Non-Operative, Active Surveillance of Larger Malignant and Suspicious Thyroid Nodules.

CONTEXT: Active surveillance for papillary thyroid cancer (PTC) meeting criteria for surgical resection is uncommon. Which patients may prove reasonable candidates for this approach is not well defined. OBJECTIVE: To examine the feasibility and safety of active surveillance for patients with known or suspected intrathyroidal PTC up to 4cm in diameter. DESIGN, SETTING, AND PARTICIPANTS: Retrospective review of all consecutive patients who underwent non-operative active surveillance of suspicious or malignant thyroid nodules over a 20-year period from 2001-2021. We included patients with an initial US-FNA confirming either: a) Bethesda 5 or 6 cytology or, b) a "suspicious" AFIRMA molecular test. The primary outcomes and measures included the rate of adverse oncologic outcomes (mortality and recurrence), as well as the cumulative incidence of size/volume growth. RESULTS: Sixty-nine patients were followed with active surveillance for 1 year or longer (average 55 months), with 26 patients (38%) having nodules ≥ 2 cm. No patients were found to develop new incident occurrence of lymph node or distant metastasis. One patient however, demonstrated concern for progression to a dedifferentiated cancer on repeat core biopsy 17 years after initial start non-operative selection. 21% of patients had an increase in maximum diameter more than 3 mm, and volume increase ≥50% was noted in 25% of patients. Thirteen patients ultimately underwent delayed (rescue) surgery, and no disease recurrence was noted after such treatment. Age and initial nodule size were not predictors of nodule growth. CONCLUSIONS: These data expand consideration of active surveillance of papillary thyroid carcinoma in select patients with intrathyroidal suspected malignancy >1cm in diameter. Rescue surgery, if required at a later timepoint, appears effective.

Impact of Obesity on Risk of Hypocalcemia After Total Thyroidectomy: Targeted National Surgical Quality Improvement Program Analysis of 16,277 Patients.

INTRODUCTION: Hypocalcemia following total thyroidectomy (TT) is common due to postoperative parathyroid dysfunction and vitamin D deficiency. Given the association between obesity and vitamin D deficiency, we sought to correlate body mass index (BMI) with hypocalcemia after TT. METHODS: Patients undergoing TT between 2016 and 2020 were identified from the American College of Surgeons National Surgical Quality Improvement Program thyroidectomy-targeted database. Univariable and multivariable regressions, stratified by BMI category (normal, overweight, obese), identified factors associated with hypocalcemia prior to discharge, within 30 d, and severe hypocalcemic events (emergent evaluation, intravenous calcium supplementation, or readmission). RESULTS: Sixteen thousand two hundred seventy seven TT were performed with available BMI data. Three thousand five hundred thirty one (21.7%) patients had normal BMI, 4823 (29.6%) were overweight, and 7772 (47.7%) were obese. Patients with BMI ≥ 25 had decreased risk of hypocalcemia before discharge (9.8% versus 13%, odds ratio [OR] 0.73, P < 0.001), 30 d (8.1% versus 10.4%, OR 0.76, P < 0.001), and severe hypocalcemic events (5.5% versus 6.4%, OR 0.84, P = 0.029) compared to normal BMI patients. On multivariable analysis for normal BMI patients, age < 45 y was a risk factor for hypocalcemia before discharge, 30 d, and severe hypocalcemic events (P < 0.05 for all). Additional risk factors in this group for 30-d hypocalcemia included parathyroid autotransplant and central neck dissection (P < 0.05) and recurrent laryngeal nerve injury for severe hypocalcemic events (P = 0.01). CONCLUSIONS: Younger patients with BMI < 25 are at an increased risk for hypocalcemia and severe hypocalcemic events after TT. These patients may benefit from preoperative counseling and increased calcium/vitamin D supplementation to reduce prolonged hospitalization and mitigate morbidity.

Additional Oncogenic Alterations in RAS-Driven Differentiated Thyroid Cancers Associate with Worse Clinicopathologic Outcomes.

