Risk Factors for Predicting Central Lymph Node Metastasis in Papillary Thyroid Microcarcinoma (CN0): a Study of 273 Resections

Objective: The role of routine central lymph node dissection (CLND) for clinically central lymph node negative (CN0) papillary thyroid microcarcinoma (PTMC) remains uncertain. We aim to determine the predictive factors for central lymph node metastasis (CLNM) in papillary thyroid microcarcinoma.

Patients And Methods: A total of 273 patients diagnosed with clinically central lymph node negative PTMC from 2014 to 2016 were included. The predictive risk factors for CLNM were analyzed with respect to age, sex, tumor size, tumor multifocal, lymphadenectasis of lateral neck, capsular invasion, extra capsular spread (ECS), coexistence of chronic lymphocytic thyroiditis (Hashimoto thyroiditis, HT) and nodular goiter (NG), BRAFV600E mutation and subtype of papillary thyroid carcinoma (PTC). Univariate and multivariate analyses were performed to identify the risk factors for CLNM.

Results: Among the 273 patients, the CLNM occurred in 80 patients (29.3%). By univariate and multivariate analyses, tumor size (OR 2.07; p<0.001), multifocal (OR 2.67; p<0.004), lymphadenectasis of lateral neck (OR 9.28; p<0.001), tumor extent (OR 42.01; p<0.001) were independently correlated with CLNM. In further study, dorsal part of solitary lesion (OR: 16.312, 95%CI: 3.349-79.455, p=0.001), capsular invasion (OR: 42.012, 95% CI: 5.209-338.861, p<0.001), 6<D≤9 (OR: 8.400, 95% CI: 1.866-37.807, p=0.006) and D=1 (OR: 11.455, 95% CI: 2.500-52.480, p=0.002) were more tended to have CLNM.

Conclusions: A prophylactic central lymph node dissection should be considered particularly to PTMC patients with each of tumor size > 6 mm, dorsal part of solitary lesion, multifocal, lymphadenectasis of lateral neck and capsular invasion.