Hitit Medical Journal (Feb 2025)

Staging Gallium-68 DOTATATE PET/CT Imaging in Neuroendocrine Tumors: Relationship between Measured SUVmax of the Primary Tumor and the Pathological Grade and Ki-67 Proliferation Index

  • Emin Büyüktalancı,
  • Özge Vural Topuz

DOI
https://doi.org/10.52827/hititmedj.1605027
Journal volume & issue
Vol. 7, no. 1
pp. 101 – 108

Abstract

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Objective: To determine whether the maximum standardized uptake value (SUVmax) of the primary lesion measured via Ga-68 DOTATATE PET/CT imaging can be used to predict histological grade and Ki-67 proliferation index in treatment-naïve neuroendocrine tumors (NETs).Material and Method: A total of 57 patients diagnosed with NET who underwent Ga-68 DOTATATE PET/CT between January 2021 and April 2024 were retrospectively evaluated. Patient data including age, histopathology, primary tumor localization, tumor size, Ki-67 proliferation index, histological grade, and SUVmax values from the same tumor were recorded. Histological grades 2 and 3 were pooled into a single group (grade 2&3).Results: The mean age was 49.44 ± 17.20 years. The most common biopsy locations were the liver (28.07%), stomach (21.05%), and pancreas (19.30%). Median Ki-67 proliferation index was 5 (interquartile range: 2–8). Grade 1 tumors were present in 19 patients (33.33%), grade 2 tumors in 35 patients (61.40%), and grade 3 tumors in 3 patients (5.26%). The SUVmax values were positively correlated with tumor size and Ki-67 proliferation index, and Ki-67 proliferation index was positively correlated with tumor size and mitotic count. Patients with grade 2&3 tumors had significantly higher SUVmax values and were older compared to those with grade 1 tumors. For predicting grade 2&3 tumors, the SUVmax value had an area under the ROC curve value of 0.669 (95% CI: 0.526–0.811, p=0.039), which yielded an overall accuracy of 64.91%, with 57.89% sensitivity, 78.95% specificity, 84.62% positive predictive value, and 48.39% negative predictive value, at a cut-off value of >12.5.Conclusion: Initial Ga-68 DOTATATE PET/CT imaging in NETs demonstrated that the SUVmax value of the primary lesion is positively correlated with Ki-67 proliferation index. A maximum standardized uptake value threshold of >12.5 g/ml was shown to distinguish grade 2&3 tumors at an early stage with high positive predictive value.

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