PURPOSE: RAS mutations occur across the spectrum of thyroid neoplasms, and more tools are needed for better prognostication. The objective of this study was to evaluate how additional genetic events affecting key genes modify prognosis in patients with RAS-mutant thyroid cancers, and specifically differentiated thyroid cancers (DTC). EXPERIMENTAL DESIGN: We performed a clinical-genomic analysis of consecutive patients with DTC, poorly differentiated (PDTC), or anaplastic thyroid cancer (ATC) between January 2014 and December 2021, in whom a custom-targeted next-generation sequencing assay was performed. Patients harboring RAS mutations were included, and we compared their clinical features and outcomes based upon the presence of additional oncogenic alterations. RESULTS: Seventy-eight patients were identified, with 22% (17/78) harboring a driver RAS mutation plus an additional oncogenic alteration. All six (100%) ATCs had an additional mutation. Compared with DTCs harboring a solitary RAS mutation, patients with DTC with RAS and additional mutation(s) were more likely to be classified as American Thyroid Association high-risk of recurrence (77% vs. 12%; P < 0.001) and to have larger primary tumors (4.7 vs. 2.5 cm; P = 0.002) and advanced stage (III or IV) at presentation (67% vs. 3%; P < 0.001). Importantly, over an average 65-month follow-up, DTC-specific-mortality was more than 10-fold higher (20% vs. 1.8%; P = 0.011) when additional mutations were identified. CONCLUSIONS: Identification of key additional mutations in patients with RAS-mutant thyroid cancers confers a more aggressive phenotype, increases mortality risk in DTC, and can explain the diversity of RAS-mutated thyroid neoplasia. These data support genomic profiling of DTCs to inform prognosis and clinical decision-making.

Limited disease progression in endocrine surgery patients with treatment delays due to COVID-19.

BACKGROUND: The COVID-19 pandemic profoundly impacted the delivery of care and timing of elective surgical procedures. Most endocrine-related operations were considered elective and safe to postpone, providing a unique opportunity to assess clinical outcomes under protracted treatment plans. METHODS: American Association of Endocrine Surgeon members were surveyed for participation. A Research Electronic Data Capture survey was developed and distributed to 27 institutions to assess the impact of COVID-19-related delays. The information collected included patient demographics, primary diagnosis, resumption of care, and assessment of disease progression by the surgeon. RESULTS: Twelve out of 27 institutions completed the survey (44.4%). Of 850 patients, 74.8% (636) were female; median age was 56 (interquartile range, 44-66) years. Forty percent (34) of patients had not been seen since their original surgical appointment was delayed; 86.2% (733) of patients had a delay in care with women more likely to have a delay (87.6% vs 82.2% of men, χ2 = 3.84, P = .05). Median duration of delay was 70 (interquartile range, 42-118) days. Among patients with a delay in care, primary disease site included thyroid (54.2%), parathyroid (37.2%), adrenal (6.5%), and pancreatic/gastrointestinal neuroendocrine tumors (1.3%). In addition, 4.0% (26) of patients experienced disease progression and 4.1% (24) had a change from the initial operative plan. The duration of delay was not associated with disease progression (P = .96) or a change in operative plan (P = .66). CONCLUSION: Although some patients experienced disease progression during COVID-19 delays to endocrine disease-related care, most patients with follow-up did not. Our analysis indicated that temporary delay may be an acceptable course of action in extreme circumstances for most endocrine-related surgical disease.

Higher SUVmax on FDG-PET is associated with shorter survival in adrenocortical carcinoma.

BACKGROUND: Adrenocortical carcinoma (ACC) is an aggressive, rare malignancy. 2-deoxy-2-[18F]-fluoro-d-glucose positron emission tomography (FDG-PET) assesses tumor metabolism and glucose utilization. We hypothesized that higher maximum standard uptake value (SUVmax) is associated with decreased survival. METHODS: We performed a retrospective analysis of patients with ACC. Included patients (n = 26) had an FDG-PET scan available with a documentable SUVmax. Patients were dichotomized into "High" (≥8.4, n = 12) and "Low" (<8.4, n = 14) SUVmax. Univariate analysis and survival analysis were performed to compare groups. RESULTS: Demographics between groups were equivalent. The high SUVmax cohort demonstrated lower survival (median 479 days or 15.7 months) compared to the low group (median 1490 days or 48.6 months, p = .01). Log-Rank curve confirmed differences in survival (p = .007). CONCLUSIONS: Higher SUVmax was associated with significantly worse survival in ACC and may reflect a more aggressive phenotype. FDG-PET may provide clinically useful information to determine prognosis and treatment. Further studies should prospectively evaluate using FDG-PET/CT in ACC.

Increased Body Mass Index is Associated With Lower Risk of Hypocalcemia in Total Thyroidectomy Patients.

