Survival Outcomes of Temporal Bone Squamous Cell Carcinoma: A Systematic Review and Meta-Analysis.

OBJECTIVE: Temporal bone squamous cell carcinoma (TBSCC) is a rare malignancy with poor prognosis, and optimal treatment for advanced cases is uncertain. Our systematic literature review aimed to assess 5-year survival outcomes for advanced TBSCC across different treatment modalities. DATA SOURCES: EMBASE, Medline, PubMed, and Web of Science. REVIEW METHODS: A systematic literature review was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines for articles published between January 1989 and June 2023. RESULTS: The review yielded 1229 citations of which 31 provided 5-year survival data for TBSCC. The final analysis included 1289 patients. T classification data was available for 1269 patients and overall stage for 1033 patients. Data for 5-year overall survival (OS) was 59.6%. Five-year OS was 81.9% for T1/2 and 47.5% for T3/4 (P < .0001). OS for T1/T2 cancers did not significantly differ between surgery and radiation (100% vs 81.3%, P = .103). For advanced-stage disease (T3/T4), there was no statistical difference in OS when comparing surgery with postoperative chemoradiotherapy (CRT) (OS 50.0%) versus surgery with postoperative radiotherapy (XRT) (OS 53.3%) versus definitive CRT (OS 58.1%, P = .767-1.000). There was not enough data to assess the role of neoadjuvant CRT. CONCLUSION: Most patients will present with advanced-stage disease, and nodal metastasis is seen in nearly 22% of patients. This study confirms the prognostic correlation of the current T classification system. Our results suggest that OS did not differ significantly between surgery and XRT for early stage disease, and combined treatment modalities yield similar 5-year OS for advanced cancers.

Checkpoint Inhibition in Addition to Dabrafenib/Trametinib for BRAFV600E-Mutated Anaplastic Thyroid Carcinoma.

Background: The dabrafenib plus trametinib combination (DT) has revolutionized the treatment of BRAFV600E-mutated anaplastic thyroid carcinoma (BRAFm-ATC). However, patients eventually develop resistance and progress. Single-agent anti-PD-1 inhibitor spartalizumab has shown a median overall survival (mOS) of 5.9 months. Combination of immunotherapy with BRAF/MEK inhibitors (BRAF/MEKi) seems to improve outcomes compared with BRAF/MEKi alone, although no direct comparison is available. BRAF-targeted therapy before surgery (neoadjuvant approach) has also shown improvement in survival. We studied the efficacy and safety of DT plus pembrolizumab (DTP) compared with current standard-of-care DT alone as an initial treatment, as well as in the neoadjuvant setting. Methods: Retrospective single-center study of patients with BRAFm-ATC treated with first-line BRAF-directed therapy between January 2014 and March 2023. Three groups were evaluated: DT, DTP (pembrolizumab added upfront or at progression), and neoadjuvant (DT before surgery, and pembrolizumab added before or after surgery). The primary endpoint was mOS between DT and DTP. Secondary endpoints included median progression-free survival (mPFS) and response rate with DT versus DTP as initial treatments, and the exploratory endpoint was mOS in the neoadjuvant group. Results: Seventy-one patients were included in the primary analysis: n = 23 in DT and n = 48 in DTP. Baseline demographics were similar between groups, including the presence of metastatic disease at start of treatment (p = 0.427) and prior treatments with surgery (p = 0.864) and radiation (p = 0.678). mOS was significantly longer with DTP (17.0 months [confidence interval CI, 11.9-22.1]) compared with DT alone (9.0 months [CI, 4.5-13.5]), p = 0.037. mPFS was also significantly improved with DTP as the initial treatment (11.0 months [CI, 7.0-15.0]) compared with DT alone (4.0 months [CI, 0.7-7.3]), p = 0.049. Twenty-three patients were in the exploratory neoadjuvant group, where mOS was the longest (63.0 months [CI, 15.5-110.5]). No grade 5 adverse events (AEs) occurred in all three cohorts, and 32.4% had immune-related AEs, most frequently hepatitis and colitis. Conclusions: Our results show that in BRAFm-ATC, addition of pembrolizumab to dabrafenib/trametinib may significantly prolong survival. Surgical resection of the primary tumor after initial BRAF-targeted therapy in selected patients may provide further survival benefit. However, conclusions are limited by the retrospective nature of the study. Additional prospective data are needed to confirm this observation.

