Sentinel lymph node localization using 1 % isosulfan blue dye in cases of early oral cavity and oropharyngeal squamous cell carcinoma

Abstract

To study the use of 1 % isosulfan blue dye in identifying sentinel node, sensitivity and specificity of frozen section and predictive value of sentinel node in predicting other nodal status in the cases of oral cavity and oropharyngeal squamous cell carcinoma. 15 patients of oral cavity and oropharyngeal SCC with clinically N0 neck, who required WLE of the primary lesion as well as neck dissection as per recommended treatment protocol, were selected from OPD. 1 % Isosulfan dye was injected peritumorally intraoperatively after the induction of general anaesthesia. Neck dissection was performed and first node taking up the blue dye was identified, dissected, removed and was sent for frozen section. In two of the 15 cases a sentinel node was identified (sensitivity of the technique-13 %). Both the sentinel nodes were positive for presence of metastasis on final histopathology (specificity-100 %). However, five cases had nodal metastasis on final histopathological examination of the neck dissection specimen (sensitivity of sentinel lymph node biopsy-40 %). Frozen section examination had a sensitivity and specificity of 100 %. All data was analyzed using SPSS 16 software. Use of 1 % Isosulfan Dye for identification of sentinel node is a simple and cheap technique, however, it has low sensitivity as compared to the use of triple diagnostic procedure consisting of lymphoscintigraphy, per op gamma probe localization and using isosulfan dye for sentinel node identification. Sentinel lymph node is representative of nodal status and correlates well with the final histopathological examination of the dissected neck nodes.

Keywords: Frozen section; Isosulfan blue dye; N0 neck; SLNB (sentinel lymph node biopsy); Sentinel node.

Fig. 1

Showing the clinical stage of patients at presentation

Fig. 2

Showing types of neck dissection performed