Medullary thyroid cancer - An update

Systemic therapies for medullary thyroid carcinoma: state of the art

Medullary thyroid carcinoma (MTC) is a rare neuroendocrine tumor accounting for less than 5% of all thyroid cancers. An estimated 25% of cases are familial secondary to a germline mutation on the rearranged during transfection proto-oncogene (RET); this gene can be present as a somatic mutation in approximately 40%-60% of sporadic MTC tumors. There is an existing genotype-phenotype correlation in the clinical behavior of MTC, with the RET M918T variant associated with aggressive disease. The current systemic treatment profile for progressive metastatic MTC involves antiangiogenics multikinase inhibitors (MKI), specifically cabozantinib and vandetanib, and high-specific RET inhibitor therapy. Decisions on the timing of systemic therapy initiation in this population should involve multidisciplinary care and individualization on a case-by-case scenario; a comprehensive evaluation of performance status, tumor burden, progression rate, medical comorbidities, possible medication interactions, and goals of care must be considered in a patient-centered approach. This review summarizes the evidence on the safety, efficacy, and limitations of systemic therapies for MTC; the aim is to empower clinicians with the knowledge to optimally manage patients with advanced, progressive, or metastatic MTC.

Inhibitory effect of luteolin on the metabolism of vandetanib in vivo and in vitro

This study aimed to examine the potential drug-drug interaction (DDI) between vandetanib and luteolin in vivo and in vitro, with the objective of establishing a scientific foundation for their appropriate utilization in clinical settings. Sprague-Dawley (SD) rats were randomly divided into two groups: a control group (vandetanib administered by gavage alone) and an experimental group (vandetanib and luteolin administered together). A series of blood samples were collected at different time intervals. The plasma concentrations of vandetanib and its metabolite N-demethyl vandetanib in rats were determined using an ultra performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS). Incubation systems were set up with rat liver microsomes (RLM) and human liver microsomes (HLM) to measure the Michaelis-Menten constant (Km) and half-maximum inhibitory concentration (IC50) values. Additionally, the inhibitory mechanism of luteolin on vandetanib was also investigated. Ultimately, the molecular mechanism of inhibition was examined through the utilization of molecular docking techniques. In vivo animal experiment results showed that compared with the control group, the AUC(0-t) and Cmax of vandetanib in the experimental group were significantly increased. The findings from the in vitro experiments revealed that luteolin exhibited a moderate inhibitory effect on the metabolism of vandetanib. The IC50 values for RLM and HLM were determined to be 8.56 μM and 15.84 μM, respectively. The identified inhibition mechanism was classified as mixed. This study utilized molecular docking analysis to provide additional evidence supporting the competitive inhibition of luteolin on vandetanib in CYP3A4. The data presented in our study indicated a potential interaction between vandetanib and luteolin, which may necessitate the need for dose adjustment during their co-administration in clinical settings.

Ultrasound Radiomics for Preoperative Prediction of Cervical Lymph Node Metastasis in Medullary Thyroid Carcinoma

Aims/Background Medullary thyroid carcinoma (MTC) is a rare thyroid malignancy with a high mortality rate. Early detection of cervical lymph node metastasis (LNM) is critical for improving prognosis for patients with MTC. This study aimed to investigate the predictive utility of ultrasound-based radiomics for preoperative prediction of cervical LNM in MTC patients. Methods The clinical, ultrasound, and pathological information of 193 patients with MTC were retrospectively examined. Radiomics features were obtained from the ultrasound images using PyRadiomics. The selected patients were randomly divided into training (n = 135) and validation (n = 58) cohorts. In the training dataset, radiomics features were selected using the least absolute shrinkage and selection operator (LASSO) regression, and the univariate and multivariate logistic regression tests were employed to identify the clinical independent predictors of cervical LNM. Three models were created: radiomics, clinical, and combined models, with the latter presented as a nomogram. The area under the curve (AUC) was calculated to evaluate the models' predictive performance. The differences in AUCs between the combined and approach-specific models were compared using the DeLong test. The clinical usefulness of the models was evaluated using decision curve analysis (DCA). Results Nineteen radiomics features were chosen, and the AUCs of the developed radiomics model in the training and validation datasets were 0.881 and 0.859, respectively. Tumour diameter, calcitonin (Ctn) level, tumour margin, and sonographers' suspicion of cervical LNM based on ultrasound findings were clinical independent predictors for cervical LNM. The AUCs of the clinical model built using these predictors were 0.800 and 0.805 in the training and validation datasets, whereas the combined model had much-improved AUCs, measuring 0.925 for the training dataset and 0.918 for the validation test. The DeLong test indicated a significant AUC difference between the combined and clinical models (training dataset p < 0.001, validation dataset p = 0.027), but the difference between the combined and radiomics models was significant only in the training dataset (training dataset p = 0.021, validation dataset p = 0.066). Furthermore, based on the DCA results, the combined model features the largest clinical net benefit. Conclusion The nomogram, the combined model merging the ultrasound-based radiomics with clinical independent predictors, effectively predicts preoperative cervical LNM in MTC patients, outperforming the radiomics and clinical models.

