Prognostic impact of N staging in 715 medullary thyroid cancer patients: proposal for a revised staging system

Axillary Node Metastases of Medullary Thyroid Cancer: A Hallmark of Terminal Disease

Little is known about axillary node metastasis of medullary thyroid cancer (MTC). To address this, a comparative study of patients with and without axillary node metastases of MTC was conducted. Among 1215 consecutive patients with MTC, 482 patients had node-negative MTC and 733 patients node-positive MTC. Among the 733 patients with node-positive MTC, 4 patients (0.5%) had axillary node metastases, all of which were ipsilateral. Patients with axillary node metastases had 5.7-6.9-fold more node metastases removed, both at the authors' institution (medians of 34.5 vs. 5 metastases; p=0.011) and in total (medians of 57 vs. 10 metastases; p=0.013), developed more frequently distant metastases (3 of 4 vs. 178 of 729 patients, or 75 vs. 24%; p=0.049), specifically to bone (2 of 4 vs. 67 of 729 patients, or 50 vs. 9%; p=0.046) and brain (1 of 4 vs. 4 of 729 patients, or 25 vs. 0.5%; p=0.027), and more often succumbed to cancer-specific death (3 of 4 vs. 52 of 729 patients, or 75 vs. 14%; p=0.005). Altogether, patients with axillary node metastases revealed 4-8-fold more node metastases in the ipsilateral lateral neck (medians of 11 vs. 3 metastases; p=0.021) and in the ipsilateral central neck (medians of 8 vs. 1 metastases; p=0.079) patients without axillary node metastases. Cancer-specific survival of patients with vs. patients without axillary node metastases of MTC was significantly shorter (means of 41 vs. 224 months; plog-rank<0.001). These findings show that patients with axillary node metastases of MTC have massive metastatic dissemination with poor survival.

Risk factor analysis of distant metastases in patients with primary medullary thyroid cancer: a population-based study

OBJECTIVE

Medullary thyroid carcinoma has a high rate of recurrence and distant metastasis. The aim of this study was to investigate the risk factors for distant metastasis in patients with primary medullary thyroid carcinoma.

METHODS

Patients diagnosed with primary medullary thyroid cancer between 2010 and 2015 were enrolled using the Surveillance, Epidemiology, and End Results (SEER) database. Patient demographics and tumor clinicopathological features were evaluated to identify potential risk factors for distant metastasis in patients with primary medullary thyroid cancer. Univariate and multivariate logistic regression analyses were used to determine independent risk factors for distant metastasis in patients with primary medullary thyroid carcinoma. All statistical analyses were performed using SPSS statistical software (version 27.0). A two-tailed P < 0.05 was considered statistically significant.

RESULTS

We collected 685 patients with primary medullary thyroid carcinoma, 40 of whom (5.84%) developed distant metastases. Univariate logistic regression analysis showed that except marital status, age, sex, race, pT stage, N stage, multifocal and capsular infiltration were significantly correlated with distant metastasis of medullary thyroid carcinoma. Multivariate logistic regression analysis showed that patients aged ≤ 18 years or > 55 years, Black race, higher pT stage and N stage were independent risk factors for distant metastasis of medullary thyroid carcinoma.

CONCLUSIONS

This study found that ≤ 18 years or > 55 years, black race, higher pT stage and N stage were significantly associated with distant metastasis of medullary thyroid cancer. This is important for clinicians to identify patients at high risk of distant metastasis in a timely manner.

A Proposed Modified Staging System for Medullary Thyroid Cancer: A SEER Analysis With Multicenter Validation

BACKGROUND

The 8th edition of the American Joint Committee on Cancer (AJCC) staging system for medullary thyroid cancer (MTC) was implemented in 2018. However, its ability to predict prognosis remains controversial.

PATIENTS AND METHODS

Patient data were obtained from the Surveillance, Epidemiology, and End Results (SEER) database and multicenter datasets. Overall survival was the primary end-point of the present study. The concordance index (C-index) was used to assess the efficacy of various models to predict prognostic outcomes.

RESULTS

A total of 1450 MTC patients were selected from the SEER databases and 349 in the multicenter dataset. According to the AJCC staging system, there were no significant survival differences between T4a and T4b categories (P = .299). The T4 category was thus redefined as T4a' category (≤3.5 cm) and T4b' category (>3.5 cm) based on the tumor size, which was more powerful for distinguishing the prognosis (P = .003). Further analysis showed that the T category was significantly associated with both lymph node (LN) location and count (P < .001). Therefore, the N category was modified by combining the LN location and count. Finally, the above-mentioned novel T and N categories were adopted to modify the 8th AJCC classification using the recursive partitioning analysis principle, and the modified staging system outperformed the current edition (C-index, 0.811 vs. 0.792).

CONCLUSIONS

The 8th AJCC staging system was improved based on the intrinsic relationship among the T category, LN location, and LN count, which would have a positive impact on the clinical decision-making process and appropriate surveillance.

Clinicopathological characteristics and prognosis of medullary thyroid microcarcinoma: a tumor with a similar prognosis to macrocarcinoma

BACKGROUND

Tumor size plays an important role in the staging and treatment of thyroid carcinoma. A tumor with a maximum diameter of 1 cm or less is referred to as microcarcinoma. It is unclear if the clinicopathological characteristics and prognosis of medullary thyroid microcarcinoma (≤ 1 cm; MTMC) and macrocarcinoma (> 1 cm) differ. The present study aims to clarify the clinical features and prognosis of patients with MTMC.

METHODS

The patients with medullary thyroid carcinoma underwent radical operation at our hospital between December 2000 and January 2022 were retrospectively studied. A database was established for this study. Patients with MTMC and macrocarcinoma were grouped for comparison. The clinicopathological characteristics of the two groups were compared by χ2 test, Fisher's exact test, t-test, and Mann-Whitney U test. Cumulative survival rates were presented by the Kaplan-Meier curves and compared using the log-rank test.

RESULTS

A total of 198 patients were included. Of them, 56 and 142 with MTMC and macrocarcinoma, respectively. Few patients in the MTMC group had lateral lymph node metastasis. One hundred and seventy-eight (89.9%) patients were followed up, with a median follow-up period of 61 (35, 105) months. The disease-free survival rate was significantly higher in the MTMC group (log-rank test, p = 0.032); however, there was no significant difference in the overall survival rate between the two groups (log-rank test, p = 0.083).

CONCLUSIONS

Patients with MTMC have a lower risk of lateral lymph node metastasis and better disease-free survival than those with macrocarcinoma. However, there was no significant difference in the overall survival rate of both groups. MTMC should be treated in the same manner as macrocarcinoma.

Radioactive iodine in the management of medullary carcinoma of the thyroid

OBJECTIVES

Although it is generally accepted that medullary thyroid cancer (MTC) cells do not take up iodine, there are reports indicating that this can occur. Additionally, the potential for radioactive iodine (RAI) to reduce the risk of recurrence within the thyroid bed following thyroid remnant ablation in MTC is uncertain. A systematic review was therefore undertaken.

METHODS

Studies of patients with MTC of any age or stage receiving RAI, either as adjuvant postoperative treatment or primary treatment for unresectable disease, or as treatment for recurrent or metastatic disease were eligible for inclusion. Randomised and non-randomised studies were identified by electronic searching of Medline and Embase databases. A risk of bias assessment (ROBINS-I) was carried out for each study. Outcome measures sought included overall survival, locoregional relapse-free survival, rates of locoregional recurrence, and changes in serum calcitonin. A protocol was registered with PROSPERO before the systematic review was undertaken.

RESULTS

There were no randomised studies. Ten non-randomised studies (525 patients) and ten case reports (21 patients) met the inclusion criteria, with all studies containing a high risk of bias. There were case reports reporting responses to RAI, both as adjuvant treatment and for recurrent/metastatic disease.

