الفهرس 
INTRODUCTIONOnly 14 pages are availabe for public view
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Abstract
Head and neck squamous cell carcinoma (HNSCC) is predominantly a locoregional disease. Determining the presence of regional metastases (N+) is critical for staging, treatment, and prognosis. Metastasis to a single regional lymph node can transform a small stage I tumor to an advanced stage III or even stage IV head and neck cancer.
The policy of elective neck dissection exposes more than 50% of stage N0 patients with cancer of the head and neck to lymphadenectomy that may not be necessary. If there were a method to accurately identify occult metastasis before neck dissection, the treatment of stage N0 patients would be more selective and the overall cost and morbidity of treatment would be minimized.
Sentinel node biopsy is a diagnostic technique that may contribute towards changing the management of this pathology.
Sentinel lymph node biopsy (SLNB) is a minimally invasive technique designed to identify, excise, and examine the specific lymph nodes representing the initial drainage of a primary malignant lesion to determine the presence of subclinical metastases. The hypothesis is that the status of the SLN represents the status of the whole lymphatic basin.
Sentinel lymph nodes are the lymph nodes that directly receive lymphatic flow from a primary cancer lesion. The sentinel lymph node (SLN) concept hypothesizes an orderly and sequential lymphatic drainage from the primary tumor site to one (or more) discrete lymph nodes -the sentinels- in the regional lymph node basin (the neck), with the remaining lymph nodes being subordinated and reached later.
The present work aimed to determine the predictive efficacy of sentinel lymph node biopsy in laryngeal and pharyngeal cancer in patients with clinically and radiologically N0 neck by comparing the pathological status of sentinel lymph nodes with that of other lymph nodes within the neck dissection to determine the indications for neck dissection according to the presence of metastasis to sentinel lymph node.
The current work included twenty patients with newly diagnosed, untreated primary squamous cell carcinoma of the larynx and pharynx.
All patients have undergone complete medical history and through head and neck examination, palpation of the neck for assessment of neck lymph nodes level and imaging for the primary tumor with CT scan.
At the time of definitive surgery, a direct laryngoscopy was performed to re-evaluate for tumor extension, and 3-5 ml of methylene blue 1:10 concentration was injected with a butterfly (scalp vein) needle 21-gauge submucosally in four quadrants around the primary tumor. The first appearing lymph nodes with visible blue dye were defined as SLN(s) and were resected. Time was recorded when the first blue dye lymph node was visible. Neck dissection was continued. SLNs were separately sent for pathologic analysis.
All SLN(s) and non-SLN(s) were examined grossly regarding the number of nodes in each group, and the size (maximum dimension) of nodes.
If the single section of the SLN was negative for malignant cells, then the SLN was further assessed by step serial sectioning at 2-mm intervals of thickness, and the sections were processed as separate blocks. from each block, one slide was stained with H&E, and if all sections of SLN turned out to be negative then a second section was stained immunohistochemically with anticytokeratins AE1/AE3.