INTRODUCTION: Hypocalcemia following total thyroidectomy is common due to postoperative parathyroid dysfunction. We sought to identify the impact of obesity on postthyroidectomy hypocalcemia. METHODS: We performed a single-center retrospective study of all total thyroidectomies performed from 2016 to 2019 after implementation of an updated calcium supplementation protocol. Patient characteristics and outcomes were measured including body mass index (BMI), postoperative hypocalcemia (Ca <8.3), and hypocalcemic symptoms. RESULTS: Overall, 559 total thyroidectomies were performed. A total of 146 patients (26.2%) developed hypocalcemia requiring supplementation adjustment and 116 patients (20.8%) developed mild hypocalcemia symptoms. On multivariable analysis, younger patients, patients with lower preoperative calcium, and lower BMI were more likely to develop postoperative hypocalcemia (all P < 0.05). Similarly, younger patients and patients with BMI <25 were more likely to develop hypocalcemic symptoms (all P < 0.05). CONCLUSIONS: Younger age and lower BMI were associated with increased risk of hypocalcemia after total thyroidectomy. These patients may benefit from preoperative and/or increased postoperative supplementation.

Effect of Lactate Export Inhibition on Anaplastic Thyroid Cancer Growth and Metabolism.

BACKGROUND: Anaplastic thyroid cancer (ATC) is an aggressive malignancy without effective treatments. ATC cells demonstrate upregulated glycolysis (Warburg effect), generating lactate that is subsequently exported by monocarboxylate transporter 4 (MCT4). This study aims to determine whether MCT4 inhibition can suppress ATC growth. STUDY DESIGN: ATC cell lines 8505C, JL30, and TCO1 were grown in low (3 mmol/L; LG) or high (25 mmol/L; HG) glucose medium containing the lactate shuttle inhibitors acriflavine (10-25 µmol/L; ACF), syrosingopine (100 µmol/L; SYR), or AZD3965 (20 µmol/L; AZD). Lactate level and cell proliferation were measured with standard assays. Seahorse analysis was performed to determine glycolytic response. RESULTS: Compared with HG, addition of ACF to LG decreased lactate secretion for both 8505C (p < 10-5) and JL30 (p < 10-4) cells, whereas proliferation was also reduced (p < 10-4 and 10-5, respectively). During Seahorse analysis, addition of oligomycin increased acidification by 84 mpH/min in HG vs 10 mpH/min in LG containing ACF (p < 10-5). Treatment with LG and SYR drastically diminished 8505C and TCO1 growth vs HG (p < 0.01 for both). LG and AZD treatment also led to reduced proliferation in tested cell lines (p ≤ 0.01 for all) that was further decreased by addition of ACF (p < 10-4 vs HG, p ≤ 0.01 vs LG and AZD). CONCLUSION: Inhibition of lactate shuttles significantly reduced proliferation and glycolytic capacity of ATC cells in a low-glucose environment. Targeting suppression of glycolytic and lactate processing pathways may represent an effective treatment strategy for ATC.

Survival After Adrenalectomy for Metastatic Lung Cancer.

BACKGROUND: Adrenal metastasectomy is associated with increased survival in non-small cell lung cancer (NSCLC) with isolated adrenal metastases. Although clinical use of adrenal metastasectomy has expanded, indications remain poorly defined. The aim of this study was to evaluate the clinical benefit of adrenal metastasectomy for all lung cancer subtypes. PATIENTS AND METHODS: We performed a retrospective cohort study of patients who underwent adrenal metastasectomy for metastatic lung cancer at six institutions between 2001 and 2015. The primary outcomes were disease-free survival (DFS) and overall survival (OS). Cox proportional hazards regressions and Kaplan-Meier survival analysis were performed. RESULTS: For 122 patients, the mean age was 60.5 years and 49.2% were female. Median time to detection of the metastasis was 11 months, and 41.8% were ipsilateral to the primary lung cancer. Median DFS was 40 months (1 year: 64.8%; 5 year: 42.9%). Factors associated with longer DFS included primary tumor resection [hazard ratio (HR): 0.001; p = 0.005], longer time to adrenal metastasis (HR: 0.94; p = 0.005), and ipsilateral metastases (HR: 0.13; p = 0.004). Shorter DFS corresponded with older age (HR: 1.11; p = 0.01), R1 resection (HR: 8.94; p = 0.01), adjuvant radiation (HR: 9.45; p = 0.02), and open adrenal metastasectomy (HR: 10.0; p = 0.03). Median OS was 47 months (1 year: 80.2%; 5 year: 35.2%). Longer OS was associated with ipsilateral metastasis (HR: 0.55; p = 0.02) and adjuvant chemotherapy (HR: 0.35; p = 0.02). Shorter OS was associated with extra-adrenal metastases at adrenalectomy (HR: 3.52; p = 0.007), small cell histology (HR: 15.0; p = 0.04), and lung radiation (HR: 3.37; p = 0.002). DISCUSSION: Durable survival was observed in patients undergoing adrenal metastasectomy and should be considered for isolated adrenal metastases of NSCLC. Small cell histology and extra-adrenal metastases are relative contraindications to adrenal metastasectomy.

