Familial non-medullary thyroid carcinoma: pathology review in 27 affected cases from 13 French families

Family history of malignant or benign thyroid tumors: implications for surgical procedure management and disease-free survival

Background

Current guidelines lack a standardized management for patients with family history of thyroid carcinoma (fTC),particularly benign thyroid neoplasm (fBTN). Our objective was to investigate the influence of various family histories on the selection of surgical approaches and disease-free survival (DFS).

Methods

A cohort study was conducted involving 2261 patients diagnosed with differentiated thyroid carcinoma including those with fTC (n=224), fBTN (n=122), and individuals without a family history of thyroid carcinoma (nfTC; n=1915). Clinicopathological characteristics were collected. DFS was estimated using Kaplan-Meier analysis and factors affecting DFS were identified using Cox proportional hazard model.

Results

Compared to nfTC, small tumor size, clinically lymph node-positive, extrathyroidal extension, vascular invasion, Hashimoto's disease and nodular goiter were more common in fTC and fBTN groups. They had lower T stage and a lower rate of good response to TSH suppression therapy but received more radioiodine therapy. It is worth noting that fTC is associated with male, bilateral and multifocal tumors, as well as central lymph node metastasis and distant metastasis. Both fTC (aHR = 2.45, 95% CI=1.11-5.38; P = 0.03) and fBTN (aHR = 3.43, 95% CI=1.27-9.29; P = 0.02) were independent predictors of DFS in patients who underwent lobectomy, but not total thyroidectomy. For 1-4 cm thyroid carcinomas with clinically node-negative, fTC was identified as an independent predictor, whereas fBTN was not.

Conclusion

Our findings indicate that a family history, particularly of malignancy, is associated with a more aggressive disease. Family history does not affect the prognosis of patients who undergo total thyroidectomy, but it may increase the risk of postoperative malignant events in those who have a lobectomy. Additionally, it may be necessary to monitor individuals with a family history of benign thyroid neoplasms.

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.

Familial non-medullary thyroid carcinoma: clinico-pathological features, current knowledge and novelty regarding genetic risk factors

Familial non-medullary thyroid cancer (FNMTC) constitutes 3-9% of all thyroid cancers and occurs in two or more first-degree relatives in the absence of predisposing environmental factors. Out of all FNMTC cases, only 5% are represented by syndromic forms (Gardner's Syndrome, familial adenomatous polyposis, Cowden's Syndrome, Carney complex 1, Werner's Syndrome and DICER1 syndrome), in which thyroid cancer occurs as a minor component and the genetic alterations are well-known. The non-syndromic forms represent the majority of all FNMTCs (95%), and the thyroid cancer is the predominant feature. Several low penetration susceptibility risk loci or genes (i.e. TTF1, FOXE1, SRGAP1, SRRM2, HABP2, MAP2K5, and DUOX2), here fully reviewed, have been proposed in recent years with a possible causative role, though the results are still not conclusive or reliable. FNMTC is indistinguishable from sporadic non-medullary thyroid cancer (sNMTC), which means that FNMTC cannot be diagnosed until at least one of the patient's first-degree relatives is affected by tumor. Some studies reported that the non-syndromic FNMTC is more aggressive than the sNMTC, being characterized by a younger age of onset and a higher rate of multifocal and bilateral tumors, extrathyroidal extension, lymph node metastasis, and recurrence. On the contrary, other studies did not find clinical differences between non-syndromic FNMTCs and sporadic cases. Here, I reported an extensive review on genetic and clinico-pathological features of the FNMTC, with particular attention on novel genetic risk factors for non-syndromic forms.

Familial Non-Medullary Thyroid Cancer Represents an Independent Risk Factor for Increased Cancer Aggressiveness: A Retrospective Analysis of 74 Families

OBJECTIVES

To assess whether familial non-medullary thyroid cancer (FNMTC) represents an independent risk factor for increased aggressiveness of the tumor, as concern as the clinical presentation and the long-term follow-up in respect of sporadic differentiated thyroid cancer (SDTC).

