Mutation-based, short-term "neoadjuvant" treatment allows resectability in stage IVB and C anaplastic thyroid cancer

Anaplastic thyroid cancer: Genetic roles, targeted therapy, and immunotherapy

Anaplastic thyroid cancer (ATC) stands as the most formidable form of thyroid malignancy, presenting a persistent challenge in clinical management. Recent years have witnessed a gradual unveiling of the intricate genetic underpinnings governing ATC through next-generation sequencing. The emergence of this genetic landscape has paved the way for the exploration of targeted therapies and immunotherapies in clinical trials. Despite these strides, the precise mechanisms governing ATC pathogenesis and the identification of efficacious treatments demand further investigation. Our comprehensive review stems from an extensive literature search focusing on the genetic implications, notably the pivotal MAPK and PI3K-AKT-mTOR signaling pathways, along with targeted therapies and immunotherapies in ATC. Moreover, we screen and summarize the advances and challenges in the current diagnostic approaches for ATC, including the invasive tissue sampling represented by fine needle aspiration and core needle biopsy, immunohistochemistry, and 18F-fluorodeoxyglucose positron emission tomography/computed tomography. We also investigate enormous studies on the prognosis of ATC and outline independent prognostic factors for future clinical assessment and therapy for ATC. By synthesizing this literature, we aim to encapsulate the evolving landscape of ATC oncology, potentially shedding light on novel pathogenic mechanisms and avenues for therapeutic exploration.

Transcriptome of Anaplastic Thyroid Cancer Reveals Two Molecular Subtypes with Distinct Tumor Microenvironment and Prognosis

Background: Although patients with anaplastic thyroid cancer (ATC) generally have a poor prognosis and there are currently no effective treatment options, survival and response to therapy vary between patients. Genomic and transcriptomic profiles of ATC have been reported; however, a comprehensive study of the tumor microenvironment (TME) of ATC is still lacking. This study aimed to elucidate the TME characteristics associated with ATC and their prognostic implications. Methods: We analyzed bulk RNA transcriptomic data from 1,634 samples-including 476 normal thyroid tissues, 25 benign thyroid adenomas, 340 RAS-like and 719 BRAFV600E-like differentiated thyroid cancers (DTC-R and DTC-B, respectively), and 74 ATCs. We assessed the TME and molecular characteristics of these thyroid cancer subtypes using deconvolution analysis. Results: The TME of ATC was characterized by a high abundance of immune cells and fibroblasts and a low abundance of epithelial cells compared to other thyroid histologies. During its malignant evolution, ATC exhibited an ecotype more closely related to DTC-B than RAS-like DTC (DTC-R). Furthermore, we identified two distinct molecular subtypes within ATC with significant differences in their TMEs. We termed the subtype with increased immune cells and fibroblasts as ATC-immune-fibroblast (ATC-IF) and the subtype with elevated epithelial and endothelial cells as ATC-epithelial-endothelial (ATC-E). The ATC-IF group had worse disease-specific survival (log-rank p = 0.035), higher ERK scores, and lower thyroid differentiation scores than the ATC-E group. While both ATC subtypes had elevated immune cells and fibroblasts compared to DTC-R and DTC-B, this increase was more pronounced in ATC-IF, with a marked rise in myeloid lineage cells and promigratory fibroblasts. Immune checkpoint gene expression and epithelial-mesenchymal transition scores were significantly higher in the ATC-IF group than in the ATC-E group. Conclusion: ATC shows a TME distinct from that of DTC and can be further divided into two molecular subtypes-each with its own unique TME. The ATC-IF group, with a poorer prognosis and higher ERK score, is enriched in immune cells and fibroblasts, which may represent potential therapeutic targets.

[Update on anaplastic thyroid cancer-What is relevant for surgeons?]

Anaplastic thyroid cancer (ATC) is the rarest but also the most aggressive carcinoma entity of the thyroid gland. In recent years, treatment options have evolved and molecular oncological treatment approaches have gained in importance. The neoadjuvant use of these innovative therapies has the potential to convert previously unresectable tumors into a resectable state, thereby expanding surgical options and significantly improving the prognosis of patients. This article provides recommendations relevant for surgery for the diagnostics and treatment of ATC, based on a current literature review and the discussions of the S3 guideline conferences.

The potential role of neoadjuvant treatment in thyroid cancers in the era of kinase inhibitors: a narrative review

AIM

To analyse the literature on the potential role of kinase inhibitors (KI) as neoadjuvant treatment (NAT) in all thyroid cancers (TC).

MATERIALS AND METHODS

Online databases were systematically examined, including MEDLINE (via PubMed) Embase, ISI Web of Science, Google Scholar, and Scopus. As many papers were published before the classification of TC was revised, our search was conducted as follows: NAT in TC, NAT in papillary thyroid cancer (PTC), NAT in follicular thyroid cancer (FTC), NAT in anaplastic thyroid cancer (ATC), and NAT in medullary thyroid cancer (MTC).

