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Hypercalcemia of malignancy (HCM) is considered an oncologic emergency associated with significant symptom burden and increased comorbid conditions and mortality. Underlying pathologic processes most often stimulate osteoclast-mediated bone resorption. Although long-term control of HCM depends on effective management of the underlying cancer, temporizing management strategies for acute and/or symptomatic HCM include hydration and antiresorptive bone-modifying agents. Although most patients respond well to the antiresorptive therapies available, further investigation into other agents for those who are refractory to both bisphosphonates and denosumab is needed.

Background Hypercalcemia of malignancy (HCM) is the most common metabolic complication of malignancies, but its incidence may be declining due to potent chemotherapeutic agents. The high mortality associated with HCM has declined markedly due to the introduction of increasingly effective chemotherapeutic drugs. Despite the widespread availability of efficacious medications to treat HCM, evidence-based recommendations to manage this debilitating condition are lacking. Objective To develop guidelines for the treatment of adults with HCM. Methods A multidisciplinary panel of clinical experts, together with experts in systematic literature review, identified and prioritized 8 clinical questions related to the treatment of HCM in adult patients. The systematic reviews (SRs) queried electronic databases for studies relevant to the selected questions. The Grading of Recommendations Assessment, Development and Evaluation (GRADE) methodology was used to assess the certainty of evidence and make recommendations. An independent SR was conducted in parallel to assess patients' and physicians' values and preferences, costs, resources needed, acceptability, feasibility, equity, and other domains relevant to the Evidence-to-Decision framework as well as to enable judgements and recommendations. Results The panel recommends (strong recommendation) in adults with HCM treatment with denosumab (Dmab) or an intravenous (IV) bisphosphonate (BP). The following recommendations were based on low certainty of the evidence. The panel suggests (conditional recommendation) (1) in adults with HCM, the use of Dmab rather than an IV BP; (2) in adults with severe HCM, a combination of calcitonin and an IV BP or Dmab therapy as initial treatment; and (3) in adults with refractory/recurrent HCM despite treatment with BP, the use of Dmab. The panel suggests (conditional recommendation) the addition of an IV BP or Dmab in adult patients with hypercalcemia due to tumors associated with high calcitriol levels who are already receiving glucocorticoid therapy but continue to have severe or symptomatic HCM. The panel suggests (conditional recommendation) in adult patients with hypercalcemia due to parathyroid carcinoma, treatment with either a calcimimetic or an antiresorptive (IV BP or Dmab). The panel judges the treatments as probably accessible and feasible for most recommendations but noted variability in costs, resources required, and their impact on equity. Conclusions The panel's recommendations are based on currently available evidence considering the most important outcomes in HCM to patients and key stakeholders. Treatment of the primary malignancy is instrumental for controlling hypercalcemia and preventing its recurrence. The recommendations provide a framework for the medical management of adults with HCM and incorporate important decisional and contextual factors. The guidelines underscore current knowledge gaps that can be used to establish future research agendas.

Medullary thyroid cancer; Selpercatinib; Targeted therapy Cáncer medular de tiroides; Selpercatinib; Terapia dirigida Càncer medul·lar de tiroide; Selpercatinib; Teràpia dirigida Selpercatinib is a first-in-class, highly selective and potent, central nervous system-active RET kinase inhibitor. In the phase I/II trial, selpercatinib demonstrated clinically meaningful antitumor activity with manageable toxicity in heavily pre-treated and treatment-naive patients with RET-mutant medullary thyroid cancer (MTC). LIBRETTO-531 (NCT04211337) is a multicenter, open-label, randomized, controlled, phase III trial comparing selpercatinib to cabozantinib or vandetanib in patients with advanced/metastatic RET-mutant MTC. The primary objective is to compare progression-free survival (per RECIST 1.1) by blinded independent central review of patients with progressive, advanced, multikinase inhibitor-naive, RET-mutant MTC treated with selpercatinib versus cabozantinib or vandetanib. Key secondary objectives are to compare other efficacy outcomes (per RECIST 1.1) and tolerability of selpercatinib versus cabozantinib or vandetanib.

Data on the diagnosis, natural course and management of immune checkpoint inhibitor (ICI)-related hypophysitis (irH) are limited. We propose this study to validate the diagnostic criteria, describe characteristics and hormonal recovery and investigate factors associated with the occurrence and recovery of irH. A retrospective study including patients with suspected irH at the University of Texas MD Anderson Cancer Center from 5/2003 to 8/2017 was conducted. IrH was defined as: (1) ACTH or TSH deficiency plus MRI changes or (2) ACTH and TSH deficiencies plus headache/fatigue in the absence of MRI findings. We found that of 83 patients followed for a median of 1.75 years (range 0.6–3), the proposed criteria used at initial evaluation accurately identified 61/62 (98%) irH cases. In the irH group (n = 62), the most common presentation was headache (60%), fatigue (66%), central hypothyroidism (94%), central adrenal insufficiency (69%) and MRI changes (77%). Compared with non-ipilimumab (ipi) regimens, ipi has a stronger association with irH occurrence (P = 0.004) and a shorter time to irH development (P < 0.01). Thyroid, gonadal and adrenal axis recovery occurred in 24, 58 and 0% patients, respectively. High-dose steroids (HDS) or ICI discontinuation was not associated with hormonal recovery. In the non-irH group (n = 19), one patient had isolated central hypothyroidism and six had isolated central adrenal insufficiency. All remained on hormone therapy at the last follow-up. We propose a strict definition of irH that identifies the vast majority of patients. HDS and ICI discontinuation is not always beneficial. Long-term follow-up to assess recovery is needed.

Context Broad genomic analyses among thyroid histologies have been described from relatively small cohorts. Objective Investigate the molecular findings across a large, real-world cohort of thyroid fine-needle aspiration (FNA) samples. Design Retrospective analysis of RNA sequencing data files. Setting Clinical Laboratory Improvement Amendments laboratory performing Afirma Genomic Sequencing Classifier (GSC) and Xpression Atlas (XA) testing. Participants A total of 50 644 consecutive Bethesda III-VI nodules. Intervention None. Main Outcome Measures Molecular test results. Results Of 48 952 Bethesda III/IV FNAs studied, 66% were benign by Afirma GSC. The prevalence of BRAF V600E was 2% among all Bethesda III/IV FNAs and 76% among Bethesda VI FNAs. Fusions involving NTRK, RET, BRAF, and ALK were most prevalent in Bethesda V (10%), and 130 different gene partners were identified. Among small consecutive Bethesda III/IV sample cohorts with one of these fusions and available surgical pathology excision data, the positive predictive value of an NTRK or RET fusion for carcinoma or noninvasive follicular thyroid neoplasm with papillary-like nuclear features was >95%, whereas for BRAF and ALK fusions it was 81% and 67%, respectively. At least 1 genomic alteration was identified by the expanded Afirma XA panel in 70% of medullary thyroid carcinoma classifier–positive FNAs, 44% of Bethesda III or IV Afirma GSC suspicious FNAs, 64% of Bethesda V FNAs, and 87% of Bethesda VI FNAs. Conclusions This large study demonstrates that almost one-half of Bethesda III/IV Afirma GSC suspicious and most Bethesda V/VI nodules had at least 1 genomic variant or fusion identified, which may optimize personalized treatment decisions.

The 16th International Multiple Endocrine Neoplasia Workshop (MEN2019) held in Houston, TX, USA, focused on emerging topics in the pathogenesis and therapy of malignant endocrine tumors associated with MEN syndromes. With MEN-2 syndromes, the most common malignancy is medullary thyroid carcinoma (MTC). In the spirit of the original MEN meeting workshop model, the conference included didactic lectures and interactive working groups of clinicians and researchers focused on the state of science in MTC and ongoing challenges or unmet needs in the understanding of MTC and to develop strategies to address these issues.

