Results of Screening in Familial Non-Medullary Thyroid Cancer

A Narrative Review of the 2023 Korean Thyroid Association Management Guideline for Patients with Thyroid Nodules

The 2023 Korean Thyroid Association (KTA) Management Guideline for Patients with Thyroid Nodules constitute an update of the 2016 KTA guideline for thyroid nodules and cancers that focuses specifically on nodules. The 2023 guideline aim to offer updated guidance based on new evidence that reflects the changes in clinical practice since the 2016 KTA guideline. To update the 2023 guideline, a comprehensive literature search was conducted from January 2022 to May 2022. The literature search included studies, reviews, and other evidence involving human subjects that were published in English in MEDLINE (PubMed), Embase, and other relevant databases. Additional significant clinical trials and research studies published up to April 2023 were also reviewed. The limitations of the current evidence are discussed, and suggestions for areas in need of further research are identified. The purpose of this review is to provide a summary of the 2023 KTA guideline for the management of thyroid nodules released in May 2023 and to give a balanced insight with comparison of recent guidelines from other societies.

Preoperative Evaluation of Thyroid Cancer: A Review of Current Best Practices

OBJECTIVE

The incidence of thyroid cancer has significantly increased in recent decades. Although most thyroid cancers are small and carry an excellent prognosis, a subset of patients present with advanced thyroid cancer, which is associated with increased rates of morbidity and mortality. The management of thyroid cancer requires a thoughtful individualized approach to optimize oncologic outcomes and minimize morbidity associated with treatment. Because endocrinologists usually play a key role in the initial diagnosis and evaluation of thyroid cancers, a thorough understanding of the critical components of the preoperative evaluation facilitates the development of a timely and comprehensive management plan. The following review outlines considerations in the preoperative evaluation of patients with thyroid cancer.

METHODS

A clinical review based on current literature was generated by a multidisciplinary author panel.

RESULTS

A review of considerations in the preoperative evaluation of thyroid cancer is provided. The topic areas include initial clinical evaluation, imaging modalities, cytologic evaluation, and the evolving role of mutational testing. Special considerations in the management of advanced thyroid cancer are discussed.

CONCLUSION

Thorough and thoughtful preoperative evaluation is critical for formulating an appropriate treatment strategy in the management of thyroid cancer.

FAMILIAL NON-MEDULLARY THYROID CARCINOMA

BACKGROUND

Familial non-medullary thyroid carcinoma (FNMTC) is defined as cancer developing in two or more first-degree relatives if predisposing factors, for example, radiation, are absent. The disease can be either syndromic, when it is a component of complex genetic syndromes, or non-syndromic (95% cases). The genetic basis of non-syndromic FNMTC is unknown; the clinical behavior of tumorsis unclear and, at times, contradictory.

AIM

To analyze clinical manifestations of FNMTC and compare them with the data for sporadic papillary thyroid carcinomas in patients of the same age groups.

MATERIALS AND METHODS

We examined 22 patients (a "parents" group and a "children" group) suffering from the non-syndromic FNMTC. For comparison, two groups of sporadic papillary carcinomas patients of the same age were drawn up("adult" and "young"). We analyzed tumor size and frequency of the distributionby the categoryof TNM system, invasiveness, multifocality, metastases to lymph nodes, type and extent of surgical and radioiodine treatment, and prognosis according to the MACIS criterion.

RESULTS

Whether sporadic or familial, the tumor size, metastatic potential, and invasive potential are higher in young people, asalready known. There was no significant difference between the "parents" and "adult" groups of patients in terms of tumor parameters. One exception was the higher frequency of multifocal tumors in the FNMTC patients. Meanwhile, compared to the "young" sporadic papillary carcinomas patients, the FNMTC "children" had a higher frequency of T2 tumors, metastasizing (N1a-N1ab), and multifocal tumors, but a lower frequency of carcinomas with intrathyroidal invasions.In the FNMTC "children" compared to FNMTC "parents" was a higher frequency of T2 tumors, metastasizing carcinomas, and tumors with capsular invasion.

CONCLUSION

FNMTC carcinomas are more aggressive than sporadic ones, especially in patients who are first-degree relatives in a family with parents already diagnosed with the disease.

The Classic, the Trendy, and the Refashioned: A Primer for Pathologists on What Is New in Familial Endocrine Tumor Syndromes

Familial endocrine tumor syndromes are continuously expanding owing to the growing role of genetic testing in routine clinical practice. Pathologists are usually the first on the clinical team to encounter these syndromes at their initial presentation; thus, recognizing them is becoming more pivotal in routine pathology practice to help in properly planning management and further family testing. Our increasing knowledge about them is reflected in the newer syndromes included in the new World Health Organization classification and in the evolving discovery of new endocrine tumors and new familial associations. In many of these syndromes, the clinical features and co-occurrence of multiple neoplasia are the only clues (multiple endocrine neoplasia syndromes). In other syndromes, specific morphologic findings (pituitary blastoma and DICER1 syndrome, cribriform morular thyroid carcinoma, and AFP syndrome) and available ancillary studies (SDHB in SDH-deficient tumor syndromes) can aid pathologists. The aim of this review is to provide a primer on recent updates on familial endocrine tumor syndromes and related tumors, focusing on recent classification changes or tumor syndromes where a clearer role for pathologists is at play.

