Andrew J. Bauer

Guidelines for the Treatment of Hypothyroidism: Prepared by the American Thyroid Association Task Force on Thyroid Hormone Replacement

BACKGROUND A number of recent advances in our understanding of thyroid physiology may shed light on why some patients feel unwell while taking levothyroxine monotherapy. The purpose of this task force was to review the goals of levothyroxine therapy, the optimal prescription of conventional levothyroxine therapy, the sources of dissatisfaction with levothyroxine therapy, the evidence on treatment alternatives, and the relevant knowledge gaps. We wished to determine whether there are sufficient new data generated by well-designed studies to provide reason to pursue such therapies and change the current standard of care. This document is intended to inform clinical decision-making on thyroid hormone replacement therapy; it is not a replacement for individualized clinical judgment. METHODS Task force members identified 24 questions relevant to the treatment of hypothyroidism. The clinical literature relating to each question was then reviewed. Clinical reviews were supplemented, when relevant, with related mechanistic and bench research literature reviews, performed by our team of translational scientists. Ethics reviews were provided, when relevant, by a bioethicist. The responses to questions were formatted, when possible, in the form of a formal clinical recommendation statement. When responses were not suitable for a formal clinical recommendation, a summary response statement without a formal clinical recommendation was developed. For clinical recommendations, the supporting evidence was appraised, and the strength of each clinical recommendation was assessed, using the American College of Physicians system. The final document was organized so that each topic is introduced with a question, followed by a formal clinical recommendation. Stakeholder input was received at a national meeting, with some subsequent refinement of the clinical questions addressed in the document. Consensus was achieved for all recommendations by the task force. RESULTS We reviewed the following therapeutic categories: (i) levothyroxine therapy, (ii) non-levothyroxine-based thyroid hormone therapies, and (iii) use of thyroid hormone analogs. The second category included thyroid extracts, synthetic combination therapy, triiodothyronine therapy, and compounded thyroid hormones. CONCLUSIONS We concluded that levothyroxine should remain the standard of care for treating hypothyroidism. We found no consistently strong evidence for the superiority of alternative preparations (e.g., levothyroxine-liothyronine combination therapy, or thyroid extract therapy, or others) over monotherapy with levothyroxine, in improving health outcomes. Some examples of future research needs include the development of superior biomarkers of euthyroidism to supplement thyrotropin measurements, mechanistic research on serum triiodothyronine levels (including effects of age and disease status, relationship with tissue concentrations, as well as potential therapeutic targeting), and long-term outcome clinical trials testing combination therapy or thyroid extracts (including subgroup effects). Additional research is also needed to develop thyroid hormone analogs with a favorable benefit to risk profile.

Management Guidelines for Children with Thyroid Nodules and Differentiated Thyroid Cancer.

BACKGROUND Previous guidelines for the management of thyroid nodules and cancers were geared toward adults. Compared with thyroid neoplasms in adults, however, those in the pediatric population exhibit differences in pathophysiology, clinical presentation, and long-term outcomes. Furthermore, therapy that may be recommended for an adult may not be appropriate for a child who is at low risk for death but at higher risk for long-term harm from overly aggressive treatment. For these reasons, unique guidelines for children and adolescents with thyroid tumors are needed. METHODS A task force commissioned by the American Thyroid Association (ATA) developed a series of clinically relevant questions pertaining to the management of children with thyroid nodules and differentiated thyroid cancer (DTC). Using an extensive literature search, primarily focused on studies that included subjects ≤18 years of age, the task force identified and reviewed relevant articles through April 2014. Recommendations were made based upon scientific evidence and expert opinion and were graded using a modified schema from the United States Preventive Services Task Force. RESULTS These inaugural guidelines provide recommendations for the evaluation and management of thyroid nodules in children and adolescents, including the role and interpretation of ultrasound, fine-needle aspiration cytology, and the management of benign nodules. Recommendations for the evaluation, treatment, and follow-up of children and adolescents with DTC are outlined and include preoperative staging, surgical management, postoperative staging, the role of radioactive iodine therapy, and goals for thyrotropin suppression. Management algorithms are proposed and separate recommendations for papillary and follicular thyroid cancers are provided. CONCLUSIONS In response to our charge as an independent task force appointed by the ATA, we developed recommendations based on scientific evidence and expert opinion for the management of thyroid nodules and DTC in children and adolescents. In our opinion, these represent the current optimal care for children and adolescents with these conditions.