Background In the face of the COVID‐19 pandemic, cancer care has had to adapt rapidly given the Centers for Disease Control and Prevention and the American College of Surgeons (ACS) issuing recommendations to postpone nonurgent surgeries. Methods An institutional multidisciplinary group of Head and Neck Surgical Oncology, Surgical Endocrinology, and Medical Endocrinology devised Surgical Triaging Guidelines for Endocrine Surgery during COVID‐19, aligned with phases of care published by the ACS. Results Phases of care with examples of corresponding endocrine cases are outlined. Most cases can be safely postponed with active surveillance, including most differentiated and medullary thyroid cancers. During the most acute phase, all endocrine surgeries are deferred, except thyroid tumors requiring acute airway management. Conclusions These guidelines provide context for endocrine surgery within the spectrum of surgical oncology, with the goal of optimal individualized multidisciplinary patient care and the expectation of significant resource diversion to care for patients with COVID‐19.

Precision oncology has opened a new era in cancer treatment focused on targeting specific cellular pathways directly involved in tumorigenesis. The REarrangement during Transfection (

BackgroundIn cancers with a chronic phase, patients and family caregivers face difficult decisions such as whether to start a novel therapy, whether to enroll in a clinical trial, and when to stop treatment. These decisions are complex, require an understanding of uncertainty, and necessitate the consideration of patients’ informed preferences. For some cancers, such as medullary thyroid carcinoma, these decisions may also involve significant out-of-pocket costs and effects on family members. Providers have expressed a need for web-based interventions that can be delivered between consultations to provide education and prepare patients and families to discuss these decisions. To ensure that these tools are effective, usable, and understandable, studies are needed to identify patients’, families’, and providers’ decision-making needs and optimal design strategies for a web-based patient decision aid.ObjectiveFollowing the international guidelines for the development of a web-based patient decision aid, the objectives of this study are to engage potential users to guide development; review the existing literature and available tools; assess users’ decision-making experiences, needs, and design recommendations; and identify shared decision-making approaches to address each need.MethodsThis study used the decisional needs assessment approach, which included creating a stakeholder advisory panel, mapping decision pathways, conducting an environmental scan of existing materials, and administering a decisional needs assessment questionnaire. Thematic analyses identified current decision-making pathways, unmet decision-making needs, and decision support strategies for meeting each need.ResultsThe stakeholders reported wide heterogeneity in decision timing and pathways. Relevant existing materials included 2 systematic reviews, 9 additional papers, and multiple educational websites, but none of these met the criteria for a patient decision aid. Patients and family members (n=54) emphasized the need for plain language (46/54, 85%), shared decision making (45/54, 83%), and help with family discussions (39/54, 72%). Additional needs included information about uncertainty, lived experience, and costs. Providers (n=10) reported needing interventions that address misinformation (9/10, 90%), foster realistic expectations (9/10, 90%), and address mistrust in clinical trials (5/10, 50%). Additional needs included provider tools that support shared decision making. Both groups recommended designing a web-based patient decision aid that can be tailored to (64/64, 100%) and delivered on a hospital website (53/64, 83%), focuses on quality of life (45/64, 70%), and provides step-by-step guidance (43/64, 67%). The study team identified best practices to meet each need, which are presented in the proposed decision support design guide.ConclusionsPatients, families, and providers report multifaceted decision support needs during the chronic phase of cancer. Web-based patient decision aids that provide tailored support over time and explicitly address uncertainty, quality of life, realistic expectations, and effects on families are needed.

Parathyroid carcinoma (PC) is a rare endocrine malignancy with no approved systemic therapies for unresectable locally invasive or distant metastatic disease. Understanding the molecular changes in advanced PC can provide better understanding of this disease and potentially help directing targeted therapy. To evaluate tumor-specific genetic changes using next-generation sequencing (NGS) panels. All patients with advanced PC were tested for hot-spot panels using NGS panels including a 50-gene panel, a 409-gene panel if the standard 50-gene panel (Ion Torrent, Life Technology) was negative or a FoundationOne panel. The University of Texas MD Anderson Cancer Center, Houston, Texas, USA. 11 patients with advanced PC were selected to undergo molecular testing. Genetic profiles of advanced PC. Among the 11 patients, 4 patients had the 50-gene panel only, 6 had 409-gene panel after a negative 50-gene panel and 1 had FoundationOne. One patient who had 50-gene panel only also had his metastatic site (esophagus) of his tumor tested with FoundationOne. The most common mutations identified were in the PI3 K (PIK3CA, TSC1 and ATM) (4/11 patients) and TP53 (3/11) pathways. Genes not previously reported to be mutated in PC included: SDHA, TERT promoter and DICER1. Actionable mutations were found in 54% (6/11) of the patients. Mutational profiling using NGS panels in advanced PC has yielded important potentially targetable genetic alterations. Larger studies are needed to identify commonly mutated genes in advanced PC patients. Development of novel therapies targeting these cellular pathways should be considered.

BACKGROUND In cancers with a chronic phase, patients and family caregivers face difficult decisions such as whether to start a novel therapy, whether to enroll in a clinical trial, and when to stop treatment. These decisions are complex, require an understanding of uncertainty, and necessitate the consideration of patients’ informed preferences. For some cancers, such as medullary thyroid carcinoma, these decisions may also involve significant out-of-pocket costs and effects on family members. Providers have expressed a need for web-based interventions that can be delivered between consultations to provide education and prepare patients and families to discuss these decisions. To ensure that these tools are effective, usable, and understandable, studies are needed to identify patients’, families’, and providers’ decision-making needs and optimal design strategies for a web-based patient decision aid. OBJECTIVE Following the international guidelines for the development of a web-based patient decision aid, the objectives of this study are to engage potential users to guide development; review the existing literature and available tools; assess users’ decision-making experiences, needs, and design recommendations; and identify shared decision-making approaches to address each need. METHODS This study used the decisional needs assessment approach, which included creating a stakeholder advisory panel, mapping decision pathways, conducting an environmental scan of existing materials, and administering a decisional needs assessment questionnaire. Thematic analyses identified current decision-making pathways, unmet decision-making needs, and decision support strategies for meeting each need. RESULTS The stakeholders reported wide heterogeneity in decision timing and pathways. Relevant existing materials included 2 systematic reviews, 9 additional papers, and multiple educational websites, but none of these met the criteria for a patient decision aid. Patients and family members (n=54) emphasized the need for plain language (46/54, 85%), shared decision making (45/54, 83%), and help with family discussions (39/54, 72%). Additional needs included information about uncertainty, lived experience, and costs. Providers (n=10) reported needing interventions that address misinformation (9/10, 90%), foster realistic expectations (9/10, 90%), and address mistrust in clinical trials (5/10, 50%). Additional needs included provider tools that support shared decision making. Both groups recommended designing a web-based patient decision aid that can be tailored to (64/64, 100%) and delivered on a hospital website (53/64, 83%), focuses on quality of life (45/64, 70%), and provides step-by-step guidance (43/64, 67%). The study team identified best practices to meet each need, which are presented in the proposed decision support design guide. CONCLUSIONS Patients, families, and providers report multifaceted decision support needs during the chronic phase of cancer. Web-based patient decision aids that provide tailored support over time and explicitly address uncertainty, quality of life, realistic expectations, and effects on families are needed.

