Survival and Long-Term Biochemical Cure in Medullary Thyroid Carcinoma in Denmark 1997-2014: A Nationwide Study

Trends in the Incidence, Organization of Care, and Surgical Treatment of Medullary Thyroid Cancer: A Population-Based Study

Background: Medullary thyroid cancer (MTC) is a rare cancer with variable disease course. To enable optimal care, centralization and consensus guidelines are essential. This study describes trends in the incidence, organization of care, surgical treatment, and outcomes of MTC over 30 years in the Netherlands. Methods: All patients with a histological MTC diagnosis between 1989 and 2018 were identified from the Netherlands Cancer Registry and linked to the Dutch Pathology register (PALGA). Incidence rates, relative to the Dutch population, were assessed throughout time. Clinicopathological parameters and extent of lymph node (LN) surgery were extracted from PALGA pathology reports. Period A (1989-1998), period B (1999-2008), and period C (2009-2018) were compared. Results: Throughout 30 years, the population-adjusted incidence remained stable with 0.17 ± 0.04 diagnoses per 100,000 people per year (p = 0.247). Of all 795 patients, 54% were female and 63% were treated in an academic hospital, at a median age of 48 years (interquartile range [IQR] 34-61). Age at diagnosis increased over time from 42 years (IQR 25-61) in period A to 52 years (IQR 42-63) in period C (p < 0.001). The proportion of treatments occurring in an academic hospital increased from 41% of patients in period A to 58% and 86% in period B and C, respectively (both p < 0.001). At primary treatment, a LN dissection was performed in 582 (73%) patients. Of these patients, 88%, 36%, and 20% underwent a central neck dissection (CND), unilateral neck dissection, and bilateral neck dissection, respectively. CND was performed more frequently in period C (93%) than in period A (77%) or B (87%) (p = 0.009, p = 0.027, respectively). Overall survival improved from period A (55%) to C (88%) and B (65%) to C (p = 0.022, p = 0.007, respectively). Locoregional recurrence rates remained stable. Conclusions: This study shows a stable incidence and improved survival of MTC in the Dutch population over the last three decades. In addition, these data indicate a transition of treatment to academic hospitals, likely due to centralization, and a higher rate of CNDs, following the introduction of recommendation guidelines.

Efficacy and Safety of Selective RET Inhibitors in Patients with Advanced Hereditary Medullary Thyroid Carcinoma

Background: Two selective RET inhibitors (RETis) are effective in treating REarranged during Transfection (RET)-altered medullary thyroid carcinoma (MTC), but clinical trials did not distinguish responses between hereditary MTC (hMTC) and sporadic MTC (sMTC) cases. We reviewed our single-center experience using a RETi to treat advanced hMTC. Methods: We conducted a retrospective cohort study of patients with hMTC treated with a selective RETi at a tertiary cancer center. The primary outcome was overall response rate using Response Evaluation Criteria in Solid Tumors (RECIST) v1.1. Secondary end points included overall survival (OS), progression-free survival (PFS), biochemical response rate, and safety. Results: We identified 23 evaluable patients as follows: 15 (65%) multiple endocrine neoplasia (MEN)2A and 8 (35%) MEN2B. Median age at start of RETi was 51 years (range, 15-79). All patients had distant metastases, and 52% (12/23) had received prior systemic therapy (median = 1, range, 0-3). Patients were treated with selpercatinib (n = 13) or pralsetinib (n = 10), 57% (13/23) within a clinical trial. Median duration of RETi was 25 months (range, 3-72) with 11/23 (48%) patients remaining on drug at data cutoff due to an ongoing response. Median duration of follow-up was 49 months (range, 9-72). Best radiographical response was partial response in 18 (78%) and stable disease in 5 (22%) patients. Median OS was 51 months (confidence interval, 40.5-61.3); median PFS was not reached. Most common adverse events (AEs) were increased alanine aminotransferase (ALT) (48%) and aspartate aminotransferase (26%), dry mouth (39%), QT interval prolongation (39%), fatigue (35%), and hypertension (26%). AEs led to dose reductions in eight (35%) patients. No grade 5 treatment-related AEs occurred. While the germline nature of the RET pathogenic variant in hMTC could hypothetically result in increased drug-related toxicity, the incidence of most AEs, other than grade 1-2 ALT elevation and QT interval prolongation, was comparable to published clinical trials. Conclusions: In patients with advanced hMTC, selective RETis appear safe and effective with outcomes similar to clinical trial cohorts, which mostly comprised patients with sMTC. Duration of response and AE profile was similar to sMTC, although longer follow-up and larger patient numbers are needed to confirm this.

Limited Thyroidectomy Achieves Equivalent Survival to Total Thyroidectomy for Early Localized Medullary Thyroid Cancer

BACKGROUND

The optimal surgical approach for localized T1 medullary thyroid cancer remains unclear. Total thyroidectomy is standard, but lobectomy and subtotal thyroidectomy may minimize mortality while maintaining oncologic control.

METHODS

This retrospective analysis utilized the National Cancer Institute's Surveillance, Epidemiology, and End Results registry to identify 2702 MTC patients including 398 patients with T1N0/1M0 MTC treated with total thyroidectomy or lobectomy/subtotal thyroidectomy from 2000 to 2019. Cox regression analyses assessed thyroid cancer-specific and overall mortality.

RESULTS

The majority (89.7%) underwent total thyroidectomy, while 10.3% had lobectomy/subtotal thyroidectomy. Nodal metastases were present in 29.6%. Over a median follow-up of 8.75 years, no significant difference was observed in cancer-specific mortality (5.7% vs. 8.1%, p = 0.47) or overall mortality (13.2% vs. 12.8%, p = 0.95). On multivariate analysis, undergoing cancer-directed surgery was associated with significantly improved overall survival (HR 0.18, p < 0.001) and cancer-specific survival (HR 0.17, p < 0.001) compared to no surgery. However, no significant survival difference was seen between total thyroidectomy and lobectomy/subtotal thyroidectomy for overall mortality (HR 0.77, p = 0.60) or cancer-specific mortality (HR 0.44, p = 0.23). The extent of surgery also did not impact outcomes within subgroups stratified by age, gender, T stage, or nodal status. Delayed surgery >1 month after diagnosis was associated with worse overall survival (p = 0.012).

CONCLUSIONS

For localized T1 MTC, lobectomy/subtotal thyroidectomy appears to achieve comparable long-term survival to total thyroidectomy in this population-based analysis. The selective use of limited thyroidectomy may be reasonable for low-risk T1N0/1M0 MTC patients. Delayed surgery is associated with worse survival and additional neck dissection showed no benefit for this select group of patients.

