The Prognostic Value of Central Lymph Node Yield and Ratio in Papillary Thyroid Carcinoma Patients Who Underwent Thyroidectomy with Prophylactic Central Compartment Neck Dissection

ABSTRACT

BACKGROUND AND OBJECTIVES: The impacts of prophylactic central compartment neck dissection (pCCND) on the prognosis of papillary thyroid cancer (PTC) are controversial. The aim of this study is to evaluate the relationship between nodal factors of pCCND and the prognosis of PTC patients. MATERIALS AND METHODS: A total of 1754 patients who underwent thyroidectomy with pCCND were retrospectively reviewed. Nodal factor was defined as the number of metastatic lymph node (MLN), lymph node yield (LNY) and lymph node ratio (LNR). In regarding the cutoff of nodal factors, patients were categorized as low/high MLN, LNR and LNY group. The correlation of clinicopathologic characteristics including nodal factors and recurrence free survival (RFS) were anlalyzed. RESULTS: Of these, 1195 patients underwent thyroidectomy with unilateral pCCND and 559 patients underwent total thyroidectomy with bilateral pCCND. During follow-up, 45 (2.57%) patients showed recurrent disease. Of these, 19 patients underwent bilateral pCCND and 26 cases were unilateral pCCND. Gross extrathyroidal extension (ETE), high MLN and LNR showed statistically significant on RFS in univariate analysis in unilateral pCCND. In multivariate analysis, gross ETE and high LNR were independent risk factor of recurrence in unilateral pCCND. In bilateral pCCND, larger tumor size, minimal ETE, high MLN and LNR were significant correlation with RFS in univariate analysis. However, in multivariate analysis, multiple larger tumor and high LNR showed significant correlation with RFS. LNY was not statistically significant in both unilateral and bilateral pCCND. CONCLUSION: In regarding nodal factors, high LNR was only independent risk factor to worse RFS in both unilateral and bilateral pCCND in cN0 PTC patients.