Background: Controversy exists regarding the extent of surgical treatment for paratracheal (level VI) lymph nodes in patients with papillary thyroid cancer (PTC). Local recurrence within lymph nodes in the central neck compartment after total thyroidectomy can be difficult to detect and more hazardous to treat surgically. An initial bilateral central lymph node dissection (CLND) can best minimize this risk of local recurrence, if CLND is established as reasonably safe and oncologically justified.
Methods: This study is based on a retrospective review of the institutional tumor registry of all patients treated for PTC between January 2000 and May 2008 at a 636-bed tertiary referral center and university-affiliated hospital. The following data were analyzed: the operative procedures, tumor characteristics (size, lymph node metastasis), injury to the recurrent laryngeal nerve (RLN), tumor recurrence, and need for further operative procedures.
Results: Of 310 patients identified as treated surgically for PTC, 281 received total thyroidectomy and 29 received a lesser operation. Bilateral CLND was performed in 169 patients, unilateral CLND in 11, and no CLND in 130. The central lymph nodes were positive in 84 (46.7%) of 180 patients with CLND. Excluding isthmus tumors and those with bilateral same-size PTC, 41 (25.5%) of 161 patients with bilateral CLND had positive contralateral lymph nodes. Of the 603 RLNs at risk, 13 temporary injuries occurred, and 8 (1.3%) permanent injuries resulted. The risk of RLN injury was not greater with bilateral CLND compared to unilateral or no CLND (P = .18), and those patients with bilateral CLND had statistically larger tumors (1.60 cm vs 0.84 cm; P < .0001). Of the 10 documented cancer recurrences requiring reoperation, 4 were in the central neck, and all of these occurred in patients who did not have CLND.
Conclusion: Lymph node metastases are present in both the ipsilateral and contralateral central lymph node basins in a significant percentage of patients with PTC. Routine bilateral CLND in patients with PTC has the potential to clear metastatic disease without significantly increasing the risk of RLN injury.