Changes in brain anatomy in focal hand dystonia

No consistent cerebral anatomical abnormality has ever been reported in primary focal hand dystonia (FHD). The present voxel‐based morphometry study showed a significant bilateral increase in gray matter in the hand representation area of primary somatosensory and, to a lesser extent, primary motor cortices in 36 patients with unilateral FHD compared with 36 controls. The presence of anatomical changes in the perirolandic cortex for the unaffected hand as well as that for the affected hand suggests that these disturbances may be, at least in part, primary.

Vascular Endothelial Growth Factor Monoclonal Antibody Inhibits Growth of Anaplastic Thyroid Cancer Xenografts in Nude Mice

BACKGROUND Anaplastic thyroid cancer (ATC) does not respond well to any treatment and is one of the most aggressive of all human cancers. Based on the importance of angiogenesis in solid tumor growth, we hypothesized that angiogenic blockade might reduce the growth of ATC. METHODS We tested the in vivo effect of vascular endothelial growth factor monoclonal antibody (VEGF-mAb) and thalidomide against ATC (ARO-81) xenografts in nude mice. Mice were injected subcutaneously with 1 x 10(6) ARO-81 cells, allowed to implant (1 week), and then given daily intraperitoneal injections of vehicle (control; n = 9), VEGF-mAb (200 microg/d; n = 9), or thalidomide (200 mg/kg per day; n = 9). Tumors were removed, sectioned, and stained for routine histology and immunohistochemistry. RESULTS At 6 weeks, VEGF-mAb-treated tumors were smaller (1603 +/- 296 mm(3)) than either the thalidomide-treated (6007 +/- 1498 mm(3); p = 0.008) or the control groups (4040 +/- 831 mm(3); p = 0.014) and the VEGF-mAb-treated animals maintained greater weight (30.4 +/- 0.84 g at week 6 versus thalidomide-treated, 26.0 +/- 0.94 g, p = 0.003; and control, 25.8 +/- 0.78 g, p = 0.001 animals). Central necrosis was observed in 3 of 9 VEGF-mAb-treated confidence interval (33%; 95% [CI] = 0.12-0.65) but in none of the control or thalidomide-treated tumors (0/18 total; 95% CI = 0.0-0.30; p = 0.029). VEGF staining intensity for VEGF-mAb- (2.0 +/- 0.24; p = 0.012) and thalidomide- (2.1 +/- 0.05; p = 0.052) treated tumors was greater than control (0.89 +/- 0.31) as was p53 staining grade (VEGF-mAb [1.3 +/- 0.37; p = 0.012]; thalidomide [1.0 +/- 0.41; p = 0.05]; and controls [0.11 +/- 0.11]). CONCLUSION We conclude that systemic VEGF-mAb significantly reduces growth of ATC xenografts and is associated with increased VEGF and p53 expression. Thalidomide has no effect on tumor growth, but is also associated with increased VEGF and p53 expression. These observations provide the first evidence that VEGF-mAb-induced angiogenesis blockade may be of use for the treatment of ATC.

Mouse Prkar1a haploinsufficiency leads to an increase in tumors in the Trp53+/− or Rb1+/− backgrounds and chemically induced skin papillomas by dysregulation of the cell cycle and Wnt signaling

PRKAR1A inactivation leads to dysregulated cAMP signaling and Carney complex (CNC) in humans, a syndrome associated with skin, endocrine and other tumors. The CNC phenotype is not easily explained by the ubiquitous cAMP signaling defect; furthermore, Prkar1a(+/-) mice did not develop skin and other CNC tumors. To identify whether a Prkar1a defect is truly a generic but weak tumorigenic signal that depends on tissue-specific or other factors, we investigated Prkar1a(+/-) mice when bred within the Rb1(+/-) or Trp53(+/-) backgrounds, or treated with a two-step skin carcinogenesis protocol. Prkar1a(+/-) Trp53(+/-) mice developed more sarcomas than Trp53(+/-) mice (P < 0.05) and Prkar1a(+/-) Rb1(+/-) mice grew more (and larger) pituitary and thyroid tumors than Rb1(+/-) mice. All mice with double heterozygosity had significantly reduced life-spans compared with their single-heterozygous counterparts. Prkar1a(+/-) mice also developed more papillomas than wild-type animals. A whole-genome transcriptome profiling of tumors produced by all three models identified Wnt signaling as the main pathway activated by abnormal cAMP signaling, along with cell cycle abnormalities; all changes were confirmed by qRT-PCR array and immunohistochemistry. siRNA down-regulation of Ctnnb1, E2f1 or Cdk4 inhibited proliferation of human adrenal cells bearing a PRKAR1A-inactivating mutation and Prkar1a(+/-) mouse embryonic fibroblasts and arrested both cell lines at the G0/G1 phase of the cell cycle. In conclusion, Prkar1a haploinsufficiency is a relatively weak tumorigenic signal that can act synergistically with other tumor suppressor gene defects or chemicals to induce tumors, mostly through Wnt-signaling activation and cell cycle dysregulation, consistent with studies in human neoplasms carrying PRKAR1A defects.