CONCLUSIONS

The proportion of metastatic or recurrent MTC which take up iodine remains unknown. A possible role of RAI ablation for patients with localised MTC and raised calcitonin post-thyroidectomy should be explored.

ADVANCES IN KNOWLEDGE

Although there is insufficient data to recommend changes to current treatment policies, this review suggests avenues for further research.

MRI-Based Metastatic Nodal Number and Associated Nomogram Improve Stratification of Nasopharyngeal Carcinoma Patients: Potential Indications for Individual Induction Chemotherapy

BACKGROUND

Metastatic lymph nodal number (LNN) is associated with the survival of nasopharyngeal carcinoma (NPC); however, counting multiple nodes is cumbersome.

PURPOSE

To explore LNN threshold and evaluate its use in risk stratification and induction chemotherapy (IC) indication.

STUDY TYPE

Retrospective.

POPULATION

A total of 792 radiotherapy-treated NPC patients (N classification: N0 182, N1 438, N2 113, N3 59; training group: 396, validation group: 396; receiving IC: 390).

FIELD STRENGTH/SEQUENCE

T1-, T2- and postcontrast T1-weighted fast spin echo MRI at 1.5 or 3.0 T.

ASSESSMENT

Nomogram with (model B) or without (model A) LNN was constructed to evaluate the 5-year overall (OS), distant metastasis-free (DMFS), and progression-free survival (PFS) for the group as a whole and N1 stage subgroup. High- and low-risk groups were divided (above vs below LNN- or model B-threshold); their response to IC was evaluated among advanced patients in stage III/IV.

STATISTICAL TESTS

Maximally selected rank, univariate and multivariable Cox analysis identified the optimal LNN threshold and other variables. Harrell's concordance index (C-index) and 2-fold cross-validation evaluated discriminative ability of models. Matched-pair analysis compared survival outcomes of adding IC or not. A P value < 0.05 was considered statistically significant.

RESULTS

Median follow-up duration was 62.1 months. LNN ≥ 4 was independently associated with decreased 5-year DMFS, OS, and PFS in entire patients or N1 subgroup. Compared to model A, model B (adding LNN, LNN ≥ 4 vs <4) presented superior C-indexes in the training (0.755 vs 0.727) and validation groups (0.676 vs 0.642) for discriminating DMFS. High-risk patients benefited from IC with improved post-IC response and OS, but low-risk patients did not (P = 0.785 and 0.690, respectively).

CONCLUSIONS

LNN ≥ 4 is an independent risk stratification factor of worse survival in entire or N1 staging NPC patients. LNN ≥ 4 or the associated nomogram has potential to identify high-risk patients requiring IC.

EVIDENCE LEVEL

4 TECHNICAL EFFICACY: 4.

A Contemporary Review of the Treatment of Medullary Thyroid Carcinoma in the Era of New Drug Therapies

Medullary thyroid cancer (MTC) is a rare neuroendocrine tumor that can be sporadic or inherited and is often associated with mutations in the RET (Rearranged during Transfection) oncogene. The primary treatment for MTC is surgical resection of all suspected disease, but recent advances in targeted therapies for MTC, including the selective RET inhibitors selpercatinib and pralsetinib, have led to changes in the management of patients with locally advanced, metastatic, or recurrent MTC. In this article, we review updates on the evaluation and management of patients with MTC, focusing on new and emerging therapies that are likely to improve patient outcomes.

Establishment and validation of a nomogram model for predicting distant metastasis in medullary thyroid carcinoma: An analysis of the SEER database based on the AJCC 8th TNM staging system

OBJECTIVE

Medullary thyroid carcinoma (MTC) patients with distant metastases frequently present a relatively poor survival prognosis. Our main purpose was developing a nomogram model to predict distant metastases in MTC patients.

METHODS

This was a retrospective study based on the Surveillance, Epidemiology, and End Results (SEER) database. Data of 807 MTC patients diagnosed from 2004 to 2015 who undergone total thyroidectomy and neck lymph nodes dissection was included in our study. Independent risk factors were screened by univariate and multivariate logistic regression analysis successively, which were used to develop a nomogram model predicting for distant metastasis risk. Further, the log-rank test was used to compare the differences of Kaplan-Meier curves of cancer-specific survival (CSS) in different M stage and each independent risk factor groups.

RESULTS

Four clinical parameters including age > 55 years, higher T stage (T3/T4), higher N stage (N1b) and lymph node ratio (LNR) > 0.4 were significant for distant metastases at the time of diagnosis in MTC patients, and were selected to develop a nomogram model. This model had satisfied discrimination with the AUC and C-index of 0.894, and C-index was confirmed to be 0.878 through bootstrapping validation. A decision curve analysis (DCA) was subsequently made to evaluate the feasibility of this nomogram for predicting distant metastasis. In addition, CSS differed by different M stage, T stage, N stage, age and LNR groups.

CONCLUSIONS

Age, T stage, N stage and LNR were extracted to develop a nomogram model for predicting the risk of distant metastases in MTC patients. The model is of great significance for clinicians to timely identify patients with high risk of distant metastases and make further clinical decisions.

A bibliometric analysis based on Web of Science from 2012 to 2021: Current situation, hot spots, and global trends of medullary thyroid carcinoma

Background

Medullary thyroid carcinoma (MTC) is a special type of thyroid carcinoma derived from the C cell of the thyroid gland. Because of the poor prognosis of MTC, a large number of studies on MTC have been conducted in the last 10 years. To better comprehend, it is necessary to clarify and define the dominant countries, organizations, core journals, important authors, and their cumulative research contributions, as well as the cooperative relationships between them.

Method

English publications with article type article or review about MTC from January 2012 to December 2021 was retrieved from Web of Science core collection, and VOSviewer, CiteSpace, and Microsoft Excel were applied for bibliometric study.

Result

A total of 1208 articles and reviews were included in this study. The 1208 papers were written by 6364 authors from 1734 organizations in 67 countries, published in 408 journals, and cited 24118 references from 3562 journals. The number of publications was essentially flat from 2012-2021, with the largest proportion of publications coming from the U.S., followed by Italy and China. Thyroid was the most productive journal, and Journal of clinical endocrinology & metabolism was the most cited journal. University of Texas MD Anderson Cancer Center was the most productive institution and Luca Giovanella, was the most productive author. Diagnostic tools, surgical treatment, non-surgical treatment, genetics and relationship with other endocrine diseases were the main research interests in this field. Prognosis has been a cutting-edge topic since 2017.

Conclusion

As a thyroid cancer with poor prognosis, MTC has received continuous attention in recent years. Current MTC studies mainly focused on disease intervention, mechanism research and prognosis. The main point of this study is to provide an overview of the development process and hot spots of MTC in the last decade. These might provide ideas for further research in the MTC field.

Value of lymph node ratio as a prognostic factor of recurrence in medullary thyroid cancer

Background and Objectives

The purpose of this study is to evaluate the relationship between lymph node status (the number of resected lymph nodes; the number of metastatic lymph nodes, LNM, and lymph node ratio, LNR) and biochemical recurrence, disease-free survival (DFS), as well as overall survival (OS) in medullary thyroid carcinoma (MTC).

Methods

This study enrolled MTC patients at Tianjin Medical University Cancer Institute and Hospital between 2011 and 2019. We used Logistic regression analysis, Cox regression models and Kaplan-Meier test to identify risk factors influencing biochemical recurrence, DFS, and OS.

