Clinical and Molecular Analysis in 2 Families With Novel Compound Heterozygous SBP2 (SECISBP2) Mutations

CONTEXT

Selenocysteine insertion sequence binding protein 2 (SECISBP2, SBP2) is an essential factor for selenoprotein synthesis. Individuals with SBP2 defects have characteristic thyroid function test (TFT) abnormalities resulting from deficiencies in the selenoenzymes deiodinases. Eight families with recessive SBP2 gene mutations have been reported to date. We report 2 families with inherited defect in thyroid hormone metabolism caused by 4 novel compound heterozygous mutations in the SBP2 gene.

CASE DESCRIPTIONS

Probands 1 and 2 presented with growth and developmental delay. Both had characteristic TFT with high T4, low T3, high reverse T3, and normal or slightly elevated TSH. The coding region of the SBP2 gene was sequenced and analysis of in vitro translated wild-type and mutant SBP2 proteins was performed. Sequencing of the SBP2 gene identified novel compound heterozygous mutations resulting in mutant SBP2 proteins E679D and R197* in proband 1, and K682Tfs*2 and Q782* in proband 2. In vitro translation of the missense E679D demonstrated all four isoforms, whereas R197* had only 2 shorter isoforms translated from downstream ATGs, and Q782*, K682Tfs*2 expressed isoforms with truncated C-terminus. Reduction in serum glutathione peroxidase enzymatic activity was also demonstrated in both probands.

CONCLUSIONS

We report 2 additional families with mutations in the SBP2 gene, a rare inherited condition manifesting global selenoprotein deficiencies. Report of additional families with SBP2 deficiency and their evaluation over time is needed to determine the full spectrum of clinical manifestations in SBP2 deficiency and increase our understanding of the role played by SBP2 and selenoproteins in health and disease.

A Novel Risk Stratification System for Thyroid Nodules With Indeterminate Cytology-A Pilot Cohort Study

Background: Thyroid ultrasound (US), fine needle aspiration biopsy (FNAB), and molecular testing have been widely used to stratify the risk of malignancy in thyroid nodules. The goal of this study was to investigate a novel diagnostic approach for cytologically indeterminate thyroid nodules (ITN) based upon a combination of US features and genetic alterations. Methods: We performed a pilot cohort study of patients with ITN (Bethesda III/IV), who underwent surgical treatment. Based on standardized sonographic patterns established by the American Thyroid Association (ATA), each ITN received an US score (X_US), ranging between 0 and 0.9 according to its risk of thyroid cancer (TC). DNA and RNA were extracted from pathologic material, available for all patients, and subjected to Oncomine™ Comprehensive Assay v2 (OCAv2) next-generation sequencing. Each genetic alteration was annotated based on its strength of association with TC and its sum served as the genomic classifier score (X_GC). The total risk score (TRS) was the sum of X_US and X_GC. ROC curves were generated to assess the diagnostic accuracy of X_US, X_GC, and TRS. Results: The study cohort consisted of 50 patients (39 females and 11 males), aged 47.5 ± 14.8 years. Three patients were excluded due to molecular testing failure. Among the remaining 47 patients, 28 (59.6%) were diagnosed with TC. BRAFV600E was the most common mutation in papillary TC, PAX8-PPARG fusion was present in NIFTP, pathogenic variants of SLX4, ATM, and NRAS were found in Hürthle cell TC and RET mutations in medullary TC. The diagnostic accuracy of X_GC and TRS was significantly higher compared with X_US (88 vs. 62.5%, p < 0.001; 85.2 vs. 62.5%, p < 0.001, respectively). However, this increased accuracy was due to significantly better sensitivity (80.7 vs. 34.6%, p < 0.001; 84.6 vs. 34.6%, p < 0.001, respectively) without improved specificity (94.7 vs. 90%, p = 0.55; 85.7 vs. 90%, p = 0.63, respectively). Conclusion: Molecular testing might not be necessary in ITN with high-risk US pattern (X_US = 0.9), as specificity of TC diagnosis based on Xus alone is sufficient and not improved with molecular testing. OCAv2 is useful in guiding the management of ITN with low-to-intermediate risk US features (X_US < 0.9), as it increases the accuracy of TC diagnosis.

Performance of a Multigene Genomic Classifier in Thyroid Nodules With Indeterminate Cytology: A Prospective Blinded Multicenter Study

Question

Can the diagnosis of benign disease or cancer in thyroid nodules with indeterminate cytology be established by molecular testing instead of diagnostic surgery?

Findings

This prospective, blinded, multicenter cohort study of a multigene genomic classifier (ThyroSeq v3) test included 257 indeterminate cytology thyroid nodules with informative test results. It demonstrated a high sensitivity (94%) and reasonably high specificity (82%), with 61% of the nodules yielding a negative test result and only 3% residual cancer risk in these nodules.

Meanings

Up to 61% of patients with indeterminate cytology thyroid nodules may avoid diagnostic surgery by undergoing multigene genomic classifier testing.