Hereditary Endocrine Tumor Registries

Context

Endocrine neoplasia syndromes are phenotypically complex, and there is a misconception that they are universally rare. Genetic alterations are increasingly recognized; however, true prevalence is unknown. The purpose of a clinical registry is to monitor the quality of health care delivered to a specified group of patients through the collection, analysis, and reporting of relevant health-related information. This leads to improved clinical practice, decision-making, patient satisfaction, and outcome.

Objective

This review aims to identify, compare, and contrast active registries worldwide that capture data relevant to hereditary endocrine tumors (HETs).

Methods

Clinical registries were identified using a systematic approach from publications (Ovid MEDLINE, EMBASE) peer consultation, clinical trials, and web searches. Inclusion criteria were hereditary endocrine tumors, clinical registries, and English language. Exclusion criteria were institutional audits, absence of clinical data, or inactivity. Details surrounding general characteristics, funding, data fields, collection periods, and entry methods were collated.

Results

Fifteen registries specific for HET were shortlisted with 136 affiliated peer-reviewed manuscripts.

Conclusion

There are few clinical registries specific to HET. Most of these are European, and the data collected are highly variable. Further research into their effectiveness is warranted. We note the absence of an Australian registry for all HET, which would provide potential health and economic gains. This review presents a unique opportunity to harmonize registry data for HET locally and further afield.

Ultrasonography screening in children and adolescents who have one parent with familial non-medullary thyroid carcinoma

AIM

To evaluate ultrasonography (US) screening for thyroid cancer in children and adolescents who have one parent with familial non-medullary thyroid carcinoma (FNMTC) unrelated to known genetic syndromes.

METHODS

In this prospective study, we selected 72 children and adolescents (age ≤18 years) without a palpable thyroid nodule or history of radiation exposure, but who have one parent diagnosed with FNMTC (i.e. at least one other affected first-degree relative). The children and adolescents were evaluated by US during initial assessment and after 5 years.

RESULTS

Initial US revealed pure cysts in five participants and nodules in seven, which were ≥5 mm in five. These patients were submitted to fine needle aspiration, which revealed benign cytology in four and a follicular lesion of undetermined significance in one. Fine needle aspiration was repeated in the last case and in one case with benign cytology but suspicious US. The second cytology was benign in both cases. After 5 years, another two participants with initially normal US had nodules <5 mm in the absence of suspicious findings. The frequency of lesions detected by US was not associated with participant sex or age, number of relatives with thyroid cancer (2 or 3), maternal or paternal origin of tumour, or age of the relatives at diagnosis.

CONCLUSION

The present results suggest that US screening is not necessary in children or adolescents when one parent has a diagnosis of FNMTC (≥2 affected relatives).

Prevalence of Thyroid Nodules and Thyroid Cancer in Individuals with a First-Degree Family History of Non-Medullary Thyroid Cancer: A Cross-Sectional Study Based on Sonographic Screening

Background: The actual rates of suspicious thyroid nodules (TNs) and confirmed thyroid cancer (TC) in putatively "at-risk" selected populations (e.g., individuals with family history of TC) are still uncertain. Methods: Our aim was to explore the prevalence of TC and TN in a cross-sectional study of a consenting population of unaffected individuals (10 years of age or older) with a first-degree relative known to have non-medullary TC (NMTC). Enrolled subjects underwent ultrasonographic studies of the neck between 2009 and 2018. Nodules considered suspicious according to current guidelines were subjected to fine-needle aspiration biopsy (FNAB) for cytology. Results: The screenee population comprised 1176 individuals (median age 42 [26-56] years, 650 females, 55.3%) from 473 kindreds (346 with 1 established NMTC diagnosis at entry, 103 with 2 established NMTC diagnoses, and 24 with 3 or more established NMTC diagnoses at entry). Screening revealed TNs in 500 screenees (42.5%; confidence interval [CI] 39.7-45.4%). Ninety-seven of these (19.4%; CI 16.2-23.1%) underwent FNAB. Only 11 cases of TC were diagnosed in the whole population (0.9%; CI 0.5-1.7%). The prevalence of TC in screenees from kindreds with ≥3 cases (3/24, 12.5%) was higher than that for kindreds with one affected member (6/346, 1.7%; p = 0.01, odds ratio [OR] 7.99; CI 1.21-40.75) and for those with two affected members (2/103, 1.9%; p = 0.05, OR 7.05; CI 0.76-89.44). The prevalence of TNs was 61.8% (CI 56.6-66.8%), 75.7% (CI 66.6-83%), and 66.7% (CI 46.7-82%) in the kindreds with 1, 2, and ≥3 cases, respectively (p = 0.03). Conclusions: On the whole, ultrasound-based screening of unaffected relatives of individuals with established diagnoses of NMTC is likely to reveal a high prevalence of TN and a low prevalence of TC. However, a significantly higher prevalence of TC may be found among screenees from kindreds with at least three established NMTC diagnoses before screening, suggesting that closer surveillance may be warranted in kindreds with this level of familiality.