Results

We identified 160 patients who satisfied the inclusion criteria from 2011 to 2019. We used ROC analysis to define the cut-off value of LNR with 0.24. Multifocality, preoperative calcitonin levels, pathologic N stage, resected lymph nodes, LNM, LNR, and the American Joint Committee on Cancer (AJCC) clinical stage were significant (P < 0.05) prognostic factors influencing biochemical cure. In univariable analyses, gross extrathyroidal extension, preoperative calcitonin levels, pathologic T classification, pathologic N stage, resected lymph nodes, LNM, LNR, AJCC clinical stage, and biochemical cure were significant (P < 0.05) factors of DFS. When the multivariable analysis was performed, LNR was identified as predictor of DFS (HR = 4.818, 95% CI [1.270-18.276]). Univariable Cox regression models reflected that tumor size, pathologic N stage, and LNR were predictor of OS. Furthermore, multivariable analysis manifested that LNR was predictor of OS (HR = 10.061, 95% CI [1.222-82.841]).

Conclusions

This study illustrated that LNR was independent prognostic factor of DFS and OS in MTC. In addition, LNR influenced biochemical cure. Further investigations are needed to determine the optimal cut-off value for predicting prognosis.

A novel prognostic model based on log odds of positive lymph nodes to predict outcomes of patients with anaplastic thyroid carcinoma after surgery

OBJECTIVE

The eighth version of the American Joint Committee on Cancer (8th AJCC) system for anaplastic thyroid carcinoma (ATC) added lymph node (LN) metastasis as the staging element. This study aimed to explore the association between LN status and ATC's prognosis, identify the optimal LN index and establish a novel prognostic model.

DESIGN AND PATIENTS

Data of 199 ATC patients after surgery were collected from the Surveillance, Epidemiology and End Results (SEER) database, then randomly divided into training and validation cohorts.

MEASUREMENTS

We compared the prognostic value of AJCC N status, number of positive LN (PLNN), ratio of LN (LNR) and log odds of positive LN (LODDS). We conducted univariate and multivariate Cox analyses to determine the independent prognostic factors for ATC, and constructed a novel prognostic model. The concordance index (C-index), area under the receiver-operating characteristic curve (AUC), calibration curves and decision curve analysis (DCA) were used to assess the nomogram's predictive performance.

RESULTS

LODDS showed the highest accuracy among four LN systems to predict overall survival (OS) for ATC. In the training cohort, the C-index of the LODDS-based nomogram was 0.738. The AUCs were 0.813, 0.850 and 0.869 for predicting 1-, 2- and 3-year OS, respectively. The calibration plots and DCA indicated the great clinical applicability of the model. The above results were verified in the validation cohort.

CONCLUSIONS

LODDS showed better predictive performance than other LN schemes in ATC. The LODDS-incorporated nomogram has the potential to more precisely predict the prognosis for ATC patients than the AJCC system.

Superiority of metastatic lymph node ratio over number of node metastases and TNM/AJCC N classification in predicting cancer-specific survival in medullary thyroid cancer

BACKGROUND

In medullary thyroid cancer (MTC), it is unclear which nodal classification system, metastatic lymph node ratio (MLNR), number of node metastases, or TNM/AJCC N classification, predicts cancer-specific survival best.

METHODS

Kaplan-Maier analysis of cancer-specific survival after operation at a tertiary center.

RESULTS

Included were 505 MTC patients. The spread of the survival curves was greatest after stratification by MLNR (in 0.20 increments), followed by number of node metastases (in 10-node and 20-node increments) and TNM/AJCC classification (N0, N1a, N1b). After collapsing overlapping survival curves, all adjacent curves (MLNRs ≤0.20 vs. 0.21-0.60 vs. >0.60; 0 vs. 1-20 vs. >20 node metastases; and TNM/AJCC N classification N0/N1a vs. N1b) significantly differed between each other.

CONCLUSIONS

In MTC, MLNR, reflecting intensity of lymphatic spread, predicts cancer-specific survival better than number of node metastases or TNM/AJCC N classification. The applicability of these findings to patients with limited neck dissection requires more research.

Inclusion of the Number of Metastatic Lymph Nodes in the Staging System for Medullary Thyroid Cancer: Validating a Modified American Joint Committee on Cancer Tumor-Node-Metastasis Staging System

Background: The current American Joint Committee on Cancer (AJCC) staging system (8th edition) for medullary thyroid cancer (MTC) was originally extrapolated from the staging system for differentiated thyroid cancer. However, the current staging system does not accurately predict the prognosis of patients with MTC. Patients and Methods: The present study was based on data from the Surveillance, Epidemiology, and End Results (SEER) database and validated by multicenter data from the Shanghai Tenth People's Hospital, Tongji University School of Medicine, Xuzhou City Central Hospital, and Suzhou Ninth People's Hospital. Hazard ratio with its 95% confidence interval [CI] was estimated by Cox proportional hazards regression analysis. The concordance index (C-index) was used to evaluate the discrimination accuracy of the current AJCC tumor-node-metastasis (TNM) staging system and the modified AJCC (mAJCC) TNM staging system. Results: A total of 1175 MTC patients were selected from the SEER database and 312 from the three hospitals in China. We redefined the N category according to the number of metastatic lymph nodes (LNs) as follows: N'0 category (0 metastatic LNs), N'1 category (1-9 metastatic LNs), and N'2 category (≥10 metastatic LNs). The four distinct tumor stages were reclassified in the mAJCC staging system as follows: stage I (T1-4N'0M0, T1N'1M0), stage II (T2-3N'1M0, T1N'2M0), stage III (T4N'1M0, T2-4N'2M0), and stage IV (TanyN'anyM1). The C-index of the current AJCC staging system and the mAJCC staging system was 0.72 [CI, 0.67-0.78] and 0.78 [CI, 0.73-0.84], respectively. Similar results were observed in the survival analysis of the multicenter data set. Conclusions: The mAJCC staging system could discriminate the prognosis of MTC patients more effectively than the current AJCC staging system, indicating that it is feasible and appropriate to modify the current AJCC staging system by introducing the number of metastatic LNs instead of the location of LNs. These findings might be adopted in the next edition of the AJCC staging system and be used to guide clinical practice.

Evaluation of Survival and Postoperative Radiation Among Patients with Advanced Medullary Thyroid Carcinoma: An Analysis of the National Cancer Database

BACKGROUND

This study compared survival between patients who had medullary thyroid cancer (MTC) treated with surgery alone and patients who underwent surgery and radiation (SRT).

METHODS

Patients from the National Cancer Database (NCDB) with a diagnosis of stage 3 or 4 MTC, lymph node disease, and no distant metastases between 2008 and 2016 were studied. Kaplan-Meier analyses and log-rank statistics were used to estimate and compare overall survival between patients treated with surgery alone and those treated with SRT. Mutlivariable Cox proportional hazards models and propensity-matching were used to adjust for confounding and selection bias.

RESULTS

Among 1370 patients, 1112 (81%) received surgery alone, and 258 (19%) received SRT. The hazard ratio for mortality in the SRT group was 1.784 (95% confidence interval [CI] 1.313-2.43) after multivariable adjustment for confounding variables. Furthermore, SRT remained associated with a higher mortality rate (p < 0.008) after propensity-matching in an effort to adjust for selection bias.

CONCLUSIONS

This analysis of NCDB patients showed that SRT is associated with a significantly higher mortality rate among patients treated for stage 3 or 4 IV MTC with positive lymph node disease. Although this observation can be attributed to unmeasured confounders or selection bias, the cause for the profound survival differences deserves prospective evaluation, especially as adjuvant therapies for this disease continue to evolve.

State of the art and future directions in the systemic treatment of medullary thyroid cancer

PURPOSE OF REVIEW

Systemic treatment is the only therapeutic option for patients with progressive, metastatic medullary thyroid cancer (MTC). Since the discovery of the rearranged during transfection (RET) proto-oncogene (100% hereditary, 60-90% sporadic MTC), research has focused on finding effective systemic therapies to target this mutation. This review surveys recent findings.

