Prognostic value of lymph node yield and metastatic lymph node ratio in medullary thyroid carcinoma

Abstract
Introduction  Lymphadenectomy and thyroidectomy is standard treatment for medullary thyroid carcinoma (MTC), but the prognostic importance
of the number of lymph nodes removed (lymph node yield, LNY) and the proportion of metastatic lymph nodes resected (metastatic
lymph node ratio, MLNR) is unknown. We hypothesized that MTC survival is influenced by LNY and MLNR.

Methods  Patients (N = 534) who underwent thyroidectomy with lymphadenectomy for MTC between 1988 and 2004 were identified in the Surveillance,
Epidemiology, and End Results (SEER) database. The Kaplan–Meier method was used for univariate comparisons of survival for
LNY and MLNR with a maximum follow-up of 12 years. Cox regression models adjusted for age, sex, extent of disease, tumor size,
nodal status, LNY, and MLNR.

Results  By univariate analysis, increasing LNY was associated with improved survival in all patients (P < 0.002) and node-positive patients (P < 0.001). In a multivariate analysis using LNY and MLNR as categorical variables, significant factors influencing survival
included: age (P < 0.001), tumor size (P < 0.001), LNY (P = 0.007), and MLNR (P < 0.02); in node-negative patients: age (P = 0.002); in node-positive patients: age (P < 0.001), tumor size (P < 0.001), and LNY (P = 0.001). Using LNY and MLNR as continuous variables, significant factors influencing survival included: age (P < 0.001), tumor size (P < 0.001), and MLNR (P = 0.01); in node-negative patients: age (P < 0.001); in node-positive patients: age (P < 0.001) and tumor size (P < 0.001).

Conclusion  In patients undergoing thyroidectomy and lymphadenectomy for MTC, LNY and MLNR predict poorer survival, but their impact on
survival was limited to node-positive patients and was otherwise dominated by the effects of age and extent of disease.

Content Type Journal ArticleCategory Endocrine TumorsDOI 10.1245/s10434-008-0022-zAuthors
Maya D. Leggett, University of California at Davis Department of Surgery, Division of Surgical Oncology, UC Davis Cancer Center 4501 X Street, Suite 3010 Sacramento CA 95817 USASteven L. Chen, University of California at Davis Department of Surgery, Division of Surgical Oncology, UC Davis Cancer Center 4501 X Street, Suite 3010 Sacramento CA 95817 USAPhilip D. Schneider, University of California at Davis Department of Surgery, Division of Surgical Oncology, UC Davis Cancer Center 4501 X Street, Suite 3010 Sacramento CA 95817 USASteve R. Martinez, University of California at Davis Department of Surgery, Division of Surgical Oncology, UC Davis Cancer Center 4501 X Street, Suite 3010 Sacramento CA 95817 USA

Journal Annals of Surgical OncologyOnline ISSN 1534-4681Print ISSN 1068-9265 (Source: Annals of Surgical Oncology)  MedWorm Sponsored Message: Find out how you can get your message across here by sponsoring this MedWorm news feed.