Medullary thyroid carcinoma (MTC) arises from malignant proliferation and differentiation of C cells, approximately 2% of all thyroid malignancies. Calcitonin (CT) and carcinoembryonic antigen (CEA) secreted by C cells are the main secretory product and serves as a marker for the diagnosis of this disease. It is also used in the follow-up of MTC patients after thyroidectomy for the identification of relapse or progression of disease. Compared with other thyroid cancers, MTC has unique biological characteristics and is insensitive to radiotherapy, chemotherapy and iodine therapy. Surgical intervention is currently the only effective, curative treatment for medullary thyroid cancer. The 2015 American Thyroid Association recommended total thyroidectomy and different range of lymph node dissection, but controversy remains surrounding the indication for prophylactic lateral lymph node dissection. This study was performed to analyze the risk factors for cervical lymph node metastases and predict the indication for prophylactic lateral neck dissection in patients with sporadic medullary thyroid carcinoma (SMTC).
The aims of this study were to analyze the risk factors of cervical lymph node metastases, and also to predict the indication of prophylactic lateral neck dissection in SMTC patients.
Metastases rates in central and lateral compartment were 46.2% (30/65) and 40.0% (26/65), respectively. Univariate analyses showed the incidence of cervical lymph node metastases was significantly higher in patients with tumor size >1cm, tumor multifocality and thyroid capsule invasion. Multivariate analyses revealed that only thyroid capsule invasion was an independent predictive factor for central compartment metastases (p < 0.001, OR = 11.080) and lateral neck metastases (p < 0.001, OR = 9.067). Moreover, the possibility of central compartment metastases was higher when preoperative value of serum carcinoembryonic antigen (CEA) was above 30 ng/mL (60% vs 34.3%, χ2=4.298, P = 0.038).
The medullary thyroid carcinoma has a high incidence of cervical lymph node metastases. Prophylactic lateral node dissection is necessary in patients with thyroid capsule invasion or with high value of serum carcinoembryonic antigen (CEA).
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All authors have declared no conflicts of interest.