Ultrasonic radiomics in predicting pathologic type for thyroid cancer: a preliminary study using radiomics features for predicting medullary thyroid carcinoma

Introduction

Medullary thyroid carcinoma (MTC) is aggressive and difficult to distinguish from papillary thyroid carcinoma (PTC) using traditional ultrasound. Objective to establish a standard-based ultrasound imaging model for preoperative differentiation of MTC from PTC.

Methods

A retrospective study was conducted on the case data of 213 thyroid cancer patients (82 MTC, 90 lesions; 131 PTC, 135 lesions) from the Department of Diagnostic and Therapeutic Ultrasonography, Tianjin Medical University Cancer Institute and Hospital. We constructed clinical model, radiomics model and comprehensive model by executing machine learning algorithms based on baseline clinical, pathological characteristics and ultrasound image data, respectively.

Results

The study showed that the comprehensive model observed the highest diagnostic efficacy in differentiating MTC from PTC with AUC, sensitivity, specificity, positive predictive value, negative predictive value and accuracy of 0.93, 0.88, 0.82, 0.77, 0.91, 85.8%. Delong test results showed that the comprehensive model was significantly better than the clinical model (Z=-3.791, P<0.001) and the radiomics model (Z=-2.017, P=0.044). Calibration curves indicated the comprehensive model and the radiomics model exhibited better stability than the clinical model. Decision curves analysis (DCA) demonstrated that the comprehensive model had the highest clinical net benefit.

Discussions

Radiomics model is effective in identifying MTC and PTC preoperatively, and the comprehensive model is better. This approach can aid in identifying the pathologic types of thyroid nodule before clinical operation, supporting personalized medicine in the decision-making process.

Anterior mediastinal tracheostomy - a salvage procedure for tracheal necrosis after thyroidectomy for medullary thyroid cancer: a case-report

A 34-year-old male patient with recently diagnosed with medullary thyroid carcinoma underwent total thyroidectomy and radical neck dissection, requiring sharp dissection to separate the tumour from the trachea. He required post operative intubation due to bilateral vocal cord paralysis. He developed ischaemic necrosis of the upper two thirds of the trachea presenting with marked surgical emphysema and an infective wound. The wound was opened, drained and an endotracheal tube was negotiated through the sloughed trachea into the distal intrathoracic trachea with the cuff inflated just above the carina. This complication was managed with total pharyngo-laryngectomy, anterior deep mediastinal tracheostomy and construction of a neo-cervical oesophagus with a free lateral thigh fascio-cutaneous flap. This case highlights the potential complications of a procedure, perseverance, collaboration amongst various disciplines and teamwork for treating a rare and complex condition. The patient was discharged and has had an excellent recovery with good quality of life over two years of follow up.

Treatment Outcomes and Toxicities of Multiple Tyrosin Kinase Inhibitors for Metastatic Medullary Thyroid Cancer: A Case Series

Background: The current possible treatments of advanced medullary carcinoma (MTC) include different drugs belonging to the class of tyrosine kinase inhibitors (TKIs): vandetanib, cabozantinb, and selpercatinib. Although the effects of these TKIs have been well described in clinical trials, the real-practice evidence of the effectiveness and safety of these treatment is scant. This real-world case series aims to describe a niche of patients with advanced MTC treated with more than one TKI by focusing on treatment responses and any reported adverse events (AEs) and to provide additional insight on the individualized approach to the management of metastatic MTC. Methods: Five patients with a diagnosis of metastastic MTC, treated with at least two different molecules of TKIs, were retrospectively selected. Results: Three patients obtained a partial response (one with cabozantinb, one with selpercatinib, and one with vandetanib), and two patients obtained disease stability (both of them treated with all three TKIs, the first two lines discontinued for AEs). The AE profile agreed with the known clinical trials AEs except for non-neoplastic ascites related to selpercatinib and lung cavitations of non-neoplastic tissue related to cabozantinb. The latter was an AE never described so far in patients receiving TKIs. Conclusions: The best management of MTC relies on an individualized approach, keeping in mind and dealing with the potential toxicity in order to minimize the treatment withdrawal.

