A comparative study of sentinel lymph node detection in laryngeal and hypopharyngeal carcinoma by lymphoscintigraphy method and blue dye

Abstract

To investigate the clinical value of sentinel lymph node (SLN) detection in laryngeal and hypopharyngeal carcinoma patients with clinically negative neck (cN0) by lymphoscintigraphy method and blue dye. Forty patients with cN0 laryngeal neoplasms and ten patients with cN0 hypopharyngeal carcinoma scheduled for tumor resection and neck dissection, were eligible for the study. single photon emission computed tomography (SPECT)/CT lymphoscintigraphy was performed with injection of radioactivity isotope ⁹⁹Tc(m) labeled sulfur colloid (⁹⁹Tc(m)-SC). Methylthioninium was injected into the same points as ⁹⁹Tc(m)-SC during surgery, and the patients underwent lymphatic mapping with a handheld gamma-detecting probe. All removed lymph nodes were examined by routine histopathology. Thirty-five patients with laryngeal carcinoma and six patients with hypopharyngeal carcinoma detected SLN by radiolabeled tracer method, the detection rate of SLN was 82.0%. Twenty-nine patients with laryngeal carcinoma and 4 patients with hypopharyngeal carcinoma detected SLN by blue dye method, the detection rate of SLN was 66.0%. There were significant difference between two groups (chi² = 2.769, P < 0.05), and the number of SLN were respectively 96 and 83 by radiolabeled tracer method and blue dye (chi² = -2.098, P < 0.05), The sensitivity of SLN detection were respectively 83.3% and 66.7%. Twelve (24.0%) patients had lymph node metastasis. Either lymphoscintigraphy or blue dye mapping can be used to detect the SLN in cN0 laryngeal and hypopharyngeal carcinoma. The lymphoscintigraphy not only preoperatively can locate the accuracy of SLN detection, but also has higher detection rate and sensitivity than dye method.