Histopathological Characteristics of N1b Papillary Thyroid Carcinoma are Associated with Risk of Recurrence.

Background: The presence of cervical lymph node (LN) metastasis at the initial presentation of papillary thyroid carcinoma (PTC) constitutes an independent risk factor for disease recurrence, increases the risk for mortality, and impacts overall outcome. The 2016 American Joint Committee on Cancer raised the age cutoff for PTC staging from 45 to 55 years for better prediction of overall survival. Age > 55 years is considered a significant risk factor for a more aggressive and advanced disease with worse outcomes. We identified histopathological factors for disease recurrence in PTC patients younger and older than 55 years of age.

Methods: Data on all patients who underwent thyroid surgery due to PTC between 2006 and 2018 in the Tel Aviv Sourasky Medical Center were retrieved for this retrospective cohort study. Patients with lymph node (LN) metastases were further investigated for preoperative presentation, pathological characteristics, and recurrence. A multivariate analysis was used to detect predictors for recurrence and patient outcome for each age-group.

Results: Twenty-two of the 183 patients (12%) with PTC who met the inclusion criteria and had sufficient follow-up period sustained recurrence. The predictors of recurrence varied between the two age-groups. The size of thyroid lesions (p = 0.003) was identified as a risk factor in the older group, while the number of metastatic cervical LNs (p = 0.001) and the ratio of metastatic-to-total dissected cervical LNs (p = 0.027) were the main predictors of recurrence for the younger group.

Conclusion: The histopathological factors predictive for disease recurrence differed among PTC patients younger and older than 55 years of age.