A Retrospective Analysis of the Correlation between Functional Imaging and Clinical Outcomes in Grade 3 Neuroendocrine Tumors (NETs G3)

Grade 3 (G3) neuroendocrine tumors (NETs) are a novel category among digestive neuroendocrine neoplasms, characterized by Ki-67 >20% and a well-differentiated morphology, presenting high intra-tumor heterogeneity. We aimed to explore the role of dual-tracer PET imaging (68Gallium (Ga)-DOTATOC and 18Fluorodeoxyglucose (FDG)) as overall survival (OS) predictor in NET G3 patients. We performed a retrospective analysis in NET G3 patients treated at our institution between 2003 and 2021. Accordingly, 30 NET G3 patients were analyzed. 68Ga-DOTA-TOC and 18F-FDG uptake were assessed by tumor/non-tumor (T-nonT) ratio. We reported a slightly better OS for patients with ≥75% concordance between 68Ga-DOTA-TOC and 18F-FDG PET/CT (p = 0.42). Among patients with discordant functional imaging, we reported a better 5-y OS rate for patients with a prevalent 68Ga-DOTATOC vs. 18F-FDG PET/CT (p = 0.016). In positive 18F-FDG PET/CT cases, we reported a better OS for <4 vs. ≥4 T/non-T ratio (p = 0.021). Among upfront-NET G3 patients with concordant exams, 5-y OS rate was 83.3% (95% CI: 27.3–97.5). Among patients with discordant exams, 5-y OS rate was 81.3% (52.5–93.5), 100% for those with prevalent receptor expression, and 50% (11.1–80.4) for those with prevalent 18F-FDG uptake. Our findings suggest that dual-tracer PET/CT can be considered as a predictor of patient outcome, able to stratify NET G3 patients with poorer prognosis.

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Dual Tracer Functional Imaging of Gastroenteropancreatic Neuroendocrine Tumors Using 68Ga-DOTA-NOC PET-CT and 18F-FDG PET-CT

Clinical Nuclear Medicine ◽

10.1097/rlu.0b013e31827a216b ◽

2014 ◽

Vol 39 (1) ◽

pp. e27-e34 ◽

Cited By ~ 30

Author(s):

Niraj Naswa ◽

Punit Sharma ◽

Santosh Kumar Gupta ◽

Sellam Karunanithi ◽

Rama Mohan Reddy ◽

...

Keyword(s):

Neuroendocrine Tumors ◽

Functional Imaging ◽

Fdg Pet ◽

Gastroenteropancreatic Neuroendocrine Tumors ◽

Pet Ct ◽

18F Fdg ◽

Fdg Pet Ct ◽

Dual Tracer

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Dual-tracer (68Ga-DOTATOC and 18F-FDG-)-PET/CT scan and G1-G2 non-functioning pancreatic neuroendocrine tumors: A single-center retrospective evaluation of 124 non-metastatic resected cases

Neuroendocrinology ◽

10.1159/000514809 ◽

2021 ◽

Author(s):

Salvatore Paiella ◽

Luca Landoni ◽

Sarah Tebaldi ◽

Michele Zuffante ◽

Matteo Salgarello ◽

...

Keyword(s):

Ct Scan ◽

Neuroendocrine Tumors ◽

Fdg Pet ◽

Pancreatic Neuroendocrine Tumors ◽

Pet Ct ◽

18F Fdg ◽

Fdg Pet Ct ◽

Work Up ◽

Pet Ct Scan ◽

Dual Tracer

Introduction:The combined use of 68Gallium [68GA]-DOTA-peptides and 18Fluorine-fluoro-2-deoxyglucose [18F-FDG] PET/TC scans in the work-up of pancreatic neuroendocrine tumors (PanNETs) is controversial. This study aimed at assessing both tracers’ capability to identify tumors and to assess its association with pathological predictors of recurrence. Methods:Prospectively collected, preoperative, dual-tracer PET/CT scan data of G1-G2, non-metastatic, PanNETs that underwent surgery between January 2013 and October 2019 were retrospectively analyzed. Results:The final cohort consisted of 124 cases. There was an approximately equal distribution of males and females(50.8%/49.2%), and G1 and G2 tumors(49.2%/50.8%). The disease was detected in 122(98.4%) and 64(51.6%) cases by 68Ga-DOTATOC and by 18F-FDG PET/CT scans, respectively, with a combined sensitivity of 99.2%. 18F-FDG-positive examinations found G2 tumors more often than G1 (59.4% versus 40.6%;p = 0.036), and 18F-FDG-positive PanNETs were larger than negative ones (median tumor size 32 mm, IQR 21 versus 26 mm, IQR 20;p = 0.019). The median Ki67 for 18F-FDG-positive and -negative examinations was 3(IQR 4) and 2(IQR 4), respectively, (p = 0.029). At least one pathologic predictor of recurrence was present in 74.6% of 18F-FDG-positive cases (versus 56.7%;p = 0.039), whereas this was not found when dichotomizing the PanNETs by their dimensions (≤/> 20 mm). None of the two tracers predicted nodal metastasis. ROC curve analysis showed that 18F-FDG uptake higher than 4.2 had a sensitivity of 49.2%, and specificity of 73.3% for differentiating G1 from G2 (AUC=0.624, p=0.009). Conclusion: The complementary adoption of 68Ga-DOTATOC and 18F-FDG tracers may be valuable in the diagnostic work-up of PanNETs despite not being a game-changer for the management of PanNETs ≤ 20 mm.

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