[The clinical significance of Delphian lymph node metastasis in papillary thyroid cancer]

Objective: To evaluate the clinical significance of Delphian lymph node (DLN) metastasis in papillary thyroid cancer (PTC). Method: A total of 505 cases with PTC confirmed pathologically in our hospital between January 2015 and December 2015 were retrospectively reviewed. 208 patients with DLN assessed separately by histopathologic examination who underwent primary surgery for PTC were included for the following analysis. Results: In 208 patients, the detection rate of DLN was 63.0% and the metastasis rate of DLN was 21.4%. DLN metastasis was correlated with PTC multifocality (P=0.038), tumor size over 1cm (P=0.001), BRAF^V600E mutation (P=0.017) and central neck node metastasis (P<0.001). Tumor size over 1cm (95%CI 1.308-9.909, OR=3.600, P=0.013) and the number of node with central neck metastasis (95%CI 1.313-2.163, OR=1.685, P<0.001) were independent risk factors for DLN metastasis. The presence of DLN metastasis was associated with an 8.8-fold higher frequency of central neck node metastasis compared to cases without DLN metastasis. Among patients with DLN metastases, central lymph node metastasis was more common in the cases with lateral neck node metastases compared to those without lateral neck node metastases (6.5±3.0 vs 1.5±0.7, P=0.009), and 5 of the 6 patients also presented with PTC multifocality and BRAF^V600E mutation. Conclusion: DLN metastasis implies a higher possibility of central neck lymph node metastasis. DLN should be assessed during operation to provide information for neck dissection, post-operative administration and follow-up strategy.