Glycolytic inhibition with 3-bromopyruvate suppresses tumor growth and improves survival in a murine model of anaplastic thyroid cancer.

BACKGROUND: Anaplastic thyroid cancer is a rare but devastating malignancy. Anaplastic thyroid cancer cells exhibit the Warburg effect by preferentially undergoing glycolysis even in aerobic conditions, leading to high glucose use. Here we assess if targeted inhibition of glycolysis can diminish anaplastic thyroid cancer growth and improve outcomes. METHODS: Human anaplastic thyroid cancer cell line 8505C was grown in medium containing high (25 mmol/L) or low (3 mmol/L) glucose concentration and hexokinase II inhibitor 3-bromopyruvate (200 µM). Cellular proliferation, migration, and invasion were measured. An orthotopic xenograft model of anaplastic thyroid cancer was generated in nude mice using 8505C cells. Animals were provided standard chow or a ketogenic diet and treated with 3-bromopyruvate (1.8 mg/kg). Overall survival time was monitored. Necropsies were performed to harvest tumors for analysis. RESULTS: Growth of 8505C in low-glucose medium with 3-bromopyruvate decreased cell proliferation by 89%, migration by 44%, and invasion by 73% (P < .001 for all) compared with high glucose. Animals concomitantly receiving a ketogenic diet and 3-bromopyruvate exhibited smaller tumor volumes (P = .03), slower tumor growth rates (P = .01), and improved overall survival (P = .006) compared with standard-diet control subjects. Monotherapy with a ketogenic diet or 3-bromopyruvate alone did not reduce tumor size or increase survival over the standard-diet control group. CONCLUSION: Glycolytic inhibition with 3-bromopyruvate inhibits tumor growth and extends survival in a murine model of anaplastic thyroid cancer when combined with the ketogenic diet. Thus, targeted glycolytic inhibition of anaplastic thyroid cancer exhibits context-specific utility and may only be effective during ketosis induced by dietary restriction of glycolytic inputs.

Oncogenic Mutations in PI3K/AKT/mTOR Pathway Effectors Associate with Worse Prognosis in BRAFV600E -Driven Papillary Thyroid Cancer Patients.

PURPOSE: The extent to which routine genomic sequencing can identify relevant secondary genomic alterations among BRAFV600E -mutant papillary thyroid carcinoma (PTC) is unknown. Such markers would prove highly valuable for prognostic purposes. EXPERIMENTAL DESIGN: We reviewed clinicopathologic data of 225 patients with BRAFV600E -mutant PTC and integrated them with genomic data derived from targeted next-generation sequencing (NGS) on tumor specimens. We defined patient subgroups based on bona fide secondary oncogenic events (separate from BRAFV600E ) and compared their clinical features and outcomes with those without additional oncogenic alterations. RESULTS: Additional oncogenic alterations were identified in 16% of tumors. Patients in the "BRAF+additional mutations" group were more likely to be at high American Thyroid Association (ATA) risk of recurrence (48.6% vs. 17.6%; P = 0.0009), had larger baseline tumor (2.7 vs. 1.9 cm; P = 0.0005) and more advanced stage at presentation (14.3% vs. 1.1% stage 4; P < 0.0001). Importantly, over a 65-month follow-up, disease-specific mortality (DSM) was increased when additional mutations were identified (13.8% vs. 1.4% in the BRAF-only group; P = 0.005). Separately, we identified a subcluster of patients harboring oncogenic mutations in key effectors of the PI3K/AKT/mTOR pathway, which were independently associated with DSM (OR = 47.9; 95% confidence interval, 3.5-1,246.5; P = 0.0043). CONCLUSIONS: Identification of additional PIK3/AKT/mTOR alterations in patients with BRAFV600E -mutant PTC provides important and actionable prognostic risk stratification. These data support genomic profiling of PTC tumors to inform prognosis and clinical strategy.

Diabetes mellitus and hyperglycemia are associated with inferior oncologic outcomes in adrenocortical carcinoma.

