Risk Factors Associated With Reoperation and Disease-Specific Mortality in Patients With Medullary Thyroid Carcinoma

Fundamentals and recent advances in the evaluation and management of medullary thyroid carcinoma

Medullary thyroid carcinoma (MTC) is a rare primary neuroendocrine thyroid carcinoma that is distinct from other thyroid or neuroendocrine cancers. Most cases of MTC are sporadic, although MTC exhibits a high degree of heritability as part of the multiple endocrine neoplasia syndromes. REarranged during Transfection (RET) mutations are the primary oncogenic drivers and advances in molecular profiling have revealed that MTC is enriched in druggable alterations. Surgery at an early stage is the only chance for cure, but many patients present with or develop metastases. C-cell-specific calcitonin trajectory and structural doubling times are critical biomarkers to inform prognosis, extent of surgery, likelihood of residual disease, and need for additional therapy. Recent advances in the role of active surveillance, regionally directed therapies for localized disease, and systemic therapy with multi-kinase and RET-specific inhibitors for progressive/metastatic disease have significantly improved outcomes for patients with MTC.

Thyroidectomy without lymph node dissection should be considered for stage T1 medullary thyroid carcinoma: a population-based cohort study

Background

The necessity and therapeutic value of lymph node dissection (LND) in early stage T1 MTC patients remain controversial.

Methods

Patients with T1MTC were identified from the Surveillance, Epidemiology, and End Results (SEER) database. Poisson regression analysis was utilized to investigate promotive factors for lymph node metastasis in T1MTC patients. Fisher's exact test was employed to calculate baseline differences between non-LND and LND groups. Propensity score match (PSM) was used to control baseline bias. Survival outcomes were calculated by Kaplan-Meier method and log-rank test. Multivariable Cox regression assessed the prognostic impact of LND across subgroups.

Results

Of 3298 MTC cases, 50.4% were T1MTC. The lymph node metastasis rate increased along with the T stage (from 22.2% to 90.5%). Among 1231 T1MTC patients included after exclusion criteria, 72.0% underwent LND and 22.0% had lymph node metastasis. Patients aged younger than 44 years (RR=1.700, p<0.001), male (RR=1.832, p<0.001), and with tumor larger than 10mm (RR=2.361, p<0.001) were more likely to have lymph node metastasis, while elderly patients (p<0.001) and those with microcarcinoma (p<0.001) were more likely to undergo non-LND procedures. LND provided no OS or DSS benefit over non-LND before and after propensity score match (matched 10-year OS/DSS: LND 83.8/96.2% vs non-LND 81.9/99.3%, p>0.05). Subgroup analyses revealed no prognostic gain with LND in any subgroup (p>0.05).

Conclusion

Nearly half of MTC patients were diagnosed at T1 stage and had low lymph node risk. Different from ATA guidelines, avoiding routine LND conferred similar prognosis to standard procedures while potentially improving quality of life. Large-scale prospective multi-center studies should be conducted to further validate these findings.

Time Kinetics and prognosis roles of calcitonin after surgery for medullary thyroid carcinoma

BACKGROUND

Medullary thyroid carcinoma (MTC) is a malignant tumor with low incidence. Currently, most studies have focused on the prognostic risk factors of MTC, whatever, time kinetic and risk factors related to calcitonin normalization (CN) and biochemical persistence/recurrence (BP) are yet to be elucidated.

METHODS

A retrospective study was conducted for 190 MTC patients. Risk factors related to calcitonin normalization (CN) and biochemical persistence/recurrence (BP) were analyzed. The predictors of calcitonin normalization time (CNT) and biochemical persistent/recurrent time (BPT) were identified. Further, the prognostic roles of CNT and BPT were also demonstrated.

RESULTS

The 5- and 10-year DFS were 86.7% and 70.2%, respectively. The 5- and 10-year OS were 97.6% and 78.8%, respectively. CN was achieved in 120 (63.2%) patients, whereas BP was presented in 76 (40.0%) patients at the last follow up. After curative surgery, 39 (32.5%) and 106 (88.3%) patients achieved CN within 1 week and 1 month. All patients who failed to achieve CN turned to BP over time and 32/70 of them developed structural recurrence. The median time of CNT and BPT was 1 month (1 day to 84 months) and 6 month (3 day to 63months), respectively. LNR > 0.23 and male gender were independent predictors for CN and BP. LNR > 0.23 (Hazard ratio (HR), 0.24; 95% CI,0.13-0.46; P < 0.01) and male gender (HR, 0.65; 95% CI, 0.42-0.99; P = 0.045) were independent predictors for longer CNT. LNR > 0.23 (HR,5.10; 95% CI,2.15-12.11; P < 0.01) was still the strongest independent predictor followed by preoperative serum Ctn > 1400ng/L (HR,2.34; 95% CI,1.29-4.25; P = 0.005) for shorter BPT. In survival analysis, primary tumor size > 2 cm (HR, 5.81; 95% CI,2.20-15.38; P < 0.01), CNT > 1 month (HR, 5.69; 95% CI, 1.17-27.61; P = 0.031) and multifocality (HR, 3.10; 95% CI, 1.45-6.65; P = 0.004) were independent predictor of DFS.

CONCLUSION

Early changes of Ctn after curative surgery can predict the long-term risks of biochemical and structural recurrence, which provide a useful real-time prognostic information. LNR significantly affect the time kinetic of biochemical prognosis. Tumor burden and CNT play a crucial role in MTC survival, the intensity of follow-up must be tailored accordingly.

Changes of biochemical factors and the effect on recurrence of medullary thyroid carcinoma after surgery

Objective

Medullary thyroid carcinoma (MTC) is a rare malignancy secreting calcitonin (Ctn). We aimed to analyze the relationship between Ctn levels at different time points in patients with MTC, and evaluate its predictive effect on recurrence.

Methods

A retrospective study of patients diagnosed with MTC in a large medical center were conducted in northern China. The interrelationships between preoperative Ctn, normalization of postoperative serum Ctn at the first month (NPS), and long-term biochemical cure as well as their predicting roles on structural recurrence were assessed.

Results

A total of 212 patients were included in this study. The median follow-up time was 59.5 months. The 5- and 10-year cumulative disease-free survival rates were 81.5 % and 66.8 %, respectively. NPS (OR: 216.33, 95 % CI: 28.69-1631.09, P < 0.001) and absence of structural recurrence (OR: 61.71, 95 % CI: 3.90-975.31; P = 0.003) were associated with biochemical cure. Non-biochemical cure (OR: 28.76; 95 % CI: 2.84-290.86; P = 0.004, HR: 14.63, 95 % CI: 2.27-94.07, P = 0.005), larger tumor size (OR: 8.79, 95 % CI: 2.12-36.40, P = 0.003, HR: 5.41, 95 % CI: 2.04-14.37, P = 0.001), and multifocality (OR: 4.02, 95 % CI: 1.06-15.17, P = 0.040, HR: 3.00, 95 % CI: 1.18-7.60, P = 0.021) were unfavorable independent predictors of structural recurrence and disease-free survival. For sporadic MTC confined to the thyroid lobe, there was no difference in biochemical or structural prognosis between the different surgeries in the subgroup analysis.

Conclusions

NPS, rather than preoperative Ctn, predicted long-term biochemical cure for MTC. Non-biochemical cure, larger tumor burden including larger tumor size and multifocality at initial surgery, served as worse prognostic predictors.

Does the extent of neck surgery based on preoperative calcitonin level influence survival in medullary thyroid carcinoma: a retrospective tertiary centre experience

INTRODUCTION

Medullary thyroid carcinoma (MTC) is a rare thyroid cancer arising from the calcitonin-secreting parafollicular cells. Previous studies suggested a preoperative calcitonin level >200ng/l is an indication for prophylactic lateral neck dissection (LND) to remove micrometastases and improve survival outcomes.

METHODS

This retrospective single-centre study assessed the efficacy of preoperative calcitonin levels as a marker for determining need for prophylactic LND in MTC. Data were obtained on demographics, preoperative calcitonin levels, size and laterality of index tumour, type of neck dissection (central neck dissection (CND), LND), nodes removed, levels with involved nodes, number of nodes histologically involved, mortality, adjuvant therapy and locoregional recurrence.

RESULTS

A total of 33 patients were identified from St George's University Hospitals NHS Foundation Trust between 1 January 2001 and 19 August 2021; 8 were excluded for data quality issues. Of the 18 classified with a high preoperative calcitonin level (>200ng/l), 10 (56%) had a LND and 8 (44%) had a CND. In the low-calcitonin group, three (43%) patients had a CND only and four (57%) had a LND. There was no difference in absolute or disease-free survival between the low and high groups (p=0.960, p=0.817), or between those who had a CND and LND in the high-calcitonin group (p=0.607, hazard ratio (HR) 0.55; p=0.129, HR 8.78).

CONCLUSION

There was no statistically significant difference in outcomes between high and low calcitonin groups. A selective approach to performing LND in MTC patients based on clinical and imaging findings suggesting disease presence in the lateral neck should be explored further.

