Performing contralateral central lymph node dissection in papillary thyroid carcinoma: a decision approach.

Background: Substantial controversy exists over the role of prophylactic neck dissection for patients with papillary thyroid carcinoma (PTC). We hypothesized that a therapeutic strategy of performing a routine intraoperative frozen section of the ipsilateral central lymph node (CLN) after elective ipsilateral CLN dissection (CLND) for all unilateral PTC and then performing a contralateral CLND if the frozen section is positive for malignancy would reduce morbidity compared to a therapeutic strategy of routine bilateral CLND.

Methods: In a group of 419 patients with PTC undergoing thyroidectomy during study the period, the 203 patients who had unilateral PTC and no evidence of adenopathy on ultrasonography were prospectively enrolled in our nonrandomized study that was performed between March 2009 and February 2010. Patients underwent a total thyroidectomy if tumor size was over 1 cm or extrathyroidal was detected on ultrasonography. Patients underwent a subtotal or near-total thyroidectomy if tumor size was <1 cm and additional benign tumor existed on contralateral lobe. There were 25 patients who had a unilateral CLND with a subtotal or near-total thyroidectomy, and 178 patients who underwent a unilateral or bilateral CLND with a total thyroidectomy.

Results: There was no difference in the rate of major complications between unilateral CLND group and bilateral CLND group. The rate of transient hypocalcemia was 31.8% in the unilateral CLND group and 45.7% in the bilateral CLND group (p = 0.084). The rate of voice change was 7.6% in the unilateral CLND group 4.3% in the bilateral CLND group (p = 0.438). The ratio of malignant to all nodes retrieved was 0.5/7.88 in the unilateral CLND group and 5.13/17.20 in the bilateral CLND group. There was 78.3% sensitivity and 100% specificity for frozen biopsy of ipsilateral CLN to predict contralateral CLN metastasis. A positive ipsilateral CLN frozen biopsy was significantly associated with contralateral CLN metastasis (p < 0.001), as was younger age (p = 0.002) and existence of extrathyroidal extension (p = 0.031), each on univariate analysis.

Conclusions: In patients with unilateral PTC, routine ipsilateral CLND with intraoperative reading of the frozen section can be employed to assess the risk of contralateral CLN metastasis. This information should be of value in deciding whether to perform contralateral CLND or not.