PURPOSE: Prior literature suggests that cancer patients with hyperglycemia and type 2 diabetes mellitus (DM) exhibit worse oncologic and overall outcomes. Tumor metabolism and anabolism pathophysiology may explain this association, although this has not been adequately studied in adrenocortical carcinoma (ACC). We hypothesized that DM would be associated with worse oncological outcomes in ACC, and we utilized data from a national database and institutional sources for multimodal analysis. METHODS: Both a multi-institutional database (the Collaborative Endocrine Surgery Quality Improvement Program or CESQIP) and a single-center longitudinal cohort (Dana Farber Cancer Institute or DFCI) were queried as unique retrospective cohorts to identify patients with ACC. Patient demographics, tumor characteristics, DM-specific variables, and oncologic outcome data were assessed. Results were analyzed via univariate analysis and multivariable linear regression analysis. Statistical significance was defined as p < 0.05. RESULTS: Forty-eight CESQIP patients met inclusion criteria; 16 (33.0%) had DM. DM patients had a higher frequency of recurrence on longitudinal follow-up (12.5% v 0.0%, p = 0.04). Persistent disease was observed in 68.8% of DM patients and 40.6% of non-DM patients (p = 0.06). Patients in the DFCI cohort with lower average glucose values (< 110 mg/dL) had a significant survival benefit (p < .0001). A mean serum glucose > 110 mg/dL had increased risk (HR 36.3, 95% confidence interval 1.6, 831.3) for all-cause mortality. CONCLUSIONS: This multi-institutional, multimodal analysis suggests that patients with DM have worse oncologic and overall outcomes for ACC. While further study is warranted, consideration should be given among clinicians to optimize glycemic control as part of their ACC management.

Completion Thyroidectomy is Less Common Following Updated 2015 American Thyroid Association Guidelines.

BACKGROUND: The 2015 American Thyroid Association (ATA) guidelines recommended that low-risk, differentiated thyroid cancers (DTC) between 1 and 4 cm may be treated with thyroid lobectomy alone. We sought to determine the effect of these guideline changes on the rate of completion thyroidectomy (CT) for low-risk DTC and factors influencing surgical decision-making. METHODS: All patients from 2014 to 2018 who received an initial thyroid lobectomy at our institution with final pathology demonstrating DTC were included. Patients were divided into "pre" and "post" guideline cohorts (2014-2015 and 2016-2018, respectively). The rate of CT was compared between the two cohorts. Patient demographics and tumor characteristics were examined for association with CT. RESULTS: A total of 163 patients met study criteria: 63 patients in the 2014-2015 ("pre") and 100 in the 2016-2018 ("post") group. In the "pre" period, 41 (65.1%) patients received CT compared with 43 (43.0%) in the "post" period (p < 0.01)-a 34% decrease in the rate of completion surgery (p < 0.01). Of low-risk patients with DTC between 1 and 4 cm in size, 17 of 35 (48.6%) received CT in the "pre" period compared with 15 of 60 (25.0%) in the post period-a 48.6% decrease in the rate of completion surgery (p = 0.02). Greater tumor size, capsular invasion, and multifocality were associated with CT in low-risk "post" guideline patients (p < 0.05 for all). CONCLUSIONS: The rate of CT decreased significantly by 48.6% for low-risk patients with DTC between 1 and 4 cm, demonstrating recognition of the 2015 ATA guidelines. However, 25% of these patients underwent CT, suggesting additional factors influencing the decision for further treatment.

Adrenalectomy for Secondary Malignancy: Patients, Outcomes, and Indications.

OBJECTIVE: The goal of this study was to examine a multi-institutional experience with adrenal metastases to describe survival outcomes and identify subpopulations who benefit from adrenal metastasectomy. BACKGROUND: Adrenalectomy for metastatic disease is well-described, although indications and outcomes are incompletely defined. METHODS: A retrospective cohort study was performed of patients undergoing adrenalectomy for secondary malignancy (2002-2015) at 6 institutions. The primary outcomes were disease free survival (DFS) and overall survival (OS). Analysis methods included Kaplan-Meier and Cox proportional hazards. RESULTS: Of 269 patients, mean age was 60.1 years; 50% were male. The most common primary malignancies were lung (n = 125, 47%), renal cell (n = 38, 14%), melanoma (n = 33, 12%), sarcoma (n = 18, 7%), and colorectal (n = 12, 5%). The median time to detection of adrenal metastasis after initial diagnosis of the primary tumor was 17 months (interquartile range: 6-41). Post-adrenalectomy, the median DFS was 18 months (1-year DFS: 54%, 5-year DFS: 31%). On multivariable analysis, lung primary was associated with longer DFS [hazard ratio (HR): 0.49, P = 0.008). Extra-adrenal oligometastatic disease at initial presentation (HR: 1.84, P = 0.016), larger tumor size (HR: 1.07, P = 0.013), chemotherapy as treatment of the primary tumor (HR: 2.07 P = 0.027) and adjuvant chemotherapy (HR: 1.95, P = 0.009) were associated with shorter DFS. Median OS was 53 months (1-year OS: 83%, 5-year OS: 43%). On multivariable analysis, extra-adrenal oligometastatic disease at adrenalectomy (HR: 1.74, P = 0.031), and incomplete resection of adrenal metastasis (R1 margins; HR: 1.62, P = 0.034; R2 margins; HR: 5.45, P = 0.002) were associated with shorter OS. CONCLUSIONS: Durable survival is observed in patients undergoing adrenal metastasectomy and should be considered for subjects with isolated adrenal metastases.