Importance

Approximately 20% of fine-needle aspirations (FNA) of thyroid nodules have indeterminate cytology, most frequently Bethesda category III or IV. Diagnostic surgeries can be avoided for these patients if the nodules are reliably diagnosed as benign without surgery.

Objective

To determine the diagnostic accuracy of a multigene classifier (GC) test (ThyroSeq v3) for cytologically indeterminate thyroid nodules.

Design, Setting, and Participants

Prospective, blinded cohort study conducted at 10 medical centers, with 782 patients with 1013 nodules enrolled. Eligibility criteria were met in 256 patients with 286 nodules; central pathology review was performed on 274 nodules.

Interventions

A total of 286 FNA samples from thyroid nodules underwent molecular analysis using the multigene GC (ThyroSeq v3).

Main Outcomes and Measures

The primary outcome was diagnostic accuracy of the test for thyroid nodules with Bethesda III and IV cytology. The secondary outcome was prediction of cancer by specific genetic alterations in Bethesda III to V nodules.

Results

Of the 286 cytologically indeterminate nodules, 206 (72%) were benign, 69 (24%) malignant, and 11 (4%) noninvasive follicular thyroid neoplasms with papillary-like nuclei (NIFTP). A total of 257 (90%) nodules (154 Bethesda III, 93 Bethesda IV, and 10 Bethesda V) had informative GC analysis, with 61% classified as negative and 39% as positive. In Bethesda III and IV nodules combined, the test demonstrated a 94% (95% CI, 86%-98%) sensitivity and 82% (95% CI, 75%-87%) specificity. With a cancer/NIFTP prevalence of 28%, the negative predictive value (NPV) was 97% (95% CI, 93%-99%) and the positive predictive value (PPV) was 66% (95% CI, 56%-75%). The observed 3% false-negative rate was similar to that of benign cytology, and the missed cancers were all low-risk tumors. Among nodules testing positive, specific groups of genetic alterations had cancer probabilities varying from 59% to 100%.

Conclusions and Relevance

In this prospective, blinded, multicenter study, the multigene GC test demonstrated a high sensitivity/NPV and reasonably high specificity/PPV, which may obviate diagnostic surgery in up to 61% of patients with Bethesda III to IV indeterminate nodules, and up to 82% of all benign nodules with indeterminate cytology. Information on specific genetic alterations obtained from FNA may help inform individualized treatment of patients with a positive test result.

Salutary Response to Targeted Therapy in Anaplastic Thyroid Cancer

Context. Anaplastic thyroid cancer (ATC) is an aggressive tumor with a median survival of 3 to 9 months, a 1-year survival of less than 10% and without definitive therapies. Recently, in BRAF V600E mutated ATCs, new targeted therapy using a combination of a BRAF inhibitor, dabrafenib (Dab), with a mitogen-activated extracellular protein kinase (MEK) inhibitor, trametinib (Tram), has shown significant promise. Case Description. We report a case of aggressive ATC with 5 sequence mutations: BRAF V600E (mutation fraction [MF] 34%), TERT E441del (MF 37%), RET N579K (MF 55%), EZH2 D154E (MF 60%), and CDK4 S259L (MF 48%). The patient had a dramatic response to the Dab/Tram combination with near complete resolution of his lung, bone, hepatic, and splenic lesions soon after starting therapy. Unfortunately, intolerable side effects (grade 2-3) on this regimen required tapering and discontinuation of the treatment. He had a quick resurgence of disease after stopping the combination therapy. The patient died approximately 3 months after discontinuing Dab/Tram. Autopsy revealed an atrophic thyroid gland with microscopic subcapsular focus of well-differentiated papillary thyroid carcinoma. There was extensive lymphatic spread of the tumor throughout bilateral lungs with fibrosis. No other metastatic site was identified. Conclusion. We report a unique case of ATC with 2 new mutations of EZH2 D154E and CDK S529L. This case exemplifies the significant promise Dab/Tram therapy holds, the potential side effects that limit their use, and autopsy findings status post use of this combination therapy.

124I Positron Emission Tomography/Computed Tomography Versus Conventional Radioiodine Imaging in Differentiated Thyroid Cancer: A Review

Background: Studies report a wide spectrum of ¹²⁴I positron emission tomography (PET)/computed tomography (CT) sensitivity and specificity in the detection of differentiated thyroid cancer (DTC) lesions. This study reviews the lesion detection rate of pretherapy ¹²⁴I PET/CT in different patient populations and further analyzes the factors necessary for a better detection on ¹²⁴I PET/CT. Methods: A literature search was performed using multiple different databases (MEDLINE, EMBASE, Northern Lights, and handsearching) covering 1996 to April 2018. Two reviewers reviewed and extracted study data for ¹²⁴I, ¹²³I, and ¹³¹I scans in DTC. Results: This review includes 4 retrospective and 10 prospective studies in which 495 DTC patients underwent ¹²⁴I and ¹³¹I imaging; no studies made comparisons with ¹²³I. In the reports that compared ¹²⁴I PET/CT with diagnostic ¹³¹I scans, there were a total of 72 patients in whom 120 lesions were detected on ¹²⁴I imaging, whereas only 52 were detected on diagnostic ¹³¹I scans. In publications that compared ¹²⁴I with post-therapy ¹³¹I scans in 266 patients, 410 lesions were detected with ¹²⁴I PET, whereas 390 were detected on post-therapy ¹³¹I scans. Based on ¹²⁴I PET/CT in six studies, TNM staging was revised in 15-21% of patients, and disease management was altered in 5-29% of patients. Conclusions:¹²⁴I PET/CT is able to identify a greater number of foci compared with diagnostic ¹³¹I scans. ¹²⁴I PET may have better detection compared with post-therapy ¹³¹I scans in patients who are ¹³¹I therapy naive, have less aggressive pathology, or do not have disseminated lung metastases. Additional metastatic lesion detection by ¹²⁴I PET may have a significant clinical impact in the management of patients before ¹³¹I therapy in some patients.