Decreasing utilization for postoperative radiation therapy in locoregionally advanced medullary thyroid cancer.

BACKGROUND: Use of postoperative radiation therapy (PORT) in locoregionally advanced medullary thyroid cancer (MTC) remains controversial. The objective was to evaluate the effect of PORT on locoregional control (LRC) and overall survival (OS). METHODS: Retrospective cohort study of 346 MTC patients separated into PORT and no-PORT cohorts. Relative indications for PORT, as well as changes in patterns of treatment, were recorded. RESULTS: 49/346 (14%) received PORT. PORT was associated with worse OS; adjusted HR = 2.0 (95%CI 1.3-3.3). PORT was not associated with improved LRC, even when adjusting for advanced stage (Stage III p = 0.892; Stage IV p = 0.101). PORT and targeted therapy were not associated with improved OS compared to targeted therapy alone; adjusted HR = 1.2 (95%CI 0.3-4.1). CONCLUSIONS: Use of PORT in MTC has decreased and its indications have become more selective, coinciding with the advent of effective targeted therapies. Overall, PORT was not associated with improved LRC or OS.

Utilization of Transcriptomic Profiling to Identify Molecular Markers Predicting Successful Recovery Following Endoscopic Sinus Surgery for Chronic Rhinosinusitis.

OBJECTIVES: Successful recovery from chronic rhinosinusitis (CRS) following endoscopic sinus surgery (ESS) can be characterized by minimal presence of symptoms and absence of disease on endoscopy. However, molecular markers of surgical success remain to be characterized. These could allow for better tailoring of perioperative therapy. This study aims to identify novel molecular markers associated with surgery responsive patient. STUDY DESIGN: Prospective cohort study. SETTING: Single academic hospital center. METHOD: One hundred eighteen consecutive patients with CRS at high risk of recurrence after surgery were followed prospectively following ESS in an academic medical center. Symptomatic and endoscopic outcomes were assessed at 4 months, with success rigorously defined subjectively as minimal or no symptoms (no symptom greater than 1 on an ordinal scale of 0-3) and objectively by the absence of nasal polyposis on sinus cavity endoscopy and Lund-Kennedy endoscopic edema score no greater than 1. Samples were obtained at the time of surgery and at 4-month postoperatively. Changes associated with surgery were determined by gene expression profiling using Affymetrix's Clariom S Human HT arrays. RESULTS: Successful ESS was characterized by a mild upregulation in Type 1 inflammation, upregulation of cell cycle progression, and epithelial barrier and proliferation-associated genes and pathways. ESS failure was associated to very high levels of Type 1 inflammation along with downregulation of epithelial barrier function and regeneration genes and pathways. CONCLUSION: Successful recovery from ESS involves restoration of epithelial function and regulated activation of Type 1 inflammation. Excessively elevated Type 1 inflammation is associated with epithelial barrier dysfunction.

Carotid blowout into the trachea: unusual entity with unexpected management outcome.

We present a case report of a patient with a history of aggressive thyroid cancer managed by surgery, chemotherapy, and radiation to the neck. A year later, he presented with hemoptysis. Endobronchial ultrasound showed a pulsatile vessel; however, a CT scan and conventional angiogram were negative. Three days later, a repeat angiogram revealed a pseudoaneurysm arising from the right common carotid artery. Carotid sacrifice was performed after passing balloon test occlusion. Three years later the patient presented with coil herniation into the trachea. The carotid stump was closed with a vascular plug to prevent rebleeding from coil removal. Four months later the patient experienced an intractable cough and underwent laryngoscopy-assisted removal of the residual coil mass. This case report discusses the rare scenario of a carotid blowout into the trachea and the subsequent course of events.

Oncologic Significance of Therapeutic Delays in Patients With Oral Cavity Cancer.