Sentinel lymph node detection in thyroid carcinoma using [68Ga]Ga-tilmanocept PET/CT: a proof-of-concept study

PURPOSE

Sentinel lymph node (SLN) biopsy is rarely used for thyroid carcinoma staging. This is due to challenges associated with conventional Tc-99m-labeled tracers, often producing a large hotspot at the injection site, potentially hiding nearby SLNs (shine-through effect). The aim of this study was to demonstrate the feasibility and effectiveness of SLN visualization using the new PET tracer [68Ga]Ga-tilmanocept.

METHODS

Patients with thyroid carcinoma underwent ultrasound-guided peritumoral injection of [68Ga]Ga-tilmanocept and ICG-[99mTc]Tc-nanocolloid. [68Ga]Ga-tilmanocept PET/CT scans were conducted at 15 min and 60 min post-injection to visualize the SLNs. SLN biopsy was performed using ICG-[99mTc]TC-nanocolloid for intraoperative identification. The corresponding lymph node level was resected for reference.

RESULTS

Seven differentiated thyroid carcinoma (DTC) and 3 medullary thyroid carcinoma (MTC) patients were included, of which 6 were clinically node-negative. The median number of SLNs detected on [68Ga]Ga-tilmanocept PET/CT and resected was 3 (range 1-4) and 3 (range 1-5), respectively. Eight SLNs were found on PET/CT in the central compartment and 19 in the lateral compartment. The SLN procedure detected (micro)metastases in all patients except one. Seventeen of 27 pathologically assessed SLNs were positive, 8 negative, and 2 did not contain lymph node tissue, which led to upstaging in 5 out of 6 clinically node-negative patients.

CONCLUSIONS

[68Ga]Ga-tilmanocept PET/CT identified SLNs in all patients, mainly in the lateral neck. The SLNs were successfully surgically detected and resected using ICG-[99mTc]Tc-nanocolloid. This technique has the potential to improve neck staging, enabling more personalized treatment of thyroid cancer according to the lymph node status.

TRIAL REGISTRATION

2021-002470-42 (EudraCT).

Early postoperative prediction of the risk of distant metastases in medullary thyroid cancer

Purpose

The purpose of this study was to develop and validate a nomogram for estimating the risk of distant metastases (DM) in the early postoperative phase of medullary thyroid cancer (MTC).

Patients and methods

We retrospectively reviewed cases of patients diagnosed with MTC from the Surveillance, Epidemiology, and End Results (SEER) database from 2007 to 2017. In addition, we gathered data on patients who diagnosed as MTC at Department of Thyroid Surgery in the First Hospital of Jilin University between 2009 and 2021. Four machine learning algorithms were used for modeling, including random forest classifier (RFC), gradient boosting decision tree (GBDT), logistic regression (LR), and support vector machine (SVM). The optimal model was selected based on accuracy, recall, specificity, receiver operating characteristic curve (ROC), and area under curve (AUC). After that, the Hosmer-Lemeshow goodness-of-fit test, the brier score (BS) and calibration curve were used for validation of the best model, which allowed us to measure the discrepancy between the projected value and the actual value.

Results

Through feature selection, we finally clarified that the following four features are associated with distant metastases of MTC, which are age, surgery, primary tumor (T) and nodes (N). The AUC values of the four models in the internal test set were as follows: random forest: 0.8786 (95% CI, 0.8070-0.9503), GBDT: 0.8402 (95% CI, 0.7606-0.9199), logistic regression: 0.8670(95%CI,0.7927-0.9413), and SVM: 0.8673 (95% CI, 0.7931-0.9415). As can be shown, there was no statistically significant difference in their AUC values. The highest AUC value of the four models were chosen as the best model since. The model was evaluated on the internal test set, and the accuracy was 0.84, recall was 0.76, and specificity was 0.87. The ROC curve was drawn, and the AUC was 0.8786 (95% CI, 0.8070-0.9503), which was higher than the other three models. The model was visualized using the nomogram and its net benefit was shown in both the Decision Curve Analysis (DCA) and Clinical Impact Curve (CIC).

Conclusion

Proposed model had good discrimination ability and could preliminarily screen high-risk patients for DM in the early postoperative period.

Preoperative identification of low-risk medullary thyroid carcinoma: potential application to reduce total thyroidectomy

Current guidelines recommend total thyroidectomy with central lymph node dissection (CND) for patients with medullary thyroid carcinoma (MTC). This study aimed to identify low-risk MTC patients who may be candidates for lobectomy. We retrospectively reviewed MTC patients who underwent primary surgery at a tertiary referral center from 1998 to 2019. Eighty-five MTC patients were enrolled, excluding patients with primary tumor size > 2.0 cm. Among them, one (1.2%) patient had bilateral tumors. During a median follow-up of 84 months, 12 of the 85 patients experienced structural recurrence. 13 patients had occult lymph node metastasis, and structural recurrence occurred in 2 patients. Factors that significantly affected disease-free survival were clinical N stage (cN0 vs. cN1, log-rank P < 0.001), pathological N stage (pN0 vs. pN1, P < 0.001), and preoperative calcitonin levels (≤ 250 vs. > 250 pg/mL, P = 0.017). After categorizing patients into four groups, patients with preoperative calcitonin levels > 250 pg/mL and cN1 or pN1 had a significantly worse prognosis. Patients with a primary tumor size of 2 cm or less, cN0, and preoperative calcitonin of 250 pg/mL or less can be classified as low-risk MTC patients. We used preoperative clinical information to identify low-risk MTC patients. Lobectomy with prophylactic CND may be a potential therapeutic approach.

The survival outcomes of prophylactic lateral neck dissection for medullary thyroid carcinoma, a retrospective cohort study

OBJECTIVES

The purpose of this study was to evaluate the benefits of prophylactic lymph node dissection in medullary thyroid carcinoma (MTC) patients without radiographically lateral neck metastases.

DESIGN

Retrospective cohort study.

SETTING

Tianjin Medical University Cancer Institute and Hospital.

PARTICIPANTS

Patients who underwent primary surgery for MTC between 2011 and 2019 and without structural disease of the lateral neck preoperatively.

MAIN OUTCOME MEASURES

Locoregional recurrence, disease-free survival (DFS), and overall survival (OS) were examined.

RESULTS

The patients were divided into two groups: the central lymph node dissection (CLND) only group and the prophylactic lateral lymph node dissection (PLND) group, which included CLND and ipsilateral lateral lymph node dissection (LLND). A total of 89 patients were included: 71 patients in the CLND group and 18 patients in the PLND group. Although there were no significant differences in age, gender, multifocality, capsule invasion or TNM stage between the two groups, the tumour size and preoperative median calcitonin levels were different. The recurrence rate was 4.2% for the CLND group and 5.6% for the PLND group (p > 0.05). DFS among the CLND and PLND groups was 95.4% and 94.4%, and OS among the groups was 100% and 94.1% (p > 0.05) at 5 years. The biochemical cure rates were similar.

CONCLUSIONS

PLND in the absence of structural disease of the lateral neck preoperatively is not associated with improved survival in patients with sporadic MTC.

Personalized Medicine in Medullary Thyroid Carcinoma: A Broad Review of Emerging Treatments

Medullary thyroid carcinoma (MTC) arises from parafollicular cells in the thyroid gland, and although rare, it represents an aggressive type of thyroid cancer. MTC is recognized for its low mutational burden, with point mutations in RET or RAS genes being the most common oncogenic events. MTC can be resistant to cytotoxic chemotherapy, and multitarget kinase inhibitors (MKIs) have been considered a treatment option. They act by inhibiting the activities of specific tyrosine kinase receptors involved in tumor growth and angiogenesis. Several tyrosine kinase inhibitors are approved in the treatment of advanced MTC, including vandetanib and cabozantinib. However, due to the significant number of adverse events, debatable efficiency and resistance, there is a need for novel RET-specific TKIs. Newer RET-specific TKIs are expected to overcome previous limitations and improve patient outcomes. Herein, we aim to review MTC signaling pathways, the most recent options for treatment and the applications for personalized medicine.

CD276 as a Candidate Target for Immunotherapy in Medullary Thyroid Cancer

Medullary thyroid cancer (MTC) is a rare malignancy, and the treatment of metastatic MTC is challenging. In previous work, immune profiling (RNA-Seq) of MTC identified CD276 as a potential target for immunotherapy. CD276 expression was 3-fold higher in MTC cells than in normal tissues. Paraffin blocks from patients with MTC were analyzed by immunohistochemistry to confirm the results of RNA-Seq. Serial sections were incubated with anti-CD276 antibody, and scored according to staining intensity and the percentage of immunoreactive cells. The results showed that CD276 expression was higher in MTC tissues than in controls. A lower percentage of immunoreactive cells correlated with the absence of lateral node metastasis, lower levels of calcitonin after surgery, no additional treatments, and remission. There were statistically significant associations of intensity of immunostaining and percentage of CD276 immunoreactive cells with clinical factors and the course of the disease. These results suggest that targeting this immune checkpoint molecule CD276 could be a promising strategy for the treatment of MTC.