Genetic susceptibility to hereditary non-medullary thyroid cancer

Non-medullary thyroid cancer (NMTC) is the most common type of thyroid cancer. With the increasing incidence of NMTC in recent years, the familial form of the disease has also become more common than previously reported, accounting for 5-15% of NMTC cases. Familial NMTC is further classified as non-syndromic and the less common syndromic FNMTC. Although syndromic NMTC has well-known genetic risk factors, the gene(s) responsible for the vast majority of non-syndromic FNMTC cases are yet to be identified. To date, several candidate genes have been identified as susceptibility genes in hereditary NMTC. This review summarizes genetic predisposition to non-medullary thyroid cancer and expands on the role of genetic variants in thyroid cancer tumorigenesis and the level of penetrance of NMTC-susceptibility genes.

Identification of NID1 as a novel candidate susceptibility gene for familial non-medullary thyroid carcinoma using whole-exome sequencing

The genetics underlying non-syndromic familial non-medullary thyroid carcinoma (FNMTC) is still poorly understood. To identify susceptibility genes for FNMTC, we performed whole-exome sequencing (WES) in a Brazilian family affected by papillary thyroid carcinoma (PTC) in three consecutive generations. WES was performed in four affected and two unaffected family members. Manual inspection in over 100 previously reported susceptibility genes for FNMTC showed that no variants in known genes co-segregated with disease phenotype in this family. Novel candidate genes were investigated using PhenoDB and filtered using Genome Aggregation (gnomAD) and Online Archive of Brazilian Mutations (ABraOM) population databases. The missense variant p.Ile657Met in the NID1 gene was the only variant that co-segregated with the disease, while absent in unaffected family members and controls. The allele frequency for this variant was <0.0001 in the gnomAD and ABbraOM databases. In silico analysis predicted the variant to be deleterious or likely damaging to the protein function. Somatic mutations in NID1 gene were found in nearly 500 cases of different cancer subtypes in the intOGen platform. Immunohistochemistry analysis showed NID1 expression in PTC cells, while it was absent in normal thyroid tissue. Our findings were corroborated using data from the TCGA cohort. Moreover, higher expression of NID1 was associated with higher likelihood of relapse after treatment and N1b disease in PTCs from the TCGA cohort. Although replication studies are needed to better understand the role of this variant in the FNMTC susceptibility, the NID1 variant (c.1971T>G) identified in this study fulfills several criteria that suggest it as a new FNMTC predisposing gene.

Bibliometric analysis of research on thyroid ultrasonography

BACKGROUND

The incidence of thyroid diseases has increased, which may be partly related to the widespread use of thyroid ultrasound resulting in a large number of asymptomatic thyroid nodules to be found. Research has found that many thyroid ultrasound examinations are completely avoidable. However, the purpose of the present study was to use bibliometrics to analyze the relevant research literature of thyroid ultrasound and understand the overall status of the current research in this field.

METHODS

We searched the Science Citation Index Expanded (SCI-E) database in the Web of Science Core Collection. Search terms were "ultrasonography" and "thyroid gland". The date range for the document search was from 1900 to May 10, 2021. Export the full record of the search results and the references in txt. format, and use the CiteSpace software to analyze the annual publication of literatures, the distribution of countries and institutions where the literatures came from, the distribution of journals and authors. The keywords used in the literature were also analyzed.

RESULTS

A total of 1,241 publications were included in the results, and the frequency of citations was 27,149. The top 5 countries for the number of publications published were the USA, Turkey, Italy, South Korea, and China; the top 5 countries by centrality were the USA, Germany, Italy, Canada, and China. The number of institution-published papers was generally low, and the centrality score was low. Research in this field was relatively scattered among institutions and cooperation between institutions was few. There was little collaboration between authors from different institutions. The most cited authors were mainly from European and North American countries. Journals, such as Thyroid, Journal of Clinical Ultrasound, and Journal of Endocrinological Investigation, had great influence in this field. Keyword analysis results showed that research is mainly focused on the differentiation of benign and malignant thyroid nodules.

CONCLUSIONS

There was an increase in thyroid ultrasound research, but there was few cooperation exist between institutions. The main research direction was the differentiation of benign and malignant thyroid nodules.

Papillary Thyroid Cancer Affecting Multiple Family Members: A Case Report and Literature Review of Familial Nonmedullary Thyroid Cancer

Familial nonmedullary thyroid cancer (FNMTC) represents 5–10% of NMTC cases. Many controversies are associated with the FNMTC, namely, the minimum required number of affected family members to define the condition, aggressiveness, prognosis, and treatment and screening recommendations. Moreover, the genetic basis of the FNMTC has not yet been identified. We report a family diagnosed with FNMTC and present a comprehensive literature review of the condition. The index case was a 26-year-old male who was diagnosed with locally advanced papillary thyroid cancer (PTC). Then, his family members became worried and asked for a neck ultrasound. Four of his six siblings, in addition to his father, were diagnosed with PTC. In addition, two of his cousins were diagnosed. The patient underwent total thyroidectomy with bilateral neck dissection, and he received 2 doses of radioactive iodine (100 mCi each). Furthermore, one of his siblings required a second surgery with repeated radioactive iodine therapy. The index case genetic screening and whole-exome sequencing did not show any abnormalities. Future genetic and clinical research should focus on kindred with 3 or more affected individuals for better identification of the FNMTC susceptibility genes and to better guide management and screening recommendations.

