Sentinel node mapping in papillary thyroid carcinoma using combined radiotracer and blue dye methods

Introduction: In the current study, we evaluated the accuracy of sentinel node mapping in thyroid cancer patients using both radiotracer and blue dye. Material and methods: 30 patients with a diagnosis of papillary thyroid carcinoma (PTC) were included in the study; 2-3 hours before surgery, 0.5 mCi 99m-Tc-Antimony Sulfide Colloid was injected intra-tumourally. 15 minutes post-injection, lymphoscintigraphy images of the neck were obtained. Immediately after anaesthesia induction, 0.5 mL patent blue V was also injected in the same fashion. Sentinel lymph nodes were detected intraoperatively using gamma probe and blue dye. Total thyroidectomy was performed for all patients with dissection of central neck lymph nodes as well as sampling of the lateral neck lymph nodes. Results: At least one sentinel node could be identified during surgery in 19 patients (63.3%). The median number of sentinel nodes per patient was 1. Sentinel nodes in 12 patients were pathologically involved. No false negative case was noted. Upstaging occurred in six patients (20%). Conclusions: Sentinel node mapping in papillary thyroid carcinoma is a feasible technique with high accuracy for the detection of lymph node involvement. This technique can guide surgeons to perform central lymph node dissection only in patients with pathologically involved sentinel nodes. Although SLN detection in the lateral neck lymph nodes increases the extension of lymphadenectomy, SLN mapping can result in upstaging in older patients (> 45 years of age) or treatment plan change in younger patients (< 45 years of age) by the detection of lateral lymph node involvement.