Localization of sentinel lymph node with radionuclide in clinically N0 laryngeal and hypopharyngeal cancers

Objective To analyze the characteristic of the radioactive lymph node with metastatic disease and to explore the method of the localization of sentinel lymph node （SLN） with radionuclide in NO clinincally laryngeal and hypopharyngeal cancer. Methods Fourty-five patients with T1-T4 and clinically NO laryngeal and hypopharyngeal cancer were recruited. For each patient a peritumoral submucosal injection of ^99mTc-labeled sulfur colloid （^99mTc-SC） was performed and lymph node mapping was performed by lymphoseintigraphy two hours afterward. The SLN was localized by a handheld gamma probe intraoperatively 10- 12 hours after the injection. All hot lymph nodes accumulating activity were harvested and initially termed sentinel nodes. Selective neck dissections were performed for all patients. The specimen of SLN was sent to the pathologist for the following analysis： formal paraffin embedded section, consecutive section and immunohistoehemistry assay. The results was compared to the remaining lymphadenectomy specimen. Resection of the primary turnout depended on the location and the T classification. Results SLNs were identified in 41 of 45 patients with 51 necks, SLNs had occult metastases in 13 cases, 15 necks with SLN- positive of these 13 cases, there was one false negative ease, they were found in non-SLNs of neck specimens. Each neck side was considered a single case. SLN identification rate was 92.7%, sensitivity was 93.7% , false-negativerate was 6.3%, and accuracy was 98.0%. In 11 （73.3%） of these SLN- positive necks, the SLN with the highest counts contained tumor; harvesting the first-three nodes with the highest radioactive counts, which could all patients with occult metastatic disease. Conelusions Excision of the first-three SLNs with the highest radioactive counts can accurately judge the presence or absence of the cervical lymph nodes metastases in patients with the clinically NO laryngeal and hypopharyngeal cancer. Key words: Laryngeal neoplasms; Hypopharyngeal neoplasms; Sentinel lymph node biopsy; Radioactive tracers