A predictive model and survival analysis for local recurrence in differentiated thyroid carcinoma

BACKGROUND

Local recurrence (LR) is associated with poor outcome in patients with differentiated thyroid carcinoma (DTC). The aim of this study was to explore potential risk factors for LR and build a predictive model.

METHODS

The medical data of patients who were diagnosed with DTC after initial surgery in three medical centers (2000-2018) were reviewed. Detailed clinicopathologic characteristics of all cases were identified.

RESULTS

Multiple factors, including extrathyroidal extension (ETE), histology, symptoms, multifocality, and tumor diameter, were significantly different between the LR and no evidence of disease groups in univariate and multivariate analysis (P ˂ 0.05). Tumor diameter, symptoms, and ETE made the greatest contributions to prognosis according to decision tree analysis and random forest algorithm. The predictive model constructed from these data achieved 98.7% accuracy of classification. A five-fold cross-validation confirmed that the model has 84.7%-89.7% accuracy of classification. Additionally, symptoms and ETE were independent predictors on survival analysis (P ˂ 0.05).

CONCLUSIONS

This study optimized the weight of risk factors, including tumor diameter, symptoms, ETE, and multifocality, in predicting LR in patients with DTC. Our predictive model provides a strong tool to distinguish between high-risk and low-risk DTC.

Contemporary Management of Thyroid Nodules

Thyroid nodules are common in the general population, with higher prevalence in women and with advancing age. Approximately 5% of thyroid nodules are malignant; the majority of this subset represents papillary thyroid cancer. Ultrasonography is the standard technique to assess the underlying thyroid parenchyma, characterize the features of thyroid nodules, and evaluate for abnormal cervical lymphadenopathy. Various risk stratification systems exist to categorize the risk of malignancy based on the ultrasound appearance of a thyroid nodule. Nodules are selected for fine-needle aspiration biopsy on the basis of ultrasound features, size, and high-risk clinical history. Cytology results are classified by the Bethesda system into six categories ranging from benign to malignant. When cytology is indeterminate, molecular testing can further risk-stratify patients for observation or surgery. Surveillance is indicated for nodules with benign cytology, indeterminate cytology with reassuring molecular testing, or non-biopsied nodules without a benign sonographic appearance. Expected final online publication date for the Annual Review of Medicine, Volume 73 is January 2022. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.

Co-Occurrence of Familial Non-Medullary Thyroid Cancer (FNMTC) and Hereditary Non-Polyposis Colorectal Cancer (HNPCC) Associated Tumors-A Cohort Study

Familial non-medullary thyroid cancer (FNMTC) is a form of endocrine malignancy exhibiting an autosomal dominant mode of inheritance with largely unknown germline molecular mechanism. Hereditary nonpolyposis colorectal cancer syndrome (HNPCC) is another hereditary autosomal dominant cancer syndrome which, if proven to be caused by germline mutations in mismatch repair genes (MMR)-MLHL, MSH2, MSH6, PMS2, and EPCAM-is called Lynch syndrome (LS). LS results in hereditary predisposition to a number of cancers, especially colorectal and endometrial cancers. Tumors in LS are characterized by microsatellite instability (MSI) and/or loss of MMR protein expression in immunohistochemistry (IHC). MSI is a rare event in thyroid cancer (TC), although it is known to occur in up to 2.5% of sporadic follicular TC cases. There are limited data on the role of germline MMR variants FNMTC. The goal of this study was to analyze the potential clinical and molecular association between HNPCC and FNMTC. We performed a cohort study analyzing the demographic, clinical, and pathologic data of 43 kindreds encompassing 383 participants (104 affected, 279 unaffected), aged 43.5 [7-99] years with FNMTC, and performed high-throughput whole-exome sequencing (WES) of peripheral blood DNA samples of selected 168 participants (54 affected by FNMTC and 114 unaffected). Total affected by thyroid cancer members per family ranged between 2 and 9 patients. FNMTC was more prevalent in women (68.3%) and characterized by a median tumor size of 1.0 [0.2-5.0] cm, multifocal growth in 44%, and gross extrathyroidal extension in 11.3%. Central neck lymph node metastases were found in 40.3% of patients at presentation, 12.9% presented with lateral neck lymph node metastases, and none had distant metastases. Family history screening revealed one Caucasian family meeting the clinical criteria for FNMTC and HNPCC, with five members affected by FNMTC and at least eight individuals reportedly unaffected by HNPCC-associated tumors. In addition, two family members were affected by melanoma. Genome Analysis Tool Kit (GATK) pipeline was used in variant analysis. Among 168 sequenced participants, a heterozygous missense variant in the MSH2 gene (rs373226409; c.2120G>A; p.Cys707Tyr) was detected exclusively in FNMTC- HNPCC- kindred. In this family, the sequencing was performed in one member affected by FNMTC, HPNCC-associated tumors and melanoma, one member affected solely by HNPCC-associated tumor, and one member with FNMTC only, as well as seven unaffected family members. The variant was present in all three affected adults, and in two unaffected children of the affected member, under the age of 18 years, and was absent in non-affected adults. This variant is predicted to be damaging/pathogenic in 17/20 in-silico models. However, immunostaining performed on the thyroid tumor tissue of two affected by FNMTC family members revealed intact nuclear expression of MSH2, and microsatellite stable status in both tumors that were tested. Although the MSH2 p.Cys707Tyr variant is rare with a minor allele frequency (MAF) of 0.00006 in Caucasians; it is more common in the South Asian population at 0.003 MAF. Therefore, the MSH2 variant observed in this family is unlikely to be an etiologic factor of thyroid cancer and a common genetic association between FNMTC and HNPCC has not yet been identified. This is the first report known to us on the co-occurrence of FNMTC and HNPCC. The co-occurrence of FNMTC and HNPCC-associated tumors is a rare event and although presented in a single family in our large FNMTC cohort, a common genetic background between the two comorbidities could not be established.