Papillary Thyroid Carcinoma with High-Grade Features Versus Poorly Differentiated Thyroid Carcinoma: An Analysis of Clinicopathologic and Molecular Features and Outcome.

Background: Similar to poorly differentiated thyroid carcinoma (PDTC), papillary thyroid carcinoma with high-grade features (PTC HGF) demonstrates increased mitotic activity and/or necrosis; however, PTC HGF is excluded from the World Health Organization (WHO) definition of PDTC based on maintained nuclear features of PTC. Methods: Consecutive tumors that met criteria for PTC HGF, defined as tumors with maintained nuclear features of PTC and mitoses numbering 5 or more per 10 contiguous high-power fields and/or tumor necrosis, and PDTC (defined as per the WHO criteria) were identified. Clinicopathologic characteristics, follow-up data, and targeted next-generation sequencing results were compared between groups. Results: There were 15 PTC HGF and 47 PDTC. PTC HGF was associated with a higher rate of pT4 disease (53% vs. 13%, p = 0.0027) and lymph node metastases (73% vs. 38%, p = 0.049). The disease-specific survival was worse for patients with PTC HGF compared with those with PDTC using Kaplan-Meier estimation (p < 0.001) and was worse in subgroup analysis evaluating patients with widely invasive PDTC (i.e., those with a similar rate of pT4 disease) and PTC HGF (p = 0.040). PTC HGF had a higher BRAFV600E mutation rate (42% vs. 3%; p = 0.003), a trend toward more gene fusions (25% vs. 3%; p = 0.052), and a higher rate of relative gain of 1q (67% vs. 15%; p = 0.002) than PDTC. Conclusions: Our results demonstrate that PTC HGF are important to recognize based on their aggressive behavior. The molecular differences between PTC HGF and PDTC suggest that PTC HGF should be considered a distinct group from PDTC.

Histopathologic Features and Clinical Outcome of Anaplastic Thyroid Carcinoma with a Minor Anaplastic Component.

Although prior studies have reported that patients with anaplastic thyroid carcinoma (ATC) with a focal anaplastic component may have a prolonged survival compared to other ATC patients, the outcome data are limited. We evaluated a cohort of ATC resected between 2003 and 2018. Tumor slides were reviewed to confirm the diagnosis and to identify cases with a minor ATC component (defined as comprising < 10% of the tumor). We evaluated the clinical outcome of these patients compared to that of all other cohort patients (characterized as having conventional ATC). Our cohort was composed of 24 cases of ATC that underwent resection, including 8 (33%) with a minor ATC component. Tumors with a minor ATC component were predominantly associated with papillary thyroid carcinoma. For patients with tumors with a minor ATC component, the 1-year and 2-year survival rates and median survival for patients who died of disease were 88%, 43%, and 17 months (range 6-73 months), respectively. In comparison, for patients with conventional ATC, the 1-year and 2-year survival rates and median survival for patients who died of disease were 56%, 44%, and 7 months (range 2-26 months), respectively. There was no difference in 1- and 2-year survival or overall survival by Kaplan-Meier analysis for patients with tumors with a minor ATC component and those with conventional ATC. In conclusion, the difference in overall survival between ATC groups in our cohort was not significant; however, this could be due to the small cohort size or due to characteristics of our group with a minor ATC component; that is, no tumors in this group were limited to the thyroid (stage IVA), resectability with negative margins was infrequent, and 38% of this group had distant metastases at diagnosis (stage IVC).

Ketogenic diet combined with antioxidant N-acetylcysteine inhibits tumor growth in a mouse model of anaplastic thyroid cancer.

