Pattern and Distribution of Lymph Node Metastases in Papillary Thyroid Cancer

Abstract

Background: The indications and extent of lymph node dissection in the treatment of papillary thyroid carcinoma remains controversial, and benefit from therapy is debatable. This study was designed to identify the pattern and distribution of lymph node metastases and to establish an optimal strategy for neck dissection for those patients. Methods: A total of 44 patients diagnosed with papillary thyroid cancer were treated from 2006 to 2013. All patients underwent total thyroidectomy, central neck dissection, and ipsilateral selective neck dissection removing lymphatic structures in levels II through V. The frequency of cervical lymph node metastases in each level, and the presence of capsular invasion were analysed. In addition, we investigated postoperative complications after total thyroidectomy and central lymph node dissection. Results: Lymph node metastases were found in 18 patients (40.9%); all of them had ipsilateral level VI nodal involvement. 7 patients had level V involvement, 2 patients had level II affection, 3 patients had level III & IV affection and 2 patients had contralateral level VI lymph node affection. We also found extracapsular invasion in 6 (13.6%) patients and grade I, II, III in 2, 40, 2 patients respectively. The frequency of temporary hypocalcaemia, permanent hypocalcaemia and temporary vocal cord paralysis were 6.8%, 2.3% and 4.5%, respectively. Conclusion: We recommend total thyroidectomy and central compartment lymph node dissection. If ipsilateral central lymph nodes are positive for metastases in frozen section, we proceed to ipsilateral selective neck dissection removing lymphatic structures in levels II through V even in the absence of clinically evident lymph node metastasis irrespective of tumor size. The technique had a low rate of complications; namely laryngeal nerve injury and hypoparathyroidism.