RECENT FINDINGS

Multikinase inhibitors are systemic agents targeting angiogenesis, inhibiting growth of tumor cells and cells in the tumor environment and healthy endothelium. In the phase III EXAM and ZETA trials, cabozantinib and vandetanib showed progression-free survival benefit, without evidence of prolonged overall survival. Selpercatinib and pralsetinib are kinase inhibitors with high specificity for RET; phase I and II studies showed overall response rates of 73% and 71% in first line, and 69% and 60% in second line treatment, respectively. Although resistance mechanisms to mutation-driven therapy will be a challenge in the future, phase III studies are ongoing and neo-adjuvant therapy with selpercatinib is being studied.

SUMMARY

The development of selective RET-inhibitors has expanded the therapeutic arsenal to control tumor growth in progressive MTC, with fewer adverse effects than multikinase inhibitors. Future studies should confirm their effectiveness, study neo-adjuvant strategies, and tackle resistance to these inhibitors, ultimately to improve patient outcomes.

Metastatic Lymph Node Ratio for Predicting Recurrence in Medullary Thyroid Cancer

Simple Summary

The anatomical staging system for thyroid cancer only contains categories for lymph node compartments. The metastatic lymph node ratio (LNR), which is the ratio of metastasized lymph nodes to the total number of evaluated lymph nodes, is suggested as a quantitative evaluation tool for lymph node metastasis in patients with medullary thyroid cancer in this study. The initial stratification implemented in this study was helpful in predicting structural recurrence, and LNR was identified as a predictor of disease-free survival.

Abstract

The lymph node ratio (LNR) has been investigated as a prognostic factor in many different types of cancers, including differentiated thyroid cancer; however, reports regarding medullary thyroid cancer (MTC) are limited. Therefore, this study aims to evaluate LNR as a risk factor for structural recurrence in patients with MTC. Medical records of patients treated for MTC in a single tertiary center between 1995 and 2017 were retrospectively reviewed. LNR is defined as the number of metastatic lymph nodes or lymph node metastases (LNM) divided by the number of retrieved lymph nodes or lymph node yield (LNY). In the survival analysis, recurrence-free survival was defined as the time from the date of total thyroidectomy to recurrence or last follow-up. To identify risk factors influencing structural recurrence, univariable and multivariable Cox proportional hazard models were used. A total of 132 patients were enrolled. The mean age of study participants was 49.7 years, and 86 patients (65%) were women. Structural recurrence was identified in 39 patients at the end of the study period, and the median follow-up period was 8.7 years. In univariable analyses, gross extra thyroidal extension, N stage, postoperative serum calcitonin and carcinoembryonic antigen (CEA) levels, and LNR were significant (p < 0.05) predictors of structural recurrence. In multivariable analysis, postoperative serum calcitonin, postoperative serum CEA, and LNR were identified as a predictor of disease-free survival (p < 0.05). LNR can potentially predict structural recurrence as a quantitative evaluation tool for lymph node metastasis in patients with MTC.

Abandoning node dissection for desmoplasia-negative encapsulated unifocal sporadic medullary thyroid cancer

BACKGROUND

Predictive criteria to determine the absence of node metastases from thyroid specimens are scarce for sporadic medullary thyroid cancer.

METHODS

Histopathologic stratification of patients with unifocal sporadic medullary thyroid cancer ≤25 mm with ≥10 neck nodes at thyroidectomy to evaluate the suitability of desmoplasia (7 increments) and tumor capsule integrity (5 decrements) for intraoperative prediction of node metastasis in unifocal sporadic medullary thyroid cancer.

RESULTS

Paraffin-embedded thyroid specimens were available for 139 eligible patients. Significant (P < .001) associations were found between increasing desmoplasia and decreasing tumor capsule integrity and nodal disease (from 0 to 79% and 0 to 62%); the number of node metastases (medians, from 0 to 3 and 0 to 2 nodes); and biochemical cure (from 100 to 36% and 100 to 58%). Desmoplasia (low-moderate to high, with fibrosis >10%) and breach of the tumor capsule (>3 extensions; 1 extension >3 mm in width; or diffuse growth without tumor capsule) yielded excellent sensitivity and negative predictive value (100%), with moderate specificity (57 and 48%) and positive predictive value (50 and 46%). In retrospect, node dissection proved unnecessary in 55 (57%) and 47 (48%) patients who harbored desmoplasia-negative and encapsulated tumors. When available frozen sections were histopathologically compared with matching paraffin-embedded thyroid tumor specimens, concordance was 98% (53 of 54 pairs): 1 of 7 upgrades changed the diagnosis to desmoplasia, whereas 1 of 3 downgrades shifted the diagnosis of tumor capsule breach from "present" to "absent."

CONCLUSIONS

Patients with desmoplasia-negative encapsulated sporadic medullary thyroid cancer may forgo node dissection at specialist centers.

Metastatic Risk Profile of Microscopic Lymphatic and Venous Invasion in Medullary Thyroid Cancer

The metastatic risk profile of microscopic lymphatic and venous invasion in medullary thyroid cancer is ill-defined. This evidence gap calls for evaluation of the suitability of microscopic lymphatic and venous invasion at thyroidectomy for prediction of lymph node and distant metastases in medullary thyroid cancer. In this study of 484 patients with medullary thyroid cancer who had≥5 lymph nodes removed at initial thyroidectomy, microscopic lymphatic and venous invasion were significantly associated with greater primary tumor size (27.6 vs. 14.5 mm, and 30.8 vs. 16.2 mm) and more frequent lymph node metastasis (97.0 vs. 25.9%, and 85.2 vs. 39.5%) and distant metastasis (25.0 vs. 5.1%, and 32.8 vs. 7.3%). Prediction of lymph node metastases by microscopic lymphatic invasion was better than prediction of distant metastases by microscopic venous invasion regarding sensitivity (97.0 vs. 32.8%) and positive predictive value (58.4 vs. 39.2%); comparable regarding negative predictive value (98.5 vs. 90.5%) and accuracy (80.4 vs. 85.1%); and worse regarding specificity (74.1 vs. 92.7%). On multivariable logistic regression, microscopic lymphatic invasion predicted lymph node metastasis better (odds ratio [OR] 65.6) than primary tumor size (OR 4.6 for tumors>40 mm and OR 2.7 for tumors 21-40 mm, relative to tumors≤20 mm), whereas primary tumor size was better in predicting distant metastasis (OR 8.3 for tumors>40 mm and OR 3.9 for tumors 21-40 mm, relative to tumors≤20 mm) than microscopic venous invasion (OR 3.2). These data show that lymphatic invasion predicts lymph node metastases better in medullary thyroid cancer than venous invasion heralds distant metastases.

Multiple endocrine neoplasia type 2: A reveiw

Multiple endocrine neoplasias are rare hereditary syndromes some of them with malignant potential. Multiple endocrine neoplasia type 2 (MEN 2) is an autosomal dominant hereditary cancer syndrome due to germline variants in the REarranged during Transfection (RET) proto-oncogene. There are two distinct clinical entities: MEN 2A and MEN 2B. MEN 2A is associated with medullary thyroid carcinoma (MTC), phaeochromocytoma, primary hyperparathyroidism, cutaneous lichen amyloidosis and Hirschprung's disease and MEN 2B with MTC, phaeochromocytoma, ganglioneuromatosis of the aerodigestive tract, musculoskeletal and ophthalmologic abnormalities. Germline RET variants causing MEN 2 result in gain-of-function; since the discovery of the genetic variants a thorough search for genotype-phenotype associations began in order to understand the high variability both between families and within family members. These studies have successfully led to improved risk classification of prognosis in relation to the genotype, thus improving the management of the patients by thorough genetic counseling. The present review summarizes the recent developments in the knowledge of these hereditary syndromes as well as the impact on clinical management, including genetic counseling, of both individual patients and families. It furthermore points to future directions of research for better clarification of timing of treatments of the various manifestations of the syndromes in order to improve survival and morbidity in these patients.