Familial non medullary thyroid carcinoma: Beyond the syndromic forms

Familial non-medullary thyroid cancer is defined as the presence of non-medullary thyroid cancer in two or more first-degree relatives, in the absence of other predisposing factors. It represents up to 9% of differentiated thyroid cancers, and only a minority appears in well-known hereditary syndromes that associate thyroid cancer among many other clinical manifestations. However, in more than 95% of cases, thyroid cancer appears isolated, and its genetic causes have yet to be elucidated. We review here the current knowledge of the genetic basis of this pathology, as well as its clinical characteristics. Understanding the genetic mechanisms implied would help to comprehend the metabolic pathways involved, with the consequent potential therapeutic application. In addition, it would allow genetic counseling and to focus our efforts on patients at risk of developing this disorder.

Familial non-medullary thyroid cancer: a critical review

BACKGROUND

Familial non-medullary thyroid carcinoma (FNMTC), mainly of papillary histotype (FPTC), is defined by the presence of the disease in two or more first-degree relatives in the absence of other known familial syndromes. With the increasing incidence of PTC in the recent years, the familial form of the disease has also become more common than previously reported and constitutes nearly 10% of all thyroid cancers. Many aspects of FNMTC are debated, concerning both clinical and genetic aspects. Several studies reported that, in comparison with sporadic PTCs, FPTCs are more aggressive at disease presentation, while other authors reported no differences in the clinical behavior of sporadic and familial PTCs. For this reason, recent guidelines do not recommend screening of family members of patients with diagnosis of differentiated thyroid cancer (DTC). FNMTC is described as a polygenic disorder associated with multiple low- to moderate-penetrance susceptibility genes and incomplete penetrance. At the moment, the genetic factors contributing to the development of FNMTC remain poorly understood, though many putative genes have been proposed in the recent years.

PURPOSE

Based on current literature and our experience with FNMTC, in this review, we critically discussed the most relevant controversies, including its definition, the genetic background and some clinical aspects as screening and treatment.

Longer Time to Reach Excellent Response to Treatment in Familial Versus Sporadic Non-medullary Thyroid Cancer (NMTC): A Matched Case-Control Study

BACKGROUND

Familial non-medullary thyroid cancer (NMTC) are supposed to be more aggressive and require more frequent treatment compared to non-familial thyroid cancer.

OBJECTIVES

This matched case-control study aimed to compare the response to treatment between the matched case-control groups of familial and sporadic NMTC.

METHODS

This is a retrospective study in patients with familial NMTC (at least one other first-degree relative involved) who were treated with surgery, followed by radio-iodine therapy (RIT) without consideration of its familial origin. Response to treatment was compared between familial NMTC and age, sex, and TNM stage-matched non-familial NMTC (control group). Response to treatment was assessed one and two years after RIT, and time to excellent response was identified.

RESULTS

Out of 2,944 NMTC patients, 81 (2.75%) patients had familial NMTC. We compared 66 patients with familial NMTC and 66 sporadic NMTC patients. There was no significant difference in first thyroglobulin, initial and accumulative iodine dose, and additional treatments (additional surgery and radiotherapy) between patients and controls. Although no significant difference was noted in one and two years' responses to treatment between the case and control groups, familial NMTC patients required more time to achieve excellent response (26.7 ± 24.9 versus 15.9 ± 9.0 months, P = 0.01). No significant difference was noted between familial NMTC patients with two or more than two involved relatives.

CONCLUSIONS

Our study showed that if patients with familial NMTCs were treated in the same way as non-familial patients, the time to excellent response would be significantly longer, even when they have only one other involved relative.