DESIGN

Retrospective study; 1976-2014.

PATIENTS AND METHODS

Seventy-four FNMTC families (151 affected individuals): family relationship and number of affected family members were evaluated. Clinical and histopathological features and outcome were compared to that of 643 SDTC patients followed in the same period according to the same institutional protocols. Median follow-up was 57.7 months (range 12-136) in FNMTC and 59.7 (range 15-94.6) in SDTC patients.

RESULTS

Three cases occurred in 3 families and 2 cases in the other 71. F:M was 3.7:1 in FNMTC and 4.3:1 in SDTC (NS). The family relationship was siblings in 62.2%. Mean age at diagnosis was lower in FNMTC than in SDTC (p < 0.005). Papillary/follicular histotype distribution was similar (86%). Papillary tumors were more frequently multifocal in FNMTC (p = 0.004) and with lymph-node metastases (p = 0.016). Disease-free survival (DFS) was shorter in FNMTC vs. SDTC (p < 0.0001) with 74.8 vs. 90.8% patients free of disease at the last control (p < 0.005). Three patients died in FNMTC group vs. 1 in SDTC (p = 0.02).

CONCLUSION

Familial non-medullary thyroid cancer displays distinct characteristics as earlier age of onset and increased aggressiveness at diagnosis and a higher rate of persistent/recurrent disease and mortality with a shorter DFS in respect with SDTC. FNMTC patients, therefore, should be followed accurately. As the specific gene (or genes) responsible for susceptibility for FNMTC has not yet been identified, a low frequency periodic screening of relatives DTC patients may be useful to identify FNMTC patients at early stage of disease.

Familial vs sporadic papillary thyroid carcinoma: a matched-case comparative study showing similar clinical/prognostic behaviour

OBJECTIVE

Familial non-medullary thyroid cancer has been proposed as an aggressive clinical entity. Our aim in this study is to investigate potential distinguishing features as well as the biological and clinical aggressiveness of familial vs sporadic papillary thyroid carcinoma (PTC). We assessed clinicopathological characteristics, outcome measures and DNA ploidy.

DESIGN

A matched-case comparative study.

METHODS

A series of patients with familial PTC (n=107) and two subgroups, one with three or more affected elements (n=32) and another including index cases only (n=61), were compared with patients with sporadic PTC (n=107), matched by age, gender, pTNM disease extension and approximate follow-up duration. Histological variant, extrathyroidal extension, vascular invasion, tumour multifocality and bilateral growth were evaluated. Ploidy pattern was analysed in available samples by DNA flow cytometry. The probabilities of disease-free survival (DFS) and overall survival (OS) were estimated according to the Kaplan-Meier (K-M) method.

RESULTS

No patient with familial PTC died of disease during follow-up (median, 72 months), contrarily to five patients (4.7%) (P=0.06) with sporadic PTC (median, 90 months). There was a significantly higher tumour multifocality in familial PTC (index cases subgroup) vs sporadic PTC (P=0.035), and a trend, in the familial PTC cohort with three or more affected elements, to show extrathyroidal extension (P=0.054) more frequently. No difference was observed in DNA ploidy status. The K-M analyses showed no significant differences between both entities in relation to DFS or OS.

CONCLUSION

Apart from multifocality, familial PTC appears to have similar clinical/prognostic behaviour when compared with sporadic forms of the disease.

Family history of malignant and benign thyroid diseases and risk of thyroid cancer: a population-based case-control study in New Caledonia

PURPOSE

Exceptionally high incidence rates of thyroid cancer have been observed in New Caledonia, particularly in Melanesian women, but familial aggregation of thyroid diseases in this population is unknown. We study the association between family history of malignant or benign thyroid diseases and non-medullary thyroid cancer in this country.

METHODS

We conducted a population-based case-control study including 332 cases with papillary or follicular carcinoma diagnosed in 1993-1999 and 412 controls, matched by sex and 5-year age-group.