Incidence of Vocal Cord Paralysis in Medullary Thyroid Cancer

OBJECTIVE

Medullary thyroid cancer (MTC) is a neuroendocrine tumor that comprises 3-5% of all thyroid cancers in the United States. Vocal cord paralysis (VCP) may be due to involvement of the recurrent laryngeal nerve (RLN) preoperatively, or nerve sacrifice during surgery. The purpose of this study was to demonstrate the incidence of VCP in MTC and evaluate whether VCP has an impact on overall survival.

METHODS

This was a retrospective chart review of patients with MTC treated at Loyola University Medical Center from 2007 to 2021. Information on demographics, cancer diagnosis and treatment, laboratory data, and survival were collected.

RESULTS

A total of 79 patients were included in our study. 47 (59.5%) patients were female. The average age at the time of diagnosis was 51.3 years (SD 13.58). VCP was identified in 13 out of 79 (16.5%) patients. There were 71 patients with at least 1-year follow-up with median (Q1, Q3) years of 7.2 (3.9, 11.0). Those with VCP within 1 year had 7.2 (95% CI: 2.3, 22.7) times the risk of death compared to those without (p < 0.001).

CONCLUSION

MTC is a rare thyroid cancer, however, its incidence is on the rise. Our study suggests that the incidence of VCP in these patients appears to be higher than seen in other thyroid malignancies, and VCP is associated with a statistically significant negative impact on survival.

LEVEL OF EVIDENCE

3 Laryngoscope, 133:890-894, 2023.

Update on C-Cell Neuroendocrine Neoplasm: Prognostic and Predictive Histopathologic and Molecular Features of Medullary Thyroid Carcinoma

Medullary thyroid carcinoma (MTC) is a C-cell-derived epithelial neuroendocrine neoplasm. With the exception of rare examples, most are well-differentiated epithelial neuroendocrine neoplasms (also known as neuroendocrine tumors in the taxonomy of the International Agency for Research on Cancer [IARC] of the World Health Organization [WHO]). This review provides an overview and recent evidence-based data on the molecular genetics, disease risk stratification based on clinicopathologic variables including molecular profiling and histopathologic variables, and targeted molecular therapies in patients with advanced MTC. While MTC is not the only neuroendocrine neoplasm in the thyroid gland, other neuroendocrine neoplasms in the thyroid include intrathyroidal thymic neuroendocrine neoplasms, intrathyroidal parathyroid neoplasms, and primary thyroid paragangliomas as well as metastatic neuroendocrine neoplasms. Therefore, the first responsibility of a pathologist is to distinguish MTC from other mimics using appropriate biomarkers. The second responsibility includes meticulous assessment of the status of angioinvasion (defined as tumor cells invading through a vessel wall and forming tumor-fibrin complexes, or intravascular tumor cells admixed with fibrin/thrombus), tumor necrosis, proliferative rate (mitotic count and Ki67 labeling index), and tumor grade (low- or high-grade) along with the tumor stage and the resection margins. Given the morphologic and proliferative heterogeneity in these neoplasms, an exhaustive sampling is strongly recommended. Routine molecular testing for pathogenic germline RET variants is typically performed in all patients with a diagnosis of MTC; however, multifocal C-cell hyperplasia in association with at least a single focus of MTC and/or multifocal C-cell neoplasia are morphological harbingers of germline RET alterations. It is of interest to assess the status of pathogenic molecular alterations involving genes other than RET like the MET variants in MTC families with no pathogenic germline RET variants. Furthermore, the status of somatic RET alterations should be determined in all advanced/progressive or metastatic diseases, especially when selective RET inhibitor therapy (e.g., selpercatinib or pralsetinib) is considered. While the role of routine SSTR2/5 immunohistochemistry remains to be further clarified, evidence suggests that patients with somatostatin receptor (SSTR)-avid metastatic disease may also benefit from the option of ¹⁷⁷Lu-DOTATATE peptide radionuclide receptor therapy. Finally, the authors of this review make a call to support the nomenclature change of MTC to C-cell neuroendocrine neoplasm to align this entity with the IARC/WHO taxonomy since MTCs represent epithelial neuroendocrine neoplasms of endoderm-derived C-cells.

Risk assessment of cytologically indeterminate thyroid nodules with integrated molecular testing and repeat biopsy: a surgical decision-oriented tool

BACKGROUND

The preoperative diagnosis of cytologically indeterminate thyroid nodules (ITNs) is very challenging. In this study, we aim to provide an integrated risk assessment for thyroid nodules with indeterminate cytology to guide surgical decision-making, which includes results of blood tests, molecular tests, and repeat fine-needle aspiration biopsy (FNAB).

METHODS

The study retrospectively included 265 ITNs between June 2019 and April 2022. According to our integrated risk assessment process that starts with blood testing, followed by supplementary DNA mutation detection on the first FNAB, and finally repeat FNAB, we divided the ITNs into high-risk and low-risk groups. Performance was evaluated with sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), area under the receiver operating characteristic curve (AUC), and the consistency between the risk evaluation and histological results.

RESULTS

Of the 265 ITNs, 87 were included in the risk assessment process. The risk assessment had a sensitivity of 84.1%, specificity of 83.3%, PPV of 95.1%, NPV of 57.7%, and AUC of 0.837. The nodules with consistent results between the risk groups and histological outcomes, which included malignant cases in the high-risk group and benign cases in the low-risk group, accounted for 83.9% of all risk-assessed nodules.

CONCLUSIONS

These data suggest that the integrated risk assessment might provide proper information for surgical decision-making in patients with ITNs.

Guideline Adherence and Practice Patterns in the Management of Medullary Thyroid Cancer

INTRODUCTION

Little is known about nationwide practice patterns for the management medullary thyroid cancer (MTC) in relation to the 2015 American Thyroid Association guidelines and their impact on survival.

METHODS

Using the Surveillance, Epidemiology, and End Results Program database (2000-2018), MTC treatment patterns were evaluated in terms of adherence to the 2015 American Thyroid Association guidelines across three time periods (2000-2009, 2010-2015, and 2016-2018). Outcomes of interest were guideline concordance, treatment utilization trends, disease-specific survival (DSS), and overall survival (OS).

RESULTS

A total of 3332 patients with MTC were identified. Of which, 53.8%, 33.2%, and 11.4% of patients had localized, regional, and distant disease, respectively. In patients with locoregional disease, the rate of guideline-concordant surgery improved over time from 63.0% in 2000-2009 to 76.0% in 2016-2018 (P < 0.001). Guideline-concordant care was associated with increased OS (HR = 1.85, 95% CI: 1.42-2.43, P < 0.001) in patients with localized disease and increased DSS (HR = 1.65, 95% CI: 1.01-2.54, P < 0.001) and OS (HR = 1.89, 95% CI: 1.35-2.58, P < 0.001) in patients with regional disease. The median OS and DSS in patients with distant disease were 31 and 55 mo, respectively, and the rate of chemotherapy use rose from 21.6% to 39.2% (P = 0.003).

CONCLUSIONS

The rate of guideline-concordant surgery for locoregional MTC increased after guideline publication in 2015, with an observed prolongment in OS and DSS. Chemotherapy use among patients with distant disease has increased over time, but their prognosis remains variable.

Design of new drugs for medullary thyroid carcinoma

Medullary thyroid carcinoma (MTC) is one of the common malignant endocrine tumors, which seriously affects human health. Although surgical resection offers a potentially curative therapeutic option to some MTC patients, most patients do not benefit from it due to the difficulty to access the tumors and tumor metastasis. The survival rate of MTC patients has improved with the recent advances in the research, which has improved our understanding of the molecular mechanism underlying MTC and enabled the development and approval of novel targeted drugs. In this article, we reviewed the molecular mechanisms related to MTC progression and the principle for the design of molecular targeted drugs, and proposed some future directions for prospective studies exploring targeted drugs for MTC.

Distant metastasis in medullary thyroid carcinoma: Clinical outcomes and implications of T stage

BACKGROUND

The eighth edition of the American Joint Committee on Cancer tumour, node, and metastasis staging system did not take T stage into consideration when evaluating Stage IV C medullary thyroid carcinoma (MTC) patients. The aim of this study is to investigate the clinical outcomes and implications of T stage in this population.

METHODS

Eligible patients from the Surveillance, Epidemiology, and End Results database and the Department of Thyroid Surgery in West China Hospital of Sichuan University and who were diagnosed with Stage IV C MTC were included in this study. The overall survival (OS), the cancer-specific survival (CSS), and the precise cause of MTC-induced death were analysed. The potential risk factors, including the T stage, in the OS and CSS were evaluated by univariate and multivariate Cox regression models.

RESULTS

This retrospective study enroled 204 Stage IV C MTC patients. The 5- and 10-year OS rates were 31.8% and 17.1%, respectively, and the 5- and 10-year CSS rates were 40.4% and 22.5%, respectively. More importantly, the rates of MTC-induced death between primary or distant metastatic lesions in Stage IV C MTC patients were comparable in our institution. Additionally, the univariate and multivariate analyses demonstrated that the presence of an advanced T stage was an independent prognostic factor for both the OS (T4 vs. T1-T3, hazard ratio [HR]: 1.714, 95% confidence interval [CI]: 1.175-2.500, p = .005) and the CSS (T4 vs. T1-T3, HR: 1.848, 95% CI: 1.229-2.780, p = .003).

