Endocrine Abstracts

Introduction: Surgical management of clinically N0 (cN0) patients with thyroid carcinomas remains debatable due to various reported frequencies of lymph node (LN) metastases. Preoperative ultrasound identifies only half of LN metastases found at surgery. The aim of this report was to present our experience with sentinel lymph node biopsy (SLNB) of jugulo-carotid regions, after methylene blue dye (MBD) mapping and frozen section analysis (FSA), in detection of LN metastases in lateral neck compartments and selection of cN0 patients with papillary and medullary thyroid carcinomas and microcarcinomas for additional one-time lateral neck dissection (LND).

Materials & methods: We present results of three studies from our Surgical Oncology Clinic that analyzed usefulness of Dzodic’s original SLNB method for LN staging in thyroid carcinomas (published in Word J Surg, 2006): the first with 153 cN0 papillary thyroid carcinomas (PTC), the second with 111 cN0 micro-PTCs and the third with 17 cN0 medullary thyroid microcarcinomas (micro-MTC) with serum calcitonin levels <1000 pg/ml. All patients underwent injection of 1%-MBD subcapsullary in both lobes, total thyroidectomy, prophylactic central neck dissection and SLNB of jugulo-carotid regions, since blue-stained LNs in central compartment are routinely dissected. All sentinel-LNs were sent to FSA. One-time LND was performed in patients in whom FSA of sentinel-LNs showed metastases. In other patients, with benign findings, surgery was not extended.

Results: LN metastases were histologically verified in 40.9% of cN0 PTCs and 25% of cN0 micro-PTCs. Only one patient with hereditary micro-MTC had LN metastases in central and both lateral regions. Dzodic’s SLNB method enabled detection of LN metastases in lateral neck compartments in 21% of patients. Skip metastases were detected in about 4% of patients with PTCs and micro-PTCs, while there were no skip metastases in micro-MTCs. Method’s overall accuracy was high in all studies, but the highest in the study with micro-MTCs (100%). None of the patients had allergic reactions to MBD.

Conclusion: Dzodic’s SLNB method with MBD mapping and frozen section examination of sentinel-LNs from jugulo-carotid regions is accurate in detection of LN metastases in lateral neck compartments of cN0 patients with papillary and medullary thyroid carcinomas and microcarcinomas. It optimizes surgery for patients without metastases in examined sentinel-LNs and helps in decision for one-time LND in patients with histologically proven sentinel-LN metastases. This method also facilitates central neck dissection and diminishes the possibility of accidental removal of parathyroid glands (that remain non-colored), even in less experienced surgeons’ hands.