Detection of Bone Metastases by ⁶⁸Ga‐DOTA‐SSAs and ¹⁸F‐FDG PET/CT: A Two‐Center Head‐to‐Head Study of Gastroenteropancreatic Neuroendocrine Neoplasms

Abstract

Purpose. This study aimed to assess the efficacy of dual-tracer [68Ga-DOTA-somatostatin receptor analogs (SSAs) and 18F-fluorodeoxyglucose (FDG)] positron emission tomography/computed tomography (PET/CT) imaging for detecting bone metastases (BMs) in patients with gastroenteropancreatic neuroendocrine neoplasms (GEP-NENs). Methods. We retrospectively enrolled 74 GEP-NEN patients with BMs from two centers, who underwent dual-tracer PET/CT from January 2014 to March 2021. We compared and analyzed effectiveness of the dual PET/CT imaging techniques on the BMs, based on 18F-FDG and 68Ga-DOTA-SSAs. Specifically, we analyzed the imaging results using χ2 tests for classification variables, paired-sample tests for number of BMs, Wilcoxon’s signed rank test for number of lesions, and the Kruskal–Wallis test for standard uptake value (SUV) ratio comparison. The correlation of dual-tracer SUVmax with Ki-67 index was analyzed by Spearman’s correlation coefficient. Results. The detection efficiencies of dual-tracer PET/CT imaging in patients with different pathologies showed discordant for detecting liver metastases and BMs in group neuroendocrine tumor (NET) G3, 68Ga-DOTA-SSAs was better at detecting BMs for NET G3 ( P = 0.049 for SUVT/B and P = 0.026 for the number of metastatic lesions). In addition, statistical significance was found among osteogenesis group, osteolysis group, and the no-change group (for bone SUVT/B value detected by 18F-FDG and Ki-67 index, osteogenesis group < osteolysis group; for bone SUVT/B detected by 68Ga-DOTA-SSAs, osteogenesis group > the no-change group). What is more, liver and bone SUVmax and Ki-67 index were positively correlated in 18F-FDG imaging ( P < 0.001 for liver; P = 0.002 for bone), and negatively correlated in 68Ga-DOTA-SSAs imaging ( P < 0.001 for liver; P = 0.039 for bone). Conclusions. 68Ga-DOTA-SSAs was superior to 18F-FDG for detecting BMs in NET G1/G2 (well and moderately differentiated NETs), as well as in NET G3 (poorly differentiated NETs). Relatively good differentiation was observed in the osteogenesis group. In addition, dual-tracer PET/CT imaging results were observably correlated with tumor differentiation.

Tumour Heterogeneity and the Consequent Practical Challenges in the Management of Gastroenteropancreatic Neuroendocrine Neoplasms

“…It may be particularly useful during surveillance, as receptor-based imaging alone may fail to show the change in tumour behaviour over time [ 76 ]. Finally, dual imaging could also be useful in detecting bone metastases that can be missed on 18F-FDG/PET alone in less differentiated GEP-NENs, as 68Ga-DOTATATE seems to be more accurate in detecting bone metastases regardless of the differentiation of the primary GEP-NEN [ 82 ].…”

Molecular Eye: A System for Precise Diagnosis and Treatment of Major Clinical Diseases Based on Molecular Probe Technology

“…22 Tian et al demonstrated that [ 68 Ga]Ga-DOTA-SSA imaging performed better than [ 18 F]fluorodeoxyglucose ([ 18 F]FDG) in lesion detection and radiopharmaceutical uptake, especially in G3 NETs. 23 SSTR2 holds immense potential in the early diagnosis, staging, and prognostic evaluation of NETs.…”

“…In 2017, SNMMI proposed [ 68 Ga]­Ga-labeled somatostatin analogue (SSA) positron emission tomography (PET)/CT imaging as the gold standard for clinical NET diagnosis, which exhibited high sensitivity for detecting primary and metastatic lesions . Tian et al demonstrated that [ 68 Ga]­Ga-DOTA-SSA imaging performed better than [ 18 F]­fluorodeoxyglucose ([ 18 F]­FDG) in lesion detection and radiopharmaceutical uptake, especially in G3 NETs . SSTR2 holds immense potential in the early diagnosis, staging, and prognostic evaluation of NETs.…”

Gastroenteropancreatic Neuroendocrine Tumors—Current Status and Advances in Diagnostic Imaging

“…Since 90% of NENs show somatostatin receptors, nuclear medicine examination methods are of great importance in the diagnosis of NENs [3,14]. Somatostatin receptors can be detected via somatostatin receptor scintigraphy and, more recently, by means of 68Gallium-DOTA-TOC/-NOC/-TATE positron emission tomography (PET) [15,16]. Nuclear medicine diagnostics are of therapeutic relevance because foci showing an uptake can be treated with biological therapy with somatostatin analogs and radioreceptor therapy with gallium-or lutetium-labeled somatostatin analogs [17,18].…”