Status of level IIb lymph nodes of the neck in squamous cell carcinoma of the oral tongue in patients who underwent modified radical neck dissection and lymph node sentinel biopsy

Status of lymph nodes of level IIb was examined to identify the incidence of nodal metastasis and the lymphatic drainage in squamous cell carcinoma of the oral tongue in patients undergoing modified radical neck dissection (MRND) and sentinel node biopsy (SNB). Overall, 72 patients were divided into two groups; 38 patients (Group A) of any T and N+ or T3-T4- N0 stage underwent MRND. The surgical specimens were sent to the Pathology Department, divided into specific levels (I, IIa, IIb, III, IV, V) and labelled. The remaining 34 patients (Group B) T1-T2 -N0 stage were submitted to SNB. The histological examination of the specimens of the two groups was performed by staining with haematoxylin and eosin several sections from each node at different levels and then using a molecular marker such as cytokeratin and Epithelial Membrane Antigen (EMA). In Group A: In N0 there were no occult metastases at level IIb; in N+ neck, 8 cases (33.3%) showed metastasis at level IIb (P = 0.04). Metastases at level IIb were observed only in combination with other levels (P = 0.03). In Group B, direct lymphatic drainage was found in 2 patients (5.9%) at level IIb. There were no occult metastases at level IIb. Out of the 54 sentinel nodes harvested, 4 lymph nodes (7.4%) were found to be metastatic; these 4 sentinel nodes were found respectively in 4 patients, 1 at level III, 3 at level II a with an occult metastasis rate of 11.7%. In conclusion, SNB has prospected a new concept of lymphatic drainage that is variable and individual. SNB has demonstrated that direct lymphatic drainage is possible to level II b. In our experience with early cancer of the tongue (T1-T2 NO ), SNB aided with lympho-scintigraphy seems to be a good technique for staging the neck with minimal morbidity.