Summary Background Oncogenic alterations in RET represent important therapeutic targets in thyroid cancer. We aimed to assess the safety and antitumour activity of pralsetinib, a highly potent, selective RET inhibitor, in patients with RET-altered thyroid cancers. Methods ARROW, a phase 1/2, open-label study done in 13 countries across 71 sites in community and hospital settings, enrolled patients 18 years or older with RET-altered locally advanced or metastatic solid tumours, including RET-mutant medullary thyroid and RET fusion-positive thyroid cancers, and an Eastern Co-operative Oncology Group performance status of 0–2 (later limited to 0–1 in a protocol amendment). Phase 2 primary endpoints assessed for patients who received 400 mg once-daily oral pralsetinib until disease progression, intolerance, withdrawal of consent, or investigator decision, were overall response rate (Response Evaluation Criteria in Solid Tumours version 1.1; masked independent central review) and safety. Tumour response was assessed for patients with RET-mutant medullary thyroid cancer who had received previous cabozantinib or vandetanib, or both, or were ineligible for standard therapy and patients with previously treated RET fusion-positive thyroid cancer; safety was assessed for all patients with RET-altered thyroid cancer. This ongoing study is registered with clinicaltrials.gov , NCT03037385 , and enrolment of patients with RET fusion-positive thyroid cancer was ongoing at the time of this interim analysis. Findings Between Mar 17, 2017, and May 22, 2020, 122 patients with RET-mutant medullary and 20 with RET fusion–positive thyroid cancers were enrolled. Among patients with baseline measurable disease who received pralsetinib by July 11, 2019 (enrolment cutoff for efficacy analysis), overall response rates were 15 (71%) of 21 (95% CI 48–89) in patients with treatment-naive RET-mutant medullary thyroid cancer and 33 (60%) of 55 (95% CI 46–73) in patients who had previously received cabozantinib or vandetanib, or both, and eight (89%) of nine (95% CI 52–100) in patients with RET fusion-positive thyroid cancer (all responses confirmed for each group). Common (≥10%) grade 3 and above treatment-related adverse events among patients with RET-altered thyroid cancer enrolled by May 22, 2020, were hypertension (24 patients [17%] of 142), neutropenia (19 [13%]), lymphopenia (17 [12%]), and anaemia (14 [10%]). Serious treatment-related adverse events were reported in 21 patients (15%), the most frequent (≥2%) of which was pneumonitis (five patients [4%]). Five patients [4%] discontinued owing to treatment-related events. One (1%) patient died owing to a treatment-related adverse event. Interpretation Pralsetinib is a new, well-tolerated, potent once-daily oral treatment option for patients with RET-altered thyroid cancer. Funding Blueprint Medicines.

Medullary thyroid carcinoma (MTC) is rare, accounting for approximately 1–2% of all thyroid cancers. Thyroidectomy is considered the primary treatment for MTC and conveys the highest chance for cure if the disease is detected early. Although typically indolent for most patients, those who demonstrate more rapid progression or symptomatic disease can be treated with either multikinase inhibitors (MKIs), such as cabozantinib and vandetanib, or selective RET inhibitors. The understanding that aberrant RET receptor activation is a primary driver of MTC led to clinical investigations with MKIs primarily targeting vascular endothelial growth factor receptor (VEGFR), as well as RET and other kinase receptors. Selective RET inhibitors demonstrate exciting results in phase I clinical trials for RET-altered cancers, which led to the recent approval by the US Food and Drug Administration of selpercatinib. This chapter uses a case-based approach to answer the questions of when to consider initiating systemic therapy and which agent to use.

Bone metastatic disease may lead to serious adverse events in patients with cancer. Bone-directed therapies, including bisphosphonates such as pamidronate and zoledronic acid and the human monoclonal antibody denosumab, are currently approved for the prevention of bone-related adverse events. However, despite the benefits of these drugs, they may cause side effects that are mostly associated with dosages and treatment durations. These side effects range from more frequent, mostly mild, and generally self-limited side effects-such as fever, myalgias, arthralgias, and electrolyte imbalances-to less frequent and more severe side effects such as medication-related osteonecrosis of the jaw and atypical femoral fractures. The purpose of this review is to familiarize clinicians with the literature regarding adverse events associated with bone-directed therapies in patients with cancer. It is important to be aware of these possible adverse events and to educate patients about the predisposing factors associated with side effects from bone-directed therapies and the preventive measures necessary to decrease the risk of occurrence.

Background Targeted kinase inhibitors have been increasingly utilized in the treatment of advanced medullary thyroid cancer (MTC) over the last decade. Recently, highly potent next generation selective RET inhibitors have been clinically validated, and selpercatinib was recently Food and Drug Administration (FDA)‐approved for advanced MTC. The advent of highly selective, potent RET inhibitors is broadening the treatment options for patients with RET‐mutated cancers. Methods We report the first published case of neoadjuvant selpercatinib followed by surgery for a patient with initially unresectable, widely metastatic, RET‐mutated MTC who was treated on a single patient protocol. Results After greater than 50% RECIST response, the patient underwent complete surgical resection followed by selpercatinib resumption. He remains locoregionally disease‐free 21 months after starting therapy with stable metastatic disease (after initial partial response); and calcitonin/CEA continue to decline. Conclusion This novel treatment strategy for locoregionally advanced RET‐mutated MTC warrants further study in clinical trials.

Introduction: Most thyroid cancers (TC) are due to mutually exclusive somatic driver mutations. NTRK fusions are rare oncogenic drivers in papillary TC (PTC), poorly differentiated TC (PDTC) and anaplastic TC (ATC), estimated to be in 2.3% of all TC. However, the clinical presentation and behavior of TRK-fusion TC remains largely unknown. Methods / Case Presentation: Using institutional databases, we identified all TC patients (pts) with an NTRK fusion reported on somatic testing performed by a CLIA-certified laboratory. Data from the medical records were collected. The objective of this study was to investigate the clinical and pathological features of TC pts whose tumors harbored an NTRK fusion. Results / Discussion: We identified 36 TC pts with somatic NTRK fusions. Fusion testing was generally done in pts with advanced or radioactive iodine refractory (RAI-R) disease. Median age at diagnosis was 27.4 years (range 4–75 years), 21 (58%) were female and 16 (44%) were pediatric. 28/36 (78%) pts had PTC, 2/36 (5%) PDTC and 6/36 (17%) ATC. There were a total of 12 (33%) NTRK1, 24 (67%) NTRK3, and no NTRK2 fusions. In ATC and PDTC pts NTRK3 was the most common NTRK fusion 7/8 (87%). In PTC pts, 11 (39%) had NTRK1 and 17 (61%) had NTRK3. In the adult pts NTRK3 was more common 17/20 (85%) (Odds Ratio 7.2, P=0.013), however, in pediatric pts rate of NTRK1 and NTRK3 were similar. One pt had additional mutations along with the NTRK fusion, an ATC pt with multiple mutations including BRAF V600E. Of the 30 PTC/PDTC pts, 23 (77%) had distant metastases (mets). 14 (38%) pts had distant mets at diagnosis and 11 (69%) pediatric pts had distant mets. Lung 21 (70%) and bone 9 (30%) were the most common distant mets sites. In the PTC pts with distant mets, 9 (41%) had RAI-avid and 11 (50%) had RAI-R disease. In the entire cohort of 36 pts, 17 (53%) were on a systemic therapy of whom 11 pts were PTC. NTRK directed was the most common systemic therapy 16 (94%). All PTC pts were alive with a median time from diagnosis of 46 months (Interquartile 1–3: 25–118 months). Four ATC and one PDTC pts had died at the time of the analysis. Conclusions: In this study we confirmed that NTRK fusions occur primarily in PTC but also in less differentiated tumors. Most were young pts but NTRK fusions were identified in tumors from adults as old as 75 years. NTRK1 and NTRK3 were the most common NTRK fusions with NTRK3 being more common in adults. In thyrocyte-derived TC pts, NTRK fusions are mutually exclusive genetic events that occur in pts of all ages and varying histologies. Given the availability of NTRK targeted therapy, consideration should be given to testing for NTRK fusions in advanced thyroid cancer pts, especially those in whom prior genetic testing did not identify an oncogenic driver.

INTRODUCTION: Medullary thyroid carcinoma (MTC) is rare in children and is hereditary (hMTC), caused by germline mutations in the RET proto-oncogene, in about 95% of cases. Very little is known about sporadic MTC (sMTC) when diagnosed in children/young adults. Our aim was to study the clinical presentation and long-term outcomes of a large cohort of sMTC seen at a tertiary cancer center and to compare sMTC with hMTC in young patients (pts). METHODS: Through a review of institutional databases, we identified pts diagnosed with MTC ≤ age 21 years (y.). Charts were retrospectively reviewed and data abstracted. The diagnosis of sMTC vs hMTC was determined based on germline RET testing and family history. RESULTS: We identified 146 pts (53% female), of whom 20 (14%) had sMTC and 126 (86%) had hMTC (80 MEN2a and 46 MEN2b), with a median follow-up of 10 y. (range: 0.08-58, IQR 4.8-18). In pts with sMTC, the stage at diagnosis was I-II in 3/15 (20%) and stage III-IV in 12/15 (80%). Somatic mutations were identified in 11/12 tumors tested (6 RET p.M918T, 1 RET p.G691S, 2 RET deletions p.L629_L633del and p.E632_L633del, 1 RET c.2698_2710delinsC, and 1 CCDC6-ALK fusion). In contrast to hMTC, pts with sMTC were diagnosed at an older age [mean 18.0 y. ± 3.4 (range: 10-21) vs 12.9 y. ± 5.4 (range: 1.5-21), p CONCLUSION: In this largest reported series of MTC in children/young adults, and the only study to look at sMTC in this population, we identified sMTC in 14% of MTC cases, a higher prevalence than is traditionally recognized but one that is possibly confounded by a referral bias. Somatic mutations were identified in 92% of samples tested, allowing for targeted therapy in those with distant metastases if needed. Compared with hMTC, patients with sMTC presented at an older age with higher tumor markers, larger tumors, and more unilateral disease. At last follow-up, persistent structural disease and distant metastases were more common in sMTC. The differences in clinical presentation and long-term outcomes likely reflect a variable path to MTC diagnosis. In conclusion, sMTC in pts ≤ age 21 y. presents at an older age with more advanced disease, frequently has an actionable driver mutation, and may be more common than previously thought.