RESULTS

Thyroid cancer was associated with a history of thyroid cancer in first-degree relatives (odds ratio (OR), 3.2; 95 % CI, 1.6-6.2) and with a family history of multinodular goiter (OR, 3.6; 95 % CI, 1.9-7.0). The ORs did not change by age at diagnosis and with the number of affected relatives. The study provides evidence that the familial component of thyroid cancer is particularly strong in men. Thyroid cancer was not associated with a family history of thyroid diseases in Melanesians from the Loyalty Islands, the area with the highest incidence rates for thyroid cancer, possibly indicating a high frequency of genetic susceptibility variants and lack of genetic variation in this population subgroup.

CONCLUSION

Overall our findings confirm an elevated risk of thyroid cancer in individuals with a family history of malignant or benign thyroid diseases, particularly in Melanesians where familial aggregation of thyroid cancer had never been investigated before. The study of genetic variants in candidate susceptibility genes for thyroid cancer may help clarifying the absence of an association in the subgroup of Melanesians from the Loyalty Islands.

Prognostic factors of papillary and follicular carcinomas in Japan based on data of kuma hospital

There are some important prognostic factors for papillary thyroid carcinoma (PTC) and follicular thyroid carcinoma (FTC). In this paper, clinicopathological features significantly affecting patient prognosis are described based on our data as well as others. Distant metastasis at diagnosis is the most important prognostic factor for both PTC and FTC. Other than that, preoperative and intraoperative findings are important to evaluate the biological behavior of PTC. Extrathyroid extension, large lymph-node metastasis, and extranodal tumor extension that can be evaluated preoperatively or intraoperatively are significant prognostic factors for PTC patients. In contrast, pathological findings are important not only for diagnosis of FTC, but also for the evaluation of its biological character. Grade of invasiveness (minimally or widely invasive) and degree of differentiation (well differentiated or including a poorly differentiated component) greatly affect the prognosis of FTC patients.

Prevalence, clinicopathologic features, and somatic genetic mutation profile in familial versus sporadic nonmedullary thyroid cancer

BACKGROUND

Although hereditary nonmedullary thyroid cancer is recognized as a distinct and isolated familial syndrome, the precise prevalence and genetic basis are poorly understood. Moreover, whether familial nonmedullary thyroid cancer (FNMTC) has a more aggressive clinical behavior is controversial. The objectives of this study were to determine the prevalence of FNMTC, and compare the extent of disease and tumor somatic genetic alteration in patients with familial and sporadic papillary thyroid cancer.

METHODS

The main study entry criterion was patients who had a thyroid nodule that required a clinical evaluation with fine-needle aspiration biopsy and or thyroidectomy. A family history questionnaire was used to determine the presence of familial and sporadic thyroid cancer. Thyroid nodule fine-needle aspiration biopsy samples and tumor tissue at the time of thyroidectomy were used to test for somatic genetic mutations (BRAF V600E, NRAS, KRAS, NTRK1, RET/PTC1, and RET/PTC3).

RESULTS

There were 402 patients with 509 thyroid nodules enrolled in the study. The prevalence of FNMTC was 8.8% in all patients with thyroid cancer and 9.4% in patients with only papillary thyroid cancer. None of the patients with FNMTC had another familial cancer syndrome. There was no significant difference in gender, tumor size, lymph node metastasis, and overall stage between sporadic and familial cases of thyroid cancer. Patients with FNMTC were younger at diagnosis than patients with sporadic papillary thyroid cancer (p < 0.002). Seventy-nine of the 504 thyroid nodules had somatic genetic mutations (29 BRAF V600E, 29 NRAS, 8 KRAS, 1 NTRK1, 4 RET/PTC1, and 8 RET/PTC3). There was no significant difference in the number or type of somatic mutations between sporadic and hereditary cases of papillary thyroid cancer.

CONCLUSIONS

We found a higher prevalence of FNMTC in patients with papillary thyroid cancer than previously reported. Patients with FNMTC present at a younger age. Somatic mutations and extent of disease are similar in sporadic and FNMTC cases.