CONCLUSION

To achieve a better risk stratification, further classification of Stage IV C MTC patients by the T stage may be preferable.

Deep learning based on ultrasound to differentiate pathologically proven atypical and typical medullary thyroid carcinoma from follicular thyroid adenoma

OBJECTIVES

To investigate the feasibility and value of deep learning based on grayscale ultrasonography in the differentiation of pathologically proven atypical and typical medullary thyroid carcinoma (MTC) from follicular thyroid adenoma (FTA).

METHODS

The preoperative 770 ultrasound images consisted of 354 MTCs (66% were typical MTCs with a high suspicion sonographic pattern, 34% were atypical MTCs with a suspicion pattern of intermediate or less) and 416 FTAs. All images were delineated manually by a senior sonographer to achieve the regions of interest. Two deep neural networks of ResNet-34 and ResNet-18 were performed on the training set (n = 690). The test data set (n = 80) was subsequently evaluated by the two models and two sonographers, their diagnostic performances and misdiagnosis lesions were compared and analyzed.

RESULTS

The ResNet-34 model shows higher diagnostic ability than the junior sonographer with an area under the receiver operating curve of 0.992 (95% CI: 0.840-0.970)versus 0.754 (95% CI:0.645-0.843). Moreover, 12 of 16 atypical MTCs were successfully identified by the ResNet-34, which is significantly better than the senior and junior sonographer, suggesting that these patients could benefit from timely serological examination and surgical strategy at an earlier stage.

CONCLUSION

Deep learning to differentiate MTC from FTA on grayscale ultrasound may be a useful diagnostic support tool, especially in atypical MTC and FTA. Moreover, the computing time of deep learning is short, which will help to incorporate it into real-time ultrasound diagnosis.

Cell-Free DNA Analysis within the Challenges of Thyroid Cancer Management

Simple Summary

Liquid biopsy is a minimally invasive method that emerged as a new promising tool for improving diagnosis, risk stratification, follow-up, and treatment of cancer patients. To date, the majority of the research in the area of liquid biopsy has focused on plasma-based cell-free DNA as a potential surrogate for tumor DNA obtained from a tissue biopsy. In the last decades, breakthrough advancements have been performed in the knowledge of thyroid cancer genetics, and the role of molecular characterization in clinical decision-making is continuously rising, from diagnosis completion to the personalization of treatment approach. Hence, it is expectable for cell-free DNA to be applicable in thyroid cancer management. This review aims to investigate the cell-free DNA utility for thyroid cancer patients’ care.

Abstract

Thyroid cancer is the most frequent endocrine malignancy with an increasing incidence trend during the past forty years and a concomitant rise in cancer-related mortality. The circulating cell-free DNA (cfDNA) analysis is a patient’s friendly and repeatable procedure allowing to obtain surrogate information about the genetics and epigenetics of the tumor. The aim of the present review was to address the suitability of cfDNA testing in different forms of thyroid cancer, and the potential clinical applications, as referred to the clinical weaknesses. Despite being limited by the absence of standardization and by reproducibility and validity issues, cfDNA assessment has great potential for the improvement of thyroid cancer management. cfDNA may support the pre-surgical definition of thyroid nodules by complementing invasive thyroid fine needle aspiration cytology. In addition, it may empower risk stratification and could be used as a biomarker for monitoring the post-surgical disease status, both during active surveillance and in the case of anti-tumor treatment.

Sentinel lymph node detection in thyroid carcinoma using 68Ga-tilmanocept PET/CT: a proof-of-concept study protocol

Sentinel lymph node biopsy (SLNB) is a diagnostic staging procedure. The procedure aims to identify the first draining lymph node(s), which are most likely to contain metastases. SLNB is applied in various cancers, but not currently in thyroid carcinoma. However, treatment strategies are changing, making SLNB clinically relevant. SLNB may lead to more accurate staging, prevent unnecessary treatment and help achieve earlier curation. 68Ga-tilmanocept PET/computed tomography (CT) can better localize sentinel lymph nodes (SLNs) near the primary tumor than planar scintigraphy and single-photon emission computed tomography (SPECT)/CT. This paper describes the rationale and design of a study investigating SLNB using 68Ga-tilmanocept PET/CT and indocyanine-green-99mTc-nanocolloid in ten differentiated and medullary thyroid carcinoma patients. Localization and number of SLNs, pathology result, optimal scan protocol, surgical time and surgeon's experience are examined. Clinical Trial Registration: 2021-002470-42 (EudraCT).

Preoperative Identification of Medullary Thyroid Carcinoma (MTC): Clinical Validation of the Afirma MTC RNA-Sequencing Classifier

Background: Cytopathological evaluation of thyroid fine-needle aspiration biopsy (FNAB) specimens can fail to raise preoperative suspicion of medullary thyroid carcinoma (MTC). The Afirma RNA-sequencing MTC classifier identifies MTC among FNA samples that are cytologically indeterminate, suspicious, or malignant (Bethesda categories III-VI). In this study we report the development and clinical performance of this MTC classifier. Methods: Algorithm training was performed with a set of 483 FNAB specimens (21 MTC and 462 non-MTC). A support vector machine classifier was developed using 108 differentially expressed genes, which includes the 5 genes in the prior Afirma microarray-based MTC cassette. Results: The final MTC classifier was blindly tested on 211 preoperative FNAB specimens with subsequent surgical pathology, including 21 MTC and 190 non-MTC specimens from benign and malignant thyroid nodules independent from those used in training. The classifier had 100% sensitivity (21/21 MTC FNAB specimens correctly called positive; 95% confidence interval [CI] = 83.9-100%) and 100% specificity (190/190 non-MTC FNAs correctly called negative; CI = 98.1-100%). All positive samples had pathological confirmation of MTC, while all negative samples were negative for MTC on surgical pathology. Conclusions: The RNA-sequencing MTC classifier accurately identified MTC from preoperative thyroid nodule FNAB specimens in an independent validation cohort. This identification may facilitate an MTC-specific preoperative evaluation and resulting treatment.

Incidental T1 stage medullary thyroid carcinoma: The effect of tumour diameter on prognosis and therapeutic implications

OBJECTIVE

The definition of the tumour diameter of micro-medullary thyroid carcinoma (micro-MTC) is insufficient. It is controversial to perform a completion thyroidectomy immediately for incidental T1 stage MTC.

DESIGN

We used the Surveillance, Epidemiology and End Results (SEER) registry to retrospectively analyze all patients with T1 stage MTC diagnosed between 2004 and 2015. The tumour diameter 1.0 and 0.5 cm were used as the cut-off points to group and analyze the differences of clinicopathological features. We analyzed the prognosis of patients with less than total thyroidectomy.

METHODS

The disease-specific survival was the main outcome. Survival was estimated with Kaplan-Meier curves and Cox regression models estimated hazard ratios for tumour characteristics.

RESULTS

A total of 908 patients diagnosed with T1 stage MTC in the SEER database were included. Our study found that tumour diameter 1.0 cm is a key point affecting the prognosis of T1 stage MTC patients, although patients with tumour diameter ≤ 0.5 cm had a lower rate of lymph node metastasis and no distant metastasis. Cox proportional hazard multivariate analysis showed that distant metastasis was the only risk factor for survival in patients with T1 stage MTC. Kaplan-Meier survival analysis showed that, regardless of tumour diameter, there was no significant difference between less than total thyroidectomy and total thyroidectomy in T1 stage patients.

CONCLUSIONS

For incidental MTC with tumour diameter ≤ 1.0 cm and without distant metastasis, if there is no significant increase in serum calcitonin level after surgery and ret proto-oncogene (RET) gene mutation is negative, it may be not necessary to perform completion thyroidectomy immediately.

Management of medullary carcinoma of the thyroid: a review

Medullary thyroid carcinoma (MTC) is an uncommon malignancy of neuroendocrine origin derived from the parafollicular C cells. Although infrequent, the interest in this cancer exceeds its incidence owing to its distinctive features and its characteristic association with other endocrine tumors. Although the majority of MTCs are sporadic, hereditary varieties occur in isolation or as a part of multiple endocrine neoplasia type 2 syndrome (MEN 2). Currently, complete surgical resection of the tumor and nodal metastases with a curative intent remains the mainstay of therapy. The role of adjuvant therapy is limited, although radiotherapy and newer targeted therapies are routinely used for metastatic disease. The lack of consensus in the available guidance regarding the most appropriate diagnostic, therapeutic and follow-up strategies has caused substantial variability in clinical practice. Therefore, this review summarizes the latest available evidence and guidelines on the management of MTC with an emphasis on diagnosis, surgical treatment and follow-up.