DICER1 Mutations and Differentiated Thyroid Carcinoma: Evidence of a Direct Association

CONTEXT DICER1 germline mutation carriers have an increased predisposition to cancer, such as pleuropulmonary blastoma (PPB) and Sertoli-Leydig cell tumor (SLCT), and a high prevalence of multinodular goiter (MNG). Although differentiated thyroid carcinoma (DTC) has been reported in some DICER1 mutation carriers with PPB treated with chemotherapy, the association of DTC with DICER1 mutations is not well established. CASE DESCRIPTION We report a family with DICER1 mutation and familial DTC without a history of chemotherapy. A 12-year-old female (patient A) and her 14-year-old sister (patient B) presented with MNG. Family history was notable for a maternal history of DTC and bilateral ovarian SLCT. Both sisters underwent total thyroidectomy. Pathological examination showed nodular hyperplasia and focal papillary thyroid carcinoma within hyperplastic nodules. Subsequently, patient A developed virilization secondary to a unilateral ovarian SLCT. During her evaluation, an incidental cystic nephroma was also found. Three other siblings had MNG on surveillance ultrasound examination; two had thyroidectomies, and one had two microscopic foci of papillary carcinoma. Patient A, her mother, and four affected siblings had a germline heterozygous pathogenic DICER1 mutation c.5441C>T in exon 25, resulting in an amino acid change from p.Ser1814Leu of DICER1. Somatic DICER1 RNase IIIb missense mutations were identified in thyroid nodules from three of the four siblings. CONCLUSIONS This family provides novel insight into an emerging phenotype for DICER1 syndrome, with evidence that germline DICER1 mutations are associated with an increased risk of developing familial DTC, even in the absence of prior treatment with chemotherapy.

Quantification of thyroid cancer and multinodular goiter risk in the DICER1 syndrome: a family-based cohort study.

Context: The risk of thyroid cancer and multinodular goiter (MNG) in DICER1 syndrome, a rare tumor-predisposition disorder, is unknown. Objective: To quantify the risk of thyroid cancer and MNG in individuals with DICER1 syndrome. Design: Family-based cohort study. Setting: National Institutes of Health (NIH) Clinical Center (CC). Participants: The National Cancer Institute DICER1 syndrome cohort included 145 individuals with a DICER1 germline mutation and 135 family controls from 48 families. Interventions: Each individual completed a detailed medical history questionnaire. A subset underwent a 3-day evaluation at the NIH CC. Main Outcome Measures: The cumulative incidence of MNG (or thyroidectomy) was quantified using the complement of the Kaplan-Meier product limit estimator. We compared the observed number of thyroid cancers in the NCI DICER1 cohort with matched data from the Surveillance, Epidemiology, and End Results (SEER) Program. We performed germline and somatic (thyroid cancer, MNG) DICER1 sequencing. Results: By the age of 40 years, the cumulative incidence of MNG or thyroidectomy was 75% in women and 17% in men with DICER1 syndrome compared with 8% of control women (P < 0.001) and 0% of control men (P = 0.0096). During 3937 person-years of observation, individuals with DICER1 syndrome had a 16-fold increased risk of thyroid cancer (95% confidence interval, 4.3 to 41; P < 0.05) compared with the SEER rates. Of 19 MNG nodules and 3 thyroid cancers, 16 (84%) and 3 (100%), respectively, harbored germline and somatic pathogenic DICER1 mutations. Conclusions: We propose a model of thyroid carcinogenesis in DICER1 syndrome. Early-onset, familial, or male MNG should prompt consideration of the presence of DICER1 syndrome.