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.

The Value of Pretherapeutic Basal Calcitonin Cut-Offs for the Therapeutic Strategy and Prediction of Long-Term Outcome of Patients with Medullary Thyroid Cancer-A 30-Year Single-Center Experience

BACKGROUND

The clinical relevance of clearly defined pretherapeutic basal calcitonin (bCt) cut-offs for predicting lymph node metastases (LNMs) and long-term outcomes (LOs) has so far not been tested in a large cohort of patients with medullary thyroid cancer included in a Ct screening program during the initial diagnostic workup of thyroid nodules.

MATERIAL AND METHODS

Female (f) patients with a bCt level of ≤23 pg/mL and male (m) patients with a level of ≤43 pg/mL were assigned to Group 1 (minimal oncologic risk), patients with a bCt between 24 and 84 pg/mL (f) and 44-99 pg/mL (m) to Group 2 (low oncologic risk), and those with a bCt of ≥85 pg/mL (f) and ≥100 pg/mL (m) to Group 3 (high oncologic risk). All patients underwent surgery applying a uniform surgical protocol. The median follow-up was 100 months.

RESULTS

The study included 306 patients. In 3/115 (2.6%) patients in Group 1 and in 3/50 (6.0%) in Group 2, LNM in the central but not lateral neck and no distant metastases (DMet) were documented. In both groups, the biochemical long-term cure rate was 95.7% and the disease-specific-survival (DSS) rate was 100% at 10, 15 and 20 years. Lateral LNM and DMet were diagnosed only in Group 3. The bCt levels of N0 and N1 patients showed broadly overlapping ranges, thus impeding the differentiation between those patients through bCt. Both the cure rate and DSS were significantly worse in Group 3. The overall biochemical long-term cure rate was 78.2%.

CONCLUSIONS

Within a Ct screening program, grouping patients upon pretherapeutic bCt provides a simple risk classification system for indicating surgery, predicting LN involvement, and LOs.

C634Y mutation in RET-induced multiple endocrine neoplasia type 2A: A case report

BACKGROUND

Multiple endocrine neoplasia type 2 (MEN2) is a rare, autosomal dominant endocrine disease. Currently, the RET proto-oncogene is the only gene implicated in MEN2A pathogenesis. Once an RET carrier is detected, family members should be screened to enable early detection of medullary thyroid carcinoma, pheochromocytoma, and hyperparatitity. Among these, medullary thyroid carcinoma is the main factor responsible for patient mortality. Accordingly, delineating strategies to inform clinical follow-up and treatment plans based on genes is paramount for clinical practitioners.

CASE SUMMARY

Herein, we present RET proto-oncogene mutations, clinical characteristics, and treatment strategies in a family with MEN2A. A family study was conducted on patients diagnosed with MEN2A. DNA was extracted from the peripheral blood of family members, and first-generation exon sequencing of the RET proto-oncogene was conducted. The C634Y mutation was identified in three family members spanning three generations. Two patients were sequentially diagnosed with pheochromocytomas and bilateral medullary thyroid carcinomas. A 9-year-old child harboring the gene mutation was diagnosed with medullary thyroid carcinoma. Surgical resection of the tumors was performed. All family members were advised to undergo complete genetic testing related to the C634Y mutation, and the corresponding treatments administered based on test results and associated clinical guidelines.

CONCLUSION

Advancements in MEN2A research are important for familial management, assessment of medullary thyroid cancer invasive risk, and deciding surgical timing.

Spontaneous and Treatment-Related Changes of Serum Calcitonin in Medullary Thyroid Cancer: Long-Term Experience in a Patient With Multiple Endocrine Neoplasia Type 2B

PURPOSE

Medullary thyroid carcinoma (MTC) in MEN2B syndrome is associated with germline RET mutation. Patients harboring de novo mutations are usually diagnosed at more advanced disease stages. We present a young woman with Met918Th mutation diagnosed with stage IV MTC at age 10 years.

METHODS

The disease progressed despite total thyroidectomy and multiple surgical interventions for cervical lymph node recurrences, leading to distant metastases in the fifth year after the initial diagnosis. Subsequently, she underwent five different types of tyrosine kinase inhibitor (TKI) treatments. The 17-year disease course was divided into periods defined by four surgical interventions and sequential treatment intervals with four multikinase (sunitinib, vandetanib, cabozantinib, and lenvatinib) and one RET-selective TKI (selpercatinib). Tumor growth for different phases of spontaneous development and drug treatment intervals was characterized by changes in serial log-transformed calcitonin measurements (n = 114).

RESULTS

Three operations (one for calcitonin-producing adrenal pheochromocytoma) were associated with drops in calcitonin levels. All of the nonselective TKIs were stopped due to adverse effects. As reflected by the negative calcitonin doubling rate, the best treatment response was observed with selpercatinib, which was associated with an initial large drop followed by a decreasing calcitonin trajectory over 514 days without any major side effects.

CONCLUSION

This case of MEN2B medullary thyroid cancer with long-term survival presents how the effectiveness of different treatment modalities can be estimated using log-transformed calcitonin levels. Furthermore, our experience supports the view that serial calcitonin measurements may be more sensitive than radiological follow-up in advanced MTC. Our patient also represents a new case of rarely reported calcitonin-producing pheochromocytomas.

Risk factors for cervical lymph node metastasis in the central or lateral cervical region in medullary thyroid carcinoma: a systematic review and meta-analysis

PURPOSE

Compared with other types of thyroid carcinoma, patients with medullary thyroid carcinoma (MTC) are more likely to develop cervical lymph node metastasis. This study was conducted to clarify the risk factors for cervical lymph node metastasis (central lymph node metastasis or lateral cervical lymph node metastasis) in MTC by meta-analysis, and to provide evidence-based basis for the treatment and prognosis of MTC.

METHODS

The literatures related to cervical lymph node metastasis in medullary thyroid carcinoma were searched in PubMed, Embase, Web of Science, Cochrane, CNKI and Wanfang databases, and statistical analysis was performed using Revman 5.3 and Stata 14.0 software.