Inherited Follicular Epithelial-Derived Thyroid Carcinomas: From Molecular Biology to Histological Correlates

Cancer derived from thyroid follicular epithelial cells is common; it represents the most common endocrine malignancy. The molecular features of sporadic tumors have been clarified in the past decade. However the incidence of familial disease has not been emphasized and is often overlooked in routine practice. A careful clinical documentation of family history or familial syndromes that can be associated with thyroid disease can help identify germline susceptibility-driven thyroid neoplasia. In this review, we summarize a large body of information about both syndromic and non-syndromic familial thyroid carcinomas. A significant number of patients with inherited non-medullary thyroid carcinomas manifest disease that appears to be sporadic disease even in some syndromic cases. The cytomorphology of the tumor(s), molecular immunohistochemistry, the findings in the non-tumorous thyroid parenchyma and other associated lesions may provide insight into the underlying syndromic disorder. However, the increasing evidence of familial predisposition to non-syndromic thyroid cancers is raising questions about the importance of genetics and epigenetics. What appears to be "sporadic" is becoming less often truly so and more often an opportunity to identify and understand novel genetic variants that underlie tumorigenesis. Pathologists must be aware of the unusual morphologic features that should prompt germline screening. Therefore, recognition of harbingers of specific germline susceptibility syndromes can assist in providing information to facilitate early detection to prevent aggressive disease.

Role of Age at Diagnosis in Defining Potential Familial Nonmedullary Thyroid Cancer in Kindreds With Two Affected Members

CONTEXT

The definition of familial nonmedullary thyroid cancer (FNMTC) in 2 or more first-degree relatives is controversial due to the high probability of observing a sporadic association when only 2 members of first-degree relatives are affected.

OBJECTIVE

To evaluate the role of age at diagnosis in differentiating the true cases of FNMTC.

DESIGN, SETTING, PARTICIPANTS, AND MAIN OUTCOME

From a group of 721 papillary thyroid cancer (PTC) patients, 95 familial PTC (FPTC) patients with 2 first-degree relatives have been identified. They were split in 2 groups: Group 1 consisted of both the proband and the affected relative, with age at diagnosis ≤ 45 years; Group 2 consisted of proband and/or the affected family member, with age at diagnosis > 45 years. The clinical-pathological features and outcome of both FPTC groups were compared with 626 sporadic PTC patients (SPTC).

RESULTS

Familial PTC patients with age at diagnosis ≤ 45 years, compared with the matched group of sporadic PTCs, had a more frequent multifocal, bilateral, and extrathyroidal extension of tumor and showed worse outcome. No differences were found between FPTC and SPTC patients with age > 45 years. At multivariate analysis, distant metastases, American Thyroid Association (ATA) risk, and FPTC ≤ 45 years were independent predictors of outcome.

CONCLUSIONS

Based on the observation that PTC is more aggressive when the diagnosis is made in 2 family members, both with age < 45years, we suggest that the definition of FPTC in kindreds with 2 affected members should also take into account the age at diagnosis as a key element of familial cancer.

BROX haploinsufficiency in familial nonmedullary thyroid cancer

BACKGROUND

The familial nonmedullary thyroid cancer (FNMTC) is suspected to be a Mendelian condition in up to 3-8% of thyroid cancers. The susceptibility chromosomal loci and genes of 95% of FNMTC cases remain to be characterized. The inheritance of FNMTC appears to be autosomal dominant with incomplete penetrance and variable expressivity. The finding of the causative gene of FNMTC and the identification of patients at risk that need genetic testing were our aim.

METHODS

We analyzed by whole-exome sequencing patients and non-affected relatives of five families with at least two family members affected by papillary thyroid cancer, selecting for new or extremely rare variants with predicted pathogenic value.

RESULTS

A family showed, in all three affected members, a new loss-of-function variant (frameshift deletion) in BROX gene at 1q41 that was absent from all internal and external databases. In a second family with three affected relatives, we found an additional new BROX variant. The smaller families presented no variants in BROX or in the other causative genes studied.

CONCLUSIONS

BROX could be a new causative gene for FNMTC. Variants in BROX may result in the haploinsufficiency of a key gene involved in the morphogenesis of MVBs, in the endosomal sorting of cargo proteins, and in EGFR. Functional studies are needed to support this result. The thorough genomic analysis by NGS in all families with three or more affected members should become a routine approach to obtain a comprehensive genetic view and find confirmative second cases.

Familial non medullary thyroid carcinoma: Beyond the syndromic forms

Familial non-medullary thyroid cancer is defined as the presence of non-medullary thyroid cancer in two or more first-degree relatives, in the absence of other predisposing factors. It represents up to 9% of differentiated thyroid cancers, and only a minority appears in well-known hereditary syndromes that associate thyroid cancer among many other clinical manifestations. However, in more than 95% of cases, thyroid cancer appears isolated, and its genetic causes have yet to be elucidated. We review here the current knowledge of the genetic basis of this pathology, as well as its clinical characteristics. Understanding the genetic mechanisms implied would help to comprehend the metabolic pathways involved, with the consequent potential therapeutic application. In addition, it would allow genetic counseling and to focus our efforts on patients at risk of developing this disorder.