Importance: Oral cavity cancer often requires multidisciplinary management, subjecting patients to complex therapeutic trajectories. Prolonged treatment intervals in oral cavity cancer have been associated with poor oncological outcomes, but there has yet to be a study investigating treatment times in Canada. Objective: To report treatment delays for patients with oral cavity cancer in Canada and evaluate the outcomes of treatment delays on overall survival. Design, Setting, and Participants: This multicenter cohort study was performed at 8 Canadian academic centers from 2005 to 2019. Participants were patients with oral cavity cancer who underwent surgery and adjuvant radiation therapy. Analysis was performed in January 2023. Main Outcomes and Measures: Treatment intervals evaluated were surgery to initiation of postoperative radiation therapy interval (S-PORT) and radiation therapy interval (RTI). The exposure variables were prolonged intervals, respectively defined as index S-PORT greater than 42 days and RTI greater than 46 days. Patient demographics, Charlson Comorbidity Index, smoking status, alcohol status, and cancer staging were also considered. Univariate (log rank and Kaplan-Meier) and multivariate (Cox regression) analyses were performed to determine associations with overall survival (OS). Results: Overall, 1368 patients were included; median (IQR) age at diagnosis was 61 (54-70) years, and 896 (65%) were men. Median (IQR) S-PORT was 56 (46-68) days, with 1093 (80%) patients waiting greater than 42 days, and median (IQR) RTI was 43 (41-47) days, with 353 (26%) patients having treatment time interval greater than 46 days. There were variations in treatment time intervals between institutions for S-PORT (institution with longest vs shortest median S-PORT, 64 days vs 48 days; η2 = 0.023) and RTI (institution with longest vs shortest median RTI, 44 days vs 40 days; η2 = 0.022). Median follow-up was 34 months. The 3-year OS was 68%. In univariate analysis, patients with prolonged S-PORT had worse survival at 3 years (66% vs 77%; odds ratio 1.75; 95% CI, 1.27-2.42), whereas prolonged RTI (67% vs 69%; odds ratio 1.06; 95% CI, 0.81-1.38) was not associated with OS. Other factors associated with OS were age, Charlson Comorbidity Index, alcohol status, T category, N category, and institution. In the multivariate model, prolonged S-PORT remained independently associated with OS (hazard ratio, 1.39; 95% CI, 1.07-1.80). Conclusions and Relevance: In this multicenter cohort study of patients with oral cavity cancer requiring multimodal therapy, initiation of radiation therapy within 42 days from surgery was associated with improved survival. However, in Canada, only a minority completed S-PORT within the recommended time, whereas most had an appropriate RTI. An interinstitution variation existed in terms of treatment time intervals. Institutions should aim to identify reasons for delays in their respective centers, and efforts and resources should be directed toward achieving timely completion of S-PORT.

The protective role of postoperative radiation therapy in low and intermediate grade major salivary gland malignancies: A study of the Canadian Head and Neck Collaborative Research Initiative.

BACKGROUND: The objective of this study was to examine the utility of postoperative radiation for low and intermediate grade cancers of the parotid and submandibular glands. METHODS: The authors conducted a retrospective, Canadian-led, international, multi-institutional analysis of a patient cohort with low or intermediate grade salivary gland cancer of the parotid or submandibular gland who were treated from 2010 until 2020 with or without postoperative radiation therapy. A multivariable, marginal Cox proportional hazards regression analysis was performed to quantify the association between locoregional recurrence (LRR) and receipt of postoperative radiation therapy while accounting for patient-level factors and the clustering of patients by institution. RESULTS: In total, 621 patients across 14 tertiary care centers were included in the study; of these, 309 patients (49.8%) received postoperative radiation therapy. Tumor histologies included 182 (29.3%) acinic cell carcinomas, 312 (50.2%) mucoepidermoid carcinomas, and 137 (20.5%) other low or intermediate grade primary salivary gland carcinomas. Kaplan-Meier LRR-free survival at 10 years was 89.0% (95% confidence interval [CI], 84.9%-93.3%). In multivariable Cox regression analysis, postoperative radiation therapy was independently associated with a lower hazard of LRR (adjusted hazard ratio, 0.53; 95% CI, 0.29-0.97). The multivariable model estimated that the marginal probability of LRR within 10 years was 15.4% without radiation and 8.8% with radiation. The number needed to treat was 16 patients (95% CI, 14-18 patients). Radiation therapy had no benefit in patients who had early stage, low-grade salivary gland cancer without evidence of nodal disease and negative margins. CONCLUSIONS: Postoperative radiation therapy may reduce LLR in some low and intermediate grade salivary gland cancers with adverse features, but it had no benefit in patients who had early stage, low-grade salivary gland cancer with negative margins.

Genetically engineered mouse models of head and neck cancers.

