Feasibility of lateral sentinel lymph node biopsy in medullary thyroid cancer: Surrogate tool for determining prophylactic lateral neck dissection—A pilot study

Backgrounds: This study aimed to evaluate usefulness of lateral sentinel lymph node biopsy (SLNB) in determining lateral neck dissection (LND) of patients with medullary thyroid cancer (MTC). Methods: Sixteen patients with MTC were enrolled in the study from January 2013 to June 2019. Intratumoral injection of technetium (Tc)-99m phytate followed by lymphoscintigraphy was performed preoperatively. Lateral sentinel lymph nodes were detected by a collimated gamma probe and underwent frozen analysis. Ipsilateral LND was performed in all patients to assess lateral LN status. Results: The identification rate of sentinel lymph nodes (SLNs) detected by radioisotope was 87.5% (14 of 16 patients). The sensitivity, specificity, positive predictive value, and negative predictive value of frozen analyses were 66.7%, 100%, 100%, and 91.6%, respectively. Based on final histopathology, however, the diagnostic values of lateral SLNB were all 100%. Conclusions: This study showed that lateral SLNB can be a promising surgical tool for decisions on LND in patients with MTC.