Construction and Validation of a Nomogram Based on the Log Odds of Positive Lymph Nodes to Predict the Prognosis of Medullary Thyroid Carcinoma After Surgery

BACKGROUND

This study aimed to explore the prognostic impact that the log odds of positive lymph nodes (LODDS) has on medullary thyroid cancer (MTC) and to develop a nomogram incorporating LODDS to predict the cancer-specific survival (CSS) of MTC.

METHODS

Data from 1110 MTC patients after total thyroidectomy were collected from the Surveillance, Epidemiology, and End Results (SEER) database and divided into training and validation cohorts. The prognostic efficiency of N status from the American Joint Committee on Cancer (AJCC) staging system, the number of positive lymph nodes (PLNN), and LODDS were compared using the Harrell concordance index (C-index), the Akaike information criterion (AIC), and area under the receiver operating characteristic (ROC) curve (AUC). A multivariate Cox analysis was performed to determine the independent prognostic factors, and a nomogram based on LODDS was constructed. The nomogram's performance was assessed with the C-index, AUC, calibration curves, and decision curve analysis (DCA).

RESULTS

Among the three lymph node (LN) staging systems, LODDS showed the highest accuracy in predicting CSS for MTC. In the training cohort, the C-index of the LODDS-based nomogram was 0.895. The AUCs were 0.949, 0.917, 0.925, and 0.901 for predicting 1-, 3-, 5- and 10-year CSS, respectively. The calibration plots and DCA showed the superior clinical applicability of the nomogram. These results were verified in the validation cohort.

CONCLUSIONS

As an independent prognostic factor for MTC, LODDS demonstrated superior prognostic efficiency over N status and PLNN. This LODDS-based nomogram yielded better performance than the AJCC tumor-node-metastasis (TNM) staging system in predicting CSS after surgery for MTC.

Nodal disease burden and outcome of medullary thyroid carcinoma

BACKGROUND

Medullary thyroid carcinoma (MTC) is a rare malignancy with high incidence of cervical lymph node (CLN) metastasis. We investigated the impact of nodal disease burden on survival.

METHODS

We searched the National Cancer Database for MTC patients treated surgically. Impact of nodal metastasis on survival was analyzed using Cox univariable and multivariable regression.

RESULTS

We identified 2627 patients from 2004 to 2015. Positive CLNs were identified in 1433 (54.5%), and 542 (20.6%) had >10 CLN+. Overall survival was 94.5% and 89.6% at 3 and 5 years. Patients with 11 to 20 CLN+ had significantly worse survival than patients with 1 to 10 CLN+ in univariable and multivariable analyses (HR = 3.56 (2.31-5.50) vs 2.26 (1.60-3.20); P < .0001). The ratio of positive to dissected CLN was associated with overall survival.

CONCLUSIONS

Higher burden of nodal disease is associated with worse survival in MTC. The number of positive nodes could be a valuable prognosticator in addition to the current staging system.

Multimodal imaging of thyroid cancer

PURPOSE OF REVIEW

Thyroid cancer is the most common endocrine cancer in adults with rising incidence. Challenges in imaging thyroid cancer are twofold: distinguishing thyroid cancer from benign thyroid nodules, which occur in 50% of the population over 50 years; and correct staging of thyroid cancer to facilitate appropriate radical surgery in a single session. The clinical management of thyroid cancer patients has been covered in detail by the 2015 guidelines of the American Thyroid Association (ATA). The purpose of this review is to state the principles underlying optimal multimodal imaging of thyroid cancer and aid clinicians in avoiding important pitfalls.

RECENT FINDINGS

Recent additions to the literature include assessment of ultrasound-based scoring systems to improve selection of nodules for fine needle biopsy (FNB) and the evaluation of new radioactive tracers for imaging thyroid cancer.

SUMMARY

The mainstay of diagnosing thyroid cancer is thyroid ultrasound with ultrasound-guided FNB. Contrast-enhanced computed tomography and PET with [F]-fluorodeoxyglucose (FDG) and MRI are reserved for advanced and/or recurrent cases of differentiated thyroid cancer and anaplastic thyroid cancer, while [F]FDOPA and [Ga]DOTATOC are the preferred tracers for medullary thyroid cancer.

Update on the Treatment of Medullary Thyroid Carcinoma in Patients with Multiple Endocrine Neoplasia Type 2

Medullary Thyroid Carcinoma (MTC) is a rare neuroendocrine cancer that accounts for 1-2% of thyroid cancers in the United States (U.S.). While most cases are sporadic, 25% of MTC cases are hereditary. These hereditary cases occur in the setting of Multiple Endocrine Neoplasia Type 2A (MEN2A) or 2B (MEN2B) driven by mutations in the Rearranged during Transfection RET proto-oncogene. This article discusses hereditary MTC in the setting of MEN2 and the treatment options available for it. The first line treatment for this disease is typically a total thyroidectomy and tyrosine kinase inhibitors. Two tyrosine kinase inhibitors, vandetanib and cabozantinib, have been approved for treatment of advanced MTC, but options beyond those are limited. However, several promising treatments are being studied, which are discussed in this review.

Prognostic significance of quantitative metastatic lymph node burden on magnetic resonance imaging in nasopharyngeal carcinoma: A retrospective study of 1224 patients from two centers

BACKGROUND AND PURPOSE

The number of metastatic lymph nodes (LNs) has been demonstrated to be an important prognosticator in some head and neck cancers. This study aimed to examine its prognostic value in nasopharyngeal carcinoma (NPC).

MATERIALS AND METHODS

Patients with newly-diagnosed, non-distant metastatic NPC from two centers were enrolled in this study. According to the radiologic criteria for involved LNs, the number of positive LNs was assessed on MRI. Univariate and multivariate models were constructed to assess the association between the number of positive LNs and clinical outcomes. Exhaustive method was used to determine the cutoff values of the number of positive LNs.

RESULTS

In 1224 patients, the number of MRI-positive LNs was an independent risk factor for overall survival (OS), distant metastasis-free survival (DMFS), relapse-free survival (RFS), progression-free survival (PFS) and regional relapse-free survival (RRFS), surpassing other nodal factors. All the patients were divided into no, low (1-4 positive LNs), moderate (5-9 positive LNs) and high (>9 positive LNs) risk groups. The HRs of high-risk group exceeded the HRs of N3 classification for OS, DMFS, RFS, PFS and RRFS. On upgrading patients with more than 9 positive LNs from N2 to N3, the revised N-staging system showed a higher C-index compared to current N-staging system for predicting OS (0.747 vs. 0.741, P = 0.002), RFS (0.655 vs. 0.640, P = 0.015) and PFS (0.674 vs. 0.669, P = 0.035).

CONCLUSIONS

The number of MRI-positive LNs was a predominant independent prognostic factor for NPC patients' survival. It may be incorporated into the future N-staging system to improve its accuracy in predicting outcomes.

Prediction of biochemical cure in patients with medullary thyroid cancer

BACKGROUND

The impact of number of node metastases versus metastatic lymph node ratio versus AJCC node category on biochemical cure in medullary thyroid cancer (MTC) is not well defined.

METHODS

Multivariable logistic regression analysis was used to determine clinical and histopathological variables that contribute to biochemical cure in node-positive MTC.

RESULTS

Some 584 of 1026 patients with MTC underwent systematic lymph node dissections for node-positive disease; 27·4 per cent (54 of 197) were biochemically cured after the initial operation and 13·5 per cent (42 of 310 patients) after repeat surgery. Cured patients had significantly less extrathyroid extension (11-14 versus 33·2-55·6 per cent), fewer lymph node metastases (median 2-4 versus 12-16), a lower metastatic lymph node ratio (median 0·05-0·08 versus 0·23-0·28), and were less likely to have AJCC pN1b disease (56-76 versus 89·9-91·6 per cent) and distant metastases (0 versus 28·4-37·1 per cent) than patients who were not cured. Biochemical cure curves advanced steadily up to 7-12 node metastases and a metastatic lymph node ratio of 0·33, eventually levelling off after 16-17 node metastases and metastatic lymph node ratios of 0·45-0·65. In logistic regression analysis, number of lymph node metastases (odds ratio (OR) 17·24 for more than 20 metastases, OR 5·28 for 11-20 metastases, OR 2·22 for 6-10 metastases), preoperative basal serum calcitonin (OR 6·24 for over 1000 pg/ml), reoperation (OR 5·34) and extrathyroid extension (OR 2·42) independently predicted failure to reach biochemical cure.