Clinical, Pathological, and Molecular Profiling of Radioactive Iodine Refractory Differentiated Thyroid Cancer

Background: Six to 20% of thyroid cancer (TC) patients develop distant metastases, and one-third become radioiodine refractory (RAIR). Available targeted therapies increase progression-free survival but are associated with toxicities. This study aims to characterize clinical, pathological, and molecular profiles of patients with RAIR TC. Methods: Data of TC patients seen during 2013-2017 at two tertiary care centers were retrospectively analyzed. Patients were considered RAIR according to American Thyroid Association guidelines. The control cohort was sex matched and age matched and had either regression or stable disease (by Response Evaluation Criteria in Solid Tumors) on follow-up at least three years after initial therapy. Molecular profiles on a subset of RAIR patients were reviewed. Results: Compared with 22 matched controls, 54 RAIR patients had an average age of 57 years (standard deviation [SD] = 13), 56% were male (41% in the control group); the average tumor size was 4 cm (SD = 2.5); tumors were multifocal in 54%, with involved surgical margins in 42%, focal invasion in 79%, and extrathyroidal extension (ETE) in 61%. Sixty-six percent had distant metastases at initial presentation with metastases to the lungs in 85%, bone in 56%, both sites in 43%, brain in 9%, and liver in 4%. There were no statistically significant differences between RAIR and controls in tumor size, focal invasion, ETE, and histology. The RAIR group received a higher cumulative radioactive iodine (RAI) dose and number of therapies compared with the controls (518 mCi vs. 302 mCi, p = 0.002 and 2.2 vs. 1.3 treatments, p = 0.001). Overall, patients >46 years had 4.5 times higher odds ratio (OR) of being RAIR; white race/ethnicity was associated with a reduced OR of RAIR disease (OR 0.33, p = 0.079). Molecular profiling data in the RAIR subgroup indicated that 50% of patients harbored mutations in the RAS/RAF pathway (11/22). Among 19 patients with a more extensive molecular panel, median tumor mutational burden was 5 megabase (range 3-16) and 26% (5/19) exhibited strong PD-L1 positivity. Conclusion: Among patients with metastatic differentiated thyroid carcinomas, patients with RAIR have similar histopathological and clinical characteristics as patients with RAI avid cancer. The risk of having RAIR TC is increased at age ≥46 and reduced in Caucasians.

Nationwide Survey on Implementation of 2011 Nuclear Regulatory Commission Policy on Release of Patients After 131I Therapy for Thyroid Cancer

The objective of this nationwide survey was to evaluate whether there has been a change in the practice regarding hospital release of differentiated thyroid cancer patients treated with ¹³¹I since the publication of Nuclear Regulatory Commission Regulatory Issue Summary 2011-01 addressing patient release. Methods: A survey was emailed to approximately 25,000 members of ThyCa: Thyroid Cancer Survivors' Association, Inc., and was available online from March to August 2018. Responses were included from adult patients regarding their most recent ¹³¹I therapy received between 2011 and 2018 ("after 2011"). Responses to this survey were compared with those of a similar previous survey for ¹³¹I therapies received between 1997 and 2009 ("before 2009"). Results: Of the 2,136 responses, 1,111 met the inclusion criteria. A similar percentage (∼98%) of patients were given oral or written radiation safety instructions (RSIs) after 2011 and before 2009, with a shift away from nuclear medicine physicians providing instructions after 2011 (43%) in comparison with before 2009 (54%; P < 0.001). More patients were able to discuss and individualize the RSIs after 2011 (67%) than before 2009 (29%; P < 0.001). However, 2% of patients do not recall ever receiving RSIs after 2011. After 2011, more patients were treated as outpatients (87%) than before 2009 (66%; P < 0.001). For outpatients, more patients were discharged within 30 min after receiving ¹³¹I therapy after 2011 (78%) than before 2009 (72%; P = 0.002). The same percentage (0.6%) of patients traveled more than 2 h with at least 2 occupants in the vehicle within approximately 1 m of the patient after 2011 and before 2009. Immediately after therapy, a similar percentage of patients stayed in a nonprivate residence after 2011 (4%) and before 2009 (5%; P = 0.28). Of the 27 outpatients released within 30 min to nonprivate residences, 2 patients received 5.55-11.1 GBq (150-299 mCi) of ¹³¹I. Conclusion: This survey suggests that since publication of the Nuclear Regulatory Commission Regulatory Issue Summary 2011-01 on patient release after radioiodine therapy, there have been improvements in some radiation safety practices on release of outpatients, as well as improvements in patient compliance on travel and lodging.