Metastases to the submandibular gland are extremely rare; a literature search retuned only three previously reported cases from a thyroid gland primary site. Herein, we report two cases of metastatic thyroid carcinoma to the submandibular gland in a 64-year-old woman with PTC and a 70-year-old-woman with medullary thyroid carcinoma (MTC). The metastases were identified on CT and PET/CT in one case and on CT in the other case, but both were diagnosed with ultrasound-guided fine-needle aspiration. Our cases highlight that while rare, both PTC and MTC can metastasize to the submandibular gland.

Incidentally detected hypercalcemia usually presents in an indolent manner and is most likely caused by primary hyperparathyroidism. In contrast, hypercalcemia in the patient with a history of cancer presents in a wide range of clinical settings and may be severe enough to warrant hospitalization. This form of hypercalcemia is usually secondary to hypercalcemia of malignancy and can be fatal. Hypercalcemia of malignancy is most commonly mediated by tumoral production of parathyroid hormone-related protein or by cytokines activating osteoclast degradation of bone. The initial workup, differential diagnoses, confirmatory laboratory testing, imaging, and medical and surgical management of hypercalcemia are described in the patient with cancer.

The receptor tyrosine kinase rearranged during transfection (RET) is an oncogenic driver activated in multiple cancers, including non–small cell lung cancer (NSCLC), medullary thyroid cancer (MTC), and papillary thyroid cancer. No approved therapies have been designed to target RET; treatment has been limited to multikinase inhibitors (MKI), which can have significant off-target toxicities and limited efficacy. BLU-667 is a highly potent and selective RET inhibitor designed to overcome these limitations. In vitro, BLU-667 demonstrated ≥10-fold increased potency over approved MKIs against oncogenic RET variants and resistance mutants. In vivo, BLU-667 potently inhibited growth of NSCLC and thyroid cancer xenografts driven by various RET mutations and fusions without inhibiting VEGFR2. In first-in-human testing, BLU-667 significantly inhibited RET signaling and induced durable clinical responses in patients with RET-altered NSCLC and MTC without notable off-target toxicity, providing clinical validation for selective RET targeting. Significance: Patients with RET-driven cancers derive limited benefit from available MKIs. BLU-667 is a potent and selective RET inhibitor that induces tumor regression in cancer models with RET mutations and fusions. BLU-667 attenuated RET signaling and produced durable clinical responses in patients with RET-altered tumors, clinically validating selective RET targeting. Cancer Discov; 8(7); 836–49. ©2018 AACR. See related commentary by Iams and Lovly, p. 797. This article is highlighted in the In This Issue feature, p. 781

Context Interpretation of calcitonin measurement to predict the prognosis of medullary thyroid carcinoma (MTC) requires multiple measurements over an extended time period, making it an imperfect biomarker for evaluating prognosis or disease behavior. Single circulating cell-free DNA (cfDNA) values have been shown to be a valuable prognostic marker for several solid tumors. Objective We tested the hypothesis that cfDNA containing the RET M918T mutation could be detected in the blood of patients with advanced MTC whose tumor harbored an M918T mutation and would be able to predict overall survival more reliably than calcitonin. Design The level of cfDNA containing RET M918T mutation was measured in the plasma of patients with MTC via droplet digital polymerase chain reaction. Patients Patients had a confirmed sporadic MTC diagnosis, a serum calcitonin measurement >100 pg/mL, and tumor tissue biopsy results providing RET M918T mutation status. There were 75 patients included in this study, 50 of whom harbored an RET M918T mutation by tissue biopsy. Results RET M918T cfDNA was detected in 16 of 50 patients (32%) with a positive tissue biopsy. The detection of RET M918T cfDNA strongly correlated with worse overall survival and more accurately predicted a worse outcome than calcitonin doubling time. Conclusions Liquid biopsy is able to detect RET M918T mutations in patient plasma with high specificity but low sensitivity. In patients with established somatic RET M918T mutations, the allelic fraction of circulating tumor DNA is prognostic for overall survival and may play a role in monitoring response to treatment.

Bone metastases (BM) can lead to devastating skeletal-related events (SREs) in cancer patients. Data regarding medullary thyroid carcinoma (MTC) with BM are lacking.We evaluated the natural history of BM and SREs in MTC patients identified by a cancer center tumor registry.The study was conducted at a tertiary cancer center.We retrospectively reviewed the charts of MTC patients with BM who received care from 1991 to 2014 to characterize BM and SREs.Of 1008 MTC patients treated, 188 were confirmed to have BM (19%), of whom 89% (168 of 188) had nonosseous distant metastases. Median time from MTC to BM diagnosis was 30.9 months (range 0-533 mo); 25% (45 of 180) had BM identified within 3 months of MTC diagnosis. Median follow-up after detecting BM was 1.6 years (range 0-23.2 y). Most patients (77%) had six or more BM lesions, most often affecting the spine (92%) and pelvis (69%). Many patients (90 of 188, 48%) experienced one or more SREs, most commonly radiotherapy (67 of 90, 74%) followed by pathological fracture (21 of 90, 23%). Only three patients had spinal cord compression. Patients with more than 10 BM lesions were more likely to experience SREs (odds ratio 2.4; P = .007), with no difference in 5-year mortality after MTC diagnosis between patients with (31%) and without SREs (23%) (P = .11).In this large retrospective series, BM in MTC was multifocal, primarily involving the spine and pelvis, supporting screening these regions for metastases in at-risk patients. SREs were common but spinal cord compression was rare. Antiresorptive therapies in this population should be investigated further with prospective trials.

Vandetanib is a once-daily oral multikinase inhibitor that targets the rearranged during transfection (RET) tyrosine kinase, vascular endothelial growth factor receptor, and epidermal growth factor receptor. Among its observed toxicity profile is QT prolongation, diarrhea, and rash, including photosensitivity. This article presents 3 patients with photoinduced cutaneous side effects of vandetanib, including both photoallergic and phototoxic reactions. We review the spectrum of cutaneous photosensitivity reactions and the necessity of histopathologic evaluation to distinguish photoallergic and phototoxic reactions. Given its high prevalence of specifically photoinduced side effects and the variety of the histologic and clinical presentations, reinforcing attentive sun protection could potentially prevent dose reduction or drug cessation in patients treated with vandetanib.

Vandetanib is an oral tyrosine kinase inhibitor approved for treatment of advanced symptomatic or progressive medullary thyroid cancer (MTC). The current study (Nbib1496313) evaluated the benefit–risk of two starting doses of vandetanib in patients with symptomatic or progressive MTC. Patients were randomized 1:1 to receive vandetanib 150 or 300 mg daily and followed for a maximum of 14 months (Part A), with the option to then enter an open-label phase (Part B) investigating vandetanib 100, 150, 200 and 300 mg daily doses. Efficacy was assessed in Part A, and safety and tolerability during Parts A and B up to 2 years post randomization. Eighty-one patients were randomized in Part A and 61 patients entered Part B, of whom 37 (60.7%) received 2 years of treatment. Overall, 25% of patients experienced an objective response (OR) at 14 months (OR rate, 0.29 (95% CI, 0.176–0.445) for 300 mg, and 0.20 (95% CI, 0.105–0.348) for 150 mg; one-sided P value approximately 0.43). The most common adverse events (AEs) included diarrhea, hypocalcemia, asthenia, QTc prolongation, hypokalemia and keratopathy, all at generally higher incidence with 300 vs 150 mg (Part A). Part B safety and tolerability was consistent with Part A. OR was observed with both vandetanib doses; the 300 mg dose showed a more favorable trend vs 150 mg as initial dose. Thus, for most patients, 300 mg vandetanib is the most appropriate starting dose; dose reductions to manage AEs and lower initial doses for patients with particular comorbidities can be considered.

