.8, < 0.0001; sacral: 13.4 ± 11.6 vs. 1.7 ± 0.5, < 0.0001). Furthermore, ganglia predominantly exhibit a band-shaped configuration (71.2%), followed by a teardrop (26.8%) and only rarely a nodular configuration (2.0%). Conversely, lymph node metastases are only rarely band-shaped (1.1%), but more often show teardrop (40.3%) or nodular appearance (58.6%) ( < 0.00001). Ga-PSMA-ligand uptake in ganglia along the sympathetic trunk as assessed byGa-PSMA-HBED-CC PET represents an important pitfall in prostate cancer PET imaging. The Ga-PSMA-ligand uptake is higher in celiac ganglia than cervical or sacral ganglia, and the level ofGa-PSMA-ligand uptake seems to be patient-related. For the differentiation between lymph node metastases and sympathetic ganglia, both intensity of Ga-PSMA-ligand uptake and exact localization and configuration of the respective lesion should be examined carefully.

Interobserver Agreement for the Standardized Reporting System PSMA-RADS 1.0 on 18F-DCFPyL PET/CT Imaging

“…In 27 of the 125 identical target lesions (21.6%), a minimum of 2 readers selected the same finding. LNs (16,59.3%) and bone lesions (8,29.6%) were seen in the majority of the cases. In approximately half the cases (15, 55.6%), both readers agreed on the PSMA-RADS score, with no concordance being seen in the remaining cases (12, 44.4%).…”

“…, have demonstrated excellent performance characteristics in identifying sites of disease in subjects with prostate cancer (PCa) (1-3). However, in patients with an extensive tumor burden (4) or for lesion detection in preoperative lymph node (LN) staging (5), clinical interpreters have to consider certain pitfalls, such as uptake in benign lesions or in nonprostatic malignancies (6)(7)(8)(9)(10). To aid in the interpretation of PSMA-targeted PET imaging studies, multiple structured reporting systems have been proposed.…”

Ga‐68‐PSMA PET/CT in treatment‐naïve patients with prostate cancer: Which clinical parameters and risk stratification systems best predict PSMA‐positive metastases?

“…8,10 In contrast, overestimation of metastatic spread could result from false-positive PSMA PET/CT findings such as cervical, coeliac, and sacral ganglia that are PSMA-avid too. 24 Nevertheless, it was not the scope of the current study to provide data on diagnostic accuracy of PSMA PET/CT.…”

Minimal residual disease in prostate cancer patients after primary treatment: theoretical considerations, evidence and possible use in clinical management

“…Importantly this resulted in significant changes in the management of patients, in terms of local versus systemic rescue therapy in 29–87% of patients [14]. Limitations of the test include the 10% of prostate cancers that do not express PMSA [15] and nonspecific labeling of lymph nodes, especially those with follicular hyperplasia [16, 17]. However, with these advances there are more patients with “less indemonstrable minimal residual disease”.…”