Metastatic medullary thyroid carcinoma: a new way forward

Medullary thyroid carcinoma (MTC) is a rare malignancy comprising 1-2% of all thyroid cancers in the United States. Approximately 20% of cases are familial, secondary to a germline RET mutation, while the remaining 80% are sporadic and also harbour a somatic RET mutation in more than half of all cases. Up to 15-20% of patients will present with distant metastatic disease, and retrospective series report a 10-year survival of 10-40% from time of first metastasis. Historically, systemic therapies for metastatic MTC have been limited, and cytotoxic chemotherapy has demonstrated poor objective response rates. However, in the last decade, targeted therapies, particularly multitargeted tyrosine kinase inhibitors (TKIs), have demonstrated prolonged progression-free survival in advanced and progressive MTC. Both cabozantinib and vandetanib have been approved as first-line treatment options in many countries; nevertheless, their use is limited by high toxicity rates and dose reductions are often necessary. New generation TKIs, such as selpercatinib or pralsetinib, that exhibit selective activity against RET, have recently been approved as a second-line treatment option, and they exhibit a more favourable side-effect profile. Peptide receptor radionuclide therapy or immune checkpoint inhibitors may also constitute potential therapeutic options in specific clinical settings. In this review, we aim to present all current therapeutic options available for patients with progressive MTC, as well as new or as yet experimental treatments.

Sporadic Medullary Thyroid Carcinoma: Towards a Precision Medicine

Medullary thyroid carcinoma (MTC) is a neuroendocrine malignant tumor originating from parafollicular C-cells producing calcitonin. Most of cases (75%) are sporadic while the remaining (25%) are hereditary. In these latter cases medullary thyroid carcinoma can be associated (multiple endocrine neoplasia type IIA and IIB) or not (familial medullary thyroid carcinoma), with other endocrine diseases such as pheochromocytoma and/or hyperparathyroidism. RET gene point mutation is the main molecular alteration involved in MTC tumorigenesis, both in sporadic and in hereditary cases. Total thyroidectomy with prophylactic/therapeutic central compartment lymph nodes dissection is the initial treatment of choice. Further treatments are needed according to tumor burden and rate of progression. Surgical treatments and local therapies are advocated in the case of single or few local or distant metastasis and slow rate of progression. Conversely, systemic treatments should be initiated in cases with large metastatic and rapidly progressive disease. In this review, we discuss the details of systemic treatments in advanced and metastatic sporadic MTC, focusing on multikinase inhibitors, both those already used in clinical practice and under investigation, and on emerging treatments such as highly selective RET inhibitors and radionuclide therapy.

Clinical Characteristics, Surgical Management, and Prognostic Factors of Medullary Thyroid Carcinoma: A Retrospective, Single-Center Study

Purpose: Medullary thyroid carcinoma (MTC) is a rare neuroendocrine malignancy with relatively early lymphatic metastatic spread. The clinical features of MTC remain controversial owing to the low incidence rate. This study aimed to analyze the clinical characteristics, prognostic factors, and long-term follow-up of MTC. Methods: Medical records of MTC patients treated at our hospital between December 2000 and November 2020 were reviewed retrospectively. Clinicopathologic features of MTC were analyzed using univariate and multivariate analyses. Cumulative survival rates were estimated using the Kaplan-Meier method. Results: In total, 152 patients with MTC were included. The rates of central and lateral lymph node metastases (LNM) were 52.0% and 42.8%, respectively. All patients were followed up with a median follow-up time of 43.5 (17.0−76.3) months. Univariate and multivariate analyses identified two independent factors associated with progressive disease. They were lateral LNM (p < 0.001) and lymph node ratio (LNR) >1/3 (p = 0.009). The 5-, 10-, and 15-year cumulative overall survival (OS) rates of MTC were 88.2%, 83.1%, and 76.2%, respectively. The 5-, 10-, and 15-year cumulative disease-free survival (DFS) rates were 61.8%, 48.6%, and 38.2%, respectively. Patients with stage I, II, and III disease had significantly longer OS and DFS than those with stage IV disease (p < 0.001). Conclusion: MTC is a rare endocrine malignancy and LNM is common. Patients with lateral LNM and LNR >1/3 are more likely to develop progressive disease. The long-term OS rates of MTC are good, but long-term DFS rates are poor.

Nitric oxide and thyroid carcinoma: A review

Thyroid carcinoma is the most common endocrine cancer in the world, and its incidence has been steadily increasing in recent years. Despite its relatively good prognosis, therapies have not improved greatly in recent years. Therefore, exploring new therapies for thyroid carcinoma represents an unmet need. Nitric oxide (NO) is a short-term endogenous signaling molecule that plays a vital role in various physiological and pathological processes and is synthesized by nitric oxide synthase (NOS). Many studies have been conducted over the past decades to explain its correlation to cancer. NO exerts a wide range of effects on cancer, involving angiogenesis, apoptosis, cell cycle, invasion, and metastasis. It also serves a dual function by promoting and halting tumor development simultaneously. The relationship between NO and thyroid carcinoma has been intensively studied and discussed. This paper reviews the role and molecular mechanism of NO in thyroid carcinoma and discusses potentials of prevention and treatment of thyroid carcinoma.

Lenvatinib as a salvage therapy for advanced metastatic medullary thyroid cancer

PURPOSE

Patients with advanced progressive metastatic medullary thyroid cancer (MTC), show poor prognosis and few available systemic therapeutic options. After the loss of clinical benefit with other tyrosine kinase inhibitors (TKI), we evaluated the use of lenvatinib as salvage therapy.

METHODS

Ten patients who experienced the loss of clinical benefit after treatment with at least one previous TKI, were treated with lenvatinib. We assessed patient's response immediately before, at the first (first-EV) and last (last-EV) evaluation, after the beginning of treatment.

RESULTS

At first-EV, one patient died, while all the remaining 9 showed a stable disease (SD) in the target lesions. At last-EV, SD was still observed in seven patients, while partial response (PR) and progressive disease (PD), in one patient each. Conversely, analyzing all target and non-target lesions, at first-EV, we observed PR in one patient and SD in eight patients. At last-EV, PR was shown in two patients and SD was shown in seven. Bone metastases showed stable disease control at both first-EV and last-EV in only approximately 60% of cases. Tumor markers (CTN and CEA) decreased at first-EV, while they increased at last-EV. Seven patients experienced at least one dose reduction during treatment with lenvatinib.

CONCLUSIONS

In this real-life clinical experience, lenvatinib showed interesting results as salvage therapy in patients with advanced progressive metastatic MTC patients. Its usefulness could be effective in patients without any other available treatment, because previously used or unsuitable, especially with negative RET status with no access to the new highly selective targeted therapies.

Long-Term Outcomes and Causes of Death among Medullary Thyroid Carcinoma Patients with Distant Metastases

Distant metastasis is a poor prognostic factor in medullary thyroid carcinoma (MTC), but the significance of differentiating the characteristics according to the site of distant metastasis remains unclear. This study aimed to evaluate the clinical characteristics and long-term oncologic outcomes in MTC patients with distant metastasis. We identified 46 MTC patients with distant metastasis between 1994 and 2019. Clinical characteristics were compared based on the timing of the detection of distant metastasis. Additionally, survival rates following the detection of distant metastasis were evaluated to compare the clinical significance of metastatic site. The detailed causes of death were also investigated. Of the 46 patients, 15 patients (32.6%) had synchronous distant metastasis and 31 patients (67.4%) had metachronous distant metastasis. There was no clinical difference between these two groups except regarding initial surgical extent. The lung (52.2%) was the most common metastatic site, followed by the bone (28.3%), mediastinum (19.6%), liver (17.4%), adrenal gland (4.3%), brain (4.3%), kidney (2.2%), and pancreas (2.2%). Patients with bone metastasis and multisite metastasis had significantly worse prognoses than those with lung metastasis (hazard ratio: 5.42; p = 0.044 and hazard ratio: 6.11; p = 0.006). Complications due to the progression of distant metastasis, airway obstruction due to tracheal invasion, and complications related to chemotherapy were leading causes of death. In conclusion, there was no difference in clinical characteristics according to the timing of distant metastasis. Oncological outcomes differed by metastatic site.

Malignant carcinoma and skin melanoma neoplasms concomitantly in the thyroid

Malignant melanomas metastatic to the thyroid gland are uncommon. Based on microscopy and DNA methylation profile, we report a rare coexistence of neoplasms in the thyroid, presumably in our case, with relapse-free condition on adjuvant therapy.

Medullary thyroid cancer: What is the optimal management of the lateral neck in a node negative patient at index operation?

BACKGROUND

Medullary thyroid cancer is a neuroendocrine malignancy that can occur sporadically or as the result of genomic rearranged during transfection mutations. Medullary thyroid cancer has a higher rate of metastasis than well-differentiated thyroid cancer. Lateral neck dissection is often performed, and its prophylactic use is controversial.

METHODS

Single-center, retrospective review (2000-2017) of patients undergoing primary surgical treatment for medullary thyroid cancer who had negative lateral neck imaging preoperatively. Demographics, genetic associations, clinical, and imaging findings were analyzed. Locoregional recurrence, overall recurrence, and overall survival were examined.