6083 Background: Receptor tyrosine kinase (RTK) fusions may be targeted by small molecule inhibitors to treat various advanced tumors, including thyroid cancer. Clinical trials have studied selective inhibitors of ALK, BRAF, NTRK and RET, leading to several FDA-approved therapies. The Afirma Genomic Sequencing Classifier (GSC) classifies cytologically indeterminate thyroid nodules as molecularly benign or suspicious. The Xpression Atlas reports 905 genomic variants and 235 fusion pairs on GSC Suspicious, Suspicious for Malignancy (SFM), and Malignant FNA samples at the time of diagnosis. Here we report the prevalence of these fusion genes in real-world clinical practice. Methods: We analyzed anonymized data from 50,644 consecutive Bethesda III-VI nodule FNA samples submitted to the Veracyte CLIA laboratory for molecular testing using whole transcriptome RNA sequencing (RNA-Seq). Gene pairs are listed alphabetically. Results: 32,080 Bethesda III/IV nodules were classified as GSC Benign and 278 were Parathyroid Classifier positive. No ALK, BRAF, NTRK1/3, or RET fusions were identified among these samples. Among 16,594 Bethesda III/IV GSC Suspicious FNAs, 3% (n = 529) were positive for ALK, BRAF, NTRK1/3 or RET fusions. Among the 1,692 Bethesda V/VI FNAs, the proportion of positive nodules was 8% (n = 135). Among these combined cohorts of Bethesda III/IV GSC Suspicious and Bethesda V/VI, the most common gene fusions observed for each of the 5 studied RTK genes was: ETV6/NTRK3 (n = 164, 72% of NTRK3 fusions), CCDC6/RET (n = 104, 55% of RET), BRAF/SND1 (n = 32, 20% of BRAF), ALK/STRN (n = 20, 37% of ALK), and NTRK1/TPM3 (n = 14, 50% of NTRK1). BRAF showed the highest diversity of fusions, with 80 gene partners. Different gene partners with RET, ALK, NTRK1, and NTRK3 numbered 25, 11, 9, and 5 , respectively . Conclusions: Whole-transcriptome RNA-seq on small sample thyroid FNA specimens can identify clinically relevant ALK, BRAF, NTRK, and RET fusions across Bethesda categories. The prevalence ranges from 3% in Bethesda III/IV Afirma GSC Suspicious specimens to 8% among Bethesda V/VI specimens. Future studies need to determine if detection of precision medicine candidates by pre-operative FNA can optimize initial treatment, predict response to treatment, and prioritize selective targeted therapy should systemic treatment be needed.[Table: see text]

3117 Background: Activation of the RET proto-oncogene has been identified in multiple cancer types, for example, gene rearrangements in non-small cell lung cancer (NSCLC) and papillary thyroid cancer (PTC) and activating mutations in medullary thyroid cancer (MTC), amongst others. The recent FDA approval of two highly selective RET inhibitors, selpercatinib and pralsetinib has changed the treatment paradigm of RET-driven cancers, but the significance of historical prognostic factors is unknown. Herein, we analyzed the outcomes of patients with RET-altered cancers enrolled in phase I trials and assess the utility of prognostic scores. Methods: A retrospective analysis was performed of patients treated with selective RET inhibitors at the MD Anderson Cancer Center (MDACC). Baseline clinical factors and survival data were assessed. Overall and progression free survival (OS and PFS) were estimated using the Kaplan-Meier method and multivariable Cox models were constructed. For all a p-value of < 0.05 was consider significant. Results: Among 126 patients, median age was 58 years (range, 15-82), most with ECOG 0-1 (n = 124). RET-mutant MTC was most frequent (n = 81), followed by RET fusion-positive NSCLC (n = 30) and RET fusion positive thyroid cancer (n = 9). RET fusion partners were KIF5B (n = 17), CCD6 (n = 12) and NCOA4 (n = 7). RET M918T mutation was the most frequent (n = 50, 63%). Most patients were treated in the relapsed/refractory (R/R) setting (n = 85) and received a median of 1 prior line of therapy (range, 0-11). Median follow up was 20 months (range, 1-43). The estimated median PFS and OS were 24 and 35 months, respectively. Overall objective response rate was 64% (81/126), 2 complete response, 79 partial response, 32 had stable disease (25%) and 13 had progressive disease (PD). The following were associated with shorter PFS and OS: age ≥50 years (p < 0.05), albumin < 4 g/dL (p < 0.01), brain metastases (p < 0.0001), hemoglobin < 12 g/dL ( < 0.05), LDH > normal (p < 0.05), WBC ≥8 (p < 0.01), PD (p < 0.0001) and NSCLC (p < 0.01). The M918T mutation and ECOG > 0 were associated with shorter OS but not PFS (p < 0.05). > 3 metastatic sites and R/R disease were associated with inferior PFS (p = 0.04 and p = 0.01, respectively) but not OS. The Royal Marsden Hospital (RMH) and MDACC prognostic scores were significantly associated with PFS and OS (p < 0.01). In multivariable models including all variables significantly associated with PFS and OS (excluding LDH as this was only tested in 58 patients) albumin < 4 (HR 6.10, p = 0.013), brain metastases (HR 4.90, p = 0.027) and WBC ≥8 (HR 4.67, p = 0.031) were associated with inferior OS. NSCLC was significantly associated with inferior PFS (HR 5.45, p = 0.02). Conclusions: The RMH and MDACC prognostic scores predict OS in RET-aberrant cancers treated on early phase trials. Low albumin, WBC > 8 and brain metastases are significantly associated with inferior survival.

Introduction: Medullary thyroid cancer (MTC) is a rare tumor of neuroendocrine origin that co-secretes various peptides leading to diarrhea and vasodilation. Ectopic Cushing syndrome due to production of adrenocorticotropic or corticotrophin-releasing hormone is a well-recognized but uncommon paraneoplastic manifestation of advanced MTC. We report an extremely rare presentation of eosinophilia in a patient with MTC that correlated with disease progression. Case: A 58-year-old woman with sporadic metastatic MTC harboring somatic RET M918T mutation developed metastatic disease to the liver, lung and bones 2 years after surgery for locally advanced disease. Calcitonin (Ctn) was 123 pg/ml and CEA was 2575 ng/ml. At that time, leukocytosis [WBC 30.8 K/ul (4-11k/ul)] and eosinophilia [eosinophil count 16.01 k/ul (0.04-0.40 k/ul)] were noted. She was asymptomatic. Extensive evaluation of hypereosinophilia ruled out hematological or infectious causes. The patient initiated vandetanib with a partial response (PR) with decrease in lung and liver metastases and a significant improvement of the paraneoplastic eosinophilia [eosinophil count 2.39 k/ul] after 10 weeks of treatment. After a year on treatment, there was progressive disease (PD) with increasing hilar and abdominal lymphadenopathy associated with increased eosinophilia of 4.34 K/ul. Vandetanib was discontinued. She was enrolled on a clinical trial with a highly potent and selective RET inhibitor. The patient achieved PR to study drug by the 2nd month on treatment and durable response for 30 months. The eosinophil count normalized [0.32 k/ul] 4 weeks after starting the new treatment. She developed PD in liver metastases associated with recurrent leukocytosis (WBC 58.6 K/ul) and eosinophilia of 28.13 K/ul. Ctn was 1646 pg/ml. CEA was 8722 ng/ml. Her bone marrow biopsy showed marked eosinophilia, focal MTC metastatic infiltrate, no increased blasts, and was negative for the BCR-ABL1 translocation and the FIP1L1-PDGFRA fusion. She was switched to a different RET Inhibitor but passed away 1 month after starting the new protocol. Discussion: Paraneoplastic eosinophilia should be considered after excluding other causes (e.g. infections, allergy, collagen, vascular or malignant hematopoietic diseases). Thyroid tumors producing colony-stimulating factors, associated with neutrophilia and/or eosinophilia have been described almost exclusively in patients with anaplastic thyroid cancer. This patient had a poorly differentiated MTC as evidenced by the disproportionally high CEA relative to Ctn. The course of the eosinophilia paralleled the clinical behavior of her disease. To our knowledge, this is only the 2nd report of eosinophil trends corresponding with MTC disease course, consistent with a paraneoplastic process. Conclusion: PNE is very rare in MTC and its presence suggests a poor prognosis.