CONCLUSION

Number of lymph node metastases, unlike metastatic lymph node ratio or AJCC node category, determines likelihood of biochemical cure after initial and repeat surgery for node-positive MTC.

Association Between Programmed Death-Ligand 1 Expression and Clinicopathological Characteristics, Structural Recurrence, and Biochemical Recurrence/Persistent Disease in Medullary Thyroid Carcinoma

Background: Expression of the programmed death-ligand 1 (PD-L1) in medullary thyroid carcinoma (MTC) has been rarely reported. In this study, we evaluated PD-L1 positivity in MTC and analyzed its correlation with clinicopathological characteristics, structural recurrence (SR), and biochemical recurrence/persistent disease (BcR/BcPD). We also evaluated the prevalence of PD-L1 expression in patients developing distant or unresectable locoregional recurrence. Methods: In total, 201 consecutive MTC patients who underwent initial surgery in our institution from January 2006 to December 2015 were included. PD-L1 expression was evaluated by immunohistochemical staining and was considered positive in case of a combined positive score ≥1. The association of PD-L1 positivity with clinicopathological characteristics, structural recurrence-free survival (SRFS), and BcR/BcPD was retrospectively investigated. Results: The median follow-up length of the entire cohort was 73 months. We observed positive PD-L1 staining in 29 (14.4%) patients who were more likely to have a larger tumor size (p = 0.002), lymph node metastases (p = 0.036), and advanced TNM staging (p = 0.019). The five-year SRFS of the PD-L1-negative and PD-L1-positive groups was 85.4% and 57.9% (p = 0.001). Multivariate Cox analysis showed that PD-L1 positivity was independently associated with SR (hazard ratio = 2.19 [95% confidence interval (CI) 1.01-4.77], p = 0.047). Furthermore, multivariate logistic analysis showed that PD-L1 positivity was significantly associated with BcR/BcPD (odds ratio = 3.16 [CI 1.16-8.66], p = 0.025). During the study period, 20 patients developed distant or unresectable locoregional recurrence, among whom 8 (40%) were PD-L1 positive, which was much higher than in the entire MTC population. Conclusions: Using a large cohort of MTC patients, we demonstrate that PD-L1 positivity is associated with aggressive clinicopathological features and is independently predictive of SR and BcR/BcPD. Furthermore, a higher rate of PD-L1 expression in patients with incurable recurrence has been observed. Therefore, immune checkpoint inhibitors targeting the programmed cell death-1 (PD-1)/PD-L1 pathway may be a potential therapeutic strategy to treat advanced MTC.

Clinico-pathologic and dynamic prognostic factors in sporadic and familial medullary thyroid carcinoma: an Israeli multi-center study

OBJECTIVE

Multiple clinical, pathological and biochemical variables, including the response to initial treatment, are associated with medullary thyroid carcinoma (MTC) prognosis. Studies that include separate analyses of familial and sporadic MTC patients followed for long period are scarce. This study evaluated the association between baseline clinico-pathologic variables and response to initial treatment and short- and long-term disease outcomes in sporadic and familial MTC.

METHODS

Patients treated for MTC at four tertiary medical centers were retrospectively analyzed. Clinical and pathological data were collected. The outcomes measured included disease persistence 1 year after diagnosis, disease persistence at last follow-up, disease-related mortality (DRM) and all-cause mortality.

RESULTS

The study enrolled 193 patients (mean age: 48.9 ± 18.7, 44.7% males), of whom 18.1% were familial cases. The mean follow-up period was 10.1 ± 9.4 years (8.5 ± 8.1 in sporadic and 16.9 ± 11.6 in familial MTC). Disease persistence 1-year after diagnosis and at last follow-up was detected in 56.1 and 60.4% patients, respectively. All-cause and DRM were 28.5 and 12.6%, respectively. Extra-thyroidal extension (ETE) and distant metastases (DM) were associated with disease persistence at last follow-up. ETE and DM were also significantly associated with DRM. Complete remission 1 year after diagnosis had high correlation with no evidence of disease at last follow-up (Cramer's V measure of association 0.884, P < 0.001) and with 100% disease-specific survival (Cramer's V measure of association 0.38, P < 0.001).

CONCLUSIONS

Apart from clinico-pathologic parameters, close correlation was found between 1-year status and long-term prognosis. These results underscore the importance of combining classical and dynamic factors for both sporadic and familial MTC prognostication and treatment decision making.

Static Prognostic Factors and Appropriate Surgical Designs for Patients with Medullary Thyroid Carcinoma: The Second Report from a Single-Institution Study in Japan

Background

Medullary thyroid carcinoma (MTC) originates from calcitonin-producing cells of the thyroid. In 2009, we published our first report on the biological characteristics and prognosis of 118 MTC patients. Herein, we enrolled a larger number of patients with longer follow-up periods to further study the biological characteristics and appropriate therapies for MTC.

Methods

In general, hemithyroidectomy and total thyroidectomy were performed for sporadic MTC confined to the thyroid lobe and for hereditary MTC with central node dissection, respectively. Moreover, prophylactic modified radical neck dissection was performed on the side of macroscopic tumors.

Results

In total, 233 patients (99 hereditary and 134 sporadic) were enrolled. The median follow-up time was 128 months (range 7–445 months). Biochemical cure was obtained in 36 (62%) of the 58 patients who underwent prophylactic MND and were pathologically positive for lateral node metastasis. None of the patients had recurrence in the preserved thyroid. Distant recurrence was detected in 19 patients, and 12 died of MTC. Preoperative calcitonin and carcinoembryonic antigen levels, tumor size (T) > 4 cm, the male sex, clinical and pathological node metastases (N1), distant metastasis (M1), extrathyroid extension (Ex), and a lack of biochemical cure had prognostic impacts on distant recurrence and/or carcinoma-related mortality on univariate analysis. On multivariate analysis, Ex was independently correlated with distant recurrence, and Ex, T > 4 cm, and M1 independently affected carcinoma-related mortality.

Conclusion

MTC patients had excellent prognosis in our institutions, indicating that our surgical strategies were appropriate.

Prognostic value of numbers of metastatic lymph node in medullary thyroid carcinoma: A population-based study using the SEER 18 database

Lymph node (LN) metastases are widely considered as a vital assessment of disease progression, as well as an essential indicator for biochemical cure of medullary thyroid carcinoma (MTC). Prognostic effect of numbers of metastatic LN has not been fully studied and the optimal cut-point of LN numbers has not been established. This population-based study designed to investigate prognostic value of numbers of positive LN and determinate the prognostic factors.Data were generated from Surveillance, Epidemiology, and End Results (SEER) database between 1998 and 2013. X-tile program was applied and cut points for division of LN numbers as low-, medium- and high-risk were 0, 1 to 10, and ≥11. The relationship between numbers of metastatic LN, age, tumor size, extent of tumor, and radiotherapy on overall survival (OS) and disease-specific survival (DSS) were evaluated.A total of 1466 diagnosed primary MTC patients without metastases were eligible for analysis in current study. 945 (64%) patients were classified as no positive LNs, 327 (22%) as 1 to 10 positive LNs, 194 (14%) as ≥11 positive LNs. Patients with older age, tumor size, ≥11 positive LN were associated with unfavorable OS. Those dispensed with radiation had statistically better prognosis than the others. When stratified by age, there was a significant difference in patients ≥45 years within LN categories (log-rank P < .001). When stratified by tumor size, a significant correlation was noted between rising numbers of involved nodes and falling rates of OS in tumor measuring >2cm setting (2-4 cm setting, log-rank P = .003 and >4 cm setting, log-rank P = .014, separately). There was no statistical difference of the area under the curve (AUC) for OS and DSS prediction between LN group and N stage, suggesting the 2 LN systems had the same predictive power for OS and DSS.Numbers of metastatic LN showed prognostic power in survival analysis and remained an independent survival predictor which can be evaluated in MTC treatment decisions for optimum assessment.