BACKGROUND: Anaplastic thyroid cancer is an aggressive and fatal malignancy. Many advanced cancers are characterized by glucose dependency, leading to oxidative stress and cellular proliferation. Therefore, we sought to determine if a low glucose environment (in vitro) or a ketogenic diet (in vivo) could inhibit anaplastic thyroid cancer tumor growth when combined with the antioxidant N-acetylcysteine. METHODS: In vivo, nude mice were injected with the anaplastic thyroid cancer cell line 8505C (n = 6/group). Group 1 was fed a standard diet; Group 2 was fed a ketogenic diet; Group 3 was given standard diet with N-acetylcysteine (40 mM in the drinking water); and Group 4 was fed ketogenic diet with N-acetylcysteine. Tumor volumes, ketones, and glucose were measured. H&E stains and immunohistochemistry for Ki-67 and Caspase 3 were performed on the tumors. In vitro, 8505C cells were cultured in high glucose (25 mM), low glucose (3 mM), high glucose plus N-acetylcysteine (200 uM), or low glucose plus N-acetylcysteine for 96 hours. We performed CyQUANT proliferation (Thermo Fisher Scientific, Waltham, MA), Seahorse glycolytic stress (Agilent, Santa Clara, CA), and reactive oxidative stress assays. RESULTS: Ketogenic diet plus N-acetylcysteine decreased in vivo tumor volume compared to standard diet (22.5 ± 12.4 mm3 vs 147 ± 54.4 mm3, P < .05) and standard diet plus N-acetylcysteine (P < .05). Blood ketone levels were significantly higher for the mice in the ketogenic diet group compared to standard diet (1.74 mmol/L vs 0.38 mmol/L at week 5, P < .001). However, blood glucose levels were not significantly different between ketogenic diet and standard diet groups. Cells cultured in low glucose plus N-acetylcysteine had significantly reduced proliferation compared to high glucose (98.1 ± 5.0 relative fluorescence units vs 157.8 ± 2.1 relative fluorescence units, P < .001). Addition of N-acetylcysteine to low glucose lowered glycolysis function compared to high glucose (39.0 ± 2.2 mpH/min/cell vs 89.1 ± 13.2 mpH/min/cell, P < .001) and high glucose plus N-acetylcysteine (37.4 ± 2.5 mpH/min/cell vs 70.3 ± 3.3 mpH/min/cell, P < .001). Low glucose plus N-acetylcysteine decreased reactive oxidative stress compared to high glucose (119 ± 34.7 relative fluorescence units vs 277 ± 16.0 relative fluorescence units, P = .014). CONCLUSION: The combination of a ketogenic diet or glucose restriction with the antioxidant- N-acetylcysteine significantly reduced tumor growth in vivo and in vitro. Further studies are warranted to explore these metabolic therapies in anaplastic thyroid cancer.

A potential diagnostic pitfall for hobnail variant of papillary thyroid carcinoma.

AIMS: Hobnail variant of papillary thyroid carcinoma (PTC) is an aggressive PTC subtype characterised by a hobnail cytomorphology. However, some classic PTC have a 'hobnail-like' cytomorphology associated with thick, hyalinised, variably oedematous fibrovascular cores that appears to be a form of ischaemic/degenerative atypia. METHODS AND RESULTS: We studied three cohorts to compare the histopathological characteristics and clinical outcome of 'hobnail-like' classic PTC and true hobnail variant of PTC: cohort 1, PTC consecutively resected between 2016 and 2017 (to assess frequency of 'hobnail-like' cytomorphology); cohort 2, 20 'hobnail-like' classic PTC resected between 2005 and 2007 (to assess clinical outcome); and cohort 3, seven true hobnail variant of PTC. A 'hobnail-like' cytomorphology was identified in 16% of consecutively resected PTC. Compared with true hobnail variant, 'hobnail-like' classic PTC occurred in younger patients (mean age 40 years versus 68 years, P < 0.001), were smaller tumours (mean tumour size 2.1 cm versus 4.4 cm, P < 0.001), had a lower rate of gross extrathyroidal extension (0% versus 71%, P < 0.001), had a lower proliferative rate (≥3 mitoses per 10 high-power fields seen in 0% versus 71%, P < 0.001; Ki67 index ≥5% in 0% versus 86%, P < 0.001), a lower rate of secondary pathogenic mutations (for cases with molecular data, 0% versus 100%, P = 0.0061) and improved survival (for cases with sufficient clinical outcome data, 10-year disease-free survival of 93% versus 0%, P = 0.0016). CONCLUSION: Classic PTC can show ischaemic/degenerative atypia that mimics the hobnail cytomorphology of true hobnail variant; however, these tumours lack aggressive histopathological features and pursue an indolent clinical course.

Prognostic Significance of Extent of Invasion in Poorly Differentiated Thyroid Carcinoma.