RESULTS

The search revealed 21 single case reports and three small series on NAT in TC. Overall, 32 cases were found: 24 follicular cell derived cancers (FCDC) of which nine were ATC, eight were MTC. We also found four major retrospective series, in two of which the cohort was divided and analysed into different groups according to the kind of treatment. In these four series, NAT was performed in in a total of 99 patients (32 FCDC, 60 ATC, and 7 MTC).

CONCLUSIONS

While awaiting large-scale clinical trials, the literature highlights that NAT may be an option for locally advanced TC (and above all ATC) when surgery may be too destructive or when the tumour is inoperable. The use of NAT should be discussed with the patient. An R0 or at least an R1 should be the goal of NAT, and the molecular profile should be performed as rapidly as possible.

Selperctinib as neoadjuvant therapy for RET-altered papillary thyroid carcinoma: Two case reports

BACKGROUND

Locally advanced papillary thyroid carcinoma (PTC) with RET fusion-positive poses significant challenges for surgical resection due to tumor invasion into critical structures. Neoadjuvant targeted therapies are a promising approach to reduce the tumor burden and improve the resectability. Selperctinib, a RET kinase inhibitor, has been approved for the treatment of advanced or metastatic RET-altered thyroid cancer. However, the efficacy of selperctinib as a neoadjuvant treatment for locally advanced RET-altered thyroid cancer is unclear.

CASE PRESENTATION

We report two cases of RET fusion-positive PTC that received neoadjuvant treatment with selperctinib (160 mg twice daily) to reduce the tumor size and enable for radical resection. Tumor sizes were reduced after neoadjuvant treatment with selperctinib. Patients successfully underwent R0 resection with no major surgical complications.

CONCLUSION

Selperctinib isa potential neoadjuvant treatment for PTC with RET fusion-positive.

Neoadjuvant systemic therapy for inoperable differentiated thyroid cancers: Impact on tumor resectability

BACKGROUND

Limited treatment options exist for inoperable thyroid cancers. We evaluated whether neoadjuvant use of systemic tyrosine kinase inhibitors facilitates surgery of differentiated thyroid cancers in this challenging context.

METHODS

A single-institution experience of 42 patients receiving tyrosine kinase inhibitors for papillary, follicular and anaplastic thyroid carcinomas between 2018 and 2023 was reviewed to identify differentiated thyroid cancers treated with neoadjuvant tyrosine kinase inhibitors (dabrafenib/trametinib, lenvatinib/pembrolizumab, or lenvatinib alone) via multidisciplinary protocols.

RESULTS

Nine patients with differentiated thyroid cancers (age 49 years, range 19-80, 5 women, 4 men) received neoadjuvant tyrosine kinase inhibitors with intent to improve resectability of primary or recurrent/residual tumors. All had locoregionally advanced disease deemed either unresectable or resectable with unacceptable morbidities. Six exhibited distant metastases (6 lungs, 6 vertebral/axial bones, 1 sternum). Tumors had BRAF V600E (6 papillary thyroid carcinoma) or RAS/TERT (2 follicular thyroid carcinoma) mutations or NCOA4-RET fusion. Most received neoadjuvant tyrosine kinase inhibitors for <6 months with visible results within weeks, radiologically and by examination. All patients completing surgery achieved R0 resection without major surgical complications or aerodigestive structure resection. Neoadjuvant tyrosine kinase inhibitors were generally well-tolerated (4 minor, 1 major toxicity that halted therapy but not surgery). Unique patients with distant metastases continued to receive adjuvant tyrosine kinase inhibitors. At median postoperative follow-up of 2 years, all patients are alive without new locoregional recurrence.

CONCLUSION

Neoadjuvant use of tyrosine kinase inhibitors seems extremely effective in downstaging surgically unresectable differentiated thyroid cancers to achieve R0 resection while avoiding unnecessary surgical morbidities. A multidisciplinary approach with early genomic profiling to guide personalized neoadjuvant use of tyrosine kinase inhibitors is essential. Prospective studies are urgently needed to define the potential role of neoadjuvant tyrosine kinase inhibitors in advanced thyroid cancer management.

Histopathologic and Molecular Insights Following the Management of Ameloblastomas via Targeted Therapies - Pathological and Clinical Perspectives

PURPOSE

Current standard of care for ameloblastoma (conventional/unicystic - mural type) usually mandates extensive bone resection that frequently necessitates immediate reconstruction with serious sequelae, especially among young patients. BRAF-mutated ameloblastomas can be targeted by BRAF inhibitors to markedly reduce their size, enabling conservative removal of residual tumor. We aimed to characterize the effect of post-treatment histomorphologic changes.

METHODS

Study included 14 patients, 11 mandibular and three maxillary tumors. Cases with very minimal residual tumor were defined as near-complete response, while those with mostly vital residual tumor as partial response. The epithelium component was scored for architectural and cellular changes, stroma - for fibrosis, inflammation and new bone formation, on a 3-tired score system: 0-no, 1-focal and 3-frequent changes. The mean scores of each parameter, total epithelium and total stroma were calculated and related to duration of treatment. Differences in the mean scores were investigated for mandibular tumors with near-complete response (n = 3) and partial response (n = 8).