Single liver metastasis of a follicular variant of papillary thyroid carcinoma: a rare pattern of organ spread

SUMMARY

Well-differentiated thyroid cancer (WDTC), including papillary, follicular, and Hurthle-cell types, is characterized by a slow course and usually remain localized to the thyroid. However, a minority of these cases develop distant metastases with the most common sites being lungs, bones, and lymph nodes. Liver metastases of WDTC are rare and are usually found along with other distant metastases sites and in a multiple or diffuse pattern of spread. The recognition of distant metastasis in WDTC has a significant impact on the treatment and prognosis. However, because of their low incidence and awareness, distant metastases are often diagnosed late. Herein, we describe a case of a 71 years old woman who during routine surveillance of a follicular variant of papillary thyroid cancer (FV-PTC), 5 years after being treated for her primary thyroid tumor, was found to have a single liver metastasis and underwent liver segmental resection. This case highlights the importance of maintaining vigilant surveillance of patients with WDTC, and illustrates the possibility of unique metastasis at unexpected sites. Further studies are needed to understand the organ tropism of some WDTC leading to distant metastases development and to better prediction of an aggressive course.

LEARNING POINTS

WDTC patients with distant metastases have a poor prognosis with a 10-year survival of about 50%. The most common sites of distant metastases are lung, bone and lymph nodes. Liver metastases are rare in WDTC, are usually multiple or diffuse and are found along with other distant metastases sites. Single liver metastasis of WDTC is an unexpected pattern of spread, and very few cases are reported in the literature. Rare sites of distant metastases in WDTC can manifest many years after the primary tumor, stressing the importance of maintaining vigilant surveillance. More studies are needed to predict which WDTC tumors may develop a more aggressive course, allowing clinicians to individualize patient management.

Long-Term Clinical Outcome in Familial and Sporadic Papillary Thyroid Carcinoma

BACKGROUND

The definition and the behaviour of familial papillary thyroid cancer (FPTC) compared to the sporadic form (SPTC) are still debated. Some authors believe that only families with 3 or more affected members represent an actual example of familial diseases.

OBJECTIVES

The objective of the study was to analyse the clinicopathological features and the outcome of sporadic and familial PTC patients also according to the number of affected members.

METHODS

Among 731 patients, we identified 101 (13.8%) with familial diseases, 79 with 2 affected members (FPTC-2) and 22 with 3 or more affected members (FPTC-3) followed for a mean period of 10 years.

RESULTS

FPTC patients had more frequently bilateral tumour (p = 0.007). No difference was found between the 2 groups for the other evaluated variables. At the time of the first follow-up (1-2 years after initial therapy), FPTC patients had a higher rate of persistent disease. However, at the last follow-up, the clinical outcome was not different between sporadic and familial patients. When the comparison between SPTC and FPTC was performed, according to the number of affected members, a significant trend between the 3 groups was observed for tumour diameter (p = 0.002) and bilaterality (p = 0.003), while we did not observe a significant trend for both response to initial therapy (p = 0.15) and last clinical outcome (p = 0.22).

CONCLUSIONS

Our results suggest that, although the clinicopathological features of FPTC may be more aggressive, the long-term outcome is similar between FPTC and SPTC. A possible explanation is that PTC has a favourable prognosis, even when clinical presentation is more aggressive.

An update on familial nonmedullary thyroid cancer

Familial nonmedullary thyroid cancer (FNMTC) constitutes 3-9% of all thyroid cancer cases. FNMTC is divided into two groups: syndromic and nonsyndromic. Nonsyndromic FNMTC is more common as compared with syndromic FNMTC. In syndromic FNMTC, patients are at risk of nonmedullary thyroid cancer (NMTC) and other tumors, and the susceptibility genes are known. In nonsyndromic FNMTC, NMTC is the major feature of the disease and occurs in isolation with an autosomal dominant pattern of inheritance and variable penetrance. New data have emerged on the genetics, clinical characteristics, and outcomes of patients with FNMTC that may have clinical relevance in the management of patients. In this review, we focus on newly characterized syndromic FNMTC entities, criteria for screening and surveillance of nonsyndromic FNMTC, and the classification of nonsyndromic FNMTC as well as the genetic background and heterogeneity of nonsyndromic FNMTC.

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

OBJECTIVE

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Genetic testing in endocrine surgery: Opportunities for precision surgery

Recent innovations in molecular and genetic diagnostic techniques have led to rapid advances in genomic medicine and their application to the clinic. The identification and classification of various genetic associations, syndromes, and susceptibility genes in endocrine surgical disorders are increasingly relevant to patient care. Hereditary endocrine disorders represent a significant proportion of disease encountered by endocrine surgeons. Hence, genetic testing has emerged as an important adjunct for the diagnosis and management of patients with endocrine surgical disorders. This article summarizes commonly encountered inherited endocrine disorders and their tumor susceptibility genes, with a focus on the clinical utility of genetic testing and its impact on the surgical management of endocrine disorders.

