Prophylactic thyroidectomies in MEN2 syndrome: Management and outcomes

Incidence of medullary thyroid carcinoma and Hirschsprung disease based on the cosmos database

PURPOSE

Multiple endocrine neoplasia Type 2A (MEN2A) can occur with Hirschsprung disease (HD) due to mutation in the RET proto-oncogene, with the majority developing medullary thyroid carcinoma (MTC). Given the comorbidity, many parents have contacted us to share concerns and unfortunate experiences about the prevalence rates of MEN2A/MTC in patients with HD. The aim is to determine the prevalence rate of patients with HD and MEN2A or medullary thyroid carcinoma, respectively.

METHODS

This is a cross-sectional study of the COSMOS database from January 01, 2017, to March 08, 2023. The database was searched for patients diagnosed with MEN2A, MTC, and HD. IRB exemption was provided (COMIRB #23-0526).

RESULTS

The database contained 183,993,122 patients from 198 contributing organizations. The prevalence of HD and MEN2A was 0.00002%, and for HD and MTC was 0.000009%. One in 66 patients (1.5%) with MEN2A also had HD. One in 319 patients (0.3%) in the HD group had MEN2A. One in 839 patients (0.1%) within the HD population had MTC.

CONCLUSION

The prevalence of MTC and HD or MEN2A and HD in the study population was low. Considering that almost all MEN2A patients have a positive family history, this data does not support the general genetic testing of HD patients.

Medullary thyroid carcinoma in children: current state of the art and future perspectives

Medullary thyroid carcinoma (MTC) is a distinct type of malignant thyroid tumor in cell origin, biological behavior, and natural history. It accounts for 1.6% of all thyroid cancers and presents either sporadically or as a hereditary disease, the latter occurring as a part of multiple endocrine neoplasia (MEN) 2A and MEN2B syndromes or as a familial MTC disease with no other manifestations. The gene responsible for the hereditary form is the rearranged during transfection (RET) gene, a proto-oncogene located to human chromosome 10. Most pediatric MTC cases have been discovered after genetic testing investigations, leading to the concept of prophylactic surgery in presymptomatic patients. Therefore, the genetic status of the child, along with serum calcitonin levels and ultrasonographic findings, determine the appropriate age for prophylactic surgical intervention. Nevertheless, a diagnosis at an early stage of MTC warrants total thyroidectomy and central lymph node dissection with the addition of lateral/contralateral lymph node dissection depending on the tumor size, ultrasonographic evidence of neck disease, or calcitonin levels. Conversely, locally advanced/unresectable or metastatic MTC is primarily treated with multikinase inhibitors, while more specific RET inhibitors are being tested in clinical trials with promising results.

Management and results of thyroidectomies in pediatric patients with MEN 2 syndrome

AIM OF THE STUDY

To evaluate the outcome of prophylactic thyroidectomies (PT) in patients with MEN 2 syndrome in a tertiary center.

METHODS

A retrospective study was designed, including all patients with MEN 2 syndrome who underwent PT between 2000 and 2019. Demographics, gene mutation, postoperative complications and histopathological findings were registered.

MAIN RESULTS

30 patients were included (29 MEN 2A and 1 MEN 2B) with a median age at surgery time of 7.0 ± 3.2 years. Familiar history was present in all but 3 patients. A therapeutic thyroidectomy was performed in 2 patients due to evidence of medullary thyroid carcinoma (MTC, both were late diagnosis), and in the other 28 cases, a PT was performed. 8 patients had a RET mutation ranked as Moderate Risk (American Thyroid Association): median age at surgery was 7.2 ± 4.2 years, and histological findings were C-cell hyperplasia (n = 6) and no alterations (n = 2). 16 patients had a high risk mutation; median age at surgery time was 6.9 ± 2.8 years and histological findings were normal thyroid gland (n = 1), C Cell Hyperplasia (n = 8), microcarcinoma (n = 6), and MTC (n = 1). The mean hospital stay was 1.4 ± 0.68 days. No intraoperative complications or recurrent laryngeal nerve injuries were registered. 7 patients presented a transient hypoparathyroidism and 1 patient had permanent hypoparathyroidism.

CONCLUSIONS

Early PT in patients with MEN 2 syndrome is a safe procedure when performed by an experienced team of Pediatric Surgeons and with a multidisciplinary approach. Early genetic analysis and familial counselling is essential to prevent the development of a MTC.

Lymph node metastases in pediatric medullary thyroid carcinoma

BACKGROUND

Unlike medullary thyroid carcinoma in adults, the vast majority of pediatric medullary thyroid carcinoma is hereditary. Pediatric medullary thyroid carcinoma is known to have different genetic alterations driving tumorigenesis, but it is not known if pediatric medullary thyroid carcinoma has different clinicopathologic features. This study aims to identify which pediatric medullary thyroid carcinoma patients might warrant elective neck dissection.

METHODS

We selected all patients ages 0 to 19 diagnosed with clinically evident medullary thyroid carcinoma in the National Cancer Database between 2004 to 2016. Clinicopathologic factors, treatments, and outcomes were analyzed and compared between this cohort and adults (ages ≥20) with medullary thyroid carcinoma.

