Medullary Thyroid Carcinoma: Why Is Specialization Mandatory?

Management of lymph nodes in medullary thyroid carcinoma: A review

Introduction

Medullary Thyroid Carcinoma (MTC) as a neuroendocrine tumor that arises from the parafollicular C-cells and shows a potentially aggressive behavior with early lymph node metastasis. MTC cells do not absorb radioactive iodine and are not sensitive to Thyroid Stimulating Hormone (TSH) suppression, and therefore surgery is the most effective option for curative therapy.

Results

Medical imaging and biomarkers (calcitonin & CEA) assessment are necessary to determine the appropriate approach to lymph nodes surgery in MTC. Prophylactic central, lateral or contralateral neck dissections are recommended based on calcitonin level and volume of tumor. In general, guidelines are in agreement with prophylactic central dissection in most cases. Central and lateral dissections are recommended in all guidelines and review articles if lymphadenopathy is confirmed in preoperative examinations. Because lymph node dissection in most cases of locally advanced or metastatic MTC has no prognostic effect, dissection is done with palliative goal with maximum attention to maintaining function in these cases. In patients with an incomplete lymph node dissection, decision for reoperation can be based on calcitonin levels and the number of metastatic lymph nodes removed in previous surgery. Symptoms as well as speed of disease progression are also important in adopting the type of surgery. Consensus is in favor of reoperation in patients with recurrent regional MTC without distant metastasis.

Conclusion

Thyroidectomy is mandatory in patients with MTC but the type and extension of lymph node dissection are depending on the calcitonin level and tumor burden.

•

Surgery is the most effective treatment option for MTC.

•

Prophylactic central, lateral or contralateral neck dissections are recommended based on calcitonin level.

•

Therapeutic central and lateral dissection is recommended if lymphadenopathy is confirmed.

•

In locally advanced or metastatic MTC dissection is done with maximum attention to maintaining function.

Does shear wave elastography for medullary thyroid carcinoma predict lateral cervical lymph node metastasis?

PURPOSE

To assess whether shear wave elastography (SWE) for medullary thyroid carcinoma (MTC) can independently predict lateral cervical lymph node metastasis (LNM).

METHOD

Patients with MTC who were treated via primary surgery between January 2015 and May 2020 and who had undergone preoperative SWE and ultrasound (US) examinations in the Harbin Medical University Cancer Hospital were retrospectively studied. The relationships between lymphatic status and the clinicopathological and imaging characteristics were evaluated. Afterwards, associations between lateral cervical LNM and SWE parameters, as well as sex, age, invasive size, extrathyroidal extension (ETE), preoperative calcitonin levels, and US features were assessed by using multivariable logistic regressions.

RESULTS

A total of 76 patients (31 men and 45 women, 48.1 ± 11.8 years) were evaluated. The following factors demonstrated significant associations with lateral cervical LNM: the male sex (P = 0.015), an age ≤ 35 years (P = 0.049), an invasive size > 1.0 cm (P = 0.028), ETE (P = 0.005), a preoperative calcitonin level > 60 pg/ml (P < 0.001), irregular shape on the US (P = 0.001), the presence of a non-circumscribed margin on the US (P = 0.009), an Emax > 66 kPa (P < 0.001), an Emean > 37.5 kPa (P < 0.001), and an ER > 1.65 (P = 0.002). In the multivariable analysis, an age ≤ 35 years (P = 0.049), a preoperative calcitonin level > 60 pg/ml (P = 0.004), an irregular shape on the US (P = 0.036), and an Emax > 66 kPa (P = 0.011) maintained independent significance.

CONCLUSION

Emax was demonstrated to be an independent predictor for lateral cervical LNM of MTC. SWE may serve as a noninvasive method of preoperative lateral cervical LNM risk assessment for MTC.

Two GEO MicroRNA Expression Profile Based High-Throughput Screen to Identify MicroRNA-31-3p Regulating Growth of Medullary Thyroid Carcinoma Cell by Targeting RASA2

Background

Medullary thyroid carcinoma (MTC), a rare type of thyroid cancer, is a big challenge in clinical treatment. However, the pathogenesis of MTC remains poorly understand. MicroRNAs (miRNAs) were previously demonstrated to be involved in the pathogenesis of MTC, however, the roles of majority of miRNAs in MTC are still undetermined.

Material/Methods

Two GEO miRNA expression profiles (GSE40807, GSE97070) were downloaded, and the differentially expressed miRNAs (DEmiRNAs) of GSE40807 and GSE97070 were analyzed by bioinformatics methods. Expressions of miRNAs were detected by quantitative real-time polymerase chain reaction; cell proliferation was examined through Cell Counting Kit-8, colony formation and in vivo tumor growth assays; the interaction between miRNA and mRNA was verified by dual-luciferase reporter assay; functional analysis of target genes was performed using the Database for Annotation, Visualization and Integrated Discovery (DAVID, www.david.ncifcrf.gov) software.

Results

Ten miRNAs were identified to be dysregulated in both GSE40807 and GSE97070 datasets, and miR-31-3p showed the highest change fold (Log fold change=−3.460625 in GSE40807 and Log fold change=−0.07084374 in GSE97070). MiR-31-3p expression was significantly downregulated in MTC, and low miR-31-3p expression showed a poor prognosis relative to high miR-31-3p expression (P<0.05). Functionally, miR-31-3p inhibited MTC cell proliferation in vitro and in vivo. Functional analysis also showed that the target genes of miR-31-3p were involved in numerous of biochemical processes and pathways, of which Ras signaling pathway was selected for further study. RASA2, overexpressed in MTC, were negatively regulated by miR-31-3p. In addition, we found that knockdown of RASA2 inhibited MTC cell proliferation.

Conclusions

Reduced expression level of miR-31-3p might play a key role in the tumorigenesis of MTC by targeting critical pathways, especially Ras signaling pathway.