Is central lymph node dissection necessary for parathyroid carcinoma?

Background. Parathyroid carcinoma is a rare cancer. Unlike other more common malignancies, the importance of lymph node (LN) status remains controversial. The purpose of this study was to determine the relative importance of LN metastases in disease-specific survival (DSS). Methods. A retrospective review of the Surveillance, Epidemiology, and End Result database was performed on parathyroid carcinoma cases diagnosed between 1988 and 2010. Results. We identified 405 parathyroid carcinoma patients. Among 114 patients with LNs examined at operation, only 12 (10.5%) had positive LNs. Sensitivity analysis found that a tumor size threshold of 3 cm best divided the cohort by DSS. Only tumors >= 3 cm and distant metastasis but not LN metastases were independent prognostic factors on multivariate analysis. When examining factors associated with LN status, only tumors >= 3 cm predicted LN metastasis. LN metastases were 7.5 times more likely in patients with tumors >= 3 cm than those with tumors <3 cm. Conclusion. Tumors >= 3 cm were associated with LN metastases in parathyroid carcinoma, but positive LN status was not associated with DSS. Tumor size can potentially risk stratify patients by their risk of LN metastases.