The head and neck region is one of the anatomic sites commonly afflicted by cancer, with ~1.5 million new diagnoses reported worldwide in 2020 alone. Remarkable progress has been made in understanding the underlying disease mechanisms, personalizing care based on each tumor's individual molecular characteristics, and even therapeutically exploiting the inherent vulnerabilities of these neoplasms. In this regard, genetically engineered mouse models (GEMMs) have played an instrumental role. While progress in the development of GEMMs has been slower than in other major cancer types, several GEMMs are now available that recapitulate most of the heterogeneous characteristics of head and neck cancers such as the tumor microenvironment. Different approaches have been employed in GEMM development and implementation, though each can generally recapitulate only certain disease aspects. As a result, appropriate model selection is essential for addressing specific research questions. In this review, we present an overview of all currently available head and neck cancer GEMMs, encompassing models for head and neck squamous cell carcinoma, nasopharyngeal carcinoma, and salivary and thyroid gland carcinomas.

Recent advances in anaplastic thyroid cancer management.

PURPOSE OF REVIEW: To summarize recent developments in the diagnosis and management of patients with anaplastic thyroid cancer (ATC). RECENT FINDINGS: An updated edition of the Classification of Endocrine and Neuroendocrine Tumors was released by the World Health Organization (WHO), in which squamous cell carcinoma of the thyroid are now a subtype of ATC. Broader access to next generation sequencing has allowed better understanding of the molecular mechanisms driving ATC and improved prognostication. BRAF-targeted therapies revolutionized the treatment of advanced/metastatic BRAFV600E -mutated ATC, offering significant clinical benefit and allowing better locoregional control of disease through the neoadjuvant approach. However, inevitable development of resistance mechanisms represents a major challenge. Addition of immunotherapy to BRAF/MEK inhibition has shown very promising results and significant improvement in survival outcomes. SUMMARY: Major advancements took place in the characterization and management of ATC in recent years, especially in patients with a BRAF V600E mutation. Still, no curative treatment is available, and options are limited once resistance to currently available BRAF-targeted therapies develops. Additionally, there is still a need for more effective treatments for patients without a BRAF mutation.

Azithromycin Mechanisms of Action in CRS Include Epithelial Barrier Restoration and Type 1 Inflammation Reduction.

OBJECTIVE: Previous in vitro transcriptomic profiling suggests azithromycin exerts its effects in patients with chronic rhinosinusitis (CRS) via modulation of type 1 inflammation and restoration of epithelial barrier function. We wished to verify these postulated effects using in vitro models of epithelial repair and in vivo transcriptional profiling. STUDY DESIGN: Functional effects of azithromycin in CRS were verified using in vitro models of wounding. The mechanism of the effect of azithromycin was assessed in vivo using transcriptomic profiling. SETTING: Academic medical center. METHODS: Effects of azithromycin on the speed of epithelial repair were verified in a wounding model using primary nasal epithelial cells (pNEC) from CRS patients. Nasal brushings collected pre-and posttreatment during a placebo-controlled trial of azithromycin for CRS patients unresponsive to surgery underwent transcriptomic profiling to identify implicated pathways. RESULTS: Administration of azithromycin improved the wound healing rates in CRS pNECs and prevented the negative effect of Staphylococcus aureus on epithelial repair. In vivo, response to azithromycin was associated with downregulation in pathways of type 1 inflammation, and upregulation of pathways implicated in the restoration of the cell cycle. CONCLUSION: Restoration of healthy epithelial function may represent a major mode of action of azithromycin in CRS. In vitro models show enhanced epithelial repair, while in vivo transcriptomics shows downregulation of pathways type 1 inflammation accompanied by upregulation of DNA repair and cell-cycle pathways. The maximal effect in patients with high levels of type 1-enhanced inflammation suggests that azithromycin may represent a novel therapeutic option for surgery-unresponsive CRS patients.

Surgery After BRAF-Directed Therapy Is Associated with Improved Survival in BRAFV600E Mutant Anaplastic Thyroid Cancer: A Single-Center Retrospective Cohort Study.