Pralsetinib as neoadjuvant therapy for RET-Altered differentiated thyroid cancer: Two case reports

BACKGROUND

5-10% of thyroid cancers are at locally advanced stage. Neoadjuvant targeted therapy will likely create surgical opportunities for these patients with unresectable or borderline resectable tumors. Pralsetinib, a RET inhibitor, has been approved for advanced or metastatic RET-altered thyroid cancer. However, there is no evidence on the efficacy of pralsetinib as neoadjuvant therapy in locally advanced RET-altered thyroid cancer.

CASE REPORT

Two patients with locally advanced pappilary thyroid carcinoma (PTC) were treated with pralsetinib (400 mg daily) to reduce tumor size and increase the chance of R0 resection. Both PTCs, characterized by RET-fusion, underwent successful R0 resection without major surgical complications after 4-months neoadjuvant pralsetinib.

CONCLUSION

There is a potential for pralsetinib as a neoadjuvant treatment in PTC with RET-fusion.

Molecular genetics, therapeutics and RET inhibitor resistance for medullary thyroid carcinoma and future perspectives

Medullary thyroid carcinoma (MTC) is a rare type of thyroid malignancy that accounts for approximately 1-2% of all thyroid cancers (TCs). MTC include hereditary and sporadic cases, the former derived from a germline mutation of rearrangement during transfection (RET) proto-oncogene, whereas somatic RET mutations are frequently present in the latter. Surgery is the standard treatment for early stage MTC, and the 10-year survival rate of early MTC is over 80%. While for metastatic MTC, chemotherapy showing low response rate, and there was a lack of effective systemic therapies in the past. Due to the high risk (ca. 15-20%) of distant metastasis and limited systemic therapies, the 10-year survival rate of patients with advanced MTC was only 10-40% from the time of first metastasis. Over the past decade, targeted therapy for RET has developed rapidly, bringing hopes to patients with advanced and progressive MTC. Two multi-kinase inhibitors (MKIs) including Cabozantinib and Vandetanib have been shown to increase progression-free survival (PFS) for patients with metastatic MTC and have been approved as choices of first-line treatment. However, these MKIs have not prolonged overall survival (OS) and their utility is limited due to high rates of off-target toxicities. Recently, new generation TKIs, including Selpercatinib and Pralsetinib, have demonstrated highly selective efficacy against RET and more favorable side effect profiles, and gained approval as second-line treatment options. Despite the ongoing development of RET inhibitors, the management of advanced and progressive MTC remains challenging, drug resistance remains the main reason for treatment failure, and the mechanisms are still unclear. Besides, new promising therapeutic approaches, such as novel drug combinations and next generation RET inhibitors are under development. Herein, we overview the pathogenesis, molecular genetics and current management approaches of MTC, and focus on the recent advances of RET inhibitors, summarize the current situation and unmet needs of these RET inhibitors in MTC, and provide an overview of novel strategies for optimizing therapeutic effects.

SPRED3 regulates the NF-κB signaling pathway in thyroid cancer and promotes the proliferation

SPRED3 (Sprouty-related EVH1 domain containing 3) mutants are depicted in various cancers, however, nothing is known about its biofunction in thyroid cancer (THCA). Bioinformatic analyses were conducted to ascertain the level of SPRED3 expression in THCA tissues and its importance in the prognosis of THCA patients. Flag-SPRED3 plasmid and SPRED3-knockout vector were developed to overexpress or deplete the SPRED3 expression in THCA cells. The function of SPRED3 on THCA cell proliferation was examined using the colony formation assay and CCK8 assay. The effect of SPRED3 expression on the transcriptional activity of NF-κB was also examined using luciferase reporter assays. High SPRED3 expression was associated with unfavorable clinical outcomes, advanced tumor characteristics, and traditional molecular markers of papillary thyroid cancer in THCA patients. Genetic analysis revealed differences in mutation rates in key genes between SPRED3-high and SPRED3-low THCA cases. It is also revealed that SPRED3 influenced the immune microenvironment, with increased stromal and immune scores and altered immune cell infiltration. Functionally, SPRED3 overexpression enhanced THCA cell viability and colony formation, while its depletion reduced cell growth and proliferation. In vivo experiments in mice confirmed the inhibitory effect of SPRED3 depletion on tumor growth. Mechanically, we found that SPRED3 activated the NF-κB signaling. For the first time, we found that SPRED3 promotes THCA cell proliferation via the NF-κB signaling pathway. This finding may provide insight into SPRED3's prognostic potential in thyroid cancer and provide the rationale for SPRED3-targeted druggable interventions.