Familial thyroid cancer: a review

Thyroid carcinomas can be sporadic or familial. Familial syndromes are classified into familial medullary thyroid carcinoma (FMTC), derived from calcitonin-producing C cells, and familial non-medullary thyroid carcinoma, derived from follicular cells. The familial form of medullary thyroid carcinoma (MTC) is usually a component of multiple endocrine neoplasia (MEN) IIA or IIB, or presents as pure FMTC syndrome. The histopathological features of tumors in patients with MEN syndromes are similar to those of sporadic tumors, with the exception of bilaterality and multiplicity of tumors. The genetic events in the familial C-cell-derived tumors are well known, and genotype-phenotype correlations well established. In contrast, the case for a familial predisposition of non-medullary thyroid carcinoma is only now beginning to emerge. Although, the majority of papillary and follicular thyroid carcinomas are sporadic, the familial forms are rare and can be divided into two groups. The first includes familial syndromes characterized by a predominance of non-thyroidal tumors, such as familial adenomatous polyposis and PTEN-hamartoma tumor syndrome, within others. The second group includes familial syndromes characterized by predominance of papillary thyroid carcinoma (PTC), such as pure familial PTC (fPTC), fPTC associated with papillary renal cell carcinoma, and fPTC with multinodular goiter. Some characteristic morphologic findings should alert the pathologist of a possible familial cancer syndrome, which may lead to further molecular genetics evaluation.

Familial nonmedullary thyroid carcinoma-clinical relevance and prognosis. A European multicenter study. ESES Vienna presentation

PURPOSE

Approximately 5% of differentiated thyroid carcinomas are of familial origin. These familial nonmedullary thyroid carcinomas (FNMTC) have an increased risk of multifocal disease and lymph node involvement. Consequently, higher recurrence rates and decreased disease-specific survival rates are described. The best surgical approach is discussed controversially.

PATIENTS AND METHODS

A survey among the international members of the German Society of Endocrine Surgeons revealed 20 families with two or more first-degree relatives with FNMTC. The mean age of the 41 patients (30 female, 11 male) with FNMTC was 40.6 years (18-73 years).

RESULTS

Total thyroidectomy was performed in 31 of 41 patients (76%). Ninety-five percent of the tumors were papillary carcinomas. Two of 41 patients had follicular carcinomas. Ten patients (24%) with papillary carcinomas were diagnosed with Hashimoto's thyroiditis. The mean tumor size was 1.45 cm. FNMTC was multifocal in 12 patients (29%). A systematic lymph node dissection was performed in 21 of 41 patients (51%). Lymph nodes metastases were found in seven of these 21 patients. Twenty-eight of the patients (68%) underwent postoperative radioiodine ablation. After a mean follow-up of 7.2 years, 39 patients (95%) were disease free. One patient developed local recurrence and lung metastases, 10 and 25 years, respectively, after initial diagnosis. Another patient died 2 years postoperatively from advanced metastatic disease.

CONCLUSIONS

FNMTC is associated with an early onset of small, mostly papillary thyroid carcinomas and an increased risk of multifocality and lymph node involvement. Total thyroidectomy and systematic neck dissection are recommended together with radioiodine ablation. Screening for first-degree relatives should start at age 18 years.

Review Article: The Familial Counterparts of Follicular Cell—Derived Thyroid Tumors

The follicular cell—derived thyroid cancers (termed nonmedullary thyroid cancers—NMTCs) occur mostly sporadically, but intriguingly, NMTC has the highest familial risk among all cancer sites. This epidemiological observation is strengthened by the clinical occurrence of NMTC in familial aggregation (FNMTC) and by the detection of chromosomal loci in linkage with the disease phenotype. FNMTC loci have been proposed at 14q, 1q21, 19p13.2, 2q21, 8p23, 8q24, 1q21, and 6q22, but to date, no causative mutations have been linked to FNMTCs. In this review, the authors focus on the clinical, morphological, and molecular aspects that characterize familial tumors. Some morphological patterns may alert for a familial disease. FNMTCs share several of the somatic molecular changes associated with sporadic tumors. New genes affected by somatic changes have been disclosed within regions harboring FNMTC loci.