Improved Survival After Multimodal Approach with 131I Treatment in Patients with Bone Metastases Secondary to Differentiated Thyroid Cancer

Background: The objective of this study was to evaluate the overall survival (OS) of radioiodine (¹³¹I) treatments alone or combined with non-¹³¹I treatments in patients with bone metastases (BM) of differentiated thyroid cancer (DTC). Methods: This was a retrospective study of patients who were evaluated between 2001 and 2018 at MedStar Washington Hospital Center and who had DTC, BM, and at least one ¹³¹I treatment after the diagnosis of BM. The OS was analyzed by Kaplan-Meier survival curves and was compared by log-rank test between two groups: patients who received ¹³¹I treatments alone and those who received treatments combining ¹³¹I with non-¹³¹I treatments (CombTx). Non-¹³¹I treatments include surgery, radiofrequency ablation, cryotherapy, arterial embolization, external beam radiation, Cyberknife, systemic targeted therapy, and anti-resorptive medication. Results: A total of 77 patients met the above criteria and were followed up to 41 years. Thirty percent (23/77) of patients received ¹³¹I treatment alone, and 70% (54/77) received CombTx. For ¹³¹I treatment alone, the median survival was 3.9 years, and the 1-, 2-, 3-, 5-, and 10-year OS rates were 86%, 81%, 61%, 35%, and 23%, respectively. For CombTx, the median survival was 7.7 years, and the 1-, 2-, 3-, 5-, and 10-year OS rates were 96%, 92%, 86%, 69%, and 30%, respectively. Patients who had undergone initial ¹³¹I therapy within six months post thyroidectomy demonstrated a better median survival after BM diagnosis than those whose initial ¹³¹I therapy was six months or more after thyroidectomy (6.5 vs. 0.5 years; p < 0.001). Patients who received external beam radiation therapy demonstrated a better median survival than those who did not (7.8 vs. 4.4 years; p = 0.016). Patients who received denosumab demonstrated a better median survival than those who did not (7.7 vs. 5.2 years; p = 0.03). Patients who were <55 years of age at the initial diagnosis of DTC or at the initial diagnosis of BM had a better median OS than those diagnosed at ≥55 years of age (both p = 0.01). In the multivariate analysis, only age at initial diagnosis of DTC and initial ¹³¹I therapy within six months post thyroidectomy, and multiple ¹³¹I treatments were independent prognostic factors. Conclusions: In patients with DTC with BM, ¹³¹I treatment in combination with one or more non-¹³¹I direct and systemic treatments was associated with a significant increase in OS compared with those patients who were treated by ¹³¹I treatment alone.

A comprehensive meta-analysis of endocrine immune-related adverse events of immune checkpoint inhibitors and outcomes in head and neck cancer and lung cancer

e14096

Background: Immune checkpoint inhibitors (ICPi) have emerged as an effective treatment for a variety of cancers. However, important immune-related adverse events (irAEs) can occur. The aim of this study was to determine the prevalence of endocrine irAEs in patients with head and neck cancer and lung cancer that have used a ICPi and outcomes. Methods: A systematic literature review was performed within PubMed and EMBASE databases. Search terms included “durvalumab”, “atezolizumab”, “nivolumab”, “pembrolizumab”, “ipilimumab”, “head & neck cancer”, “lung cancer”. Studies published before September 2018 were included. The search was limited to randomized controlled trials (RCTs) phase III written in English. Data were extracted about patient characteristics, interventions, overall survival (OS), progression free survival (PFS), and endocrine irAEs. A summary hazard ratio (HR) and 95% confidence interval were calculated using the software Comprehensive Meta-Analysis and a scatter plot was generated. Results: Twelve RCTs comprising 7060 patients were reviewed; 3815 used an ICPi (treatment arm). The mean follow-up time of 12.2 months ± 7.1 SD. The survival rate of the treatment arm was enhanced (HR, 0.75; 95% CI, 0.70-0.80), compared to the alternate arm. Similarly, the PFS of the treatment arm was improved (HR, 0.77; 95% CI, 0.72-0.81) but with a higher incidence of endocrine irAEs. The most common endocrine irAE reported was hypothyroidism;193 patients in the treatment arm vs. 29 in the alternate arm (p < 0.001); grade 3/4 AE was observed in 10 patients vs. 1 patient, respectively. Other endocrine irAEs were reported in 168 patients in the treatment arm vs. 26 patients in the alternate arm (p < 0.001); grade 3/4 AE was observed in 28 patients vs. 3 patients, respectively. A significant positive correlation between endocrine irAEs and OS was observed (p = 0.019). Conclusions: ICPi are a powerful tool in the treatment of cancer. The prevalence of endocrine irAEs in this meta-analysis was 9%. There is evidence of improved overall survival in patients who developed endocrine irAEs. Further studies are needed to correlate the development of irAEs and OS advantage.

