Lymph node ratio predicts persistence/recurrence in medullary thyroid cancer

Esra Canavar; Tan Oksuz Sinem Başak; Rıfat Emral; Sevim Gullu

doi:10.1530/endoabs.110.P1167

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%).

Table 1: The characteristics of patients with a persistence/recurrence and remission status.
Parameter	Persistence/Recurrence (n = 25)	Remission (n = 27)	P value
Age, y (mean ± SD)	42 ± 13	50 ± 17	0.053
Gender, female n. (%)	11 (44)	19 (70.4)	0.054
RET positivity n. (%)	6 (24)	10 (37)	0.663
Tumor size (mm), mean ± SD	2.6 ± 1.5	2 ± 1.4	0.074
Multifocal tumor, n. (%)	6 (24)	8 (29.6)	0.647
Lymphovascular invasion, n. (%)	12 (48)	3 (11.1)	0.003
Extracapsular invasion, n. (%)	5 (20)	1 (3.7)	0.94
Metastatic lymph node, n (median, IQR)	6 (2.5 -13)	0 (0 - 3)	<0.001
Lymph node ratio, n (median, IQR)	0.36 (0.25 - 0.64)	0 (0 - 0.14)	<0.001
Postoperative calcitonin, pg/mL (median, IQR)	216 (29.5 - 497)	3.8 (0.6 - 9.4)	<0.001
Postoperative carcinoembryonic antigen, ng/mL (median, IQR)	3.8 (1.9 - 16.1)	2.1 (1.3 - 4.3)	0.029

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

Endocrine Abstracts

P1167