Replication of newly proposed TNM staging system for medullary thyroid carcinoma: a nationwide study

A recent study proposed new TNM groupings for better survival discrimination among stage groups for medullary thyroid carcinoma (MTC) and validated these groupings in a population-based cohort in the United States. However, it is unknown how well the groupings perform in populations outside the United States. Consequently, we conducted the first population-based study aiming to evaluate if the recently proposed TNM groupings provide better survival discrimination than the current American Joint Committee on Cancer (AJCC) TNM staging system (seventh and eighth edition) in a nationwide MTC cohort outside the United States. This retrospective cohort study included 191 patients identified from the nationwide Danish MTC cohort between 1997 and 2014. In multivariate analysis, hazard ratios for overall survival under the current AJCC TNM staging system vs the proposed TNM groupings with stage I as reference were 1.32 (95% CI: 0.38-4.57) vs 3.04 (95% CI: 1.38-6.67) for stage II, 2.06 (95% CI: 0.45-9.39) vs 3.59 (95% CI: 1.61-8.03) for stage III and 5.87 (95% CI: 2.02-17.01) vs 59.26 (20.53-171.02) for stage IV. The newly proposed TNM groupings appear to provide better survival discrimination in the nationwide Danish MTC cohort than the current AJCC TNM staging. Adaption of the proposed TNM groupings by the current AJCC TNM staging system may potentially improve accurateness in survival discrimination. However, before such an adaption further population-based studies securing external validity are needed.

Diagnostic Accuracy of 18F-FDG PET/CT in Patients With Biochemical Evidence of Recurrent, Residual, or Metastatic Medullary Thyroid Carcinoma

OBJECTIVE

Medullary thyroid carcinoma (MTC) is a rare malignancy. Location of residual, recurrent, or metastatic disease is crucial to treatment management and outcome. We aimed to evaluate the use of F-FDG PET/CT in localizing MTC foci in patients with biochemical relapse.

METHODS

This is a retrospective cohort study. Review of 51 FDG PET/CT studies of 45 patients referred to restage MTC due to increased calcitonin (Ctn) and carcinoembryonic antigen (CEA) values at follow-up. FDG PET/CT diagnostic accuracy was determined through a patient-based analysis, using histology as criterion standard when available, or other imaging studies and clinical follow-up otherwise (mean, 4 years).

RESULTS

There were 25 positive scans. Sensitivity, specificity, positive and negative predictive values, diagnostic accuracy, and positive likelihood ratio were 66.7%, 83.3%, 88.0%, 57.7%, 72.5%, and 4.0, respectively. Using a Ctn cutoff of 1000 pg/mL, sensitivity increased to 76.9%. There were significant differences of Ctn and CEA values between positive and negative FDG PET/CT (P < 0.05). Regarding true-positive studies, average SUVmax comparing locoregional and metastatic disease was at the limit of significance (P = 0.046).

CONCLUSIONS

PET/CT can be useful to restage patients with biochemical relapse of MTC, with a better performance in higher Ctn levels. Its high positive predictive value (88%) may impact in the therapeutic management, although its low negative predictive value (57.7%) makes strict follow-up mandatory in examinations without pathologic findings.

Thyroid Cancer: Risk-Stratified Management and Individualized Therapy

Thyroid cancer is the most common endocrine malignancy. Differentiated thyroid cancer (DTC) with the two subtypes, papillary thyroid cancer (PTC) and follicular thyroid cancer (FTC), is the most frequent subtype of thyroid cancer; more rare subtypes are medullary thyroid cancer (MTC) and anaplastic thyroid cancer (ATC). The incidence of DTC has increased rapidly in recent years due to the more frequent use of imaging methods such as ultrasound of the neck and fine-needle aspiration (FNA) of thyroid nodules. After total thyroidectomy and radioiodine treatment, DTC remains an indolent and curable disease in most patients, whereas the cure rate in MTC is lower and depends on early diagnosis. Most ATCs are incurable. In recent years, there has been great progress in identifying genetic changes in thyroid cancer, and genetic testing of FNA samples or blood samples provides useful information for clinical decision making. Tumor staging, either postoperatively or by imaging, and measuring the tumor markers thyroglobulin for DTC and calcitonin for MTC, allow for dynamic risk-adapted stratification for follow-up procedures. In advanced metastatic thyroid cancer, molecular targeted therapy using tyrosine kinase receptor inhibitors, including sorafenib, lenvantinib, vandetanib, and cabozantinib, helps control tumor progression and prolongs progression-free survival. Using a dynamic risk-stratified approach to manage thyroid cancer, the outcomes for most thyroid cancer patients are excellent compared with those for other cancers. The major challenge in the future is to identify high-risk patients and to treat and monitor them appropriately. Clin Cancer Res; 22(20); 5012-21. ©2016 AACR SEE ALL ARTICLES IN THIS CCR FOCUS SECTION, "ENDOCRINE CANCERS REVISING PARADIGMS".

Medullary Thyroid Carcinoma in MEN2A: ATA Moderate- or High-Risk RET Mutations Do Not Predict Disease Aggressiveness

CONTEXT

High-risk RET mutations (codon 634) are associated with earlier development of medullary thyroid carcinoma (MTC) and presumed increased aggressiveness compared with moderate-risk RET mutations.

OBJECTIVE

To determine whether high-risk RET mutations are more aggressive.

DESIGN

Retrospective cohort study using institutional multiple endocrine neoplasia type 2 registry.

SETTING

Tertiary cancer care center.

PATIENTS

Patients with MTC and moderate- or high-risk germline RET mutation.

INTERVENTION

None (observational study).

MAIN OUTCOME MEASURES

Proxies for aggressiveness were overall survival (OS) and time to distant metastatic disease (DMD).

RESULTS

A total of 127 moderate-risk and 135 high-risk patients were included (n = 262). Median age at diagnosis was 42.3 years (range, 6.4 to 86.4 years; mean, 41.6 years) for moderate-risk mutations and 23.0 years (range, 3.7 to 66.8 years; mean, 25.6 years) for high-risk mutations (P < 0.0001). Moderate-risk patients had more T3/T4 tumors at diagnosis (P = 0.03), but there was no significant difference for N or M stage and no significant difference in OS (P = 0.40). From multivariable analysis for OS, increasing age [hazard ratio (HR), 1.05/y; 95% confidence interval (CI), 1.03 to 1.08], T3/T4 tumor (HR, 2.73; 95% CI, 1.22 to 6.11), and M1 status at diagnosis (HR, 3.93; 95% CI, 1.61 to 9.59) were significantly associated with worse OS but high-risk mutation was not (P = 0.40). No significant difference was observed for development of DMD (P = 0.33). From multivariable analysis for DMD, only N1 status at diagnosis was significant (HR, 2.10; 95% CI, 1.03 to 4.27).

CONCLUSIONS

Patients with high- and moderate-risk RET mutations had similar OS and development of DMD after MTC diagnosis and therefore similarly aggressive clinical courses. High-risk connotes increased disease aggressiveness; thus, future guidelines should consider RET mutation classification by disease onset (early vs late) rather than by risk (high vs moderate).

