Endocrine Abstracts

JOINT1703

Introduction: The lymph node ratio (LNR) is defined as the number of metastatic lymph nodes or divided by the number of resected lymph nodes. LNR has been suggested as a predictive factor in various cancer types; however, the data regarding medullary thyroid cancer (MTC) is limited. The aim of the study is to evaluate LNR as a risk factor for persistence/recurrence in patients with MTC.

Methods: Medical records of 52 patients treated for MTC in a single tertiary center between 2001 and 2023 were retrospectively reviewed. Persistent and recurrent diseases were defined as those detected within the first 12 months of diagnosis or during subsequent follow-up periods, respectively. To identify risk factors influencing persistence/recurrence, univariable and multivariable Cox proportional hazard models were used.

Results: Persistent and recurrent disease was identified in eight and seventeen patients, respectively. The median follow-up period was 86.5 months (IQR:30.75 - 165). The characteristics of patients with a persistence/recurrence and remission status are outlined in Table 1. In univariable analysis, lymphovascular invasion, postoperative serum calcitonin and carcinoembryonic antigen (CEA) levels, and LNR were significant (p < 0.05) predictors of persistence/recurrence. In multivariable analysis persistent/recurrent disease was independently associated with the LNR value and was accurately predicted by a cut-off value of 0.22 (area under the curve = 0.97; sensitivity 90%, specificity 91%).

Conclusion: LNR can potentially predict persistence/recurrence as a quantitative evaluation tool for lymph node metastasis in patients with MTC.