467 Background: Recent tumor-agnostic drug approvals have resulted in a paradigm shift in cancer treatment away from organ/histology specific indications to biomarker-guided tumor-agnostic approaches. Pralsetinib is a potent and selective RET inhibitor, which has recently been approved by the U.S. Food and Drug Administration (FDA) for the treatment of adults with metastatic RET fusion–positive non-small cell lung cancer (NSCLC) and is under New Drug Application review for RET mutant thyroid cancers by the FDA. RET fusions occur in up to approximately 7‒8% of patients with gastrointestinal malignancies, including pancreatic, liver, and colorectal cancers. There are currently no approved selective RET inhibitors for patients with RET fusion–positive solid tumors other than NSCLC and thyroid cancer. Here, we present data on the clinical activity of pralsetinib in patients with RET fusion–positive solid tumor types other than NSCLC enrolled in the Phase I/II ARROW study (NCT03037385). Methods: ARROW consists of a phase I dose escalation (30–600 mg once [QD] or twice daily) followed by a phase II expansion (400 mg QD) in patients with advanced RET-altered solid tumors. Primary objectives are overall response rate (ORR), per RECICT v1.1 and safety. Results: A total of 13 patients with RET fusion–positive thyroid cancer (12 papillary, 1 poorly differentiated; enrollment cutoff July 11, 2019) and 14 patients with RET fusion–positive solid tumors other than NSCLC and thyroid (3 pancreatic, 3 colon, 2 cholangiocarcinoma, 6 other; enrollment cutoff November 19, 2019) were enrolled in ARROW and received pralsetinib. At the February 13, 2020, data cutoff, the ORR (blinded central review) in response-evaluable patients with RET fusion–positive thyroid cancer was 91% (10/11; 95% CI: 59‒100) and disease control rate was 100% (95% CI: 72‒100). Treatment was ongoing in 7 of 11 patients. In RET fusion–positive solid tumors other than NSCLC and thyroid, ORR (investigator’s assessment) was 50% (6/12; 95% CI: 21‒79) and responses were observed in all patients with pancreatic cancer (3/3) and cholangiocarcinoma (2/2). Treatment was ongoing in 6 of 12 patients, including 2 of 3 patients with pancreatic cancer and 1 of 2 patients with cholangiocarcinoma. Responses were observed across multiple fusion genotypes. In the 27 patients with RET fusion–positive tumors other than NSCLC, most frequent treatment-related adverse events (TRAEs) were grade 1–2, and included anemia (33%), increased aspartate aminotransferase (33%), decreased white blood cell count (33%), hypertension (30%), increased alanine aminotransferase (26%), hyperphosphatemia (19%), and neutropenia (19%). No patients discontinued due to TRAEs. Conclusions: Pralsetinib demonstrated broad and durable antitumor activity across multiple advanced solid tumor types, regardless of RET fusion genotype, and was well tolerated. The study is ongoing. Clinical trial information: NCT03037385.

PurposeTo evaluate for an association between 25-hydroxyvitamin D levels (vitamin D) and outcome measures in patients with melanoma after evaluation is controlled for systemic inflammatory response (SIR) on the basis of simultaneous C-reactive protein (CRP) measurement.Materials and MethodsPlasma samples from 1,042 prospectively observed patients with melanoma were assayed for vitamin D and CRP. The associations of demographics and CRP with vitamin D were determined, followed by a determination of the association between vitamin D and stage and outcome measures from the date of blood draw. The vitamin D level was considered sufficient if it was 30 to 100 ng/mL. Kaplan-Meier and Cox regression analyses were performed.ResultsThe median vitamin D level was 25.0 ng/mL. The median follow-up time was 7.1 years. A lower vitamin D was associated with the blood draw during fall/winter months (P < .001), older age (P = .001), increased CRP (P < .001), increased tumor thickness (P < .001), ulcerated tumor (P = .0105), and advanced melanoma stage (P = .0024). On univariate analysis, lower vitamin D was associated with poorer overall (OS; P < .001), melanoma-specific survival (MSS; P = .0025), and disease-free survival (DFS; P = .0466). The effect of vitamin D on these outcome measures persisted after adjustment for CRP and other covariates. Multivariable hazards ratios per unit decrease of vitamin D were 1.02 for OS (95% CI, 1.01 to 1.04; P = .0051), 1.02 for MSS (95% CI, 1.00 to 1.04; P = .048), and 1.02 for DFS (95% CI, 1.00 to 1.04; P = .0427).ConclusionLower vitamin D levels in patients with melanoma were associated with poorer outcomes. Although lower vitamin D was strongly associated with higher CRP, the associations of lower vitamin D with poorer OS, MSS, and DFS were independent of this association. Investigation of mechanisms responsible for these associations may be of value to patients with melanoma.

6584 Background: Activating RAS mutations are recognized as important drivers in sporadic medullary thyroid cancer (sMTC), with a reported prevalence between 0-43%. However, few studies have looked at correlations between RAS-mutated sMTC and clinicopathologic features. Methods: Patients with sMTC diagnosed between 1992 – 2019 with NGS testing for RET and RAS mutations seen at a tertiary cancer center were retrospectively evaluated. The objective was to analyze demographic and clinical features among patients with RAS-mutated sMTC and to evaluate associations between these features and overall survival (OS). Analyses were performed to correlate patient demographics and pathologic staging with treatment characteristics, disease course, and OS. Results: We identified 42 patients (50% female) with RAS-mutated sMTC out of 218 pts with sMTC. Median age at diagnosis was 50 years (range 24-78 years). 26 (62%) patients had stage IV disease at time of diagnosis. 28 (67%) of patients had HRAS mutations and 14 (33%) had KRAS mutations. HRAS Q61R was the most common HRAS mutation type (n = 19, 45%). Median follow-up time was 64 months (range 23-274 months) during which 11 (26%) patients died. The median OS was 16.2 years, with 5- and 10- year OS of 88% and 73% respectively. Of the 20 (48%) patients who received systemic therapy, 79% had stage IV disease and tended to be older (median age 54). Median time from diagnosis to initiation of systemic therapy was 33 months. Factors associated with worse OS included distant metastases at diagnosis, shorter time interval between diagnosis and treatment, and Ctn/CEA doubling times < 6 months. HRAS Q61R mutations were associated with a better prognosis, with 100% 10-year OS compared with 10-year OS of 39% and 51% (p = 0.02) for other HRAS and KRAS mutations respectively. Conclusions: At a tertiary cancer center, patients with RAS-mutated sMTC had a 10-year OS rate of 73%, with significantly worse OS in patients with HRAS/KRAS mutations other than HRAS Q61R. In comparison, prior studies have reported 10-year OS rates between ~71-90% in sMTC and 10-year OS rates as low as 56% for more aggressive RET M918T sMTC mutations. The findings here are consistent with other studies that have suggested patients with RAS-mutated sMTC are at intermediate risk for aggressive disease, though there are limited data on OS rates in RAS or RAS-/RET- sMTC. Future research comparing outcomes between various RAS mutations and in comparison to RET+ and RAS-/RET- patients is needed, especially as systemic therapy use in RAS-mutated sMTC evolves.

