Risk Factors for Lateral Neck Recurrence of N0/N1a Papillary Thyroid Cancer

Current guidelines advocate no prophylactic dissection of the lateral neck compartment for papillary thyroid carcinoma (PTC) without clinical evidence of lateral neck metastasis (cN1b). However, lateral neck recurrence can affect patient treatment outcomes and quality of life. Therefore, this study examined the risk factors for lateral neck recurrence after the definitive treatment of PTC without cN1b.

The study enrolled 1928 consecutive patients who underwent total thyroidectomy between 2006 and 2012 for PTC without cN1b. Logistic regression analysis was used to identify the relationship of clinicopathologic factors with lateral neck recurrence. Uni- and multivariate Cox-proportional hazards regression analyses were used to identify factors predictive of lateral neck recurrence-free survival (LRFS).

During a median follow-up period of 94 months (range, 24-133 months), lateral neck recurrence occurred in 47 patients (2.4%). Binary logistic regression showed that tumor size (>2 cm), multifocality, clinical central neck metastasis (cN1a), number of positive lymph nodes (LNs, >5), and LN ratio (>0.5) were significantly associated with lateral neck recurrence (P < 0.05). Multivariate analyses showed that multifocality (hazards ratio [HR], 2.338; 95% confidence interval [CI], 1.126-4.858; P = 0.023), cN1a (HR, 5.301; 95% CI, 2.416-11.630; P < 0.001), LN ratio (HR, 2.628; 95% CI, 1.228-5.626; P = 0.013), extranodal extension (HR, 2.570; 95% CI, 1.063-6.213; P = 0.036), and MACIS (distant metastasis, patient age, completeness of resection, local invasion and tumour size) score (HR, 2.513; 95% CI, 1.211-5.216; P = 0.013) were independent factors for LRFS.

Lateral neck recurrence after thyroidectomy is predicted by the clinicopathologic factors of multifocality, cN1a, LN ratio, extranodal extension, and MACIS score in N0/N1a PTC patients.