Metastatic Lymph Node Ratio for Predicting Recurrence in Medullary Thyroid Cancer

Area of Science:

• Oncology
• Endocrinology
• Surgical Pathology

Background:

• The lymph node ratio (LNR) is a prognostic factor in various cancers, but its role in medullary thyroid cancer (MTC) requires further investigation.
• Limited reports exist on the prognostic value of LNR in MTC, highlighting a gap in understanding its predictive capabilities for recurrence.

Purpose of the Study:

• To evaluate the lymph node ratio (LNR) as a potential risk factor for structural recurrence in patients diagnosed with medullary thyroid cancer (MTC).
• To assess the utility of LNR as a quantitative tool for evaluating lymph node metastasis in MTC.

Main Methods:

• Retrospective review of medical records from 132 MTC patients treated between 1995 and 2017 at a single tertiary center.
• LNR calculated as the ratio of metastatic lymph nodes to retrieved lymph nodes.
• Univariable and multivariable Cox proportional hazard models used to identify predictors of structural recurrence, with recurrence-free survival as the endpoint.

Main Results:

• Structural recurrence was observed in 39 patients over a median follow-up of 8.7 years.
• Univariable analysis identified gross extrathyroidal extension, N stage, postoperative calcitonin, CEA, and LNR as significant predictors of recurrence (p < 0.05).
• Multivariable analysis confirmed postoperative calcitonin, CEA, and LNR as significant predictors of disease-free survival (p < 0.05).

Conclusions:

• The lymph node ratio (LNR) demonstrates potential as a valuable quantitative tool for predicting structural recurrence in medullary thyroid cancer (MTC).
• Incorporating LNR assessment may enhance risk stratification and guide management strategies for MTC patients.
• Further prospective studies are warranted to validate the prognostic significance of LNR in MTC.