RESULTS

One hundred twenty-five pediatric medullary thyroid carcinoma (median age: 13) and 5,086 adult medullary thyroid carcinoma (median age: 57) patients were identified. Pediatric patients had smaller tumors (median diameter: 1.2 cm vs 2.0 cm; P < .001), lower rates of nodal metastases (n = 31, 36.9% vs 1,689, 50.4%; P = .02) but double the incidence of multifocal tumors (n = 70, 59.3%, vs 1,412, 29.9%; P < .001) compared with adults. Multifocal tumors conferred a significantly increased risk of nodal metastases in adult medullary thyroid carcinoma (64.4% vs 43.2%; P < .001) but not pediatric medullary thyroid carcinoma (37.7% vs 35.7%; P = .85). Nodal metastases were more frequent among older children (0-5 years: 0.0%, 6-12: 40.7%, 13-19: 41.7%; P = .04). However, rates of occult nodal metastases were similar between older children (6-19 years: n = 12, 21.4%) and adults (557, 25.8% P = .56).

CONCLUSION

Pediatric medullary thyroid carcinoma has lower rates of lymph node metastases compared with adults. The risk of nodal disease was low among the youngest children, but older children ages 6 to 19 were at considerable risk for occult metastases. These findings could guide clinicians in selecting pediatric patients considered for elective lymph node dissection.

Preimplantation Genetic Testing of Multiple Endocrine Neoplasia Type 2A

Background: When discussing matters of reproduction, the 2015 revised guidelines for the management of medullary thyroid carcinoma recommend that patients diagnosed with multiple endocrine neoplasia type 2A (MEN 2A) are informed about the option of Preimplantation Genetic Testing for Monogenic Disorders (PGT-M). In addition, patients seem to have a genuine interest in reproductive options. However, there are just two reports worldwide of this technology being used for patients with MEN 2A. We here present, in a Danish couple where the man has MEN 2A, the first European family with children born after PGT-M. Objective: To report the results of PGT-M in relation to multiple endocrine neoplasia type 2A with the aim to increase awareness among physicians treating this and other genetic disorders. Methods: A Danish couple was referred to the PGT Center at Copenhagen University Hospital Rigshospitalet and opted for PGT-M after counseling by a clinical geneticist and a fertility doctor. The embryos were diagnosed using microsatellite polymorphic marker close to RET. Results: The couple had two healthy children born in 2017 and 2019 as a result of a total of three ICSI treatments including controlled ovarian stimulation, oocyte retrieval and PGT-M, and a total of six blastocyst transfers. Conclusion: A session with a clinical geneticist covering all reproductive options for patients in early adult life is a relevant part of the clinical management of patients with MEN 2A, and other patients with hereditary cancer predisposition syndromes.

Prophylactic thyroidectomy in multiple endocrine neoplasia type 2A in children: a single centre experience

Background To describe the complications and long-term results in patients with multiple endocrine neoplasia type 2A (MEN 2A) syndrome in whom a prophylactic thyroidectomy was performed, in relation to the recommendations of the American Thyroid Association (ATA). Methods A retrospective study of 14 patients with MEN 2A thyroidectomized between 2000 and 2017. We reviewed demographic, clinical, analytical and radiological data. Postoperative complications and long-term follow-up were analyzed. Results We treated eight boys and six girls with a median age of 5 years old (range 2-10). The predominant genetic mutation belonged to codon 634 (8/14, 57.14%). Total thyroidectomy (TT) without cervical lymphadenectomy was performed in all patients. A right upper parathyroidectomy was performed in one patient due to intraoperative suspicion of increased volume. Histological study revealed no alterations. Two patients presented transient hypocalcemia postoperatively and no patient had permanent hypocalcemia or nerve damage. Pathological anatomy confirmed medullary thyroid microcarcinoma in 5/14 patients: all carrying codon 634 mutation and three of them with preoperative basal calcitonin levels <20 pg/mL. No recurrences or metastases have been detected after a mean follow-up of 8 years. A patient with codon 634 mutation developed a unilateral pheochromocytoma at 25 years of age. No patient has presented hyperparathyroidism. Conclusions Prophylactic thyroidectomy without cervical lymphadenectomy is an effective and safe preventive treatment in patients with MEN 2A syndrome when it is performed by experienced surgeons in reference centers.

Pediatric thyroidectomy: Favorable outcomes can be achieved by a multidisciplinary team of pediatric providers

AIM OF THE STUDY

Recent publications suggest pediatric surgeons may not be well suited to perform thyroid surgeries unless considered high volume. We sought to assess the outcome of thyroidectomies performed by pediatric surgeons in an academic setting.

METHODS

We reviewed charts of patients younger than 18 years who underwent thyroid surgeries at a free standing children's hospital between April 2006 and October 2015.

MAIN RESULTS

The analysis included 118 surgeries in 98 patients (mean age 11.8 years). Most surgeries were performed by a single pediatric surgeon (average 10 thyroidectomies per year). The commonest indication for resection was thyroid nodule (64%). 80% of patients had a single surgery; the remainder had two, including 13 completion hemithyroidectomies. Cancer was found in 37% of specimens, with papillary subtype being most common (72%). Seven patients had locoregional metastases and one had pulmonary metastases. Among the 17 malignant cases that had a second intervention, 6 had malignancy in the resected specimen. There were no deaths in the follow up period (mean 2.7 years). Two patients had permanent hypocalcemia, and three had persistent unilateral recurrent laryngeal nerve injuries causing dysphonia for a total permanent complication rate of 4.2%.

CONCLUSIONS

We conclude that pediatric thyroidectomy is a safe procedure when performed by pediatric surgeons. Our rate of complications is comparable to those reported in the literature. Our data highlight the need for a vigilant and multidisciplinary approach for children with thyroid pathology.

TYPE OF STUDY

Treatment study.

LEVEL OF EVIDENCE

IV.