Sporadic and Familial Medullary Thyroid Carcinoma: A Retrospective Single Center Study on Presentation and Outcome

BACKGROUND

Medullary Thyroid Carcinoma (MTC) is a neuroendocrine tumor that arises from the thyroid C-cells. Most cases are sporadic (sMTC) while, approximately 25%, are hereditary (hMTC) due to germline mutations of REarranged during Transfection (RET) gene mutations and manifest in the framework of multiple endocrine neoplasia (MEN) 2A or 2B, or as pure familial MTC syndrome (FMTC).

OBJECTIVE

The aim of this study is to evaluate the clinical, histopathological, biochemical and outcome differences between sMTC and hMTC.

METHODS

Retrospective analysis of a consecutive series of 102 patients with histologically proven MTC diagnosed in the period between 2000 and 2022. For the analysis patients with MTC diagnosed during screening through genetic test were excluded.

RESULTS

Patients with hMTC had higher incidence of multifocal and bilateral MTC and younger age at diagnosis. We did not found differences on tumor stage at diagnosis between sMTC and hMTC, such as time to progression and rate of persistent and recurrent disease. At univariate analysis, factors associated with persistent and recurrent disease during follow-up in patients with sMTC were tumor size, extrathyroidal extension, presence of lymph node metastases at diagnosis, pre- and post-operative calcitonin, post-operative CEA; in patients with hMTC, features associated with persistent and recurrent disease were lymph node metastases, post-operative calcitonin and pre- and post-operative CEA values.

CONCLUSION

Patients with hMTC and sMTC had similar histopathological characteristics and clinical outcome.

The relationship between the gut microbiota and thyroid disorders

Disorders of the thyroid gland are common, more prevalent in women than in men, and range from inflammatory to neoplastic lesions. Autoimmune thyroid diseases (AITD) affect 2-5% of the population, while thyroid cancer is the most frequent endocrine malignancy. Treatment for AITD is still restricted to management rather than prevention or cure. Progress has been made in identifying genetic variants that predispose to AITD and thyroid cancer, but the increasing prevalence of all thyroid disorders indicates that factors other than genes are involved. The gut microbiota, which begins to develop before birth, is highly sensitive to diet and the environment, providing a potential mechanism for non-communicable diseases to become communicable. Its functions extend beyond maintenance of gut integrity: the gut microbiota regulates the immune system, contributes to thyroid hormone metabolism and can generate or catabolize carcinogens, all of which are relevant to AITD and thyroid cancer. Observational and interventional studies in animal models support a role for the gut microbiota in AITD, which has been confirmed in some reports from human cohorts, although considerable geographic variation is apparent. Reports of a role for the microbiota in thyroid cancer are more limited, but evidence supports a relationship between gut dysbiosis and thyroid cancer.

Critically evaluated key points on hereditary medullary thyroid carcinoma

Medullary thyroid carcinoma (MTC) accounts for only 3% of all thyroid carcinomas: 75% as sporadic MTC (sMTC) and 25% as hereditary MTC (hMTC) in the context of multiple endocrine neoplasia type 2 (MEN2). Early diagnosis is possible by determining the tumour marker calcitonin (Ctn) when clarifying nodular goitre and by detecting the mutation in the proto-oncogene RET in the MEN2 families. If the Ctn level is only slightly elevated, up to 30 pg/ml in women and up to 60 pg/ml in men, follow-up checks are advisable. At higher levels, surgery should be considered; at a level of > 100 pg/ml, surgery is always advisable. The treatment of choice is total thyroidectomy, possibly with central lymphadenectomy. In the early stage, cure is possible with adequate surgery; in the late stage, treatment with tyrosine kinase inhibitors is an option. RET A mutation analysis should be performed on all patients with MTC. During follow-up, a biochemical distinction is made between: healed (Ctn not measurably low), biochemically incomplete (Ctn increased without tumour detection) and structural tumour detection (metastases on imaging). After MTC surgery, the following results should be available for classification in follow-up care: (i) histology, Ctn immunohistology if necessary, (ii) classification according to the pTNM scheme, (iii) the result of the RET analysis for categorisation into the hereditary or sporadic variant and (iiii) the postoperative Ctn value. Tumour progression is determined by assessing the Ctn doubling time and the RECIST criteria on imaging. In most cases, "active surveillance" is possible. In the case of progression and symptoms, the following applies: local (palliative surgery, radiotherapy) before systemic (tyrosine kinase inhibitors).

