Risk factors for central neck lymph node metastases in papillary thyroid microcarcinoma.

e17583 Background: Papillary thyroid microcarcinoma (PTMC) accounts for nearly half of all cases of thyroid papillary cancer. Although PTMC has a good prognosis, lymph node metastasis, especially central lymph node metastasis (CLNM), is the leading cause of local recurrence. The value of central lymph node dissection in PTMC remains controversial. Few studies have focused on the relationship between CLNM and multifocality in PTMC. This retrospective study of a large cohort of patients with PTMC aimed to identify assess the predictive value of multifocality for identifying patients at high risk of CLNM who may benefit from central lymph node dissection. Methods: Patients with PTMC who underwent total or hemi-thyroidectomy with effective unilateral or bilateral central lymph node dissection at Zhejiang Caner Hospital between January 2007 and December 2015 were enrolled ( n = 3543). Number and laterality of PTMC foci, extrathyroidal extension (ETE), tumor size, age, sex, positive/total number of central lymph nodes and other clinicopathological factors were recorded. The chi-square test was used for univariate analysis; logistic regression, for multivariate analysis. Results: Multifocality, age, sex, tumor size, ETE and nodular goiter were significantly associated with central lymph node metastasis (CLNM) in univariate analysis. Multifocality was an independent predictive factor for CLNM in multivariate analysis. Compared to unifocal disease, the odds ratio (OR) for CLNM was 1.447 for patients with ¡Ý 2 tumor foci ( P < 0.001) and 2.978 for patients with ¡Ý 3 tumor foci ( P < 0.001). Conclusions: Multifocality with ¡Ý 3 tumor foci was an independent predictive factor for CLNM in PTMC. Multifocality should be assessed when selecting patients for prophylactic central neck lymph node dissection, and we recommend patients with multifocality should undergo more radical treatment.