Brain Metastases From Differentiated Thyroid Carcinoma: Prevalence, Current Therapies, and Outcomes

BACKGROUND AND OBJECTIVE

The brain is an unusual site for distant metastases of differentiated thyroid carcinoma (DTC). The aim of this study was to document the prevalence of brain metastases from DTC at our institutions and to analyze the current therapies and the outcomes of these patients.

METHODS

We performed a retrospective chart review of patients with DTC and secondary neoplasia of the brain.

RESULTS

From 2002 to 2016, 9514 cases of thyroid cancer were evaluated across our institutions and 24 patients met our inclusion criteria, corresponding to a prevalence of 0.3% of patients with DTC. Fourteen (58.3%) were female and 10 (41.7%) were male. Fifteen patients had papillary thyroid cancer (PTC) (62.5%). Brain metastases were diagnosed 0 to 37 years (mean ± SD, 10.6 ± 10.4 years) after the initial diagnosis of thyroid cancer. Patients undergoing surgery had a median survival time longer than those that did not undergo surgery (27.3 months vs 6.8 months; P = 0.15). Patients who underwent stereotactic radiosurgery (SRS) had a median survival time longer than those that did not receive SRS (52.5 months vs 6.7 months; P = 0.11). Twelve patients (50%) were treated with tyrosine kinase inhibitors (TKIs), and they had a better survival than those who have not used a TKI (median survival time, 27.2 months vs 4.7 months; P < 0.05).

CONCLUSION

The prevalence of brain metastases of DTC in our institutions was 0.3% over 15 years. The median survival time after diagnosis of brain metastases was 19 months. In our study population, the use of TKI improved the survival rates.

Molecular aberrations and signaling cascades implicated in the pathogenesis of anaplastic thyroid cancer

Anaplastic Thyroid Cancer (ATC) accounts for >40% thyroid cancer-related deaths and has a dismal prognosis. In the past decade, significant efforts have been made towards understanding the pathogenesis of this disease and developing novel therapeutics. Unfortunately, effective treatment is still lacking and a more thorough understanding of ATC pathogenesis may provide new opportunities to improve ATC therapeutics. This review provides insights into ATC clinical presentation and pathology, and the putative role of genetic aberrations and alterations in molecular signaling pathways in ATC pathogenesis. We reviewed prevalent mutations, chromosomal abnormalities and fusions, epigenetic alterations and dysregulations in ATC, and highlighted several signaling cascades which appeared to be integral to ATC pathogenesis. Moreover, these features offer insights into de-differentiated, aggressive and drug-resistant phenotype of ATC, and thus may help in exploring potential new molecular targets for developing novel therapeutics.

Detection at Public Facilities of 131I in Patients Treated for Differentiated Thyroid Cancer: Frequency, Sites, Management by Security Agents, and Physician Documentation Recommended for Patients

Patients treated with ¹³¹I may be identified at security checkpoints at various public facilities. The objective of this survey was to determine the frequency of detection, the spectrum of public facilities, the various methods of management of the situation by security agents, and the spectrum of physician documentation for patients regarding their ¹³¹I therapy. Methods: Data were tabulated from a Thyroid Cancer Survivors' Association, Inc., survey emailed to approximately 15,000 associates and available online from December 2013 to December 2014. Responses were tabulated from respondents who reported that they were 18 y old or older, had received at least 1 ¹³¹I treatment for differentiated thyroid cancer, and were responding regarding their last ¹³¹I treatment. Results: Of 621 respondents, 595 reported an attempt to pass through a public facility security checkpoint. Of these 595 patients, approximately 10% (57) were identified as being radioactive. The facility reported by 43 respondents was an airport for 35% (15), border crossing for 33% (14), government building for 19% (8), shopping mall for 7% (3), train station for 5% (2), and steel recycling plant for 2% (1). The security agent's management of the situation reported by 47 respondents included questioning for 81% (38), allowing them to proceed without a change in travel plans for 57% (27), requesting documentation of the therapy for 55% (26), rescanning for 55% (26), calling a member of the treating team for validation for 17% (8), "strip" searching for 4% (2), detaining such that a change in travel plans was required for 6% (3), and prohibiting continued travel for 4% (2). The period of detainment reported by these 47 respondents was less than 30 min for 57% (27), 30 to less than 60 min for 21% (10), 1 to less than 1.5 h for 15% (7), 1.5 to less than 2 h for 2% (1), 2-4 h for 0% (0), and greater than 4 h for 4% (2). Data regarding physician documentation are presented. Conclusion: The detection of radioactivity at a variety of security checkpoints at public facilities after¹³¹I therapy occurred in approximately 10% of respondents. Travel inconvenience is not infrequent and may require alteration of travel plans. Physicians should take steps to ensure that patients not only have appropriate documentation of their ¹³¹I therapy with them but also have instructions regarding how security agents may verify their ¹³¹I therapy.

