PO085 131I-SPECT/CT in neck lymph node metastasis detection in patients with differentiated thyroid carcinomas (DTC) in long-term follow-up A. Marongiu1, S. Nuvoli2, I. Gelo2, L. Mele2, B. Piras2, M.L. Stazza2, S. Galassi2, G. Madeddu2, A. Spanu2 1Unit of Nuclear Medicine, Department of Clinical, Surgical and Experimental Sciences, University of Sassari, Sassari, Italy. 2Unit of Nuclear Medicine, Department of Clinical, Surgical and Experimental Sciences, University of Sassari, Sassari, Italy Background-aim: The prognostic importance of regional lymph node metastases in DTC is controversial even if it is generally accepted that their presence, especially if in bilateral regions, correlates with tumor recurrences and with adverse prognosis, in particular in older age group. Thus, their identification is mandatory to achieve early the most appropriate treatment. We further investigated the usefulness of 131I-SPECT/CT with diagnostic dose in neck lymph node metastasis detection in DTC patients in long term follow-up. Methods: We retrospectively evaluated 215 consecutive DTC patients already submitted to total thyroidectomy and radioiodine therapy, all of them with ascertained radioiodine avid foci in the neck at 131I-SPECT/CT during long-term follow-up; at surgery, 62 patients were classified at high risk (H), 61 at low risk (L), 92 at very low risk. All patients underwent 131I-whole body scanner (WBS) followed by SPECT/CT 48 h after an orally radioiodine administered dose of 185 MBq, using a hybrid variable dual head gamma camera, including a low dose-x-ray, and equipped with high energy, parallel hole collimators. Results: SPECT/CT detected 456 iodine avid foci in the neck in the 215 patients, while WBS evidenced 323 foci in 161/215, patients all also identified by SPECT/CT.WBS classified as residues 262/323 foci and as unclear 61 foci. SPECT/CT confirmed 253/262 foci as residues but correctly characterized the remaining 9 cases as 8 neck lymph node metastases and 1 physiologic structure. Moreover, SPECT/CT appropriately characterized the 61 foci unclear at WBS as 18 lymph node metastases, 24 residues and 19 iodine avid physiologic structures. In 73 patients, SPECT/CT also detected 133 occult foci at WBS, among whom 54 cases with foci completely occult at WBS, characterizing these as 59 residues and 74 lymph node metastases. Globally, SPECT/CT identified 100 metastatic foci as neck lymph node metastases in 54 patients (23 H, 11L, 20VL), while WBS evidenced 26 (p\0.0001) in 22 cases, in part wrongly classified as residues and in part as unclear foci. Twelve VL patients, seven of whom with lymph nodes near submandibular glands, had thyroglobulin undetectable or\2.5 ng/ml and were T1aN0M0. Globally, SPECT/CT obtained an incremental value than WBS in 43.2% of cases, a more correct patient classification changing therapeutic approach in 27.4% of cases and contributed to avoid unnecessary therapies in presence of single foci of physiologic uptakes not classified by WBS in 7% of cases. Conclusions: 131I-SPECT/CT proved a reliable tool in detecting and characterizing neck lymph node metastases in DTC patients in long term follow-up improving WBS performance, including the interpretation of unclear foci, and reducing the false positive results. The role of SPECT/CT appears particularly significant in patients with WBS inconclusive, VL, T1aN0MO and with undetectable or very low thyroglobulin levels.
Scheda prodotto non validato
Attenzione! I dati visualizzati non sono stati sottoposti a validazione da parte dell'ateneo
|Titolo:||131I-SPECT/CT in neck lymph node metastasis detection in patients with differentiated thyroid carcinomas (DTC) in long-term follow-up|
|Data di pubblicazione:||2019|
|Appare nelle tipologie:||1.5 Abstract in rivista|