Purpose: Several characteristics of lymph node metastasis (LNM) as predictors of the risk of recurrence or death were examined in patients with papillary thyroid carcinoma (PTC). The presence of cancerous nodules as a characteristic of LNMs in PTC has not yet been reported. The objective of this study was to evaluate the use of the cancerous nodules in the lymph node (CNLN) to determine the risk of distant metastasis and survival in patients with PTC.
Methods: This retrospective observational cohort study enrolled 1408 patients with pathologically confirmed PTC without initial distant metastasis who underwent thyroidectomy and neck dissection. All patients were divided into two groups (CNLN group and Non-CNLN group) according to the presence of CNLN.
Results: Multivariate analyses showed that the presence of a special histologic variant (OR 3.31), CNLN (OR 7.13), and lateral LNM (OR 4.02) was an independent factor predictive of distant metastasis. Distant metastasis was found in 23.1% and 2.3% of patients in the CNLN and Non-CNLN group, respectively (p < 0.001). Furthermore, tumor-specific death was found in 7.7% and 0.6% of patients in the CNLN and Non-CNLN group, respectively (p < 0.001). Patients in the CNLN group had a shorter distant metastasis-free survival and overall survival than patients in the Non-CNLN group (p < 0.001).
Conclusions: The presence of CNLN in patients with PTC is a novel indicator of distant metastasis and poor survival. PTC patients accompanied with CNLN should undergo more aggressive treatment and careful follow-up.
Keywords: Distant metastasis; Lymph node metastasis; Papillary thyroid cancer; Predictor; Survival.