[Hereditary thyroid cancer]

Hereditary thyroid carcinomas are present in about 5% of differentiated (DTC) and 25% of medullary thyroid carcinomas (MTC). They are part of a multiorgan tumour syndrome (e. g. FAP Gardner's syndrome with DTC and MEN 2 syndrome with MTC) or confined to the thyroid gland. Hereditary thyroid carcinomas typically show multifocal growth and occur in young patients. Due to germ cell mutations as the underlying cause of disease, partial thyroidectomies that may be justified in early sporadic carcinomas are not indicated in this type of tumours. In the case of hereditary DTC, the genetic basis of the disease has been demonstrated only in syndromatic tumour variants. In most nonsyndromatic cases, specific genetic alterations have not yet been identified. In both types of hereditary DTC, prophylactic thyroidectomy is not warranted due to the favourable prognosis of tumours that do not differ from sporadic ones. Point mutations of the RET proto-oncogene have been known for 15 years to be the genetic basis of hereditary MTC. Recently several new mutations were discovered; however, final conclusions regarding their clinical significance are not possible at present. Basically it has been shown that the clinical aggressivity of tumour development follows a genotype-phenotype correlation (risk groups 1-3). However, in mutations of all risk classes there exists a wide spectrum of different stages of hereditary C-cell disease in individual risk groups. Regarding time and extent of prophylactic thyroidectomy (without or with lymph node dissection) a combined molecular-biochemical concept including the use of pentagastrin-stimulated calcitonin values is therefore recommended.

Familial thyroid carcinoma: a diagnostic algorithm

Thyroid carcinomas derived from follicular cells are the most common endocrine malignancies, and papillary thyroid carcinoma (PTC) is the most common type. Although, the majority of papillary and follicular thyroid carcinomas (FTCs) are sporadic, familial forms have been described in recent years. Familial syndromes are classified into familial medullary thyroid carcinoma and familial nonmedullary thyroid carcinoma. Multifocal papillary carcinoma is the most frequent presentation of familial nonmedullary thyroid carcinoma, and based on clinico-pathologic findings it is divided into 2 groups. The first includes familial syndromes characterized by a predominance of nonthyroidal tumors, such as familial adenomatous polyposis, PTEN-hamartoma tumor syndrome, Carney complex type 1, and Werner syndrome. The second group includes familial syndromes characterized by a predominance of NMTC, such as pure familial (f) PTC with or without oxyphilia, fPTC with papillary renal cell carcinoma, and fPTC with multinodular goiter. Medullary thyroid carcinoma is derived from calcitonin-producing C cells. The familial form accounts for 20% to 25% of cases, and is usually a component of multiple endocrine neoplasia (MEN) IIA or IIB, or presents as pure familial medullary thyroid carcinoma syndrome. C-cell hyperplasia is the precursor lesion of these heritable syndromes. Some characteristic morphologic findings should alert the pathologist of a possible familial cancer syndrome, which may lead to further molecular genetic evaluation.

