Detection of Sentinel Lymph Nodes in Patients With Thyroid Cancer With the Use of Toluidine Blue

Abstract

Introduction. Treatment of patients with thyroid cancer (TС) with clinically undetected metastases to regional lymph nodes remains an unsolved problem of modern oncology. The search for reliable diagnostic methods, which underlie the decision to perform an adequate lymphadenectomy for TC, is one of the priorities of oncosurgery. The aim of the research: to find an effective method of intraoperative contrasting of sentinel lymph nodes (SLN) in patients with TC using toluidine blue and to evaluate its effectiveness. Methods. A study of 123 patients with TC who underwent surgical treatment using the contrast-visual method in the amount of thyroidectomy with central and bilateral selective cervical lymph node dissection (levels VI; IIA; III; IV). During surgery, a 1% solution of toluidine blue was injected into the tumor using a syringe. Surgical treatment was performed in two stages. At the first stage – thyroidectomy was performed in a block with a central lymphatic collector of the neck (level IV), which included removal of paratracheal, prelaryngeal, parathyroid tissue of the neck. Urgent intraoperative histological examination of thyroid tumor and distant SLN was performed. In the second stage of the operation performed cervical lymph node dissection with removal of fiber IIA; III; IV levels of the neck, with mandatory revision of the level of VB. After the operation, the final histological examination of the removed specimen with the tumor and all lymph nodes was performed. Results. After the application contrasting technique, SLN were found in 120 (97.6%) patients. Their number varied from 2 to 12. These lymph nodes were mainly localized in the central collector of the neck on the side of the primary tumor (central, ipsilateral SLN) in 91 (75.8%) patients. Based on the results of an intraoperative study of SLN, metastases were found in 33 (27.5%) of 120 patients. In most cases (83.3%) SLNs were detected in the central lymphatic collector of the neck (level VI). In 76 (63.3%) patients, staining of the lymph nodes of the III level of the neck (middle ipsilateral jugular lymphatic collector) occurred, in 11 (9.2%) SLNs were found only at levels III, IV and VB of the neck. Very rarely (5.8%), the lymph nodes of the anterior-superior mediastinum were contrasted. Conclusions. The method of contrast visualization of the regional collector in patients with TC using a 1% solution of toluidine blue is a highly informative study that allows to determine the regional lymph nodes affected by metastases and to differentiate the choice of the volume of lymph node dissection in the early stages of tumors. The method is simple to implement, does not involve considerable costs and can be recommended for use in oncology clinics.