The Evaluation of the Diagnostic Properties of Intra-operative In-situ Thyroglobin Levels of Cervical Lymph Nodes, in the Discrimination Between Benign and Malignant Lymph Nodes in Thyroid Cancer: a Prospective Multicentre Study.

Cytological examination of punctured lymph nodes is the gold standard for confirming metastatic lymph node spread of differentiated thyroid cancers. In order to increase the diagnostic sensitivity of fine-needle cyto-punctured lymph nodes, an assessment of Tg levels of the aspirate could be included. Although this technique has been well proven, many uncertainties remain, especially with regards to a pathological cut-off value and its clinical utility when the thyroid is still intact. This uncertainty is mainly due to discordancy between low Tg levels found in cytopunctured lymph nodes with normal cytology, and their final histopathological analyses. To eliminate this uncertainty, cyto-punction will be performed intra-operatively after localizing and isolating the target lymph nodes for assessment of cytology and Tg values. The thyroid gland might be present or absent (already operated) depending on the case. Finally, the cyto-punctured lymph nodes will be excised for complete histopathological analysis. In order to determine whether the Tg values are appropriate in cases where the thyroid is intact, a control group has been included (First operation for thyroid cancer or benign pathology). To eliminate the possible iatrogenic risks of lymph node dissection and resection in patients for whom it is not indicated, only lymph nodes found along the incision path for neuromonitoring of the recurrent laryngeal nerve (performed systematically) will be analysed and excised.