Measuring discrepancies between simple medullary and synchronous medullary/papillary thyroid carcinomas: a comparative cross-sectional study

Objective

To study the clinicopathological characteristics of patients with synchronous medullary and papillary thyroid carcinomas.

Methods

The clinical data of patients with medullary thyroid carcinoma (MTC) operated in our hospital (Department of Thyroid Surgery, China-Japan Union Hospital, Jilin University) from February 2009 to February 2023 were evaluated using an analytical review approach. They were divided into an observation group (patients with synchronous MTC and papillary thyroid carcinoma PTC) and a control group (simple MTC) according to whether the clinical data were associated with MTC, in order to compare the clinical features, pathological types, stage characteristics and molecular biology characteristics of the two groups and to investigate the follow-up of the two groups.

Results

The study included 122 MTC, 30 with synchronous MTC/PTC and 92 simple MTC. When the data were compared, the sex ratio, preoperative calcitonin level, preoperative CEA level, presence of calcifications in the MTC lesions, surgical methods, number of MTC lesions, presence of nodular goitre and presence of thyroiditis were higher in the observation group than in the control group. There was a significant difference between the groups when the MTC lesion diameter was ≤1cm in terms of preoperative CEA value (P<0.05); when the MTC lesion diameter was >1cm, there was a statistical difference between the two groups in terms of preoperative Ctn value (P<0.05). Type III was significantly different from the simple group, while type IV was more similar to the simple group. The preoperative serum Ctn value was positively correlated with maximum tumour diameter in both groups, although the correlation was stronger in the easy group. Preoperative CEA was positively correlated with maximum tumour diameter in both groups, with a stronger correlation in the combination group. Preoperative Ctn and CEA were positively correlated with lymph node metastasis in the simple group, whereas there was no apparent correlation with lymph node metastasis in the combination group. The cut-off value of preoperative serum Ctn for cervical lymph node metastases in the simple group was 39.2pg/ml and for lateral cervical lymph node metastases 195.5pg/ml. The cut-off value of preoperative serum Ctn for cervical lymph node metastases in the combination group was 60.79pg/ml and for lateral cervical lymph node metastases 152.6pg/ml. In the simple group, prognosis was significantly worse in the progression group (P<0.001), with no statistical difference between the remission and stable groups. In the combination group, the prognosis of the progression and stable groups was significantly worse than that of the remission group (P<0.001), with no statistical difference between the progression and stable groups.

Conclusion

In patients with synchronous medullary and papillary thyroid carcinomas, preoperative Ctn and CEA levels, calcifications, solitary lesions, combined goitre or thyroiditis differ significantly from simple MTC. Therefore, clinical management should pay attention to the above factors and early risk screening should be performed to improve prognosis as much as possible.

Cabozantinib for different endocrine tumours: killing two birds with one stone. A systematic review of the literature

PURPOSE

Cabozantinib is an oral multi-tyrosine kinase inhibitor (TKI) that has been approved in Europe for advanced renal cell carcinoma, hepatocellular carcinoma, locally advanced and metastatic medullary thyroid carcinoma (MTC) and radioiodine-refractory differentiated thyroid cancer. Merkel cell carcinoma (MCC) is a rare and highly aggressive cutaneous malignant neuroendocrine tumour that usually presents in sun-exposed skin areas of immunosuppressed patients. Conflicting data exist about cabozantinib for MCC and this TKI is currently under investigation in several onco-endocrine frameworks.

METHODS

We herein report a case of an 83-year-old man who was diagnosed with MCC during the treatment of an advanced metastatic MTC. The diagnosis of MCC was established based on clinical, histopathologic evaluation and immunohistochemistry. A systematic review of the literature on cabozantinib use for advanced endocrine and neuroendocrine tumours has been performed.

RESULTS

The patient was initially treated with surgery and adjuvant radiotherapy. Cabozantinib was therefore started to control both MTC and MCC. After 24 months, no sign of local or metastatic MCC relapse was evidenced.

CONCLUSION

Promising data on cabozantinib treatment for endocrine and neuroendocrine neoplasms is recently emerging in the literature. In our clinical case, we reported that, besides the good response for the MTC, cabozantinib also seems to effectively control metastatic MCC, along with efficient surgery and adjuvant radiotherapy. Further investigations are needed to determine the efficacy and safety of cabozantinib in MCC patients and in off-label endocrine tumours.

