Impact of extensive neck dissection on survival from papillary thyroid cancer

Background: Cervical lymph node metastasis commonly occurs in papillary thyroid cancer. Emerging evidence from large population-based studies demonstrates decreased survival with regional lymph node metastasis. There is considerable debate in the literature regarding the optimal initial treatment for papillary thyroid cancer. We hypothesized that overall survival is influenced by the extent of neck involvement and neck dissection. Methods: The Surveillance, Epidemiology and End Results database was used to identify all patients with papillary thyroid cancer who underwent thyroidectomy. Patients with distant metastasis, invalid, or missing staging, and neck dissection information were excluded. A Kaplan-Meier survival estimate and a multivariate adjusted Cox regression model were used to estimate survival rates of patients undergoing selective, modified, and radical neck dissection as compared to those who did not have a neck dissection. Results: 3,439 eligible patients were included in this analysis. The mean age was 45 years; 76% were females and 86% were white. 2,414 (70.1%) of the patients underwent thyroidectomy without any neck dissection, whereas selective (limited), modified and radical neck dissections were performed on 19.3, 7.9 and 2.7% of the patients, respectively. Five-year patient survival rates were 96.6, 96.4, 89.5 and 80.9% among patients who had no neck dissection, selective, modified, and radical neck dissections, respectively. After adjusting for age, gender and race, the hazard ratios and 95% confidence intervals of survival for modified and radical neck dissection were 2.35 (95% CI: 1.46-3.78) and 4.48 (95% CI: 2.57-7.84), respectively, as compared to no neck dissection (p < 0.001). Similar associations were also noted after stratifying by localized or regional tumor. Conclusions: Extensive neck dissection among patients with papillary thyroid cancer did not result in an improved survival benefit. Further study is warranted to better understand the extent and requirement of neck dissection among this group of patients.