Purpose The receptor tyrosine kinase rearranged during transfection (RET) can be oncogenically activated by gene fusions or point mutations. Multikinase inhibitors such as cabozantinib, lenvatinib and vandetanib have demonstrated activity in RET-dependent malignancies, and selective RET inhibitors (Selpercatinib and Pralsetinib) are in clinical trials. However, the responsiveness of RET-dependent malignancies to immune checkpoint inhibitors (ICIs) is unknown. We compared the time to treatment discontinuation (TTD) for ICI versus non-ICI therapy in patients with malignancies harbouring activating RET mutations or fusions (RET+). Methods A retrospective review of all RET+ patients who were referred to the phase I clinical trials programme at the University of Texas MD Anderson Cancer Center was conducted. TTD was estimated using Kaplan-Meier analysis. Multivariate analysis using the Cox proportional hazard model was performed to identify independent risk factors of treatment discontinuation. Results Of 70 patients who received systemic therapy for RET+ malignancies, 20 (28.6%) received ICI and 50 (71.4%) received non-ICI therapy. Non-ICI therapy was associated with decreased risk for treatment discontinuation compared with ICI in the overall population (HR=0.31; 95% CI 0.16–0.62; p=0.000834) and in patients with RET point mutations (HR=0.13; 95% CI 0.04–0.45; p=0.00134). In patients with RET fusions, non-ICI therapy was associated with a non-statistically significant decreased risk of treatment discontinuation (HR=0.59; 95% CI 0.25–1.4; p=0.24). ICI therapy and a diagnosis other than medullary thyroid cancer (MTC) were independent risk factors for treatment discontinuation. Conclusion Our study supports the prioritisation of non-ICI over ICI therapy in patients with RET+ tumours.

Incidentally detected hypercalcemia usually presents in an indolent manner and is most likely caused by primary hyperparathyroidism. In contrast, hypercalcemia in the patient with a history of cancer presents in a wide range of clinical settings and may be severe enough to warrant hospitalization. This form of hypercalcemia is usually secondary to hypercalcemia of malignancy and can be fatal. Hypercalcemia of malignancy is most commonly mediated by tumoral production of parathyroid hormone-related protein or by cytokines activating osteoclast degradation of bone. The initial workup, differential diagnoses, confirmatory laboratory testing, imaging, and medical and surgical management of hypercalcemia are described in the patient with cancer.

The receptor tyrosine kinase rearranged during transfection (RET) is an oncogenic driver activated in multiple cancers, including non-small cell lung cancer (NSCLC), medullary thyroid cancer (MTC), and papillary thyroid cancer. No approved therapies have been designed to target RET; treatment has been limited to multikinase inhibitors (MKI), which can have significant off-target toxicities and limited efficacy. BLU-667 is a highly potent and selective RET inhibitor designed to overcome these limitations.

Hypercalcemia of malignancy is an oncologic emergency due to tumoral factors that stimulate osteoclast-mediated bone resorption. It requires a combination of recommended treatments (i.e., hydration, bisphosphonate and calcitonin), which may be deleterious in patients with compromised cardiac or renal function or may not control serum calcium levels long term. Recurrent or refractory hypercalcemia may preclude the use of chemotherapeutic agents needed to effectively treat the underlying cancer, which is the cause of hypercalcemia. Denosumab, a fully human monoclonal antibody against RANKL, inhibits the maturation, function and survival of osteoclasts. An open-label, single-arm study of denosumab in patients with hypercalcemia of malignancy despite recent bisphosphonate treatment revealed positive results. Thus, the US FDA recently approved denosumab for the indication of hypercalcemia of malignancy, increasing the options available for patients with this debilitating and life-threatening condition.

Medullary thyroid cancer (MTC)-related diarrhea can be debilitating, reduces quality of life (QOL), and may be the only indication for initiating systemic therapy. Conventional antidiarrheal drugs are not always helpful and may have side effects. Calcium aluminosilicate antidiarrheal (CASAD), a natural calcium montmorrilonite clay, safely adsorbs toxins and inflammatory proteins associated with diarrhea. It was hypothesized that CASAD would reduce the severity of diarrhea and improve QOL in MTC patients.This was a prospective pilot trial (NCT01739634) of MTC patients not on systemic therapy with self-reported diarrhea of three or more bowel movements (BMs) per day for a week or more. The study design included a one-week run-in period followed by one week of CASAD ± a two-week optional continuation period. The primary endpoint was efficacy of one week of CASAD treatment in decreasing the number of BMs per day by ≥20% when compared with the baseline run-in period. Secondary objectives included tolerability and safety and the impact on QOL using the MD Anderson Symptom Inventory-Thyroid questionnaire (MDASI-THY).Ten MTC patients (median age = 52 years, 70% female, 80% white) were enrolled. All had distant metastases, and median calcitonin was 5088 ng/mL (range 1817-42,007 ng/mL). Ninety percent had received prior antidiarrheals, and 40% of these had used two or more drugs, including tincture of opium (30%), loperamide (50%), diphenoxylate/atropine (20%), colestipol (10%), or cholestyramine (10%). Of seven evaluable patients, four (56%) had ≥20% reduction in BMs per day. Six out of seven patients discontinued their prior antidiarrheals. Best response ranged from 7% to 99% reduction in mean BMs/day from baseline. Five out of seven patients considered CASAD a success, and they opted for the two-week continuation period. Improvements in diarrhea and all six interference items assessed by MDASI-THY were noted at weeks 1 and 3. Total interference score was significantly improved at three weeks compared with baseline (p = 0.05). An oral levothyroxine absorption test was performed in one patient; malabsorption of levothyroxine was not observed. Adverse events included flatulence (40%), bloating (10%), heartburn (10%), and constipation (10%).CASAD is a promising strategy for treatment of MTC-related diarrhea. In this small pilot study, improvements in frequency and quality of diarrhea as well as QOL were noted. Further studies in this population are warranted.

Context: Medullary thyroid cancer (MTC) is a rare form of thyroid cancer comprising approximately 4% of all thyroid cancers. The majority of patients have a relatively good prognosis; however, a subgroup of patients will require systemic therapy. Large phase III randomized trials led to the approval of two drugs—vandetanib and cabozantinib—for progressive or symptomatic MTC. The decision regarding which drug to initiate first is not entirely clear and is a common concern amongst treating physicians. Evidence Acquisition and Synthesis: A review of the literature in English was conducted, and data were summarized and integrated into a decision matrix. Conclusions: The decision regarding which drug to initiate first for progressive MTC should be based on a careful review of the medical history, physical examination findings, medication list, electrocardiogram, laboratory results, and tumor characteristics. It is necessary to consider the relative contraindications when choosing which drug to initiate first.

Background The purpose of this retrospective analysis was to evaluate the benefits of an elective lateral neck dissection (ELND) in patients with medullary thyroid cancer (MTC) without radiographically apparent lateral neck metastases. Methods Patients with sporadic MTC without radiographic evidence of lateral neck metastasis who underwent definitive surgery were divided into 2 groups based on surgical approach: no ELND (the observation group) and ipsilateral or bilateral ELND (the ELND group). Primary outcomes were biochemical cure, locoregional recurrence, distant metastasis, and overall survival (OS). Results Sixty-six patients met inclusion criteria: 44 patients (67%) in the observation group and 22 patients (33%) in the ELND group. Two of 44 patients (5%) in the observation group developed subsequent (ipsilateral) lateral neck disease. At last follow-up, locoregional disease control rates among the observation and ELND groups were 98% and 100% (P > .999), respectively, whereas biochemical cure rates were 82% and 85% (P > .999), respectively, and 5-year OSs were 84% and 100% (P = .156), respectively. Conclusion Patients with MTC without lateral neck metastasis have similar biochemical cure rates with observation or elective dissection of lateral neck compartments.