RESULTS

A total of 28 papers were included in this paper, and meta-analysis showed that the occurrence of central lymph node metastasis (CLNM) in MTC patients was significantly associated with tumor size (OR = 3.07, 95%CI: 2.04-4.63, P < 0.00001), multifocality (OR = 0.29, 95%CI: 0.19-0.44, P < 0.00001), bilaterality (OR = 3.75, 95% CI: 1.95-7.14, P < 0.0001), capsular invasion (OR = 9.88, 95% CI: 5.93-16.45, P < 0.00001) and extrathyroidal extension (OR = 5.48, 95% CI: 2.61-11.51, P < 0.00001). While the occurrence of lateral cervical lymph node metastasis (LLNM) in MTC patients was strongly correlated with gender (OR = 2.97, 95%CI: 2.46-3.58, P < 0.00001), tumor size (OR = 3.88, 95%CI: 1.90-7.92, P = 0.0002 < 0.05), multifocality (OR = 0.43, 95%CI: 0.35-0.51, P < 0.00001), bilaterality (OR = 2.93, 95% CI: 1.72-4.98, P < 0.0001), capsular invasion (OR = 8.44, 95% CI: 6.11-11.64, P < 0.00001), extrathyroidal extension (OR = 7.04, 95% CI: 5.54-8.94, P < 0.00001), margin of the tumor (OR = 4.47, 95% CI: 2.37-8.44, P < 0.00001), shape of the tumor (OR = 6.81, 95% CI: 3.64-12.73, P < 0.00001), preoperative calcitonin level (SMD = 1.39, 95% CI: 0.98-1.80, P < 0.00001), preoperative carcinoembryonic antigen level (SMD = 0.97, 95% CI: 0.74-1.20, P < 0.00001) and CLNM (OR = 19.70, 95% CI: 14.16-27.43, P < 0.00001).

CONCLUSION

Tumor size, multifocality, bilaterality, capsular invasion and extrathyroidal extension are the main risk factors for developing CLNM in MTC patients; And risk factors for developing LLNM in MTC patients include: gender, tumor size, multifocality, bilaterality, capsular invasion, extrathyroidal extension, margin of the tumor, shape of the tumor, preoperative calcitonin level, preoperative carcinoembryonic antigen level and central lymph node metastasis. These risk factors can guide the individualized treatment plan and improve the prognosis of MTC patients.

Clinicopathological and prognostic significance of PD-L1 and TIM-3 expression in medullary thyroid carcinoma: a retrospective immunohistochemistry study

PURPOSE

Expression of the programmed death-ligand 1 (PD-L1) and T-cell immunoglobulin and mucin-domain containing-3 (TIM-3) in medullary thyroid carcinoma (MTC) has been controversial and rarely reported.

METHODS

Surgical specimens of 190 MTC patients who had initial curative-intent surgery were collected. Immunohistochemistry of PD-L1 and TIM-3 was performed using 22C3 pharmDx (Dako, Carpinteria, CA) and anti-TIM-3 (1:500, ab241332, Abcam). Stained slides were scored using a combined positive score (CPS) with a cutoff of ≥ 1. We established correlations between PD-L1 expression, TIM-3 expression, clinicopathological, and survival data.

RESULTS

13 cases (13/190, 6.84%) were positive for PD-L1 expression, and 42 cases (42/154, 27.27%) for TIM-3 expression. PD-L1 expression was correlated to TIM-3 expression (P = 0.002), but was not related to overall survival (OS) or progression-free survival (PFS). TIM-3 expression was correlated to perineural invasion (P = 0.040). Multivariate Cox analysis showed that lymphovascular invasion (LVI) was independently associated with OS. And tumor size, LVI, and lymph node metastases were significantly associated with PFS. Furthermore, the multivariate logistic analysis showed multifocal status, LVI, pathological T stage and lymph node metastasis were independent risk factors for biochemical recurrence/persistent disease.

CONCLUSIONS

We demonstrated that PD-L1 and TIM-3 expression were not frequent in MTC and were not associated with survival prognosis. Our results should be considered when clinical trials of PD-L1 or TIM-3 blockades are implemented.

Male gender as a poor prognostic factor in medullary thyroid carcinoma: behavior or biological difference?

BACKGROUND

Due to the low incidence and heterogeneous behavior of medullary thyroid carcinoma (MTC), its prognostic factors are still not well stablished. While several large studies have investigated the impact of gender in differentiated thyroid cancer (DTC), its role in MTC outcomes remains controversial. We aim to identify MTC prognostic features, specially focusing on the role of gender.

METHODS

The present study is a retrospective analysis of 76 patients diagnosed with MTC between 1984 and 2018 at a Portuguese Comprehensive Cancer Center.

RESULTS

Patients presented a median age at diagnosis of 49 years and multiple endocrine neoplasia type 2 (MEN2) was identified in 27.6% of them, with those individuals being significantly younger (P<0.001). Most cases were diagnosed as stage IV disease (46.9%), except for the subgroup detected through presymptomatic genetic screening (55.6% at stage I). The 5- and 10-year survival rates were 87.6% and 75.6%, respectively. Univariate analysis identified male gender (P=0.010), age ≥45 years (P=0.007), presence of distant metastasis at diagnosis (P<0.01), capsule invasion (P=0.004), extrathyroidal invasion (P=0.003) and absence of biochemical cure after surgery (P=0.042) as having a negative impact on prognosis. On multivariate analysis, male gender (P=0.046) remained an independent predictor of mortality, as well as an older age (P<0.001) and the presence of distant metastases (P=0.012).

CONCLUSIONS

Male gender independently predicted worse survival in MTC patients even after adjusting for age and disease stage. The few older studies on the topic pointed to a behavioral explanation regarding medical care seeking patterns by men, but our study and newer genetic and basic-science oriented publications raise the possibility of a true biological difference between genders in the tumorigenesis of MTC that should me further investigated.

Clinicopathological features and prognostic factors analysis of multiple synchronous distinct subtypes of primary thyroid carcinoma

PURPOSE

To investigate the clinicopathological features, diagnosis, treatment, and prognosis of multiple synchronous distinct subtypes of primary thyroid carcinomas.

METHODS

The clinical data of 68 cases of synchronous carcinomas of the thyroid (STC) admitted to the Department of Thyroid Surgery in our hospital from January 2013 to December 2021 were reviewed. According to the pathological type, they were divided into the Synchronous differentiated and differentiated thyroid Carcinoma (SDDTC) group (42 cases), the Synchronous medullary and differentiated thyroid Carcinoma (SMDTC) group (18 cases), and the Synchronous Anaplastic and differentiated thyroid Carcinoma (SADTC)group (8 cases). The diagnosis, treatment, and survival of patients in each group were analyzed.

