Clinical indications to the use of (99m) Tc-EDDA/HYNIC-TOC to detect somatostatin receptor-positive neuroendocrine tumors
Parisella, M.G.; Chianelli, M.; D'Alessandria, C.; Todino, V.; Mikolajczak, R.; Papini, E.; Dierckx, R.A.; Scopinaro, F.; Signore, A.
Quarterly Journal of Nuclear Medicine and Molecular Imaging Official Publication of the Italian Association of Nuclear Medicine and the International Association of Radiopharmacology and Section of the Society Of. 56(1): 90-98
2012
ISSN/ISBN: 1824-4785 PMID: 21068709 Document Number: 660520
The aim of this study was to define, retrospectively, the utility to perform (99m)Tc-EDDA/HYNIC-Tyr3-octreotide ((99m)Tc-EDDA/HYNIC-TOC) scan in patients with NET. We studied 50 consecutive patients affected by different types of NET and divided in two groups. Group 1: 34 patients with known lesions in which (99m)Tc-EDDA/HYNIC-TOC was performed for staging, characterisation or to choose the appropriate treatment. Group 2: 16 patients suspected of having NET or in follow up after surgery. Patients were injected with 370 MBq of (99m)Tc-EDDA/HYNIC-Tyr3-octreotide and whole-body and SPET images acquired 2-3 hours after injection. Overall, 29 patients (58%) had a positive scan, with a sensitivity, specificity and accuracy of 70.3%, 76.9% and 72%, respectively (78.1%, 50% and 76.5%, in group 1 and 20%, 81.2%, 62.5% in group 2). In patients from group 1 (99m)Tc-HYNIC-TOC scintigraphy showed a concordance of 68% with another imaging procedure and in 9 patients revealed a greater number of lesions. In the second group, false negative results were especially found in patients with medullary thyroid cancer with negative radiological findings and elevated calcitonin. In conclusion, (99m)Tc-EDDA/HYNIC-TOC is highly indicated for in vivo histological characterization of known NET lesions, previously identified by other imaging modalities or biopsy, to plan appropriate therapy especially for patients with inoperable disease. In patients with only biochemical suspicion of NET and in those with negative markers, this scintigraphy does not significantly modify the clinical management.