Identifying risk factors of recurrence for clinically node negative papillary thyroid carcinoma with pathologic N1a

BACKGROUND: Whether or not to perform prophylactic central lymph node dissection (CLND) in the case of clinically node-negative papillary thyroid cancer (PTC) is controversial. The purpose of this study was to investigate the risk factors for recurrence in clinically node-negative PTC patients who underwent total thyroidectomy plus bilateral central neck dissection and was verified pathologic N1a. METHODS: We retrospectively reviewed the medical records of 1082 PTC patients who underwent total thyroidectomy and prophylactic bilateral CLND between January 2004 and December 2012. We used Cox-proportional hazard regression analyses in order to explore potential predictive factors for recurrence. RESULTS: During a median follow-up (range) of 78 (12–158) months, recurrence occurred in 62 (5.7%) patients. Main tumor size more than 1 cm, gross extrathyroidal extension (ETE), positive lymph node (LN) more than 3, and LN ratio > 0.5 were all significantly associated with recurrence according to univariate analysis. In model I multivariate analysis (tumor size, gross ETE, LN ratio), LN ratio > 5 (hazards ratio [HR], 4.794; 95% confidence interval [CI], 2.674–8.595; p < 0.001) was found to be predictive of recurrence. Gross ETE (HR, 1.794; 95% CI, 1.024–3.143; p = 0.041) and positive LN more than 3 (HR, 2.505; 95% CI, 1.513–4.146; p < 0.001) were predictors for recurrence in model II multivariate analysis (tumor size, gross ETE, the number of positive LN). CONCLUSIONS: We recommend that surgeons try to focus completely on performing prophylactic CLND for patients with suspicious gross ETE during preoperative evaluation. Close monitoring and thorough management are needed for clinically node-negative PTC patients with LN ratio of more than 0.5 and more than 3 positive LN in the central compartment.