RESULTS

Women with coexisting thyroid cancer were predominant (59 cases). Most of the symptoms were found on physical examination (47.1%) and neck mass (45.6%). The median age of patients in the SDDTC group, SADTC group, and SMDTC group was 47.5 (28-74) years old, 68.5 (26-75) years old, and 56.5 (39-74) years old. The age of the SADTC group and SMDTC group was older than that of the SDDTC group (P = 0.04, P = 0.03), and the rate of lymph node metastasis in groups SADTC (62.5%) and SMDTC (55.6%) was higher than in group SDDTC (21.4%). The disease course time, tumor location, clinical stage, and mortality of the SADTC group were significantly different from those of the SDDTC group and SMDTC group (P < 0.05). The overall survival of patients with synchronous carcinomas of the thyroid was 6-105 months, and the median overall survival was 38.5 months. The tumor-free survival was 0-90 months, 19.1% of patients developed distant metastasis, 11.8% of patients had postoperative recurrence, as well as the survival rate was estimated 91.18%. Cox model multivariate analysis showed that cervical lateral lymph node metastasis and tumor stage III/IV were independent risk factors for progression-free survival(PFS). The comparison results of the survival curves showed that the overall survival (OS)of the patients in the SADTC group was significantly worse (P < 0.01), while there was no significant difference in the PFS of different pathological types (χ2 = 5.024, P = 0.081).The OS of different treatment methods was significantly different (P = 0.002), but there was no significant difference in OS between local recurrence and distant metastases with or without surgery (χ2 = 0.954, P = 0.329).

CONCLUSIONS

The STC has relatively unique clinical characteristics, and most patients can get a better prognosis after radical surgery. Pathological type, lateral cervical lymph node metastasis, tumor stage, and treatment are important factors which affect the prognosis of the disease. Since there are two distinct tumors with different aggressiveness, treatment options, and prognosis, individualized management is required.

Diagnostic, Prognostic, and Predictive Role of Ki67 Proliferative Index in Neuroendocrine and Endocrine Neoplasms: Past, Present, and Future

The introduction of Ki67 immunohistochemistry in the work-up of neuroendocrine neoplasms (NENs) has opened a new approach for their diagnosis and prognostic evaluation. Since the first demonstration of the prognostic role of Ki67 proliferative index in pancreatic NENs in 1996, several studies have been performed to explore its prognostic, diagnostic, and predictive role in other neuroendocrine and endocrine neoplasms. A large amount of information is now available and published results globally indicate that Ki67 proliferative index is useful to this scope, although some differences exist in relation to tumor site and type. In gut and pancreatic NENs, the Ki67 proliferative index has a well-documented and accepted diagnostic and prognostic role and its evaluation is mandatory in their diagnostic work-up. In the lung, the Ki67 index is recommended for the diagnosis of NENs on biopsy specimens, but its diagnostic role in surgical specimens still remains to be officially accepted, although its prognostic role is now well documented. In other organs, such as the pituitary, parathyroid, thyroid (follicular cell-derived neoplasms), and adrenal medulla, the Ki67 index does not play a diagnostic role and its prognostic value still remains a controversial issue. In medullary thyroid carcinoma, the Ki67 labelling index is used to define the tumor grade together with other morphological parameters, while in the adrenal cortical carcinoma, it is useful to select patients to treated with mitotane therapy. In the present review, the most important information on the diagnostic, prognostic, and predictive role of Ki67 proliferative index is presented discussing the current knowledge. In addition, technical issues related to the evaluation of Ki67 proliferative index and the future perspectives of the application of Ki67 immunostaining in endocrine and neuroendocrine neoplasms is discussed.

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.

A Case Study of Multiple Endocrine Neoplasia Type 2A

Multiple endocrine neoplasia type 2 is an autosomal dominant neoplastic syndrome with subtypes multiple endocrine neoplasia type 2A, multiple endocrine neoplasia type 2B, and familial medullary thyroid carcinoma. Medullary thyroid carcinoma universally coincides with multiple endocrine neoplasia type 2. Multiple endocrine neoplasia type 2A is a rare disease and the affected patients are generally asymptomatic. The morbidity and mortality are mainly due to medullary thyroid carcinoma and often proper clinical workup is warranted for expedited surgical intervention. Total thyroidectomy along with neck dissection may be required for disease control. This report will cover a patient who presented with medullary thyroid carcinoma and was worked up to have multiple endocrine neoplasia type 2A. She underwent total thyroidectomy with central neck dissection.

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.

Multiple endocrine neoplasia 2: an overview

This review article discusses the diagnosis and treatment of patients with multiple endocrine neoplasia type 2 (MEN2). The most common tumors associated with MEN2 are those of the parathyroid, thyroid, and adrenal glands. Additional manifestations include characteristic clinical phenotypes or features as described in the article. This review provides an overview of clinical manifestations, screening, diagnosis, treatment, and surveillance of patients with MEN2.

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.

[Medullary thyroid carcinoma: current clinical progress]

Medullary thyroid cancer (MTC) is infrequently found among all thyroid nodules in previously iodine deficient regions. Measurement of serum calcitonin is an important tool for early identification of MTC among the large number of thyroid nodules. With the use of modern laboratory assays and sex-specific reference intervals, clinical diagnostic specificity has considerably improved. While the prognosis of MTC confined to the thyroid (stage I/II tumors) is favorable with a disease specific survival similar to the general population, biochemical cure rates by surgery decreases in extensive disease. Few patients present with aggressive tumours that show rapid progression or advanced disease at diagnosis. Oncogenic mutations in the RET protooncogene occur in ~25 % of patients as part of the multiple endocrine neoplasia type 2 syndromes and are present as somatic mutations in 60 % of all MTC and up to 90 % of metastatic cases.The multi-tyrosine kinase inhibitors vandetanib and cabozantinib have been approved for progressive advanced disease but have low specificity for the RET tyrosine kinase. With the advent of highly selective RET inhibitors selpercatinib and pralsetinib, the treatment landscape has profoundly changed. Selpercatinib is approved in the EU for treatment in the second and later lines of treatment. They have demonstrated a favorable safety profile and high objective response rates also in previously treated MTC patients. The use of selective RET inhibitors in the first line setting is currently the subject of clinical trials.