RESULTS

A total of 110 patients were identified, of which 18 underwent prophylactic lateral neck dissection and 92 did not. Age, sex distribution, preoperative calcitonin levels, and follow-up were similar among groups. Overall recurrence was 20% for no prophylactic lateral neck dissection and 39% for prophylactic lateral neck dissection (P = .46). Most recurrences were locoregional recurrence, 7.6% for no prophylactic lateral neck dissection versus 22% for prophylactic lateral neck dissection (P = .08), half of it being to the lateral neck in both groups. A total of 7 patients from the no prophylactic lateral neck dissection group required treatment for recurrences versus 4 patients in prophylactic lateral neck dissection group (P = .57). Overall survival at 5 years was similar, 43% the no prophylactic lateral neck dissection group and 31% for prophylactic lateral neck dissection group (P = .52).

CONCLUSION

Lateral neck dissection has no effect in decreasing locoregional or overall recurrences in medullary thyroid cancer and has no effect in overall survival when performed prophylactically at index surgical intervention.

Surgeon Volume and Long-Term Oncologic Outcomes in Patients with Medullary Thyroid Carcinoma

BACKGROUND

Surgery is the most important curative treatment for medullary thyroid carcinoma (MTC). The relationship between surgeon volume (the number of surgeries performed) and short-term surgical outcomes, such as increased postoperative complication or costs, is well established. This study evaluated whether surgeon volume influenced long-term oncologic outcomes.

METHODS

We retrospectively reviewed 246 patients diagnosed with MTC after initial thyroid surgery from 1995 to 2019. After exclusion, 194 patients were eligible for inclusion in the study. Surgeons were categorized as low/intermediate volume (fewer than 100 operations per year) or high volume (at least 100 operations per year).

RESULTS

Of the 194 included patients, 60 (30.9%) developed disease recurrence, and 9 (4.6%) died of MTC during the median follow-up of 92.5 months. Having a low/intermediate-volume surgeon was associated with high disease recurrence (log-rank test, p < 0.001). After adjustment for age, sex, tumor type (sporadic versus hereditary), primary tumor size, presence of central lymph node metastasis (LNM), presence of lateral LNM, extrathyroidal extension, and positive resection margin, surgeon volume was a significant factor for disease recurrence (hazard ratio 2.28, p = 0.004); however, cancer-specific survival was not affected by surgeon volume (hazard ratio 4.16, p = 0.115).

CONCLUSIONS

Surgeon volume is associated with long-term oncologic outcome. MTC patients will be able to make the best decisions for their treatment based on the results of this study.

A new proposed tumor-node-metastasis-age staging system for stage IV medullary thyroid carcinoma based on the SEER database

Medullary thyroid carcinoma (MTC) is a rare and lethal cancer. There are currently controversies regarding its staging. This study aimed to verify the significance of the patient's age in the prognosis of MTC and propose its addition to the current staging system. Data on cancer-specific survival (CSS) from the Surveillance, Epidemiology, and End Results database between 2010 and 2015 were used. X-Tile, nomograms, Cox proportional hazards regression analysis, Kaplan-Meier curves, and log-rank tests were used to evaluate mortality rates to create a new staging system. A total of 849 patients were included. Patients were divided into three categories based on their ages at diagnosis: ≤41 years, n = 224 (26.4%); 42-71 years, n = 516 (60.8%); and ≥72 years, n = 109 (12.8%). Independent factors for survival in the multivariate analysis included age (42-71 years, hazard ratio [HR], 2.81, 95% confidence interval [CI], 1.07-7.42; ≥72 years, HR, 8.71, 95% CI, 2.88-26.34), T stage (T2, HR, 3.60, 95% CI, 1.31-9.88), and M stage (M1, HR, 8.43, 95% CI, 4.40-16.16), with P<0.05. The Harrell's concordance index for tumor node metastasis (TNM) nomogram and TNM-age nomogram was 0.904 and 0.908, respectively. The areas under the curve (AUCs) for a 3-year CSS were 0.88 and 0.873, respectively. The corresponding AUCs for a 5-year CSS were 0.892 and 0.888, respectively. A new TNM-age staging system based on cancer-specific mortality rate analysis is proposed. This system provides a more accurate risk stratification and ensures more rational treatment measures for patients with stage IV MTC.

Evaluation of grade in a genotyped cohort of sporadic medullary thyroid carcinomas

AIMS

Tumour grade and RET mutation status, especially the presence of high-risk exon 15 and 16 RET mutations, have been reported to be prognostic in patients with sporadic medullary thyroid carcinoma (MTC). The aims of our study were to evaluate the performance of two recently proposed grading systems and to assess the association between grade and genotype in a cohort of sporadic MTCs.

METHODS AND RESULTS

We identified 44 sporadic MTCs. All available tumour slides were examined, and cases were assigned a grade on the basis of either mitotic count and tumour necrosis, or mitotic count, tumour necrosis, and Ki-67 proliferative index, as described in two recent studies. Additional clinicopathological features and outcome information were obtained from the pathology reports and electronic medical records. The presence of RET and RAS mutations was determined either with direct sequencing or with massively parallel sequencing. Both grading systems were prognostic for progression-free survival and disease-specific survival on univariate analysis. There was no correlation between grade and mutation status. Specifically, neither RET nor high-risk RET mutations were enriched in high-grade tumours, as assessed by either grading scheme.

CONCLUSION

Our findings suggest that grade is not correlated with RET/RAS mutation status, indicating that grade and genotype may give independent prognostic information.

Ultrasound features value in the diagnosis and prognosis of medullary thyroid carcinoma

PURPOSE

Ultrasound (US) is the most important imaging in the preoperative diagnosis of medullary thyroid carcinoma (MTC). MTC are easy to be misdiagnosed due to lacking typical malignant US features. This study investigated US features, clinical characteristics, prognosis, and detection methods, aimed to explore the association between US features and biological behavior, and improve early diagnosis of MTC.

METHODS

A total of 189 MTC patients were enrolled in the study. Based on US features, 29 MTC were categorized as "indeterminate" (i-MTC) and 160 MTC were categorized as "malignant" (m-MTC) according to Thyroid Imaging, Reporting and Data System published by America College of Radiology (ACR TI-RADS). We compared US features, clinical characteristics and prognosis between both groups. We analyzed cytological categories of fine needle aspiration (FNA) within each i-MTC and m-MTC group according to the 2017 Bethesda System for Reporting Thyroid Cytopathology (TBSRTC). We assessed the positive rate of FNA, frozen pathological examination, and preoperative serum calcitonin (Ctn) level in i-MTC and m-MTC groups.

RESULTS

Preoperative US features were significantly different in shape, margin, composition, echogenicity, and calcifications between i-MTC and m-MTC (p < 0.05). I-MTC showed a hypoechoic solid or solid-cystic nodule lacking malignant US features. While m-MTC was presented as a solid nodule with obviously malignant US features. There were significant differences in lymph node dissection, extent of tumor, lymph node metastasis, and TNM stage and prognosis between i-MTC and m-MTC (p < 0.05). Compared to m-MTC, i-MTC underwent central neck dissection more frequently rather than lateral neck dissection at the time of the initial operation; i-MTC had less extrathyroidal invasion and lymph node metastasis, earlier stage, higher rate of biochemical cure, and lower rate of structural persistence/recurrence (p < 0.05). The 2017 TBSRTC of i-MTC and m-MTC was significantly different (p < 0.05). Preoperative serum Ctn level had a higher diagnostic sensitivity for both i-MTC and m-MTC when comparing to FNA and frozen pathological examination (p < 0.05).

CONCLUSIONS

US features were associated with biological characteristics and prognosis of MTC. I-MTC lack malignant US features, preformed less aggressiveness, and better prognosis. TBSRTC according to FNA combined with serum Ctn were helpful for the detection of i-MTC.

Complications after medullary thyroid carcinoma surgery: multicentre study of the SQRTPA and EUROCRINE® databases

BACKGROUND

Surgery is the curative therapy for patients with medullary thyroid carcinoma (MTC). In determining the extent of surgery, the risk of complications should be considered. The aim of this study was to assess procedure-specific outcomes and risk factors for complications after surgery for MTC.

METHODS

Patients who underwent thyroid surgery for MTC were identified in two European prospective quality databases. Hypoparathyroidism was defined by treatment with calcium/active vitamin D. Recurrent laryngeal nerve (RLN) palsy was diagnosed on laryngoscopy. Complications were considered at least transient if present at last follow-up. Risk factors for at-least transient hypoparathyroidism and RLN palsy were identified by logistic regression analysis.

RESULTS

A total of 650 patients underwent surgery in 69 centres at a median age of 56 years. Hypoparathyroidism, RLN palsy and bleeding requiring reoperation occurred in 170 (26·2 per cent), 62 (13·7 per cent) and 17 (2·6 per cent) respectively. Factors associated with hypoparathyroidism were central lymph node dissection (CLND) (odds ratio (OR) 2·20, 95 per cent c.i. 1·04 to 4·67), CLND plus unilateral lateral lymph node dissection (LLND) (OR 2·78, 1·20 to 6·43), CLND plus bilateral LLND (OR 2·83, 1·13 to 7·05) and four or more parathyroid glands observed (OR 4·18, 1·46 to 12·00). RLN palsy was associated with CLND plus LLND (OR 4·04, 1·12 to 14·58) and T4 tumours (OR 12·16, 4·46 to 33·18). After compartment-oriented lymph node dissection, N0 status was achieved in 248 of 537 patients (46·2 per cent).