Background: The aim of this study was to describe the oncologic outcomes of patients with BRAFV600E-mutated anaplastic thyroid cancer (ATC) who had neoadjuvant BRAF-directed therapy with subsequent surgery. For context, we also reviewed patients who received BRAF-directed therapy after surgery, and those who did not have surgery after BRAF-directed therapy. Methods: This was a single-center retrospective cohort study conducted at a tertiary care cancer center in Texas from 2017 to 2021. Fifty-seven consecutive patients with BRAFV600E-mutated ATC and at least 1 month of BRAF-directed therapy were included. Primary outcomes were overall survival (OS) and progression-free survival (PFS). Results: All patients had stage IVB (35%) or IVC (65%) ATC. Approximately 70% of patients treated with BRAF-directed therapy ultimately had surgical resection of residual disease. Patients who had neoadjuvant BRAF-directed therapy followed by surgery (n = 32) had 12-month OS of 93.6% [confidence interval (CI) 84.9-100] and PFS of 84.4% [CI 71.8-96.7]. Patients who had surgery before BRAF-directed therapy (n = 12) had 12-month OS of 74.1% [CI 48.7-99.5] and PFS of 50% [CI 21.7-78.3]. Finally, patients who did not receive surgery after BRAF-directed therapy (n = 13) had 12-month OS of 38.5% [CI 12.1-64.9] and PFS of 15.4% [CI 0-35.0]. Neoadjuvant BRAF-directed therapy reduced tumor size, extent of surgery, and surgical morbidity score. Subgroup analysis suggested that any residual ATC in the surgical specimen was associated with significantly worse 12-month OS and PFS (OS = 83.3% [CI 62.6-100], PFS = 61.5% [CI 35.1-88]) compared with patients with pathologic ATC complete response (OS = 100%, PFS = 100%). Conclusions: We observed that neoadjuvant BRAF-directed therapy reduced extent of surgery and surgical morbidity. While acknowledging potential selection bias, the 12-month OS rate appeared higher in patients who had BRAF-directed therapy followed by surgery as compared with BRAF-directed therapy without surgery; yet, it was not significantly different from surgery followed by BRAF-directed therapy. PFS appeared higher in patients treated with neoadjuvant BRAF-directed therapy relative to patients in the other groups. These promising results of neoadjuvant BRAF-directed therapy followed by surgery for BRAF-mutated ATC should be confirmed in prospective clinical trials.

Clinical outcomes of combined cervical and transthoracic surgical approaches in patients with advanced thyroid cancer.

BACKGROUND: Advanced thyroid disease involving the mediastinum may be managed surgically with a combined transcervical and transthoracic approach. Contemporary analysis of this infrequently encountered cohort will aid the multidisciplinary team in personalizing treatment approaches. METHODS: Retrospective review of patients undergoing combined transcervical and transthoracic surgery for thyroid cancer at a single high-volume institution from 1994 to 2015. RESULTS: Thirty-eight patients with median age 59 years (range 28-76) underwent surgery without perioperative mortality. Most patients had primary disease. A majority had distant metastases outside the mediastinum but had locoregionally curable disease. Common complications were temporary (39%) and permanent (18%) hypoparathyroidism, and wound infection (13%). One-year overall survival was 84%; 1-year locoregional disease-free survival was 64%. Median time to locoregional recurrence was 36 months. Only esophageal invasion was associated with worse oncologic outcomes. CONCLUSIONS: Combined transcervical and transthoracic surgery for advanced thyroid cancer can be performed without mortality and with acceptable morbidity.

Prior Thyroid and Nonthyroid Cancer History Do Not Significantly Alter Overall Survival in Patients Diagnosed with Anaplastic Thyroid Cancer.

Background: A history of thyroid and nonthyroid malignancies has traditionally been an exclusion criterion in patients with anaplastic thyroid cancer (ATC) seeking to enroll in clinical trials. In this study, we examined the impact of prior malignancies on overall survival (OS) in patients diagnosed with ATC. Methods: In our retrospective cohort study, we identified 451 patients with ATC treated at MD Anderson between 2000 and 2019. Clinical and pathological information was obtained through chart review. Survival analyses were conducted using the Kaplan-Meier method and multivariable Cox proportional hazard models. Results: A history of clinically documented differentiated thyroid cancer (DTC) was reported in 14% of patients with ATC (n = 62), most commonly papillary thyroid cancer (81%, n = 50). The median time from diagnosis of prior DTC to ATC diagnosis was 3.5 years (range: 6 months to 35 years). Concomitant DTC was found on pathology in a higher proportion of patients (52%, n = 234). A history of nonthyroid cancer was reported in 23% of patients (n = 102), where 19% (n = 87) had one, 2% (n = 10) had two, and 1% (n = 5) had three prior cancers. The median time from diagnosis of prior nonthyroid cancer to ATC diagnosis was 8 years (range: 3 months to 53 years). The most common prior nonthyroid cancers were nonmelanoma skin (28.4%), prostate (19.6%), and breast cancers (16.7%). In a subgroup analysis performed in patients with available tumor mutation information (n = 183), the frequency of detected tumor driver mutations (BRAF, RAS, TP53) was not significantly different between patients with ATC with and without a history of nonthyroid cancer. On multivariate analysis after adjusting for age and overall stage, prior DTC, concomitant DTC, and prior nonthyroid cancers, all had no significant impact on OS. Conclusions: The presence of prior malignancy does not significantly impact OS in patients with ATC. Revision of eligibility criteria for enrollment of patients with ATC into clinical trials is warranted.