Update on Preclinical Development and Clinical Translation of Cholecystokinin-2 Receptor Targeting Radiopharmaceuticals

The cholecystokinin-2 receptor (CCK2R) has been a target of interest for molecular imaging and targeted radionuclide therapy for two decades. However, so far CCK2R targeted imaging and therapy has not been introduced in clinical practice. Within this review the recent radiopharmaceutical development of CCK2R targeting compounds and the ongoing clinical trials are presented. Currently, new gastrin derivatives as well as nonpeptidic substances are being developed to improve the properties for clinical use. A team of specialists from the field of radiopharmacy and nuclear medicine reviewed the available literature and summarized their own experiences in the development and clinical testing of CCK2R targeting radiopharmaceuticals. The recent clinical trials with novel radiolabeled minigastrin analogs demonstrate the potential for both applications, imaging as well as targeted radiotherapy, and reinforce the clinical applicability within a theranostic concept. The intense efforts in optimizing CCK2R targeting radiopharmaceuticals has led to new substances for clinical use, as shown in first imaging studies in patients with advanced medullary thyroid cancer. The first clinical results suggest that the wider clinical implication of CCK2R-targeted radiopharmaceuticals is reasonable.

Active Surveillance in RET Gene Carriers Belonging to Families with Multiple Endocrine Neoplasia

Simple Summary

MEN2 has a very high penetrance for the development of medullary thyroid cancer. However, intra- and inter-familial variabilities have been described. Accordingly, in this precision medicine era, a personalized approach should be adopted in subjects harboring RET mutations. In these subjects, we showed that thyroid surgery could be safely timed according to basal and stimulated calcitonin, especially in children who can reach adulthood, avoiding the risks of thyroid surgery and decreasing the period of a long-life hypothyroidism treatment.

Abstract

Multiple Endocrine Neoplasia 2 (MEN2) is a hereditary cancer syndrome for developing medullary thyroid cancer (MTC) due to germline mutations of RET gene. Subjects harboring a germline RET mutation without any clinical signs of MTC are defined as gene carriers (GCs), for whom guidelines propose a prophylactic thyroid surgery. We evaluate if active surveillance of GCs, pursuing early thyroid surgery, can be safely proposed and if it allows safely delaying thyroid surgery in children until adolescence/adulthood. We prospectively followed 189 GCs with moderate or high risk germline RET mutation. Surgery was planned in case of: elevated basal calcitonin (bCT) and/or stimulated CT (sCT); surgery preference of subjects (or parents, if subject less than 18 years old); other reasons for thyroid surgery. Accordingly, at RET screening, we sub-grouped GCs in subjects who promptly were submitted to thyroid surgery (Group A, n = 67) and who were not (Group B, n = 122). Group B was further sub-grouped in subjects who were submitted to surgery during their active surveillance (Group B1, n = 22) and who are still in follow-up (Group B2, n = 100). Group A subjects presented significantly more advanced age, bCT and sCT compared to Group B. Mutation RET^V804M was the most common variant in both groups but it was significantly less frequent in Group A than B. Analyzing age, bCT, sCT and genetic landscape, Group B1 subjects differed from Group B2 only for sCT at last evaluation. Group A subjects presented more frequently MTC foci than Group B1. Moreover, Group A MTCs presented more aggressive features (size, T and N) than Group B1. Accordingly, at the end of follow-up, all Group B1 subjects presented clinical remission, while 6 and 12 Group A MTC patients had structural and biochemical persistent disease, respectively. Thank to active surveillance, only 13/63 subjects younger than 18 years at RET screening have been operated on during childhood and/or adolescence. In Group B1, three patients, while actively surveilled, had the possibility to reach the age of 18 (or older) and two patients the age of 15, before being submitted to thyroid surgery. In Group B2, 12 patients become older than 18 years and 17 older than 15 years. In conclusion, we demonstrated that an active surveillance pursuing an early thyroid surgery could be safely recommended in GCs. This patient-centered approach permits postponing thyroid surgery in children until their adolescence/adulthood. At the same time, we confirmed that genetic screening allows finding hidden MTC cases that otherwise would be diagnosed much later.

Outcomes of Advanced Medullary Thyroid Carcinoma in the Era of Targeted Therapy

BACKGROUND

Medullary thyroid carcinoma (MTC) can be targeted with tyrosine kinase inhibitors (TKIs). We aimed to report the outcomes of surgically managed MTC and to evaluate the impact of TKI use on patient survival.

METHODS

Consecutive patients treated surgically for MTC from 1986 to 2020 were identified from a prospectively collected database and were compared on the basis of stage at operation and TKI use. The primary outcome was overall survival (OS).

RESULTS

Among 154 patients with a median age of 52 years, 40% presented with stage I/II disease and 60% presented with advanced (stage III or IV) disease. During a median follow-up of 7.5 years, 21% received TKIs for systemic disease. Those presenting with advanced disease were more likely to receive a TKI (31% vs. 7%), present with tumor invasion of the recurrent laryngeal nerve (RLN; 12% vs. 0%) and undergo reoperation (42% vs. 23%) compared with stage I-II patients. For the 11 patients found to have invasion of the RLN, five had preoperative functional vocal cords. Five-year OS was 84% for advanced disease, and stage IV patients who received TKIs had a median survival of 21 years, versus 15 years for those who did not (p = 0.3).

CONCLUSIONS

Surgery achieves long-term survival for patients with advanced disease, however these patients are at greater risk of requiring RLN resection due to invasion. A significant OS benefit was not seen for TKI use. For patients with local invasion, neoadjuvant TKI therapy may have a role in reducing local morbidity if confirmed to be of benefit in clinical trials.

Similar Stage-dependent Survival and Outcome in Sporadic and Hereditary Medullary Thyroid Carcinoma

CONTEXT

Long-term data are scarce on large cohorts with sporadic (sMTC) and hereditary medullary thyroid carcinoma (hMTC).

OBJECTIVES

To compare long-term disease-specific survival (DSS) and outcomes between sMTC and hMTC groups.

DESIGN

Retrospective analysis.

SETTING

German tertiary referral center.

PATIENTS

A total of 673 patients with MTC that underwent surgery from January 1974 to July 2019.

INTERVENTION

None (observational study).

MAIN OUTCOME MEASURE

Differences between sMTC and hMTC in long-term, stage-dependent survival and outcomes.

RESULTS

Surgery was performed at median ages of 49 years for sMTC (n = 477, 44% male) and 29 years for hMTC (n = 196, 43% male; P < 0.0001). The mean follow-up times were 9.2 ± 8.0 (sMTC) and 14.6 ± 10.3 years (hMTC). Age and tumor stage at diagnosis were significantly different between the 2 groups (P < 0.0001). The sMTC and hMTC groups had different overall DSS (log rank, P = 0.0183), but similar stage-dependent DSS (log rank, P = 0.1242-0.8981). In a multivariate analysis, sMTC and hMTC did not differ in DSS (hazard ratio [HR] = 1.56; 95% CI, 0.94-2.57), but in both groups, a worse DSS was significantly associated with age at diagnosis (HR = 1.04; 95% CI, 1.02-1.05), male sex (HR = 0.49; 95% CI, 0.32-0.76), and stages III and IV at diagnosis (HR = 20.00; 95% CI, 2.74-145.91 and HR = 97.47; 95% CI, 13.07-726.67, respectively). The groups had significantly different (P < 0.0001) outcomes (i.e., cured, minimal residual disease, structural detectable disease, and death), but similar stage-dependent outcomes (P = 0.9449-0.0511), except for stage III (P = 0.0489).

