Intra-operative lymphatic mapping and sentinel node biopsy in laryngeal carcinoma using radiotracer injection.

Objective: The purpose of this study was to determine the value of sentinel lymph node biopsy (SLNB) in the laryngeal SCC, using intra-operative peri-tumoral injection of Tc-99m-phytate.

Methods: Patients with biopsy-proven squamous cell carcinoma of the larynx were included. On the day of surgery, after anesthesia induction, suspension laryngoscopy was performed to inject 74 MBq/0.4 ml Tc-99m-phytate in four aliquots into the sub-mucosal peri-tumoral location. After a 10-min wait, a portable gamma probe was used to locate sentinel nodes. Subsequently, all patients underwent laryngectomy and neck dissection. Both sentinel nodes and non-sentinel nodes were examined using hematoxylin and eosin (H&E) staining.

Results: Twenty-six patients with a diagnosis of laryngeal carcinoma were included in the study. The SLN detection rate was 65.4%, with a 100% detection rate in the supraglottic region and a 52.6% detection rate for glottis/transglottic patients. Permanent pathology results showed lymph node involvement in four patients, but only one patient had a negative result in the SLNB, resulting in an overall false negative rate of 25%. The sensitivity of the SLN technique was 75% overall, 100% in the supraglottic region, and 67% in the glottis/transglottic region.

Conclusion: The accuracy and feasibility of SLNB may be related to the location of the tumors in the larynx. For supraglottic tumors, the technique seems to be feasible with a low false negative rate. For glottis/transglottic tumors, both the detection rate and false negative rate seem to be suboptimal. Further studies are needed to validate our results.