RESEARCH PAPER
Diagnostic and prognostic value of 99mTc-Tektrotyd scintigraphy and 18F-FDG PET/CT in a single-center cohort of neuroendocrine tumors
 
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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
CORRESPONDING AUTHOR
Jelena Saponjski   

Centar for Nuclear Medicine and PET, Clinical Center of Serbia, Belgrade, Serbia, Serbia
Submission date: 2020-08-21
Final revision date: 2020-11-13
Acceptance date: 2020-11-29
Online publication date: 2021-03-18
 
 
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ABSTRACT
Introduction:
The 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 methods:
In 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.

Results:
Out 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.

Conclusions:
In 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.

eISSN:1896-9151
ISSN:1734-1922