CONCLUSION

Patients with sMTC and hMTC had different ages of onset, but similar stage-dependent DSS and outcomes after the MTC diagnosis. This finding suggested that tumor behavior was similar in sMTC and hMTC.

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.

Omission of lateral lymph node dissection in medullary thyroid cancer without a desmoplastic stromal reaction

BACKGROUND

Medullary thyroid cancer can be subdivided during surgery into tumours with or without a desmoplastic stromal reaction (DSR). DSR positivity is regarded as a sign of disposition to metastasize. The aim of this study was to analyse whether lateral lymph node dissection can be omitted in patients with DSR-negative tumours.

METHODS

This was a retrospective cohort study of a prospectively maintained database of patients with medullary thyroid cancer treated using a standardized protocol, and subdivided into DSR-negative and -positive groups based on the results of intraoperative frozen-section analysis. Patients in the DSR-negative group did not undergo lateral lymph node dissection. Long-term clinical and biochemical follow-up data were collected, and baseline parameters and histopathological characteristics were compared between groups.

RESULTS

The study included 360 patients. In the DSR-negative group (17.8 per cent of all tumours) no patient had lateral lymph node or distant metastases at diagnosis or during follow-up, and all patients were biochemically cured. In the DSR-positive group (82.2 per cent of all tumours), lymph node and distant metastases were present in 31.4 and 6.4 per cent of patients respectively. DSR-negative tumours were more often stage pT1a and were significantly smaller. The median levels of basal calcitonin and carcinoembryonic antigen were significantly lower in the DSR-negative group, although when adjusted for T category both showed widely overlapping ranges.

CONCLUSION

Lymph node surgery may be individualized in medullary thyroid cancer based on intraoperative analysis of the DSR. Patients with DSR-negative tumours do not require lateral lymph node dissection.

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.

Predicting Outcomes in Sporadic and Hereditary Medullary Thyroid Carcinoma over Two Decades

Background: Medullary thyroid cancer (MTC) can be associated with significant morbidity and mortality in advanced cases. Hence, we aimed to identify factors at the time of MTC surgery that predict overall survival (OS), disease-specific survival (DSS), locoregional recurrence/persistence (LR), and distant metastases (DM). Methods: We performed a retrospective study of clinicopathologic, radiological, and laboratory data in MTC patients who underwent thyroidectomy at Mayo Clinic from January 1995 to December 2015. Results: We identified 163 patients (mean age 48.4 years, 48% males), 102 with sporadic MTC and 61 with hereditary disease (n = 46 multiple endocrine neoplasia [MEN] 2A, n = 3 MEN 2B, n = 12 familial MTC) with a median follow-up time of 5.5 years. On univariate analysis, age >55 years, male sex, DM at the time of surgery (M1), lateral neck lymph node (LN) involvement (N1b), gross extrathyroidal extension (ETE), American Joint Committee on Cancer (AJCC) stage 3/4, tumor size (T) 3/4, tumor size, and postoperative calcitonin (Ctn) and carcinoembryonic antigen (CEA) were significant predictors of worse OS and DSS. On multivariable analysis, both gross ETE (hazard ratio [HR] 4.62, 6.58) and M1 (HR 5.11, 10.45) remained significant predictors of worse OS as well as DSS, while age >55 years (HR 3.21), male sex (HR 2.42), and postoperative Ctn (HR 1.002 for every 100 pg/mL increase) were significant only for worse OS. On univariate analysis, male sex, M1, N1b, gross ETE, stage 3/4, T 3/4, tumor size, number of LNs involved, and postoperative Ctn were significant predictors of LR and DM; age >55 years was additionally significant for DM. On multivariable analysis, gross ETE (HR 3.16, 5.93) and N1b (HR 4.31, 4.64) remained significant predictors of LR and DM; ratio of resected/involved LN (HR 10.91) was additionally predictive for LR and postoperative Ctn (HR 1.003 for every 100 pg/mL increase) for DM. Conclusions: Disease burden at initial surgery, especially gross ETE, lateral neck LN involvement, and DM, as well as the biochemical response to surgery appear to be more important than demographic factors in terms of MTC prognosis. These findings highlight the importance of rigorous perioperative assessment to better predict MTC outcomes.

Hereditary medullary thyroid carcinoma syndromes: experience from western India

The data from the Indian subcontinent on Medullary thyroid carcinoma (MTC) and associated endocrinopathies in hereditary MTC (HMTC) syndromes are limited. Hence, we analyzed clinical and biochemical characteristics, management, and outcomes of HMTC and other associated endocrinopathies [Pheochromocytoma (PCC) and Primary hyperparathyroidism (PHPT)] and compared with apparently sporadic MTC. The records of 97 (51 sporadic and 46 hereditary) consecutive MTC patients were retrospectively analyzed. RET mutation was available in 38 HMTC patients. HMTC group was subclassified into Multiple endocrine neoplasia (MEN) 2A index (n = 25), MEN2B index (n = 8), and MEN2A detected by familial screening (n = 12). Patients with HMTC and MEN2B index were younger at presentation than sporadic MTC. MEN2A patients detected by familial screening, but not MEN2A index and MEN2B index patients, had significantly lower serum calcitonin, smaller thyroid nodule size, more frequent early stage presentation (AJCC Stage ≤ II), and higher cure rate than sporadic MTC, which emphasizes the need for early diagnosis. RET (REarranged during Transfection) 634 mutations were the most common cause of HMTC and more frequently associated with PCC (overall 54% and 100% in those aged ≥ 35 years). Patients in ATA-Highest (HST) group had a universal presentation in stage IV with no cure. In contrast, the cure rate and postoperative disease progression (calcitonin doubling time) were similar between ATA-High (H) and ATA- Moderate (MOD) groups, suggesting the need for similar follow-up strategies for the latter two groups. Increased awareness of endocrine (PCC/PHPT) and non endocrine components may facilitate early diagnosis and management.