CONCLUSION

Complications after surgery for MTC are procedure-specific and may relate to the unavoidable consequences of radical dissection needed in some patients.

Risk Assessment in Thyroid Lobectomy and Total Thyroidectomy using Over 100 Thousand Cases

OBJECTIVES

To assess risk factors and non-thyroid specific postoperative complications for thyroid lobectomy compared to total thyroidectomy.

METHODS

A retrospective, cross-sectional study of adults undergoing a lobectomy or total thyroidectomy using the National Surgical Quality Improvement Program database between 2005 and 2017. Patients not treated by otolaryngologists or general surgeons and with unknown demographic variables were excluded.

RESULTS

A total of 106 915 patients were analyzed, 64 763 total thyroidectomies and 42 152 lobectomies. Multivariable analysis demonstrated that total thyroidectomy patients were half as likely to return to the operating room (OR = 0.491 (95%CI 0.445-0.542), P < .001). Within this cohort, patients at greater risk for reoperation had a history of hypertension (OR = 1.225 (95%CI 1.090-1.376), P < .001), a malignant pathology (OR = 1.921 (95%CI 1.734-2.128), P < .001), and smoked (OR = 1.237 (95%CI 1.087-1.407), P = .001). Conversely, diabetes and body mass index did not impact the rate of reoperation when assessing total thyroidectomy and lobectomy. The most frequent non-thyroid specific complications in total thyroidectomy were unplanned intubation (0.5%), urinary tract infection (0.3%), and superficial surgical site infection (0.3%). In thyroid lobectomy, the most common complications were superficial surgical site infection (0.3%) and urinary tract infection (0.2%).

CONCLUSIONS

Our multi-institutional study indicates specific risk factors for returning to the operating room that may warrant closer follow up after surgery for total thyroidectomy or thyroid lobectomy. We also identified the most common post-operative complications. During pre-operative planning, these findings should be considered by thyroid surgeons to help mitigate risk to patients.

Anlotinib in Locally Advanced or Metastatic Medullary Thyroid Carcinoma: A Randomized, Double-Blind Phase IIB Trial

PURPOSE

Medullary thyroid cancer (MTC) accounts for about 2% of all thyroid cancer, but has a relatively poor prognosis compared with differentiated thyroid cancer. Anlotinib is a novel multitarget tyrosine kinase inhibitor targeting VEGFR, PDGFR, FGFR, and c-Kit. This multicenter, randomized, double-blind, placebo-controlled phase IIB study (ALTER 01031 and NCT02586350) was conducted to investigate the efficacy and safety of anlotinib in MTC.

PATIENTS AND METHODS

Patients with histopathologically confirmed, unresectable locally advanced or metastatic MTC were enrolled and randomly assigned in a 2:1 ratio to receive anlotinib (12 mg once daily from day 1 to 14 every 3 weeks) or placebo. Patients in placebo group were allowed to receive open-label anlotinib after disease progression. The primary endpoint was progression-free survival (PFS); secondary endpoints included objective response rate (ORR), disease control rate (DCR), and overall survival (OS).

RESULTS

Ninety-one patients were enrolled. At data cutoff date, the median PFS was significantly prolonged in the anlotinib group than in the placebo group (20.7 months vs. 11.1 months, P = 0.029; HR, 0.53; 95% confidence interval, 0.30-0.95). The ORR of anlotinib treatment was 48.4%. The incidence of treatment-related adverse events (TRAE) was 100% and 89.7% in the anlotinib and placebo groups, respectively. The most common TRAEs of all grades in the anlotinib group were palmar-plantar erythrodysesthesia syndrome (62.9%), proteinuria (61.3%), and hypertriglyceridemia (48.4%).

CONCLUSIONS

Anlotinib demonstrates its efficacy and safety in this phase IIB trial for the treatment of MTC and may become a new choice for this rare disease, especially for Chinese patients.

Prophylactic Lateral Neck Dissection for Medullary Thyroid Carcinoma is not Associated with Improved Survival

BACKGROUND

Patients with medullary thyroid carcinoma (MTC) often receive lateral lymph node dissection with total thyroidectomy when calcitonin levels are elevated, even in the absence of structural disease, but the effect of this intervention on disease-specific outcomes is not known.

PATIENTS AND METHODS

We retrospectively reviewed patients from 1986 to 2017 who underwent thyroidectomy with curative intent for MTC at our institution. The association of disease-specific survival and clinicopathologic features was examined using univariate and multivariate Cox regression.

RESULTS

We identified 316 patients who underwent curative resection for MTC. Overall and disease-specific survival were 76% and 86%, respectively, at 10 years. To investigate the effect of prophylactic ipsilateral lateral lymph node dissection, we analyzed 89 patients without known structural disease in the neck lymph nodes at the time of resection and preoperative calcitonin > 200 pg/ml, of whom 45 had an ipsilateral lateral lymph node dissection (LND) and 44 did not. There were no differences in tumor size or preoperative calcitonin levels. There was no difference at 10 years in cumulative incidence of recurrence in the neck (20.9% LND vs. 30.4% no LND, p = 0.46), cumulative incidence of distant recurrence (18.3% vs. 18.4%, p = 0.97), disease-specific survival (86% vs. 93%, p = 0.53), or overall survival (82% vs. 90%, p = 0.6).

CONCLUSION

Lateral neck dissection in the absence of clinical or radiologic abnormal lymph nodes is not associated with improved survival in patients with MTC.

Genomics and Epigenomics of Medullary Thyroid Carcinoma: From Sporadic Disease to Familial Manifestations

Our understanding of the genomics and epigenomics of medullary thyroid carcinoma (MTC) has advanced since the initial recognition of RET as a driver of MTC tumorigenesis in familial MTC. We now have insight into the frequency and prognostic significance of specific RET mutations in sporadic MTC. For example, the most common RET mutation in sporadic MTC is the RET Met918Thr mutation, the same mutation that underlies MEN2B and a poor prognosticator. This mutation is relatively infrequent in medullary thyroid microcarcinomas but is over-represented in advanced-stage disease. RAS mutations are detected in 70% of sporadic, RET wild-type MTC. Although next-generation and whole-exome sequencing studies have shown that tumors that are wild-type for RET and RAS mutations essentially lack other recurrent mutations, additional pathways and epigenetic alterations have been implicated in MTC tumorigenesis. Increased insight into the clinical course of patients with familial MTC with specific RET mutations has guided treatment recommendations for these patients. Finally, an understanding of the genomics has informed treatment for patients with advanced MTC. In this review, we will examine the genomics and epigenomics of sporadic and familial MTC, along with the prognostic significance of molecular alterations, management of patients with germline RET mutations, and treatment strategies for MTC patients.

Prognostic Value of Preoperative Serum Calcitonin Levels for Predicting the Recurrence of Medullary Thyroid Carcinoma

BACKGROUND

Serum calcitonin level is a useful biomarker for predicting primary tumor size, the extent of lymph node, and distant metastasis in patients with medullary thyroid carcinoma (MTC). However, the association between preoperative serum calcitonin levels and long-term oncologic outcomes has not yet been established. The aims of this study were to determine the preoperative serum calcitonin cut-off value for predicting disease recurrence and to evaluate its prognostic value.

METHODS

Patients with MTC (n = 169) who were treated at a tertiary referral hospital in Korea between 1995 and 2019 were enrolled. To determine the preoperative serum calcitonin cut-off value for predicting structural recurrence, the maximum of the standardized log-rank statistics of all possible cut-off values was used. Multivariable Cox regression analysis was used to determine prognostic factors for disease-free survival.

RESULTS

The overall disease-free survival rate was 75.7%. The preoperative serum calcitonin cut-off value that predicted structural recurrence was 309 pg/mL. Preoperative serum calcitonin levels of > 309 pg/mL were the strongest independent predictor of disease recurrence (hazard ratio (HR) 5.33, 95% confidence interval (85% CI) 1.67-16.96; P = 0.005). Lateral lymph node metastasis (HR 3.70, 95% CI 1.61-8.51; P = 0.002) and positive resection margins (HR 3.57, 95% CI 1.44-8.88; P = 0.006) were also significant predictors of disease recurrence.