Therapeutic advances in anaplastic thyroid cancer: a current perspective

Thyroid cancer incidence is increasing at an alarming rate, almost tripling every decade. In 2017, it was the fifth most common cancer in women. Although the majority of thyroid tumors are curable, about 2-3% of thyroid cancers are refractory to standard treatments. These undifferentiated, highly aggressive and mostly chemo-resistant tumors are phenotypically-termed anaplastic thyroid cancer (ATC). ATCs are resistant to standard therapies and are extremely difficult to manage. In this review, we provide the information related to current and recently emerged first-line systemic therapy (Dabrafenib and Trametinib) along with promising therapeutics which are in clinical trials and may be incorporated into clinical practice in the future. Different categories of promising therapeutics such as Aurora kinase inhibitors, multi-kinase inhibitors, epigenetic modulators, gene therapy using oncolytic viruses, apoptosis-inducing agents, and immunotherapy are reviewed. Combination treatment options that showed synergistic and antagonistic effects are also discussed. We highlight ongoing clinical trials in ATC and discuss how personalized medicine is crucial to design the second line of treatment. Besides using conventional combination therapy, embracing a personalized approach based on advanced genomics and proteomics assessment will be crucial to developing a tailored treatment plan to improve the chances of clinical success.

Use of 99mTc-sestamibi SPECT/CT when conventional imaging studies are negative for localizing suspected recurrence in differentiated thyroid cancer: a method and a lesson for clinical management

PURPOSE

The detection of recurrent disease in differentiated thyroid cancer (DTC) patients with elevated or rising serum thyroglobulin (Tg) levels and multiple negative conventional imaging studies can be challenging, especially when ¹⁸F-FDG PET/CT scan is also negative. We report a patient and review the literature on the diagnostic use of ^99mTc-sestamibi scans to identify the source of elevated or rising Tg in patients with negative conventional imaging including negative ¹⁸F-FDG PET/CT scans.

PATIENT AND METHODS

A 73-year-old woman was referred for widely-invasive metastatic follicular thyroid cancer with bone metastasis to her left mandible. She had a total thyroidectomy, left mandibular resection, and ¹³¹I therapy of 145 mCi (5.4 GBq) and her subsequent unstimulated serum Tg level was 29 ng/ml (TgAb negative). At six months' follow-up, her stimulated Tg was 527 ng/ml (TSH 188 mIU/L, TgAb negative). All imaging studies performed within the prior 12 months were reported as negative for recurrence or metastasis; this included neck ultrasound, diagnostic radioiodine scan, chest CT and, ¹⁸F-FDG PET/CT. The patient was injected with 24.6 mCi (910 MBq) of ^99mTc-sestamibi intravenously, and whole-body and SPECT/CT images were acquired.

RESULTS

The ^99mTc-sestamibi whole-body posterior image demonstrated abnormal focal uptake in the right posterior calvarium and corresponded to an occipital lytic bone lesion on the SPECT/CT. The patient underwent surgical resection of the skull metastasis, and pathology confirmed metastatic follicular thyroid cancer. Five months post-surgery, the suppressed Tg was markedly reduced and remained stable at ~3.2 ng/ml. With the knowledge of the DTC recurrence location, the two sets of ¹⁸F-FDG images were re-evaluated. The more thorough and targeted interpretation underscored the importance of structured image reporting. The current literature on the utility of ^99mTc-sestamibi scans when radioiodine, ¹⁸F-FDG PET/CT, and other imaging studies are negative is sparse and inconsistent.

CONCLUSIONS

^99mTc-sestamibi may have a role in thyroid cancer localization when physical exam, neck ultrasound, radioiodine scan, chest/abdomen CT, and ¹⁸F-FDG PET/CT does not identify the source of elevated Tg levels in DTC.

Poor patient compliance with instructions for continuous sialogogues after 131 I therapy

OBJECTIVES

To analyze the role of patient compliance as a factor in evaluating the effectiveness of continuous sialogogues to prevent salivary side effects from ¹³¹ I therapy in differentiated thyroid cancer patients.

METHODS

Differentiated thyroid cancer patients who were clinically scheduled for an ¹³¹ I therapy at MedStar Washington Hospital Center between 2012 and 2013 were given instructions for continuous sialogogues per standard clinical protocol. The prospective survey was given at multiple time points.

RESULTS

Ninety-nine patients consented to participate of whom 94 participants had complete data. The mean prescribed ¹³¹ I activity was 121 ± 50 mCi (4.5 ± 1.9 GBq), range 27.5-288 mCi (1.0-10.7 GBq ). Overall, only 10% (9/94) of patients were compliant with continuous sialogogues. Even though all patients took sialogogues on the first day of post-therapy, 17% of participants did not continuously take sialogogues during the first day, 60% during the first night, and 72% on the second day despite rigorous instructions to continue for two days.

CONCLUSION

Despite repetitive instructions to use sialogogues continuously, most patients (90%) were not compliant. In future studies, strict monitoring and evaluation of patient compliance will be crucial when assessing the effect of continuous versus intermittent or delayed initiation of sialogogues.