Charting a course through the CEAs: diagnosis and management of medullary thyroid cancer

Medullary thyroid cancer (MTC) is an uncommon thyroid cancer that requires a high index of suspicion to facilitate diagnosis of early-stage disease amenable to surgical cure. The challenges of diagnosis, as well as management in the setting of persistent disease, are explored in the context of a case presenting with the incidental finding of elevated carcinoembryonic antigen (CEA) and an (18) F-fluorodeoxyglucose positron emission tomography ((18) F-FDG-PET)-positive thyroid incidentaloma detected following treatment of colorectal cancer. Strategies to individualize prognosis, and emerging PET-based imaging modalities, particularly the potential role of (18) F-DOPA-PET in staging, are reviewed.

Surgical cure rates of sporadic medullary thyroid cancer in the era of calcitonin screening

OBJECTIVE

Time trends of the extent of disease at first diagnosis and biochemical cure remain ill-defined for sporadic medullary thyroid cancer (MTC). This investigation aimed to delineate time trends and biochemical cure rates for sporadic MTC.

DESIGN

This was an observational study of consecutive patients operated on for sporadic MTC between 1995 and 2015.

METHODS

Time trends of clinical and histopathological variables indicative of the extent of disease and biochemical cure were calculated for 600 patients with sporadic MTC, 322 of whom had initial neck surgery and 278 of whom had neck reoperation at a tertiary surgical center in Germany.

RESULTS

From 1995-2000 to 2011-2015, significant declines (all P<0.001) were noted in the percentage of node-positive tumors (from 73 to 49%), mediastinal lymph node metastasis (from 21 to 6%) and distant metastasis (from 23 to 6%). These changes were paralleled by significant increases (all P<0.001) in mean patient age (from 49.1 to 57.3years) and the percentage of MTC ≤10mm (from 19 to 39%) and biochemical cure (from 28 to 62%). When only patients with primary tumors >10mm were considered, the decreasing percentage of mediastinal lymph node metastasis and distant metastasis, and rising mean patient age and biochemical cure rates remained statistically significant.

CONCLUSIONS

Significant reductions in the extent of the disease and improved biochemical cure rates pointed toward increasing therapeutic control of sporadic MTC. The independent contribution of routine calcitonin screening to these time-dependent changes warrants more research.

Management of hereditary medullary thyroid carcinoma

Hereditary medullary thyroid carcinoma (MTC) represents up to one-third of MTC cases and includes multiple endocrine neoplasia syndrome type 2A (and its variant familial MTC) and 2B. The aim of this paper is to provide an overview of the disease focusing on the management of hereditary MTC patients, who have already developed tumor, as well as discuss the recommended approach for asymptomatic family members carrying the same mutation. A PubMed search was performed to review recent literature on diagnosis, genetic testing, and surgical and medical management of hereditary MTC. The wide use of genetic testing for RET mutations has markedly influenced the course of hereditary MTC. Prophylactic thyroidectomy of RET carriers at an early age eliminates the risk of developing MTC later in life. Pre-operative staging is a strong prognostic factor in patients, who have developed MTC. The use of recently approved tyrosine kinase inhibitors (vandetanib, cabozantinib) holds promising results for the treatment of unresectable, locally advanced, and progressive metastatic MTC. Genetic testing of the RET gene is a powerful tool in the diagnosis and prognosis of MTC. Ongoing research is expected to add novel treatment options for patients with advanced, progressive disease.

Changing trends in the clinicopathological features and clinical outcomes of medullary thyroid carcinoma

BACKGROUND

The early detection of papillary thyroid cancer has contributed to the increase in the incidence and improved clinical outcomes. However, recent changes of medullary thyroid carcinoma (MTC) over time remain unclear. We evaluated changes of the clinicopathological characteristics and clinical outcomes in patients with MTC in recent years.

METHODS

A total of 109 MTC patients were classified based on the year of initial surgery: 1996-2000 (n = 14), 2001-2006 (n = 39), and 2007-2011 (n = 56).

RESULTS

The primary tumor size significantly decreased and the proportion of microMTCs (size ≤1 cm) increased over time (P = 0.002 and P < 0.001, respectively). The proportion of patients with cervical lymph node (LN) metastasis significantly decreased (P = 0.037), and the ratio of metastatic LNs significantly decreased (P = 0.011). Disease-free survival (DFS) rate of patients was significantly improved over time (P = 0.007). There was no significant difference in DFS between microMTC and macroMTC patients. However, more advanced LN stage patients demonstrated more recurrences (P < 0.001). Especially, there were significantly more recurrences in patients with N1b diseases in comparison with patients without cervical LN metastases (P < 0.001).

CONCLUSIONS

The prognosis of MTC patients has significantly improved in recent years. These changes could be associated with the early diagnosis before development of lateral and extensive cervical LN metastases. J. Surg. Oncol. 2016;113:152-158. © 2015 Wiley Periodicals, Inc.

Integration of a postoperative calcitonin measurement into an anatomical staging system improves initial risk stratification in medullary thyroid cancer

OBJECTIVE

Staging systems applied to medullary thyroid cancer (MTC) rely on initial clinical and pathological features and do not consider the response to treatment. To determine whether MTC staging can be improved by incorporating the first postoperative calcitonin measurement.

PATIENTS AND MEASUREMENTS

Eighty-five patients being monitored for MTC (median follow-up 5 years) were retrospectively classified according to both the American Joint Committee on Cancer (AJCC) and the proposed combined risk stratification system (low, intermediate and high risk), which incorporates the first postoperative calcitonin measurement, using the outcomes no evidence of disease (NED), biochemical evidence of disease, structurally identifiable disease and death.

RESULTS

Ninety per cent of AJCC I patients were classified as NED at final follow-up. When we added a postoperative calcitonin measurement, 95% low-risk patients were classified as NED at final follow-up. AJCC stages I and IV were associated, respectively, with no occurrence and a high rate (63%) of structurally identifiable disease. Stages II and III yielded similar predictions of structurally identifiable disease, 13% and 14%, respectively. When we included the postoperative calcitonin level, the patients with structural evidence of disease included none from the low-risk group, 10% from the intermediate group and 63% from the high-risk group. The proportion of variance explained analysis (PVE) was better for the combined risk stratification system (54%) than for the AJCC system alone (32%).

CONCLUSION

Including the first postoperative calcitonin measurement with the anatomical staging system can better predict the clinical outcome of patients with MTC and refine the follow-up of these patients.

Elevated level of serum carbohydrate antigen 19.9 as predictor of mortality in patients with advanced medullary thyroid cancer

BACKGROUND

Medullary thyroid cancer (MTC) is capable of secreting several proteins, such as calcitonin (Ct), carcinoembryonic antigen (CEA), chromogranin and others. Recently, we observed an aggressive MTC with high levels of serum carbohydrate antigen 19.9 (Ca 19.9) and a rapid evolution to death.

OBJECTIVE

The aim of this study was to evaluate whether high levels of serum Ca 19.9 could be a prognostic factor of death in patients with advanced MTC.

PATIENTS AND METHODS

We measured Ca 19.9, CEA and Ct in 100 advanced structural recurrent/persistent MTC patients and in 100 cured or biochemically affected MTC patients. Clinical and pathological data were also collected.

RESULTS

Sixteen percent of the patients with advanced MTC had high levels of Ca 19.9. The group with abnormal Ca 19.9 levels had significantly higher levels of CEA and Ct compared with the group with normal values of Ca 19.9 (P<0.0001 for both Ct and CEA). At variance, all 100 patients in the MTC control group showed normal levels of Ca 19.9. Moreover, among the advanced cases, the Ca 19.9-positive group showed a higher mortality rate than the group with normal levels. A logistic regression analysis demonstrated that an elevated level of Ca 19.9 is a predictor of mortality (OR=3.78, P=0.04), independent from Ct doubling time.

CONCLUSIONS

These results demonstrated that an elevated value of serum Ca 19.9 appears to be a predictive factor of poor prognosis in advanced MTC patients and identifies those cases with a higher risk of mortality in the short term.