Screening for differentiated thyroid cancer in selected populations

The main purpose of cancer screening programmes should not be to detect all cancers, but to discover potentially fatal or clinically relevant cancers. The US Preventive Services Task Force recommends against screening for thyroid cancer in the general, asymptomatic adult population, as such screening would result in harms that outweigh any potential benefits. This recommendation does not apply to patients with symptoms or to individuals at increased risk of thyroid cancer because of a history of exposure to ionising radiation (in childhood, as radioactive fallout, or in medical treatment as low-dose radiotherapy for benign conditions or high-dose radiation for malignancy), inherited genetic syndromes associated with thyroid cancer (eg, familial adenomatous polyposis), or one or more first-degree relatives with a history of thyroid cancer. We discuss the evidence for and against screening individuals who are at high risk, and consider the different screening tools available.

Identification of susceptibility gene mutations associated with the pathogenesis of familial nonmedullary thyroid cancer

Background

Familial nonmedullary thyroid cancer (FNMTC) accounts for approximately 3%–9% of all thyroid cancers; however, the mechanisms underlying FNMTC remain unclear. Environmental and genetic (especially genetic mutation) factors may play important roles in FNMTC etiology, development, and pathogenesis.

Methods

Three affected members, including two first‐degree relatives, and three healthy members of a family with FNMTC were studied. We performed whole‐exome and targeted gene sequencing to identify gene mutations that may be associated with FNMTC pathogenesis. The results were analyzed using Exome Aggregation Consortium data and the Genome Aggregation Database and further validated using Sanger sequencing.

Results

Of 28 pivotal genes with rare nonsynonymous mutations found, 7 were identified as novel candidate FNMTC pathogenic genes (ANO7, CAV2, KANK1, PIK3CB, PKD1L1, PTPRF, and RHBDD2). Among them, three genes (PIK3CB, CAV2, and KANK1) are reportedly involved in tumorigenesis through the PI3K/Akt signaling pathway.

Conclusion

We identified seven pathogenic genes in affected members of a family with FNMTC. The PI3K/Akt signaling pathway is thought to be closely related to the development of FNMTC, and three of the susceptibility genes identified herein are associated with this pathway. These findings expand our understanding of FNMTC pathogenesis and underscore PI3K/Akt pathology as a potential therapy target.

Long non-coding RNA H19 knockdown inhibits the cell viability and promotes apoptosis of thyroid cancer cells through regulating the PI3K/AKT pathway

Certain long non-coding (lnc)RNAs have been reported to serve important roles in the genesis and progression of thyroid cancer (TC). Recent studies have demonstrated that the expression of lncRNA H19 is upregulated in TC tissues; however, knowledge of the associated molecular mechanisms is limited. Therefore, the present study aimed to clarify the roles of H19 in TC. The mRNA expression of lncRNA H19 in TC tissues was determined using reverse transcription-quantitative polymerase chain reaction analysis, and the effects of H19 knockdown on cell viability and apoptosis in vitro were assessed using MTT and flow cytometric assays, respectively. Finally, the signaling pathways involved in the effects of H19 were examined. The results indicated that H19 was upregulated in TC tissues. Silencing of H19 inhibited the cell viability and promoted apoptosis of FTC-133 and TPC-1 TC cells, accompanied by an increased expression of B-cell lymphoma 2 (Bcl-2)-associated X protein and caspase 3, and repressed expression of Bcl-2. The results of western blot analysis suggested that the levels of phosphorylated phosphoinositide-3 kinase (PI3K) and phosphorylated AKT were attenuated by H19 silencing. These results suggest that lncRNA H19 exerts an oncogenic function in TC, in part through the PI3K/AKT pathway.

Do patients with familial nonmedullary thyroid cancer present with more aggressive disease? Implications for initial surgical treatment

BACKGROUND

There are conflicting reports on whether familial nonmedullary thyroid cancer is more aggressive than sporadic nonmedullary thyroid cancer. Our aim was to determine if the clinical and pathologic characteristics of familial nonmedullary thyroid cancer are different than nonmedullary thyroid cancer.

METHODS

We compared patients with familial nonmedullary thyroid cancer to a cohort of 53,571 nonmedullary thyroid cancer patients from the Surveillance, Epidemiology, and End Results database.

RESULTS

A total of 78 patients with familial nonmedullary thyroid cancer from 31 kindreds presented at a younger age (P = .04) and had a greater rate of T1 disease (P = .019), lymph node metastasis (P = .002), and the classic variant of papillary thyroid cancer on histology (P < .001) compared with the Surveillance, Epidemiology, and End Results cohort. Patients with ≥3 affected family members presented at a younger age (P = .04), had a lesser female-to-male ratio (P = .04), and had a greater rate of lymph node metastasis (P = .009). Compared with the Surveillance, Epidemiology, and End Results cohort, we found a higher prevalence of lymph node metastasis in familial nonmedullary thyroid cancer index cases (P = .003) but not in those diagnosed by screening ultrasonography (P = .58).

CONCLUSION

Patients with familial nonmedullary thyroid cancer present at a younger age and have a greater rate of lymph node metastasis. The treatment for familial nonmedullary thyroid cancer should be more aggressive in patients who present clinically and in those who have ≥3 first-degree relatives affected.