Synchronous Independent Papillary Thyroid Carcinomas in Struma Ovarii and the Thyroid Gland With Different RAS Mutations

Struma ovarii is a rare ovarian teratoma predominantly composed of thyroid tissue. The simultaneous presence of thyroid carcinoma in the struma ovarii and the thyroid gland is extremely rare. It remains unclear if these carcinomas represent independent primary tumors and whether the molecular mechanisms of the tumors developing in the thyroid and ovarian tissues are similar. We present the case of a patient with two independent papillary thyroid carcinomas (PTCs) in struma ovarii and the thyroid gland that are driven by different RAS mutations. A 62-year-old woman with a history of chronic lymphocytic leukemia/small lymphocytic lymphoma was diagnosed with a pelvic mass during a CT scan. She had surgery that included removal of her ovaries. A 7.2-cm classical variant of PTC arising in a struma ovarii was identified in the right ovary. Two months after the pelvic surgery, total thyroidectomy was performed, and a small nodule (0.8 cm) in the left lobe was diagnosed as a classical variant of PTC. Molecular analysis of tissues obtained from both the malignant struma ovarii and thyroid gland was performed. RAS mutations both in the PTC located in the thyroid and ovarian tissues were identified. However, whereas the thyroid gland tumor showed an HRAS Q61R mutation, the PTC in struma ovarii harbored an NRAS Q61R mutation. In this case, the finding of distinct types of RAS point mutation in thyroid cancers at two different locations provides definitive evidence that these cancers are synchronously developed independent primary tumors.

Eliminating the Age Cutoff in Staging of Differentiated Thyroid Cancer: The Safest Road?

BACKGROUND

Unlike virtually all other cancer types, thyroid cancer is unique in that patient age is a key component in its staging. Pathologists and clinicians worldwide have accepted an age cutoff of 45 years for staging; in 2018, this advances to age 55 years in the eighth edition of the American Joint Commission on Cancer staging system.

EVIDENCE ACQUISITION

Clinical and basic research studies, reviews, and previous editions of consensus statements regarding thyroid cancer staging were reviewed, with particular focus on the influence of age in thyroid cancer prognosis.

PURPOSE

This perspective briefly reviews the basis for this practice and challenges it as no more appropriate than for other malignancies.

EVIDENCE SYNTHESIS

The majority of findings report an association of age with thyroid cancer survival but do not support a specific age cutoff; rather, they suggest that outcome is affected by age as a continuous variable. Conceivably, other factors interact with age on a continuous basis over time, affecting prognosis. When identified, these factors could alter our current concept of the importance of an age cutoff in staging.

CONCLUSIONS

Among all cancers, age has an important role in only thyroid cancer staging. The consideration of age as a continuous variable and the search for age-associated prognostic variables could elucidate a more accurate staging system.

Stable Isotope Pharmacokinetic Studies Provide Insight into Effects of Age, Sex, and Weight on Levothyroxine Metabolism

BACKGROUND

This study sought to determine whether levothyroxine pharmacokinetics (PKs) are affected by age, weight, and sex.

METHODS

A PK study was performed after administration of a tracer dose of carbon-13-labeled LT4 (¹³C-LT4). The study was conducted at an academic medical center. Adults of any age being treated with levothyroxine for hypothyroidism were enrolled in the study. A single dose of ¹³C-LT4 was administered. Eighteen serial plasma samples were collected. One sample was obtained before the ¹³C-LT4 dose, and the majority of the remaining samples were collected over the 120-hour period post dosing. ¹³C-LT4 concentration was quantified using liquid chromatography tandem mass spectrometry. PK analysis was conducted using a linear log trapezoidal non-compartmental analysis using Phoenix 6.4.

RESULTS

Eight males and 33 females with a median age of 50 years (range 22-78 years) and median weight of 65.9 kg (range 50-150 kg) were enrolled in the study. The median ¹³C-LT4 dose administered was 100 μg (range 70-300 μg). The median oral clearance rate (CL/F), apparent volume of distribution (V/F), time to peak concentration (T_max), and dose-normalized peak concentration (C_max) of ¹³C-LT4 were estimated to be 0.712 L/h, 164.9 L, 4 h, and 7.5 ng/L/μg, respectively. The dose-normalized area under the concentration-time curve from time 0 to 120 hours and half-life of the terminal distribution phase were 0.931 ng.h/mL/μg and 172.2 h, respectively. There was no significant difference in any ¹³C-LT4 PK parameter between patients aged >60 years (n = 10) and patients aged ≤60 years (n = 31), nor was there a relationship between age as a continuous variable and ¹³C-LT4 PK parameters. Sex only affected CL/F, V/F, and dose-normalized C_max in univariate analyses. However, after adjusting for weight, sex was no longer a significant covariate. Weight was a significant predictor for CL/F, V/F and dose-normalized C_max of ¹³C-LT4 in multivariate analyses.

CONCLUSION

Prior studies suggest that patient age affects levothyroxine dose requirement. This study did not identify an effect of age and suggests that age-related changes in levothyroxine pharmacokinetics may be mediated by age-related weight differences. Physicians should consider a patient's weight, rather than age, for estimating levothyroxine dosage requirement.