CONCLUSIONS

The preoperative serum calcitonin cut-off value is useful in clinical practice. It is also the best predictive factor for disease-free survival. Preoperative serum calcitonin levels may help determine the optimal postoperative follow-up strategy for patients with MTC.

miR‑592 acts as an oncogene and promotes medullary thyroid cancer tumorigenesis by targeting cyclin‑dependent kinase 8

Medullary thyroid carcinoma (MTC) is a relatively rare subtype of thyroid cancer, accounting for 5‑10% of all cases of thyroid cancer worldwide. Due to the current lack of knowledge regarding the tumorigenesis of MTC, the clinical treatment of MTC remains a challenge. It has been reported that microRNAs (miRNAs) regulate the progression of MTC; however, the regulatory network of miRNAs and the exact underlying mechanisms are not completely understood. In the present study, an miRNA expression profile (GSE40807), consisting of 80 samples, was downloaded and analyzed using Gene Expression Omnibus‑2R to identify differentially expressed miRNAs between MTC and normal samples. miR‑592 expression levels were significantly increased in MTC tissues and cell lines compared with normal tissues and cell lines. Patients with high miR‑592 expression levels exhibited a less favorable prognosis compared with patients with low miR‑592 expression. The results suggested that miR‑592 overexpression promoted TT and MZ‑CRC‑1 cell proliferation in vitro. In addition, miR‑592 negatively regulated cyclin‑dependent kinase 8 (CDK8) via targeted binding in MTC cells. Moreover, co‑transfection of CDK8 overexpression plasmid and miR‑592 mimic reversed miR‑592‑mediated MTC cell proliferation. In conclusion, miR‑592 may serve as an oncogene in MTC by decreasing the expression of CDK8, indicating that the miR‑592/CDK8 axis might serve as a promising therapeutic target for MTC.

Medullary Thyroid Cancer - Feature Review and Update on Systemic Treatment

Medullary thyroid carcinoma (MTC) is a rare malignancy that originates from parafollicular (C cells) of the thyroid and accounts for 2-4% of all thyroid malignancies. MTC may be sporadic or inherited, the latter as part of the MEN 2 syndromes. Germline mutations in the RET proto-oncogene (REarranged during Transfection) are driver mutations in hereditary MTC, whereas somatic RET mutations and, less frequently, RAS mutations, have been described in tumor tissues of sporadic MTC. Genetic screening for germline mutations in RET proto-oncogene identifies gene carriers of germline mutations. That enables primary prevention (the avoidance of disease onset by total prophylactic thyroidectomy), or at least secondary prevention (early detection) of the disease. Radical surgery with complete tumor resection is still pivotal in attaining cure for MTC. Despite recent advances, the treatment of advanced, metastatic, and progressive MTC remains challenging. Metastatic MTC can have an indolent clinical course; therefore, it is necessary to assess which patient to cure and when to initiate the treatment. Multidisciplinary boards of various specialists involved in the diagnostics and therapy of the patients with MTC in highly specialized centers with a high volume of patients provide optimal patient management. Multikinase inhibitors (MKI) vandetanib and cabozantinib were approved for the treatment of progressive or symptomatic metastatic/unresectable MTC. Although these treatments have been shown to improve progression-free survival (PFS) with higher overall response rates (ORR) compared with placebo, no MKI has been shown to increase the overall survival (OS) yet, except in the subgroup of patients with RETM918T-mutations on cabozantinib therapy. As these drugs are nonselective, significant off-target toxicities may occur. Recently, next-generation small-molecule tyrosine kinase inhibitors (TKIs) have been developed. These highly selective RET-inhibitors are specifically designed for highly potent and selective targeting of oncogenic RET alterations, making them promising drugs for the treatment of advanced MTC. The selective RET-inhibitor selpercatinib has been very recently registered for the treatment of RET-mutated thyroid cancer.

The American Association of Endocrine Surgeons Guidelines for the Definitive Surgical Management of Thyroid Disease in Adults

OBJECTIVE

To develop evidence-based recommendations for safe, effective, and appropriate thyroidectomy.

BACKGROUND

Surgical management of thyroid disease has evolved considerably over several decades leading to variability in rendered care. Over 100,000 thyroid operations are performed annually in the US.

METHODS

The medical literature from 1/1/1985 to 11/9/2018 was reviewed by a panel of 19 experts in thyroid disorders representing multiple disciplines. The authors used the best available evidence to construct surgical management recommendations. Levels of evidence were determined using the American College of Physicians grading system, and management recommendations were discussed to consensus. Members of the American Association of Endocrine Surgeons reviewed and commented on preliminary drafts of the content.

RESULTS

These clinical guidelines analyze the indications for thyroidectomy as well as its definitions, technique, morbidity, and outcomes. Specific topics include Pathogenesis and Epidemiology, Initial Evaluation, Imaging, Fine Needle Aspiration Biopsy Diagnosis, Molecular Testing, Indications, Extent and Outcomes of Surgery, Preoperative Care, Initial Thyroidectomy, Perioperative Tissue Diagnosis, Nodal Dissection, Concurrent Parathyroidectomy, Hyperthyroid Conditions, Goiter, Adjuncts and Approaches to Thyroidectomy, Laryngology, Familial Thyroid Cancer, Postoperative Care and Complications, Cancer Management, and Reoperation.

CONCLUSIONS

Evidence-based guidelines were created to assist clinicians in the optimal surgical management of thyroid disease.

Carcinoembryonic antigen should be concurrently checked with calcitonin to identify distant metastases in medullary thyroid cancer

Aim: This study investigates if serum calcitonin or carcinoembryonic antigen (CEA) levels can differentiate between locoregional and metastatic medullary thyroid cancer. Methods: A single institution retrospective analysis was performed on 88 patients with medullary thyroid cancer between 2008 and 2014. Results: In M0disease, calcitonin (p < 0.001) and CEA (p = 0.003) significantly decreased postoperatively. Not only was the correlation significant between calcitonin and CEA preoperatively (r = 0.72; p < 0.001) and postoperatively (r = 0.68; p < 0.001), calcitonin could extrapolate CEA levels (p < 0.001). These findings were statistically insignificant in metastatic disease. Conclusion: Independently, calcitonin and CEA fail to differentiate between locoregional and metastatic disease. Both are essential for prognostication: loss of concordance is suspicious for metastatic disease. Hence, discordant CEA and calcitonin levels should be an indication to pursue additional imaging.

Controversies in the surgical management of sporadic medullary thyroid carcinoma

PURPOSE OF REVIEW

Medullary thyroid carcinoma (MTC) represents a wide spectrum of tumours with differing biology, behaviour and natural history. The only current available curative treatment is surgery in the form of thyroidectomy with or without ipsilateral or bilateral neck dissection. There is a lack of consensus in the available published guidelines on the optimum extent of initial surgery, and there is significant variation in clinical practice. This review focuses on the most recently published evidence.

RECENT FINDINGS

Many patients with limited disease do not receive total thyroidectomy and central neck compartment dissection as recommended by international guidelines. Despite this, 5-year disease-specific survival is over 90% in those without distant metastases at presentation. Over 20% of patients may harbour occult lateral compartment nodal metastases, and baseline calcitonin alone (>1000 pg/ml) is not a good predictor of nodal metastasis. Although delayed lateral neck compartment dissection results in similar survival outcomes to prophylactic neck dissection for clinically node-negative patients, there is an underappreciated psychological effect of having biochemical evidence of persistent disease following limited surgery.

SUMMARY

No single currently available prognostic indicator is sufficient to predict disease behaviour and evidence of occult nodal metastases. In clinically ad radiologically node-negative patients, the extent of neck dissection at initial operation, therefore, needs to be planned and executed on an individual patient basis.

Long-Term Outcomes and Aggressiveness of Hereditary Medullary Thyroid Carcinoma: 40 Years of Experience at One Center

CONTEXT

Recent data on long-term outcomes and aggressiveness of medullary thyroid carcinoma (MTC) are lacking for patients with multiple endocrine neoplasia type 2 (MEN2).

OBJECTIVES

To analyze the long-term outcomes in MEN2 and compare MTC aggressiveness in three defined RET mutation-risk categories: moderate risk (MOD), high risk (H), and highest risk (HST).

DESIGN, SETTING

Retrospective study of 263 operated patients with MEN2 from one German tertiary referral center from 1979 to 2017 comparing demographic, biochemical, genetic, and outcome parameters.

INTERVENTION

None (observational study).

MAIN OUTCOME MEASURE

Long-term survival and outcomes in three risk groups.

RESULTS

Surgery was performed at a mean age of 35.3 ± 18.8 (MOD, n = 122), 23.0 ± 15.7 years (H, n = 120), and 14.9 ± 9.3 (HST, n = 21) years (P < 0.05). The mean follow-up was 12.9 ± 9.8 years. Age and tumor stage at diagnosis differed among the three risk groups (P < 0.0001). Multivariate analysis of disease-specific survival (DSS) showed that increasing age [hazard ratio (HR), 1.06; 95% CI, 1.02 to 1.09], stage III/IV at diagnosis (HR, 7.39; 95% CI, 2.39 to 22.8), and HST group (HR, 14.4; 95% CI, 3.32 to 62.6) were significantly associated with worse DSS; the H group was not (P = 0.175). The DSS rates and outcomes were not different between the MOD and H groups (P = 0.179 and P = 0.893, respectively) but were significantly inferior in the HST group (P < 0.0008 and P < 0.0001, respectively).

CONCLUSION

MTC in patients with MEN2 showed a clearly different age of onset in the different risk groups. DSS and outcomes after MTC diagnosis were similar in the MOD and H groups, suggesting similar tumor behavior. The HST group had inferior outcomes and survival vs the MOD and or H groups.