Margin Positivity and Survival Outcomes: A Review of 14,471 Patients with 1-cm to 4-cm Papillary Thyroid Carcinoma

Abstract

Background: Papillary thyroid carcinoma (PTC) comprises the majority of thyroid malignancy, but it is associated with excellent long-term survival. Highly prevalent, with increasing incidence, the optimal operative management for patients with 1- to 4-cm PTC remains unclear. This study determined factors that affect clinical outcomes, including survival, in this patient population.

Study design: Patients with 1- to 4-cm PTC, who underwent thyroidectomy between 2004 and 2016, were identified in the National Cancer Database (NCDB). Factors affecting survival, including margin status, extent of resection, operative volume, and institution type, were studied. Outcomes were estimated by Kaplan-Meier and log rank tests. Cox proportional hazard and binary logistic regression analyses identified factors affecting survival as well as margin positivity.

Results: Of 14,471 patients with 1- to 4-cm PTC, 2,269 (15.7%) exhibited lymphovascular invasion, 6,925 (47.9%) had multifocality, 14,235 (98.3%) underwent total thyroidectomy, and 2,212 (15.3%) had microscopic margin positivity, which conferred lower survival (hazard ratio [HR] 1.464, p < 0.05), with 30-day and 90-day mortality of 0.1% and 0.2%, respectively. Operative volume (odds ratio [OR] 0.979, p < 0.01) and thyroid surgery at an academic center (OR 0.623, p < 0.001) were associated with lower odds of margin positivity.

Conclusions: In patients with 1- to 4-cm PTC, margin positivity confers lower survival. Factors associated with lower rate of margin positivity are higher operative volume and referral for treatment at academic center. Because margin positivity is a modifiable risk factor, referral of patients with aggressive features of PTC to high volume academic centers may improve survival.