Background: The 2017 World Health Organization (WHO) Classification of Tumors of Endocrine Organs defines poorly differentiated thyroid carcinoma (PDTC) as a tumor with conventional criteria of malignancy (capsular penetration or vascular invasion) with solid, insular, or trabecular growth, a lack of nuclear features of papillary thyroid carcinoma, and increased mitotic activity, tumor necrosis, or convoluted nuclei. The extent of invasion has been shown to be prognostic in follicular thyroid carcinoma and Hürthle cell carcinoma. Our aim was to evaluate how extent of invasion impacts clinical outcome for PDTC. Methods: We retrospectively identified 47 consecutively diagnosed cases of PDTC that were resected between 2005 and 2018. All cases were reviewed to confirm that the tumors met the 2017 Endocrine WHO criteria of PDTC. In addition, tumors were categorized as follows: encapsulated with capsular penetration only, encapsulated with focal vascular invasion (fewer than four foci), encapsulated with extensive vascular invasion (four or more foci), or widely invasive. Histopathologic characteristics and clinical outcome data were recorded. Results: A total of 47 cases of PDTC, including 15 oncocytic tumors, were identified from 28 (60%) women and 19 (40%) men (mean age of 57 years at diagnosis). The mean tumor size was 4.3 cm. Mitoses numbered 8 per 10 high-power fields (HPF) on average (range: 1-34), and necrosis was present in 21 (45%) cases. Eight (17%) cases were encapsulated with capsular penetration only, 5 (11%) were encapsulated with focal vascular invasion, 18 (38%) were encapsulated with extensive vascular invasion, and 16 (34%) were widely invasive. Of the 42 (89%) patients with follow-up data, 7 (17%) died of disease (with a mean survival time of 6.4 years), 11 (26%) have distant metastatic disease, and 24 (57%) have no evidence of disease (mean follow-up 5.6 years). Eight (19%) patients presented with M1 disease at diagnosis. The 5-year disease-free survival (DFS) for patients with M0 disease at diagnosis was 100% for patients with tumors with capsular invasion only or focal vascular invasion (n = 7), 73% for patients with encapsulated tumors with extensive vascular invasion (n = 11), and 17% for patients with widely invasive PDTCs (n = 6). DFS estimates by Kaplan-Meier analysis were significantly different between these groups (p = 0.0016). Conclusions: Extent of invasion appears to be an important parameter that affects clinical outcome for patients with PDTC. In our cohort, patients with encapsulated PDTC with capsular invasion only or focal vascular invasion had an excellent outcome.

A Cohort Analysis of Clinical and Ultrasound Variables Predicting Cancer Risk in 20,001 Consecutive Thyroid Nodules.

CONTEXT: Assessing thyroid nodules for malignancy is complex. The impact of patient and nodule factors on cancer evaluation is uncertain. OBJECTIVES: To determine precise estimates of cancer risk associated with clinical and sonographic variables obtained during thyroid nodule assessment. DESIGN: Analysis of consecutive adult patients evaluated with ultrasound-guided fine-needle aspiration for a thyroid nodule ≥1 cm between 1995 and 2017. Demographics, nodule sonographic appearance, and pathologic findings were collected. MAIN OUTCOME MEASURES: Estimated risk for thyroid nodule malignancy for patient and sonographic variables using mixed-effect logistic regression. RESULTS: In 9967 patients [84% women, median age 53 years (range 18 to 95)], thyroid cancer was confirmed in 1974 of 20,001 thyroid nodules (9.9%). Significant ORs for malignancy were demonstrated for patient age <52 years [OR: 1.82, 95% CI (1.63 to 2.05), P < 0.0001], male sex [OR: 1.68 (1.45 to 1.93), P < 0.0001], nodule size [OR: 1.30 (1.14 to 1.49) for 20 to 19 mm, OR: 1.59 (1.34 to 1.88) for 30 to 39 mm, and OR: 1.71 (1.43 to 2.04) for ≥40 mm compared with 10 to 19 mm, P < 0.0001 for all], cystic content [OR: 0.43 (0.37 to 0.50) for 25% to 75% cystic and OR: 0.21 (0.15 to 0.28) for >75% compared with predominantly solid, P < 0.0001 for both], and the presence of additional nodules ≥1 cm [OR: 0.69 (0.60 to 0.79) for two nodules, OR: 0.41 (0.34 to 0.49) for three nodules, and OR: 0.19 (0.16 to 0.22) for greater than or equal to four nodules compared with one nodule, P < 0.0001 for all]. A free online calculator was constructed to provide malignancy-risk estimates based on these variables. CONCLUSIONS: Patient and nodule characteristics enable more precise thyroid nodule risk assessment. These variables are obtained during routine initial thyroid nodule evaluation and provide new insights into individualized thyroid nodule care.