Unexpected Pathogenic RET p.V804M Variant Leads to the Clinical Diagnosis and Management of Medullary Thyroid Carcinoma

Patient: Female, 62-year-old

Final Diagnosis: Medullary thyroid microcarcinoma

Symptoms: No pain or swelling in her neck • no dysphagia or odynophagia • no changes in voice

Medication: —

Clinical Procedure: Genetic analysis

Specialty: Genetics

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.

High Ratio of Early Postoperative Calcitonin to Preoperative Calcitonin Could be a Novel Indicator of Poor Prognosis in Patients with Biochemical Incomplete Responses in Sporadic Medullary Thyroid Cancer

OBJECTIVE

In a cohort of medullary thyroid cancer (MTC) patients with biochemical incomplete responses, 37 to 48% developed structural persistent disease; however, few indictors were available to distinguish those patients who were more likely to develop structural disease. We hypothesized that the relationship between preoperative calcitonin (Ctn) and postoperative Ctn (within 3 days after surgery) could be used to predict early prognosis of these patients.

METHODS

A total of 92 sporadic MTC patients were enrolled in this study. Our team proposed a novel indicator of structural persistent MTC called the calcitonin ratio (CR; CR = postoperative Ctn/preoperative Ctn). Cox regression models and the Kaplan-Meier method were used to evaluate the prognostic capability of CR. The area under the time-dependent receiver-operating characteristic curves (AUC) and the Harrell concordance index (C-index) were used for analysis.

RESULTS

The cutoff CR value used to determine MTC prognosis was 0.15. Multivariate Cox analysis revealed that CR (hazard ratio [HR]: 22.974, 95% confidence interval [CI]: 3.259 to 161.959, P = .002), tumor-node-metastasis (HR: 3.968, 95% CI: 1.360 to 21.857; P = .031), and multifocality (HR: 8.466, 95% CI: 1.286 to 55.716; P = .026) independently correlated with MTC prognosis. Kaplan-Meier survival curves demonstrated a lower proportion with structural persistent disease in patients with CR <0.15 (P<.001). The 3, 5, and 10-year AUC values were 0.798, 0.752, and 0.743, respectively. The C-index of CR was 0.788 (95% CI: 0.763 to 0.813).

CONCLUSION

In this study, CR was identified as a sensitive and specific risk stratification marker for patients with biochemical incomplete responses in sporadic MTC.

ABBREVIATIONS

ATA = American Thyroid Association; AUC = area under curve; CEA = carcinoembryonic antigen; CR = calcitonin ratio; Ctn = calcitonin; HR = hazard ratio; MTC = medullary thyroid cancer; ROC = receiver operating characteristic; TNM = tumor-node-metastasis.

Primary hyperparathyroidism as first manifestation in multiple endocrine neoplasia type 2A: an international multicenter study

OBJECTIVE

Multiple endocrine neoplasia type 2A (MEN 2A) is a rare syndrome caused by RET germline mutations and has been associated with primary hyperparathyroidism (PHPT) in up to 30% of cases. Recommendations on RET screening in patients with apparently sporadic PHPT are unclear. We aimed to estimate the prevalence of cases presenting with PHPT as first manifestation among MEN 2A index cases and to characterize the former cases.

DESIGN AND METHODS

An international retrospective multicenter study of 1085 MEN 2A index cases. Experts from MEN 2 centers all over the world were invited to participate. A total of 19 centers in 17 different countries provided registry data of index cases followed from 1974 to 2017.

RESULTS

Ten cases presented with PHPT as their first manifestation of MEN 2A, yielding a prevalence of 0.9% (95% CI: 0.4-1.6). 9/10 cases were diagnosed with medullary thyroid carcinoma (MTC) in relation to parathyroid surgery and 1/10 was diagnosed 15 years after parathyroid surgery. 7/9 cases with full TNM data were node-positive at MTC diagnosis.

CONCLUSIONS

Our data suggest that the prevalence of MEN 2A index cases that present with PHPT as their first manifestation is very low. The majority of index cases presenting with PHPT as first manifestation have synchronous MTC and are often node-positive. Thus, our observations suggest that not performing RET mutation analysis in patients with apparently sporadic PHPT would result in an extremely low false-negative rate, if no other MEN 2A component, specifically MTC, are found during work-up or resection of PHPT.

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.

Gastropharyngeal Anastomotic Leak in Medullary Thyroid Carcinoma Following Initiation of a Tyrosine Kinase Inhibitor: A Case Report of an Unusual Side Effect of Cabozantinib

Background:

Medullary thyroid carcinoma (MTC) accounts for 1% to 2% of thyroid cancers in the United States. When identified early, total thyroidectomy is most often curative. However, in advanced disease, more aggressive treatment such as laryngectomy and esophagectomy may be indicated. Postsurgical fistula formation and leak is a potential complication in such cases. These fistulas are most likely to occur at the anastomotic site in cases of laryngectomy or esophagectomy. Concomitant chemotherapy and radiation increase this risk. Tyrosine kinase inhibitors (TKI) such as Cabozantinib are used as therapy for metastatic MTC. These drugs have previously been associated with dehiscence of anastomotic sites in the gastrointestinal tract. While previously identified in the bowel, this report represents the first documented case of gastropharyngeal anastomosis leak described in the context of TKI use for head and neck cancer.

Case Presentation:

We present the case of a 72-year-old male previously diagnosed with MTC. His gastropharyngeal anastomosis status-post laryngopharyngectomy and gastric pull up had been stable for 23 years. Over the past year, he developed back pain and was found to have spinal metastases of MTC. He was subsequently started on Cabozantinib to slow the progression of the disease. Within months of starting this TKI, a bleeding pharyngocutaneous fistula developed at the anastomosis site of the gastric pull up and pharynx. Upon discontinuation of Cabozantinib, the fistula healed with no further complications.

Conclusions:

To our knowledge, this is the first documented case of gastropharyngeal anastomotic leak related to TKI use. A causal relationship is highly plausible given the previously stable anastomosis and the suspicious advent of complications within months of initiation of this new drug. While previously limited to cases of intraabdominal bowel dehiscence, this report now suggests that wound dehiscence must be considered a known side effect of TKIs throughout the gastrointestinal tract, including the gastropharynx. As such, the risk of anastomotic dehiscence should be discussed with the patient prior to starting a TKI.

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.