Prevalence and prognosis of familial follicular thyroid carcinoma

Although the responsible gene has not yet been identified, patients with differentiated thyroid carcinoma, including papillary and follicular carcinomas, demonstrating a family history have been reported and patients having one or more family members with differentiated carcinoma among their first-degree relatives are designated as having familial nonmedullary thyroid carcinoma (FNMTC). In this study, we investigated the biological characteristics, including prognosis, of familial follicular carcinoma. Three hundred and nineteen patients who underwent initial surgery for follicular thyroid carcinoma between 1987 and 2004 who were enrolled in this study. Of these 319 patients, 6 patients (1.9%) in 6 families were classified as having familial follicular carcinoma based on the criteria described above. The incidence of aggressive characteristics such as male gender, age 45 years or older, poor differentiation, widely invasive carcinoma, tumor larger than 4 cm and distant metastasis at diagnosis did not differ between familial and sporadic follicular carcinomas. One patient with familial follicular carcinoma underwent re-operation because of newly detected papillary carcinoma in the remnant thyroid 160 months after the initial surgery, but none of the 6 patients with familial carcinoma showed recurrence or died of follicular carcinoma. We can therefore conclude that FMNTC of the follicular type is very rare and there is no evidence that familial follicular carcinoma is more aggressive or has a worse prognosis than sporadic follicular carcinoma. The therapeutic strategy for follicular carcinoma might depend on conventional prognostic factors such as poor differentiation and distant metastasis at diagnosis, but not on whether the carcinoma is familial or sporadic.

Familial non-medullary thyroid carcinoma: an update

Familial thyroid cancer can arise from follicular cells (familial non-medullary thyroid carcinoma (FNMTC)) or from the calcitonin-producing C-cell (familial medullary thyroid carcinoma). This is usually a component of multiple endocrine neoplasias (MEN) IIA or IIB, or as pure familial medullary thyroid carcinoma syndrome. The genetic events in the familial C-cell-derived tumors are known and genotype-phenotype correlations are well established. In contrast, the case for a familial predisposition of non-medullary thyroid carcinoma is only now beginning to emerge. Although the majority of papillary (PTC) and follicular thyroid carcinomas (FTC) are sporadic, familial tumors account for over 5% of cases. The presence of multifocal papillary carcinoma is a common feature of FNMTC. The familial follicular cell-derived tumors or non-medullary thyroid carcinomas encompass a heterogeneous group of diseases, including diverse syndromic-associated tumors and non-syndromic tumors. Based on clinico-pathologic findings, FNMTC is divided into two groups. The first includes familial syndromes characterized by a predominance of non-thyroidal tumors, such as familial adenomatous polyposis (FAP), PTEN hamartoma tumor syndrome (PHTS), Carney complex type 1, and Werner syndrome. The second group includes familial syndromes characterized by a predominance of NMTC, such as pure familial (f) PTC with or without oxyphilia, fPTC with papillary renal cell carcinoma, and fPTC with multinodular goiter. Some characteristic morphologic findings should alert the pathologist of a possible familial cancer syndrome, which may lead to further molecular genetic evaluation.

[Familial nommedullary thyroid cancer]

Nonmedullary thyroid carcinoma, originating from thyroid epithelial cells, is the most frequent thyroid malignant neoplasia. Since 1955, there has been increasing evidence that this cancer may have a familial predisposition. It is now established that around 4.2% of all nonmedullary thyroid carcinomas occurs on the background of familial predisposition. These cases are often more aggressive, due to early onset, multifocality and a higher percentual of recurrences. An autossomal dominant inheritance pattern appears likely in most families, although the exact genes responsible for this syndrome have not yet been identified. Patients affected by this cancer should be treated with total thyroidectomy routinely and, in most cases, lymph node dissection, followed by iodine ablation and TSH suppressive therapy with levothyroxine. Some authors also recommend that first-degree relatives of patients with nonmedullary thyroid cancer (especially women) should be submitted to neck ultrasound for thyroid cancer screening, aiming early diagnosis for better treatment results.

An Evidence-based Approach to Familial Nonmedullary Thyroid Cancer: Screening, Clinical Management, and Follow-up

Approximately 5% of nonmedullary thyroid cancers are of familial origin. When two or more family members are diagnosed with nonmedullary thyroid cancer in the absence of other known associated syndromes it is termed familial nonmedullary thyroid cancer (FNMTC). The genetic inheritance of FNMTC remains unknown, but it is believed to be an autosomal dominant mode of inheritance with incomplete penetrance and variable expressivity. FNMTC has been shown to be more aggressive and to have a worse prognosis than sporadic nonmedullary thyroid cancer. For example, studies have demonstrated that individuals with FNMTC have an increased risk of multifocal disease, local invasion, and lymph node metastases. These aggressive features appear to contribute to the higher recurrence rate and decreased disease-free survival seen in FNMTC patients compared to those with sporadic differentiated thyroid cancer. This article is an overview of the literature available in the English language discussing FNMTC. Critical questions regarding the screening, management, and follow-up of these patients are addressed with answers proposed based on the available literature. The quality of the evidence is ranked according to Sackett's criteria. Overall, the literature quality is somewhat limited, based on the low prevalence of FNMTC, the difficulty in identifying familial cases, the variable study designs, and limited long-term follow-up.