Thrombosis in Thyroid Cancer

BACKGROUND

The number of studies on venous thromboembolism (VTE) and thyroid cancer is very scarce and existing data are contradictory. This paper reviews VTE in thyroid cancer.

METHODS

The following words were used for a comprehensive literature review using MEDLINE database: Blood coagulation factors; thyroid hormones; blood coagulation tests; venous thromboembolism; receptors thyroid hormone; hemostasis; fibrinolysis; bleeding; blood coagulation disorders; thyroid neoplasms; Thyroid cancer, papillary; Thyroid cancer, follicular; Thyroid carcinoma, anaplastic; Thyroid cancer, Hurthle cell; Familial medullary thyroid carcinoma; venous thrombosis; Pulmonary embolism; Blood coagulation factors. The studies, which include any changes in hemostasis and thyroid cancer were included and reviewed.

RESULTS

Although few studies have shown a possible increase in VTE occurrence in thyroid cancer in patients ≥ 60 years old and in proximity to cancer diagnosis, other studies could not find any difference compared to general population. New thyroid cancer classification excluding common subtype(s) with benign nature, may affect the results of the future studies on association of VTE and thyroid cancer.

CONCLUSIONS

Prospective studies on the occurrence of VTE in various types and severities of thyroid cancer and in different age groups are warranted, as the results would affect clinical practice on the necessity of usage of anticoagulants in some thyroid cancer groups.

Selected Radiation Safety Aspects Including Transportation and Lodging After Outpatient 131I Therapy for Differentiated Thyroid Cancer

BACKGROUND

Whether radioactive iodine (¹³¹I) treatments for differentiated thyroid cancer should be performed as an outpatient or inpatient remains controversial. The objective of this study was to survey selected aspects of radiation safety of patients treated with ¹³¹I for differentiated thyroid cancer as an outpatient.

METHODS

An e-mail invitation was sent to over 15,000 members of ThyCa: Thyroid Cancer Survivors' Association, Inc. to complete a web-based survey on selected aspects of radiation safety regarding their last outpatient ¹³¹I treatment.

RESULTS

A total of 1549 patients completed the survey. Forty-five percent (699/1541) of the respondents reported no discussion on the choice of an inpatient or outpatient treatment. Moreover, 5% (79/1541) of the respondents reported that their insurance company made the decision. Survey respondents recalled receiving oral and written radiation safety instructions 97% (1459/1504) and 93% (1351/1447) of the time, respectively. Nuclear medicine physicians delivered oral and written instructions to 54% (807/1504) and 41% (602/1462) of the respondents, respectively. Eighty-eight percent (1208/1370) of the respondents were discharged within 1 hour after receiving their ¹³¹I treatment, and 97% (1334/1373) traveled in their own car after being released from the treating facility. Immediately post-therapy, 94% (1398/1488) of the respondents stayed at their own home or a relative's home, while 5% (76/1488) resided in a public lodging. The specific recommendations received by patients about radiation precautions varied widely among the respondents. Ninety-nine percent (1451/1467) of the respondents believed they were compliant with the instructions.

CONCLUSION

This is the largest, patient-based survey published regarding selected radiation safety aspects of outpatient ¹³¹I treatment. This survey suggests several concerns about radiation safety, such as the decision process regarding inpatient versus outpatient treatment, instructions about radiation safety, transportation, and lodging after radioiodine therapy. These concerns warrant further discussion, guidelines, and/or policies.

Amifostine does not protect thyroid cancer cells in DNA damaging in vitro models

BACKGROUND

Amifostine is a potent scavenger of reactive oxygen species that is used for the salivary gland protection during therapy with radioactive iodine for thyroid cancer. There are no data on the potential effect of amifostine on thyroid cancer cells.

METHODS

We investigated the effects of the active form of amifostine (WR-1065) on the response of thyroid cancer cells to treatment with DNA-damaging agents. WR-1065 was examined in human thyroid cancer cell lines (FTC133, TPC1, BCPAP and C643) and embryonic fibroblast cells NIH3T3. DNA damage was induced by exposure to H₂O₂ (0.1 mM), by treatment with the radiomimetic neocarzinostatin (NCS 250 ng/mL) and by γ-radiation (6 Gy). DNA damage, cell viability and apoptosis were examined.

RESULTS

We demonstrated the selective action of WR-1065 (0.1 mM), which prevented oxidative stress-induced DNA damage in fibroblasts, but did not protect thyroid cancer cells from DNA damage and apoptosis documented by caspase-3 and PARP cleavage after exposure to H₂O₂, NCS and γ-radiation. Prolonged exposure to WR-1065 (0.1 mM for 24 h) was toxic for thyroid cancer cells; this treatment decreased the number of viable cells by 8% in C643 cells, 47% in TPC cells, 92% in BCPAP cells and 82% in FTC 133 cells. The cytotoxic effects of WR-1065 were not associated with induction of apoptosis.

CONCLUSIONS

Our data show that amifostine has no protective effect on thyroid cancer cells against DNA-damaging agents in vitro and suggest that amifostine will not attenuate the efficacy of radioiodine treatment in patients with thyroid cancer.