Variability in Medullary Thyroid Carcinoma in RET L790F Carriers: A Case Comparison Study of Index Patients

Background: Previous studies have suggested that the variability in age of onset and aggressiveness of medullary thyroid carcinoma (MTC) in patients with multiple endocrine neoplasia type 2A (MEN 2A) carrying the same REarranged during Transfection (RET) mutation may be caused by additional RET germline variants or somatic variants. Methods: This study was a retrospective case comparison study of all MEN 2A index patients (n = 2) with the RET L790F germline mutation in Denmark. Whole blood and MTC tissue were analyzed for RET germline variants and other somatic variants (>500), respectively. Results: Patient 1 presented with MTC (T1aN1bM0) at age 14 years, while patient 2 presented with MTC (T1bN0M0) at age 70 years. No germline RET germline variants nor other variants were found to explain this MTC variability. Conclusions: We could not confirm the previously reported finding of a somatic RET variant as likely responsible for the early onset and aggressiveness of MTC in a RET germline mutation carrier. Also, we found no RET germline variants that could explain the MTC variability among our index patients. We did, however, identify a somatic FLT3 R387Q variant with an unknown potential as genetic modifier. Further large-scale studies are needed to investigate genetic modifiers in RET L790F carriers.

The added diagnostic value of complementary gadoxetic acid-enhanced MRI to 18F-DOPA-PET/CT for liver staging in medullary thyroid carcinoma

Background

A high proportion of patients with advanced stages of medullary thyroid carcinoma (MTC) present with liver metastasis metastases. The aim of our study was to investigate the added diagnostic value of complementary gadoxetic acid-enhanced MRI to ¹⁸F-DOPA-PET/CT for liver staging in MTC.

Methods

Thirty-six patients (14 female, median age 55 years) with histologically confirmed MTC undergoing gadoxetic acid-enhanced liver MRI within 1 month of matching contrast-enhanced ¹⁸F-DOPA-PET/CT between 2010 and 2016 were selected for this IRB-approved retrospective study. ¹⁸F-DOPA-PET/CT and multiparametric MRI data sets were read consecutively and liver lesions were categorised on a 5-point Likert scale (1–definitely benign; 2–probably benign; 3–intermediate risk for metastasis; 4–probably metastasis; 5–definitely metastasis). It was noted if gadoxetic acid-enhanced MRI detected additional, ¹⁸F-DOPA-PET/CT-occult metastases (category 5) or if gadoxetic acid-enhanced MRI allowed for a definite classification (categories 1 and 5) of lesions for which ¹⁸F-DOPA-PET/CT remained inconclusive (categories 2–4). Follow-up PET/CT and MRI examinations were used as a reference standard.

Results

A total of 207 liver lesions (¹⁸F-DOPA-PET/CT 149, MRI 207; 152 metastases, 37 benign cysts, 18 hemangiomas) were analysed. Fifty-eight additional lesions were detected by MRI, of which 54 were metastases (median diameter 0.5 cm [interquartile range 0.4–0.7 cm]) occult on ¹⁸F-DOPA-PET/CT. MRI allowed for a definite lesion classification (categories 1 and 5) in 92% (190/207) whereas ¹⁸F-DOPA-PET/CT allowed for a definite lesion classification in 76% (113/149). MRI lead to a change in lesion categorisation in 14% (21/149).

Conclusion

Gadoxetic acid-enhanced MRI allows for a more precise liver staging in MTC patients compared to ¹⁸F-DOPA-PET/CT alone, particularly for ¹⁸F-DOPA-negative metastases and lesions < 1 cm.

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.

Long-term follow-up of RET Y791F carriers in Denmark 1994-2017: A National Cohort Study

BACKGROUND AND OBJECTIVES

Recently, a comprehensive study presented evidence that a long-disputed REarranged during Transfection (RET) variant, RET Y791F, should be classified as nonpathogenic. In spite of this, several subsequently published papers, including the revised American Thyroid Association guidelines for medullary thyroid carcinoma, refer to the variant as pathogenic. This study presents data from a unique national Danish cohort of RET Y791F carriers who have been followed by watchful waiting instead of being subjected to early thyroidectomy, to determine if any carrier shows evidence of multiple endocrine neoplasia 2A (MEN2A) at long-term follow-up.

METHODS

A national cohort of all patients tested for RET mutations in Denmark from September 1994 to October 2017 was searched for carriers of RET Y791F. Medical records and laboratory reports of carriers were reviewed for signs of MEN2A at latest follow-up (medullary thyroid carcinoma, primary hyperparathyroidism, pheochromocytoma, cutaneous lichen amyloidosis, or Hirschsprung's disease).

RESULTS

In total, twenty RET Y791F-carriers were identified, none of whom showed any evidence of MEN2A, despite an age range from 7 to 87 years.

CONCLUSIONS

Our national cohort study of all Danish RET Y791F carriers substantiates the claim that the RET Y791F variant is nonpathogenic.

Completeness of RET testing in patients with medullary thyroid carcinoma in Denmark 1997-2013: a nationwide study

Background

The completeness of REarranged during Transfection (RET) testing in patients with medullary thyroid carcinoma (MTC) was recently reported as 60%. However, the completeness on a population level is unknown. Similarly, it is unknown if the first Danish guidelines from 2002, recommending RET testing in all MTC patients, improved completeness in Denmark. We conducted a nationwide retrospective cohort study aiming to evaluate the completeness of RET testing in the Danish MTC cohort. Additionally, we aimed to assess the completeness before and after publication of the first Danish guidelines and characterize MTC patients who had not been tested.

Methods

The study included 200 patients identified from the nationwide Danish MTC cohort 1997–2013. To identify RET tested MTC patients before December 31, 2014, the MTC cohort was cross-checked with the nationwide Danish RET cohort 1994–2014. To characterize MTC patients who had not been RET tested, we reviewed their medical records and compared them with MTC patients who had been tested.

Results

Completeness of RET testing in the overall MTC cohort was 87% (95% CI: 0.81–0.91; 173/200). In the adjusted MTC cohort, after excluding patients diagnosed with hereditary MTC by screening, completeness was 83% (95% CI: 0.76–0.88; 131/158). Completeness was 88% (95% CI: 0.75–0.95; 42/48) and 81% (95% CI: 0.72–0.88) (89/110) before and after publication of the first Danish guidelines, respectively. Patients not RET tested had a higher median age at diagnosis compared to those RET tested. Median time to death was shorter in those not tested relative to those tested.

Conclusion

The completeness of RET testing in MTC patients in Denmark seems to be higher than reported in other cohorts. No improvement in completeness was detected after publication of the first Danish guidelines. In addition, data indicate that advanced age and low life expectancy at MTC diagnosis may serve as prognostic indicators to identify patients having a higher likelihood of missing the compulsory RET test.

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.