Abstract
Background: The current American Thyroid Association risk-stratification system for papillary thyroid carcinoma (PTC) incorporates the number and size of positive lymph nodes (LNs) but places less weight on extranodal extension (ENE). This study investigated how to incorporate ENE into the current system to predict recurrence better in PTC N1 patients.Methods: A total of 369 N1 PTC patients without distant metastasis were enrolled. The combination of number of positive LNs and LNs with ENE that had the highest C-index were identified with multivariable Cox proportional hazards models. ENE number was incorporated into the current system considering the recurrence rate and unadjusted and adjusted hazard ratios (HRs) of the subgroups. Kaplan–Meier curves for recurrence based on current and alternative systems were compared by log-rank test.Results: The recurrence rate for the subgroup with five or fewer positive LNs and one to three ENEs (7/61; 11.5%) was higher than that of the subgroup with five or fewer positive LNs without ENE (5/129; 3.9%; adjusted HR = 3.42 [confidence interval (CI) 0.99–11.75]; p = 0.050). In contrast, adjusted HRs of the subgroup with more than five positive LNs and one to three ENEs (2.33 [CI 0.52–10.35]) or with four or more ENEs (3.86 [CI 1.05–14.17]) were not higher than those of the subgroup with more than five LNs without ENE (4.47 [1.16–17.19]). Incorporating ENE into the current system as an intermediate-risk group yielded a lower log-rank p-value (0.05 vs. 0.01) than the current system.Conclusions: The presence of ENE in low volume LN metastasis confers an intermediate risk of recurrence. Incorporating ENE into the current system allows more accurate decisions regarding further management of PTC N1 patients.
Highlights
Physicians currently use the risk-stratification system of the American Thyroid Association (ATA) to determine further management options for patients with papillary thyroid carcinoma (PTC), including radioactive iodine (RAI) treatment, degree of thyrotropin (TSH) suppression, and surveillance
The ATA guidelines state that patients with lymph nodes (LNs) with three or fewer extranodal extension (ENE) are at low risk of recurrence (2%), while those with LNs with more than three ENEs are at high risk of recurrence [1]
This study defined the optimal combination of number of ENEs and number of positive LNs composed of six subgroups
Summary
Physicians currently use the risk-stratification system of the American Thyroid Association (ATA) to determine further management options for patients with papillary thyroid carcinoma (PTC), including radioactive iodine (RAI) treatment, degree of thyrotropin (TSH) suppression, and surveillance. The currently used system incorporates two lymph node (LN) criteria to stratify nodal disease: the number and largest size of positive LNs [1]. Suggested that the number of ENEs is associated with an increased risk of recurrence of PTC [9]. The current American Thyroid Association risk-stratification system for papillary thyroid carcinoma (PTC) incorporates the number and size of positive lymph nodes (LNs) but places less weight on extranodal extension (ENE). This study investigated how to incorporate ENE into the current system to predict recurrence better in PTC N1 patients. ENE number was incorporated into the current system considering the recurrence rate and unadjusted and adjusted hazard ratios (HRs) of the subgroups. Conclusions: The presence of ENE in low volume LN metastasis confers an intermediate risk of recurrence. Incorporating ENE into the current system allows more accurate decisions regarding further management of PTC N1 patients
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More From: Thyroid : official journal of the American Thyroid Association
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