CONCLUSIONS

To date, the optimal clinical approach is yet to be established, but improved awareness and screening will permit earlier detection, more timely intervention, and hopefully improved outcomes for patients and their families.

On the prevalence of familial nonmedullary thyroid cancer in multiply affected kindreds

Clinical and genetic studies of familial nonmedullary thyroid cancer (FNMTC) have yielded conflicting results concerning the aggressiveness of the tumors, and uncertainty of their genetic makeup. In most reports of multiply affected families, the composition of the kindreds has favored families of 2 affected members. Using data for differentiated thyroid cancer (DTC) provided by the Surveillance Epidemiology and End Results (SEER) branch of the National Cancer Institute, and fine-needle aspiration data from Mayo Clinic, I found that the likelihood of 2 cases of sporadic DTC (RR) in a 9-member first-degree family was 1.25% of all DTC families, amounting to 39.4% of 306 multi-hit families reported in the literature. To study the remaining affected families I used the Bernouilli trials model of exact probability. The 60.6% of non-RR, multiply affected families are mostly concentrated in kindreds of 2 to 5 affected members. In 2-hit families, 62%-69% of affected members are sporadic (RR) cases. In families having 3 or more affected members, fewer than 6% have 1 or more sporadic (R) cases, and fewer than 0.15% have 2 or more. In families of 3 to 5 affected members, more than 96% of affected members have the familial (F) trait. Approximately 1 of 338 DTC cases carries the F-trait. Since approximately 40% of multiply affected member first-degree kindreds of DTC, and a significant majority of 2-hit families, are composed of clinically evident, sporadic cases only clinical and genetic investigations of FNMTC should center on families of 3 or more affected members.

Detection of Asymptomatic Differentiated Thyroid Carcinoma by Neck Ultrasonographic Screening for Familial Nonmedullary Thyroid Carcinoma

Mass screening for the purpose of detecting thyroid cancer at its earliest stage may not be recommended at the present time, but screening focused on certain risk groups is advocated. Familial nonmedullary thyroid carcinoma (FNMTC) is a distinct clinical entity with a high incidence of multifocality and association with multiple benign nodules. FNMTC patients have shorter disease-free survival than do sporadic disease patients because of frequent locoregional recurrence. Screening by neck ultrasonography was performed for symptom-free family members of patients with FNMTC. A total of 149 subjects representing 53 FNMTC families were examined in this study. The average age of the patients was 41.0+/-19.0 years (range 3-76 years) with a female/male ratio of 104:45. At least one thyroid nodule was found in 77 (51.7%) of the 149 patients. Surgery was performed in 18 patients, and thyroid cancer was discovered in 15 of them (10.1%; 14 women, 1 man; 32-61 years of age). Papillary thyroid cancer (PTC) was found in 14 and follicular thyroid cancer combined with PTC in 1. The tumors averaged 9.1+/-5.4 mm (3-21 mm) in greatest diameter. Intraglandular metastases were found in 7 (47%) of the 15 patients with thyroid cancer. Lymph node metastases were found in 6 (43%). Ultrasonographic screening for FNMTC family members may enable the discovery of asymptomatic thyroid cancer. Because of the high incidence of intraglandular and lymph node metastases, we recommend screening with ultrasonography for early detection in family members of patients with FNMTC.

