D. Bu Ali1, K. Mohsin1, D. Monlezun1, E. Kandil1 1Tulane University School Of Medicine,Surgery,New Orleans, LA, USA
Introduction:
Several studies have reported the association between large thyroid nodules and the increased incidence of lymph node metastasis in differentiated thyroid cancer. We aim to investigate the use of thyroid nodule size in predicting lymph node (LN) metastasis in differentiated thyroid cancer (DTC).
Methods:
This is a retrospective review of all patients who underwent thyroidectomy for (DTC) by a single surgeon in an academic institution over 5 years. Clinicodemographic data, histopathological data and preoperative ultrasound features including nodule size and presence of internal vascularity or calcification were analyzed. Patients were divided into two groups based on the presence of positive LN.
Results:
A total of 139 patients were included, 28 (20.9%) had positive LN metastasis and 106 (79.1%) were non metastatic. There was no significant difference in nodule size on ultrasound between the two groups. The mean nodule size for the group with metastatic LN was 2.7 ± 1.5 cm and 2.5 ± 1.4 cm, for the non-metastatic group (p=0.48). In addition, there was no association between larger nodule size and presence of positive LN metastasis, even in the combination with other ultrasound features such as calcification and internal vascularity (p>0.05). However, there was a significant association of positive LN metastasis with the presence of positive BRAF mutation (OR: 14.32, p<0.001, Sens.= 87.5%, Spec. = 67.2%, PPV= 48.8%, NPV= 93.8%, Acc.= 72.5%)
Conclusion:
Larger thyroid nodule size on ultrasound is not associated with increased risk of LN metastasis in DTC. However, the presence of positive BRAF mutation was predictive of increased risk of presence of metastatic LN. Further future larger studies are required to validate these findings.