Hypercalcemia of malignancy (HCM) in patients with advanced cancer is often caused by excessive osteoclast-mediated bone resorption. Patients may not respond to or may relapse after iv bisphosphonate therapy.We investigated whether denosumab, a potent inhibitor of osteoclast-mediated bone resorption, reduces serum calcium in patients with bisphosphonate-refractory HCM.In this single-arm international study, participants had serum calcium levels corrected for albumin (CSC)12.5 mg/dL (3.1 mmol/L) despite bisphosphonates given7 and ≤30 days before screening.Patients received 120 mg sc denosumab on days 1, 8, 15, and 29 and then every 4 weeks.The primary endpoint was the proportion of patients with CSC ≤11.5 mg/dL (2.9 mmol/L) (response) by day 10. Secondary endpoints included response by visit, duration of response, and the proportion of patients with a complete response (CSC ≤10.8 mg/dL [2.7 mmol/L]) by day 10 and during the study.Patients (N = 33) had solid tumors or hematologic malignancies. By day 10, 21 patients (64%) reached CSC ≤11.5 mg/dL, and 12 patients (33%) reached CSC ≤10.8 mg/dL. During the study, 23 patients (70%) reached CSC ≤11.5 mg/dL, and 21 patients (64%) reached CSC ≤10.8 mg/dL. Estimated median response duration was 104 days. The most common serious adverse events were hypercalcemia worsening (5 patients, 15%) and dyspnea (3 patients, 9%).In patients with HCM despite recent iv bisphosphonate treatment, denosumab lowered serum calcium in 64% of patients within 10 days, inducing durable responses. Denosumab may offer a new treatment option for HCM.

Background: Age-related risk of medullary thyroid carcinoma (MTC) development in presymptomatic carriers of lower risk germline RET mutations is uncertain; such data may aid counseling patients regarding timing of thyroidectomy. Methods: From an institutional database and an exhaustive literature review, we identified 679 patients with American Thyroid Association (ATA) level A or B mutations who were identified because of family screening (index cases of MTC were excluded to minimize selection bias). We evaluated age at thyroidectomy or last evaluation if no thyroidectomy, preoperative calcitonin level (elevated or not), the mutated codon, and outcome (MTC vs. no MTC after thyroidectomy or no clinical evidence of MTC if thyroid intact). Data were used to estimate the cumulative prevalence of MTC and/or assess likelihood of MTC stratified by codon. After exclusion of cases with missing data or small representation, 503 patients with mutations in codons 533, 609, 611, 618, 620, 791, and 804 were analyzed. Results: 236 patients had MTC. Cumulative prevalence and median time to MTC varied by codon and within ATA risk levels (p

BackgroundMultiple endocrine neoplasia type 2 is an autosomal dominant inherited syndrome caused by activating mutations in the RET proto-oncogene. The RETK666N DNA variant was previously reported in two isolated medullary thyroid carcinoma (MTC) cases, but no family studies are available, and its oncogenic significance remains unknown.MethodsThe clinical features, genetic data, and family information of eight index MTC patients with a germline RETK666N variant were assessed.ResultsFour probands presented with MTC and extensive nodal metastasis, one with biopsy-confirmed distant metastasis. Two additional probands presented with localized disease. However, nodal status was not available. Of the final two probands, one had an incidental 1.5 mm MTC and C-cell hyperplasia uncovered after surgery for papillary thyroid carcinoma, and one had two foci of MTC (largest dimension 2.3 cm) detected after surgery for dysphagia. Genetic screening identified 16 additional family members carrying the K666N variant (aged 5-90 years), 11 of whom have documented evaluation for MTC. Of these, only two were found to have elevated basal serum calcitonin upon screening, and the remaining patients had calcitonin levels within the reference range. One patient who elected to have a thyroidectomy at 70 years of age was confirmed to have MTC. The other subject, 57 years old, elected surveillance. Four prophylactic thyroidectomies were performed, with one case of C-cell hyperplasia at 20 years and three cases that revealed normal pathology at ages 21, 30, and 30 years. None of the K666N DNA variant carriers had evidence of primary hyperparathyroidism or pheochromocytoma.ConclusionsFrom this case series, the largest such experience to date, it is concluded that the RETK666N variant is likely pathogenic and associated with low penetrance of MTC. However, the findings are insufficient to define its pathogenicity clearly and make firm recommendations for screening and treatment. Given the potential benefit associated with early detection of aberrant C-cell growth, and the noninvasive nature of genetic testing, "at risk" individuals should be screened, and if the K666N variant is identified, they should be managed using a personalized screening approach for detection of MTC.

6087 Background: Systemic therapies targeting specific genomic alterations in advanced MTC are available or under investigation. The Afirma Genomic Sequencing Classifier (GSC) uses RNA sequencing to assess FNA specimens from cytologically indeterminate thyroid nodules, which are also tested for specific molecular aberrations associated with thyroid cancer via a suite of highly accurate malignancy classifiers. This suite can be applied independently to Bethesda V/VI nodules. The Afirma Xpression Atlas (XA) is an additional test that can be combined with Afirma GSC to report nucleotide variants and fusions across 511 cancer-associated genes. Here we report the prevalence and genomic landscape of MTC classifier positive (MTC+) FNA samples. Methods: All Afirma GSC and malignancy classifier tests run in the Veracyte Clinical Laboratory between July 2017 and January 2019 were deidentified and examined for MTC+ cases. Afirma XA was run on all such cases, and all variants and fusions were tabulated. Results: Examination of 29,895 FNAs revealed 90 MTC cases. Of 22,793 Bethesda III cases, 32 (0.14%) were MTC+. Of 5,491 Bethesda IV cases, 33 (0.60%) were MTC+. Provider-ordered testing was done on an additional 16 and 9 MTC cases from Bethesda V and VI nodules, respectively. 58% of all MTC+ samples harbored a RET variant (+/- others), 9% contained a KRAS variant (+/- others), 6% included an HRAS variant, 1% had a BRAF fusion, 1% demonstrated other fusions, and 26% held no variant/fusion. Conclusions: In our cohort, Afirma XA identified a variant or fusion in 74% of MTC+ FNAs. Currently approved or investigational therapies exist for cancers with RET, BRAF and HRAS alterations, suggesting that 64% of our series might be eligible for treatment based on genomic information from FNA. In advanced MTC, noninvasive FNA sample collection at the time of diagnosis may ultimately impact on targeted therapy selection, with the option to repeat FNA testing should the disease progress. Future studies may investigate how finding a genomic alteration by FNA can inform the management of MTC and, in the case of progressive disease, improve our understanding of the mechanisms of disease progression and drug resistance.

6018 Background: RET alterations are targetable oncogenic drivers in ~90% of advanced medullary thyroid cancer (MTC) and 20% of papillary thyroid cancer (PTC), yet no selective RET inhibitors are approved. BLU-667 is an investigational highly potent and selective RET inhibitor targeting oncogenic RET alterations including those that confer resistance to multikinase inhibitors (MKIs). We provide an update on the expanded experience of BLU-667 in RET-altered thyroid cancer from the registration-enabling ARROW study (NCT03037385). Methods: ARROW is a global DE (30-600 mg daily [QD or BID]) and dose expansion (DX; 400 mg QD) study in pts with advanced solid tumors. Primary objectives are response rate (ORR; RECIST 1.1) and safety. Results: As of 19Dec2018, 60 pts with RET-mutated MTC (M918T [37], C634R/S/W [8], V804M [4], other/pending [11]) and 5 pts with RET-fusion+ PTC (NCOA4 [3], CCDC6 [2]) received BLU-667 (37 DE, 28 DX). 58% had prior MKI therapy. Among 49 response-evaluable MTC pts, ORR is 47% (95% CI: 33, 62; 2 complete and 21 partial responses (PR); 4 PR pending confirmation; 25 stable disease; 1 progressive disease). 96% (22/23) of responding pts continue treatment; 15 with response duration ≥ 6 months. 2/4 evaluable PTC pts had PR; all 5 enrolled PTC pts continue treatment at 8-11 months. Responses in MTC occur regardless of MKI resistance (prior cabozantinib/vandetanib: ORR 46% (12/26)) or RET genotype (PR in 2/3 evaluable pts with V804M). Disease control rate in MTC pts is 98%. Rapid plasma clearance of RET variants and marked reduction in CEA and calcitonin is observed. Treatment-related toxicity in MTC/PTC pts, generally low-grade and reversible (28% had grade 3 events, no grade 4/5 events, no events requiring discontinuation), includes decreased WBC (23%), increased AST (17%), increased ALT, blood creatinine, and phosphate, hypertension, and decreased neutrophils (all 15%). Conclusions: BLU-667 demonstrates potent, durable and broad antitumor activity and is well tolerated in MTC/PTC pts regardless of MKI resistance and may significantly improve outcomes for pts with RET-altered thyroid cancers. Enrollment of the expansion is ongoing with registrational intent. Clinical trial information: NCT03037385.