Pathogenesis of cancers derived from thyroid follicular cells

The genomic simplicity of differentiated cancers derived from thyroid follicular cells offers unique insights into how oncogenic drivers impact tumour phenotype. Essentially, the main oncoproteins in thyroid cancer activate nodes in the receptor tyrosine kinase-RAS-BRAF pathway, which constitutively induces MAPK signalling to varying degrees consistent with their specific biochemical mechanisms of action. The magnitude of the flux through the MAPK signalling pathway determines key elements of thyroid cancer biology, including differentiation state, invasive properties and the cellular composition of the tumour microenvironment. Progression of disease results from genomic lesions that drive immortalization, disrupt chromatin accessibility and cause cell cycle checkpoint dysfunction, in conjunction with a tumour microenvironment characterized by progressive immunosuppression. This Review charts the genomic trajectories of these common endocrine tumours, while connecting them to the biological states that they confer.

Innovation and Precision Medicine Applied to a Medullary Thyroid Cancer: A Clinical Case

Medullary thyroid carcinoma (MTC) is a rare type of neuroendocrine tumor, accounting for 3%-4% of all thyroid cancers. Seventy-five percent are sporadic, of which 60% have pathogenic REarranged during Transfection (RET) somatic mutations. The sporadic RET-mutated MTC poses novel challenges for targeted treatment. The authors present a case of a 60-year-old male diagnosed in 2018 with MTC who underwent total thyroidectomy with sternotomy and bilateral cervical lymph node dissection - pT3N1b R1 L1 V1 Pn0 cM1 (hepatic and lung metastasis). According to the decisions made by the multidisciplinary tumor board, the patient received multiple palliative systemic treatments. Despite an initial response, vandetanib was accompanied by grade 3 high blood pressure and progression after 14 months of treatment. The patient also received cabozantinib, which led to an initial response, but with grade 3 hypertension and skin toxicity. The patient progressed, including symptomatic bone metastasis, after 15 months of treatment. Following the next sequencing genome result, which showed a somatic mutation in the RET M918T gene, the patient was treated with selpercatinib, a highly selective and potent RET inhibitor. The treatment led to clinical and radiological responses without significant toxicities. The objective of this case report is to highlight the impact of innovative treatment and precision medicine on the management of cancer patients, which not only has a direct effect on their survival but also on their quality of life.

Cabozantinib, Vandetanib, Pralsetinib and Selpercatinib as Treatment for Progressed Medullary Thyroid Cancer with a Main Focus on Hypertension as Adverse Effect

This manuscript investigates cabozantinib, vandetanib, pralsetinib, and selpercatinib, four tyrosine kinase inhibitors (TKIs), which are used to treat advanced and/or metastatic medullary thyroid cancer (MTC). Data on efficacy and safety are presented with the main focus on treatment-related hypertension, a well-known adverse effect (AE) of these TKIs. Taken together, TKI-induced hypertension is rarely a dose-limiting side effect. However, with increasing survival times of patients under treatment, hypertension-associated complications can be expected to be on the rise without proper medication.

Unilateral Surgery for Medullary Thyroid Carcinoma: Seeking for Clinical Practice Guidelines

Optimized preoperative diagnostic tools with calcitonin tests, ultrasound features, functional imaging modalities, and genetic testing to detect hereditary forms have led to an increased rate of earlier diagnosis and surgery for medullary thyroid cancer (MTC). This helps to adapt the primary surgery to the tumor stage and avoid surgical overtreatment for localized tumor growth, i.e., deviating from the regularly recommended thyroidectomy with bilateral central lymph node dissection in favor of a limited unilateral approach. To limit primary surgical therapy, it is crucial that the MTC is clinically unifocal, sporadic, and confined to the thyroid, and that calcitonin levels indicate biochemical recovery after surgery. The main requirement for such a limited approach is the availability of frozen section studies that reliably indicate (i) R0 resection of the MTC, (ii) absence of infiltration of the organ capsule, (iii) lack of desmoplasia (i.e., evidence of the metastatic potential of the MTC), (iiii) absence of contralateral disease or precancerous lesions. Informed consent is mandatory from the patient, who has been fully informed of the advantages, disadvantages, and potential risks of not undergoing the "classic" surgical procedure. The aim of this article is to review the guidelines for the management of early-stage MTC.