Human herpes simplex viruses in benign and malignant thyroid tumours

To test the hypothesis that herpes viruses may have a role in thyroid neoplasia, we analysed thyroid tissues from patients with benign (44) and malignant (65) lesions for HSV1 and HSV2 DNA. Confirmatory studies included direct sequencing, analysis of viral gene expression, and activation of viral‐inducible signalling pathways. Expression of viral entry receptor nectin‐1 was examined in human samples and in cancer cell lines. In vitro experiments were performed to explore the molecular mechanisms underlying thyroid cancer cell susceptibility to HSV. HSV DNA was detected in 43/109 (39.4%) examined samples. HSV capsid protein expression correlated with HSV DNA status. HSV‐positive tumours were characterized by activation of virus‐inducible signalling such as interferon‐beta expression and nuclear NFκB expression. Lymphocyte infiltration and oncocytic cellular features were common in HSV‐positive tumours. HSV1 was detected with the same frequency in benign and malignant thyroid tumours. HSV2 was significantly associated with papillary thyroid cancer and the presence of lymph node metastases. The expression of HSV entry receptor nectin‐1 was increased in thyroid tumours compared to normal thyroid tissue and further increased in papillary thyroid cancer. Nectin‐1 expression was detected in all examined thyroid cancer cell lines. Nectin‐1 expression in cancer cells correlated with their susceptibility to HSV. Inhibition of PI3K/AKT or MAPK/ERK signalling did not affect the level of nectin‐1 expression but decreased thyroid cancer cell susceptibility to HSV. These findings showed that HSV is frequently detected in thyroid cancer. During tumour progression, thyroid cells acquire increased susceptibility to HSV due to increased expression of viral entry mediator nectin‐1 and activation of mitogenic signalling in cancer cells. Copyright

Evaluation of adult papillary thyroid carcinomas by comparative genomic hybridization and microsatellite instability analysis

To clarify the mechanism of tumorigenesis in papillary thyroid carcinoma (PTC) and ascertain whether genomic changes correlate with histologic features, we conducted a comprehensive molecular evaluation of PTC using comparative genomic hybridization (CGH) and microsatellite instability (MSI) analysis in a set of 17 histologically well-characterized PTC specimens. To our knowledge, this is the first study that evaluates chromosomal and nucleotide instability in the same PTC tumor specimens. Four of 15 samples (27%) had aberrations detected by CGH. All four had a partial or complete gain of chromosome 20, and 3 of 4 had a partial or complete loss of chromosome 13. No MSI was detected in any of the PTC samples (n=16), and all samples examined by immunohistochemistry (n=9) expressed the DNA repair enzymes hmlh1 and hmsh2. All PTC samples with abnormal CGH had vascular invasion or invasion of the thyroid capsule, and there was a significant correlation between the presence of chromosomal aberrations and capsular/vascular invasion (P=0.026). We conclude that although chromosomal and microsatellite instability are uncommon in PTC, tumors with chromosomal aberrations are more likely to be associated with invasion.

BRAF(V600E) mutation analysis from May-Grünwald Giemsa-stained cytological samples as an adjunct in identification of high-risk papillary thyroid carcinoma.

The BRAFV600E mutation is specific for thyroid papillary cancer (PTC) and correlates with PTCs invasiveness. This study investigated whether detection of BRAFV600E mutation can be performed on routinely stained FNABs. We also examined if establishment of the BRAFV600E mutation could help in identification of patients at higher risk for metastatic disease. DNA was isolated from 134 FNABs samples (20 follicular neoplasm, ten suspicious for malignancy, and 104 malignant) using Pinpoint Slide DNA Isolation System. BRAFV600E mutation was detected by PCR followed by sequencing. DNA was successfully extracted from all examined FNABs samples. In follicular neoplasm, suspicious for malignancy and malignant FNABs, BRAFV600E mutation was found in 0/20 (0%), 2/10 (20%), and 47/104 (45.2%) of cases, respectively. Extra-thyroidal extension was detected in 35/47 (74.4%) BRAFV600E positive and in 24/57 (42.1%) wild-type BRAF cases (p = 0.001). Metastases were detected in 37/47 (78.7%) BRAFV600E positive and in 28/57 (49.1%) wild-type BRAF cases (p = 0.002). Our results showed that stained FNAB specimens can be used for DNA extraction and assessment of BRAFV600E mutation. Detection of BRAFV600E mutation had limited value in diagnoses of malignancy in follicular neoplasms but can ascertain malignancy in subset of suspicious for malignancy FNABs. In malignant FNABs, BRAFV600E mutation was significantly associated with presence of extra-thyroidal extension and metastases after surgery.