Familial nonmedullary thyroid cancer

Familial Non-Medullary Thyroid Carcinoma in Pediatric Age: Our Surgical Experience

Background

The purpose of the article was to evaluate the existence of significant clinical, pathological and prognostic differences between familial and sporadic form of pediatric non-medullary thyroid carcinoma, in order to tailor the therapeutic strategy to be adopted for patients with family history.

Methods

We analyzed the records of 76 pediatric patients that underwent surgery for differentiated thyroid cancer from 2014 to 2019 at the Surgical Pathology Department of the University of Pisa, Italy. Among these, 20 (26,3%) had positive family history (familial non-medullary thyroid carcinoma—FNMTC group) while 56 (73.7%) were affected by sporadic forms (sporadic non-medullary thyroid carcinoma—SNMTC group).

Results

In our study, the correlation between the FNMTC and the SNMTC group showed no difference in terms of tumor features like multifocality, bilaterality, capsular/extracapsular invasion and the presence of vascular emboli. A statistical significance, on the other hand, was revealed by observation of clinical outcomes, such as distant metastasis (p = 0,022), persistence of disease (p = 0,054) and necessity of radioiodine sessions (p = 0,005).

Conclusions

These findings suggest that family history may have an independent role on the outcome, expressing its action through an intrinsic more aggressive biological behavior. Therefore, familial non-medullary thyroid carcinoma in children represents a nosological entity that requires an accurate pre-operative evaluation, an adequate surgical strategy and a careful follow up.

Is Familial Nonmedullary Thyroid Cancer A More Aggressive Type of Thyroid Cancer?

OBJECTIVES

Familial non-medullary thyroid cancer (FNMTC) is a distinct entity, increasingly diagnosed. By lacking an accurate genetic diagnostic test, its diagnosis is currently clinically based, with an ongoing debate over whether it has a more aggressive clinical behavior than sporadic non-medullary thyroid cancer (SNMTC). We seek to compare in this study, the clinicopathological variables, and the outcome of FNMTC versus SNMTC patients.

METHODS

We retrospectively searched a database of 465 patients that underwent thyroidectomy at Assaf Harofeh Medical Center (91.4% between 1990 and 2019) for demographics, risk factors, medical history, diagnostic workup, primary treatment, follow-up, and disease outcome data. We compared 47 FNMTC versus 321 SNMTC patients, and FNMTC patients with ≥2 (n = 34) versus ≥3 (n = 13) first-relative affected members.

RESULTS

There were no significant differences in demographics, histopathology, TNM stage, treatment, and disease outcome between the FNMTC and SNMTC groups. The T2 and T4 tumor stage in the ≥3-member group were 25% and 8.3% compared to 0% and 0% in the two-member group (P = .02 and P = ns, respectively). Also, LN involvement was significantly higher in the ≥3-member group (61.6% vs. 24.2%, respectively; P = .036).

CONCLUSION

FNMTC is not a more aggressive disease than SNMTC, but this may not apply for the ≥3-affected-relatives group. A large multicenter study including only families with three or more affected relatives is needed. Until then, a family history of NMTC should not be overlooked.

LEVEL OF EVIDENCE

3/5 Laryngoscope, 131:E677-E681, 2021.

Familial Endocrine Syndromes

Endocrine tumors may present as sporadic events or as part of familial endocrine syndromes. Familial endocrine syndromes (or inherited tumor/neoplasm syndromes) are characterized by multiple tumors in multiple organs. Some morphologic findings in endocrine tumor histopathology may prompt the possibility of familial endocrine syndromes, and these recognized histologic features may lead to further molecular genetic evaluation of the patient and family members. Subsequent evaluation for these syndromes in asymptomatic patients and family members may then be performed by genetic screening.

[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.

Gene therapy for thyroid cancer

Although most thyroid cancers may be cured by surgery and ¹³¹I therapy, approximately 10-20% of patients die from advanced differentiated and anaplastic tumors that are unresponsive to conventional treatments. Thus, alternative approaches such as gene therapy are of interest, especially using targeted therapeutic gene delivery. Several strategies have been designed specifically for thyroid cancer and some have proven to be feasible in preclinical studies. In particular, it is suggested that combined gene therapy approaches, as well as multimodality therapeutic regimens, including gene therapy and conventional treatments, should be pursued to achieve clinically significant results. The recent discovery of new markers of thyroid cancer should improve the efficacy of gene therapy.

Prophylaktische Chirurgie der Schilddrüse

Early diagnosis for thyroid carcinoma, potentially before neoplastic transformation has taken place, would allow preventive and thus curative surgical intervention. Identifying and characterizing the RET proto-oncogene as the disease-causing gene for hereditary medullary thyroid carcinoma and then establishing a genotype-phenotype correlation served as the prerequisite for the risk-adapted prophylactic surgical approach practised today. Carriers of RET mutations associated with very aggressive tumour behaviour should be subjected to prophylactic thyroidectomy within the 1st year of life. For individuals harbouring less virulent types of mutations, prophylactic intervention is recommended at 5-20 years. Although genetic research on hereditary nonmedullary thyroid cancer is still in progress, initial results indicate the need of prophylactic surgical treatment also for this subgroup of thyroid neoplasia.

The T1799A BRAF mutation is not a germline mutation in familial nonmedullary thyroid cancer

OBJECTIVE

Familial nonmedullary thyroid cancer (FNMTC) is relatively common but its predisposing genetic alteration is unclear. As the somatic T1799A BRAF mutation is highly prevalent in papillary thyroid cancer, the aim was to test whether this mutation was a susceptibility mutation for FNMTC.

SUBJECTS AND METHODS

The T1799A BRAF mutation as a possible germline mutation was examined in 40 subjects from 23 families with a history of FNMTC. Direct DNA sequencing was performed on white blood cell DNA samples to analyse the mutation status.

RESULTS

No T1799A BRAF mutation was found in this group of subjects as germline mutation.

CONCLUSION

The T1799A BRAF mutation is not a germline mutation or susceptibility genetic event for FNMTC.

Familial nonmedullary thyroid cancer

Familial nonmedullary thyroid cancer (FNMTC) is a syndrome of familial clustering of thyroid cancers of follicular cell origin. It is characterized by multifocality, early onset, more recurrences, and a higher degree of aggressiveness than nonfamilial thyroid cancers of follicular cell origin. An autosomal dominant inheritance pattern with reduced penetrance appears likely in most pedigrees. Although several candidate genes responsible for isolated clinical variants of FNMTC have been identified in single families, the gene(s) responsible for the vast majority of FNMTC cases has yet to be identified. Members of FNMTC cohorts should be followed longitudinally with physical examination and ultrasonography, and aggressively treated when cancer is diagnosed. When cancer is diagnosed, total thyroidectomy should be performed, and most patients should have a prophylactic central neck dissection and a therapeutic lateral functional neck dissection, postoperative radioiodine ablation and thyroid-stimulating hormone (TSH) suppressive therapy. Close follow-up with stimulated thyroglobulin levels, neck ultrasounds, and radioiodine scans are also central to the management strategy.