Preoperative Nodal US Features for Predicting Recurrence in N1b Papillary Thyroid Carcinoma

SIMPLE SUMMARY: The presence of lateral neck lymph node (LN) metastasis (N1b) is a known prognostic factor for poor prognosis and high morbidity after surgery in papillary thyroid carcinoma (PTC). Previous studies have suggested that tumor size and metastatic LN characteristics, including LN size, number, ratio, and extranodal extension, are associated with recurrence; however, the prognostic role of imaging features of LNs in the lateral neck have rarely been reported. In this study, we investigated whether ultrasound imaging features of lateral neck LN metastases can be prognostic markers for predicting recurrence and thereby guide surgical extent and posttreatment surveillance in N1b PTC. ABSTRACT: This study aimed to investigate whether preoperative ultrasonographic (US) features of metastatic lymph nodes (LNs) are associated with tumor recurrence in patients with N1b papillary thyroid carcinoma (PTC). We enrolled 692 patients (mean age, 41.9 years; range, 6–80 years) who underwent total thyroidectomy and lateral compartment LN dissection between January 2009 and December 2015 and were followed-up for 12 months or longer. Clinicopathologic findings and US features of the index tumor and metastatic LNs in the lateral neck were reviewed. A Kaplan-Meier analysis and Cox proportion hazard model were used to analyze the recurrence-free survival rates and features associated with postoperative recurrence. Thirty-seven (5.3%) patients had developed recurrence at a median follow-up of 66.5 months. On multivariate Cox proportional hazard analysis, male sex (hazard ratio [HR], 2.277; 95% confidence interval [CI]: 1.131, 4.586; p = 0.021), age ≥55 years (HR, 3.216; 95% CI: 1.529, 6.766; p = 0.002), LN size (HR, 1.054; 95% CI: 1.024, 1.085; p < 0.001), and hyperechogenicity of LN (HR, 8.223; 95% CI: 1.689, 40.046; p = 0.009) on US were independently associated with recurrence. Preoperative US features of LNs, including size and hyperechogenicity, may be valuable for predicting recurrence in patients with N1b PTC.