Anaplastic Thyroid Cancer: New Horizons and Challenges.

Anaplastic thyroid cancer (ATC) remains one of the most aggressive and deadliest malignancies. Traditionally, treatment consisted of cytotoxic chemotherapy and radiation therapy, with or without surgery, although a large proportion of patients were often directed toward palliative/hospice care. In the past decade, significant advances have been made through the advent of targeted therapies and immunotherapy. For patients with targetable disease and considerable treatment response, surgery and other multidisciplinary adjuvant therapies can now be considered. Overall, the era of untreatable ATC is progressively being replaced by highly personalized multidisciplinary therapies, actively shifting the treatment pendulum of this disease.

The Effect of Radiation and Chemoradiation Therapy on the Head and Neck Mucosal Microbiome: A Review.

Radiation (RT) and chemoradiation therapy (CRT) play an essential role in head and neck cancer treatment. However, both cause numerous side effects in the oral cavity, paranasal sinuses, and pharynx, having deleterious consequences on patients' quality of life. Concomitant with significant advances in radiation oncology, much attention has turned to understanding the role of the microbiome in the pathogenesis of treatment-induced tissue toxicity, to ultimately explore microbiome manipulation as a therapeutic intervention. This review sought to discuss current publications investigating the impact of RT and CRT-induced changes on the head and neck microbiome, using culture-independent molecular methods, and propose opportunities for future directions. Based on 13 studies derived from a MEDLINE, EMBASE, and Web of Science search on November 7, 2021, use of molecular methods has uncovered various phyla and genera in the head and neck microbiome, particularly the oral microbiome, not previously known using culture-based methods. However, limited research has investigated the impact of RT/CRT on subsites other than the oral cavity and none of the studies aimed to examine the relationship between the head and neck microbiome and treatment effectiveness. Findings from this review provide helpful insights on our current understanding of treatment-induced oral mucositis, dental plaque, and caries formation and highlight the need for future research to examine the effect of RT/CRT on the sinonasal and oropharyngeal microbiome. In addition, future research should use larger cohorts, examine the impact of the microbiome on treatment response, and study the effect of manipulating the microbiome to overcome therapy resistance.

Novel Anaplastic Thyroid Cancer PDXs and Cell Lines: Expanding Preclinical Models of Genetic Diversity.

CONTEXT: Anaplastic thyroid cancer (ATC) is a rare, aggressive, and deadly disease. Robust preclinical thyroid cancer models are needed to adequately develop and study novel therapeutic agents. Patient-derived xenograft (PDX) models may resemble patient tumors by recapitulating key genetic alterations and gene expression patterns, making them excellent preclinical models for drug response evaluation. OBJECTIVE: We developed distinct ATC PDX models concurrently with cell lines and characterized them in vitro and in vivo. METHODS: Fresh thyroid tumor from patients with a preoperative diagnosis of ATC was surgically collected and divided for concurrent cell line and PDX model development. Cell lines were created by generating single cells through enzymatic digestion. PDX models were developed following direct subcutaneous implantation of fresh tumor on the flank of immune compromised/athymic mice. RESULTS: Six ATC PDX models and 4 cell lines were developed with distinct genetic profiles. Mutational characterization showed one BRAF/TP53/CDKN2A, one BRAF/CDKN2A, one BRAF/TP53, one TP53 only, one TERT-promoter/HRAS, and one TERT-promoter/KRAS/TP53/NF2/NFE2L2 mutated phenotype. Hematoxylin-eosin staining comparing the PDX models to the original patient surgical specimens show remarkable resemblance, while immunohistochemistry stains for important biomarkers were in full concordance (cytokeratin, TTF-1, PAX8, BRAF). Short tandem repeats DNA fingerprinting analysis of all PDX models and cell lines showed strong concordance with the original tumor. PDX successful establishment rate was 32%. CONCLUSION: We have developed and characterized 6 novel ATC PDX models with 4 matching cell lines. Each PDX model harbors a distinct genetic profile, making them excellent tools for preclinical therapeutic trials.