Familial clustering of non-medullary thyroid cancer

Although genetical inheritance is an well established fact with medullary cancer of thyroid no such clear cut proof exist with papillary or follicular neoplasm of thyroid It's a fact that family clusters of non-medullary thyroid tumor exist, it requires more precise identification of genetical inheritance These clusters behave in a separate way and requires a more aggressive treatment for low recurrence rate and better prognosis.

Nonpalpable thyroid carcinoma: clinical controversies on preoperative selection

This article emphasizes some controversies concerning the preoperative selection of nonpalpable thyroid tumors. The prevalence of occult thyroid carcinoma in surgical series (1.8-10%) is not higher than in autopsy thyroid series (2.7-24%). The prevalence of occult thyroid carcinoma in thyroid glands examined in the same institution by ultrasound, for a clinical thyroid abnormality or for investigation of other neck structures without clinically evident or suspected thyroid disease, varies from 3% to 8% and is very similar independent of the fact that a thyroid abnormality is or is not the indication for ultrasonography. These data suggest that the presence of a thyroid disease is not a risk factor for harboring an occult thyroid carcinoma (except for C-cell hyperplasia in the rare case of MEN 2 syndromes). As it is not cost effective to examine all the nonpalpable lesions with fine-needle aspiration (FNA) guided by ultrasounds, it is necessary to define to which extent ultrasound is useful in selecting those lesions to be examined cytologically by FNA. The use of ultrasound to select these lesions is very controversial. Ultrasound-guided cytologic diagnosis of nonpalpable nodules is not as accurate as in the case of palpable nodules. Sampling of material adequate for cytologic analysis depends on the lesion size; it is 64% for a 0.7-cm lesion and it increases to 86.7% for a mean size of 1.1 cm. For the diagnosis of occult thyroid carcinomas (< or =1 cm), sensitivity is 35.8% and false-negative results are 49.3%. Nonpalpable nodules with a size of 1.5 cm represent an absolute indication to perform an ultrasound-guided FNA because this is the size limit for dividing thyroid nodules in probably innocuous or potentially dangerous categories and because the cytologic diagnosis of nodules of this size is sufficiently reliable. For the smaller incidentally discovered thyroid nodules following ultrasound, physicians should discuss with the patient whether and when to perform an ultrasound-guided FNA considering the patient's data (risk factors, age, health state, etc.), the natural history of a small thyroid carcinoma, as well as the accuracy of ultrasound and ultrasound-guided FNA in the specific institution.

Familial thyroid cancer

Familial thyroid cancer can arise from parafollicular cells (familial medullary thyroid cancer) or from follicular cells (familial nonmedullary thyroid cancer). Familial medullary thyroid cancer may occur in isolation or as part of multiple endocrine neoplasia (MEN) type II syndromes. Genetic testing for a RET mutation on chromosome 10 is used to identify new family members who are gene carriers. Total thyroidectomy should be used in gene carriers without clinical disease before age 6 in medullary thyroid cancer and MEN type IIA, and as soon as the diagnosis is made in MEN type IIB after the first year of life. Those with clinical disease should have at least a bilateral central neck dissection. Modified radical neck dissection is recommended for patients when the primary tumor is 1.5 cm. A normal postoperative serum calcitonin level suggests that the operation has been curative. Physicians need to be aware of ethical and lifestyle issues related to patients with familial disease and their family members. Familial nonmedullary thyroid cancer occurs as a discrete entity or as part of other family cancer syndromes such as Gardner syndrome, Cowden disease, and other rare syndromes. Familial nonmedullary thyroid cancer almost exclusively includes patients with papillary or Hurthle cell cancers. These families appear to have more benign thyroid conditions. The gene (or genes) for familial papillary thyroid cancer is yet to be identified, whereas that for some Hurthle cells (TCO) has been mapped to chromosome 19p13.2. Familial nonmedullary thyroid cancer is somewhat more aggressive than its sporadic counterpart, but is less aggressive than medullary thyroid cancer. Total thyroidectomy and central neck dissection followed by radioactive iodine ablation and thyroid hormone suppression appear to be the most effective therapy.