Affiliation:
1. Center for Nuclear Medicine and PET, University Clinical Center of Serbia, Belgrade, Serbia
2. Clinic for Endocrinology, Diabetes and Metabolic Diseases, University Clinical Center
of Serbia, Belgrade, Serbia
3. Faculty of Medicine, University of Belgrade, Serbia
4. Institute for Medical Statistics and Informatics, Faculty of Medicine, University of Belgrade,
Serbia
Abstract
IntroductionThe aim was to assess the diagnostic value of 99mTc-Tektrotyd scintigraphy (TCT) and positron emission tomography/computed tomography using F-18 fluorodeoxyglucose (18F-FDG PET/CT) in the detection and
follow-up of neuroendocrine tumors (NETs), and their predictive value for
disease progression.Material and methodsIn this retrospective cohort, TCT and 18F-FDG PET/CT
were performed in 90 patients (37 men, 53 women, mean age 52.7 ±15.1), with
NET. Correlation of Ki67 and tumor grade versus Krenning score and SUVmax
was assessed, Kaplan-Meier analysis was used for progression-free survival
(PFS), and Cox regression analysis was performed to identify the association
between progression-related factors and PFS.ResultsOut of 90, true positive TCT was detected in 56 (62.2%) patients, true
negative in 19 (21.1%), false positive in 4 (4.4%), false negative in 11 (12.2%),
while 18F-FDG PET/CT was true positive in 69 (76.7%) patients, true negative in
10 (11.1%), false positive in 5 (5.5%), false negative in 6 (6.7%). Mean 18F-FDG
PET/CT SUVmax was 6.8 ±6.2. Diagnostic sensitivity of TCT was 83.6%, specificity 82.6%, accuracy 83.3% vs. 18F-FDG PET/CT sensitivity was 92.0%, specificity
66.7%, accuracy 87.8%. A significant correlation between Ki67 and SUVmax was
found in positive 18F-FDG PET/CT findings, unlike the correlation between Ki67
and Krenning score. Median PFS was 25 months (95% CI: 18.2–31.8), in 18F-FDG
PET/CT positive patients 23 months (95% CI: 16.3–29.7) and 18F-FDG PET/CT negative 26 months (p = 0.279). Progression-free survival predictors were SUVmax
and Krenning score.ConclusionsIn our study, TCT and 18F-FDG PET/CT have high diagnostic accuracy in detection of NET. Higher Krenning score on TCT and SUVmax in positive 18F-FDG PET/CT findings are predictors of disease progression. 99mTc-Tektrotyd scintigraphy and 18F-FDG PET/CT can be useful complementary tools
in management of patients with NETs and in predicting patients’ outcome.