RESULTS

There were no significant differences in mean epithelium or stroma scores between tumors with near-complete and those with partial response (2.22 ± 0.68 versus 2.08 ± 0.43, p = 0.55; 1.41 ± 1.04 versus 1.43 ± 0.44, p = 0.27), suggesting that ameloblastomas have potential to undergo complete response to targeted treatment. This is probably dependent upon tumor/patient/treatment-related factors. Response to treatment appears to be predictable with neoplastic epithelium being first, while the stromal response increases during treatment, the entire process expanding over weeks-to-months.

CONCLUSION

Albeit preliminary, these are the first comprehensive histomorphologic findings on BRAF-treated ameloblastomas. Analyzing the suggested parameters in tumors with partial response, should highlight which tumor component has responded/failed to respond. This could serve as a basis for decision-taking toward subsequent steps in adjuvant treatment (e.g., follow-up, conservative surgery, modifications/changes in treatment regimen, combinations of approaches), with a prime aim of jaw preservation and minimal risk of sequelae.

Pralsetinib as neoadjuvant therapy for RET-Altered differentiated thyroid cancer: Two case reports

BACKGROUND

5-10% of thyroid cancers are at locally advanced stage. Neoadjuvant targeted therapy will likely create surgical opportunities for these patients with unresectable or borderline resectable tumors. Pralsetinib, a RET inhibitor, has been approved for advanced or metastatic RET-altered thyroid cancer. However, there is no evidence on the efficacy of pralsetinib as neoadjuvant therapy in locally advanced RET-altered thyroid cancer.

CASE REPORT

Two patients with locally advanced pappilary thyroid carcinoma (PTC) were treated with pralsetinib (400 mg daily) to reduce tumor size and increase the chance of R0 resection. Both PTCs, characterized by RET-fusion, underwent successful R0 resection without major surgical complications after 4-months neoadjuvant pralsetinib.

CONCLUSION

There is a potential for pralsetinib as a neoadjuvant treatment in PTC with RET-fusion.

Role of [18F]FDG PET/CT in the management of follicular cell-derived thyroid carcinoma

Follicular cell-derived thyroid carcinomas constitute the majority of thyroid malignancies. This heterogeneous group of tumours includes well differentiated, poorly differentiated, and undifferentiated forms, which have distinct pathological features, clinical behaviour, and prognosis. Positron emission tomography with 2-[18F]fluoro-2-deoxy-D-glucose combined with computed tomography ([18F]FDG PET/CT) is an imaging modality used in routine clinical practice for oncological patients. [18F]FDG PET/CT has emerged as a valuable tool for identifying patients at high risk of poor clinical outcomes and for facilitating individualized clinical decision-making. The aim of this comprehensive review is to summarize current knowledge regarding the role of [18F]FDG PET/CT in primary diagnosis, treatment, and follow-up of follicular cell-derived thyroid carcinomas considering the degree of differentiation. Controversial issues, including significance of accidentally detected [18F]FDG uptake in the thyroid, the role of [18F]FDG PET/CT in the early assessment of response to molecular targeted therapies, and its prognostic value are discussed in detail.

Efficacy and safety of BRAF/MEK inhibitors in BRAFV600E-mutated anaplastic thyroid cancer: a systematic review and meta-analysis

PURPOSE

Approximately 45% of anaplastic thyroid cancer (ATC) patients harbor a BRAFV600E mutation and are eligible for target therapy (TT) with BRAF and MEK inhibitors (BRAFi/MEKi), nevertheless, few data advocate for this. Hence, we've conducted a systematic review and meta-analysis investigating the effectiveness and safety of BRAFi/MEKi in BRAFV600E ATC patients.

METHODS

PubMed, Embase, and the Cochrane Library were systematically searched for BRAFi/MEKi TT in BRAFV600E ATC patients. Outcomes included objective response rate (ORR), disease control rate (DCR), overall survival (OS), progression-free survival (PFS), duration of response (DOR) and adverse events (AEs).

RESULTS

Nine studies with 168 patients were included. Median follow-up ranged from 2.0 to 47.9 months. 75% of patients had stage IVc. In a pooled analysis, ORR was 68.15% (95% CI 55.31-80.99, I2 = 47%) and DCR was 85.39% (95% CI 78.10-92.68, I2 = 0), with a median DOR of 14.4 months (95% CI 4.6-14.4) and a median PFS of 6.7 months (95% CI 4.7-34.2). Moreover, 1-year OS rate was 64.97% (95% CI 48.76-81.17, I2 = 84%) and 2-years OS rate was 52.08% (95% CI 35.71-68.45, I2 = 79%). Subgroup analysis showed patients in the neoadjuvant setting had higher rates of 1 and 2-years OS and observational studies tended to report higher rates of ORR than clinical trials. No new or unexpected adverse events were found.

CONCLUSIONS

Our study demonstrated BRAFi/MEKi have a decent activity for BRAFV600E ATC patients, especially in the neoadjuvant setting, with a tolerable safety profile. However, further clinical trials are warranted to investigate these findings.

Neoadjuvant Treatment in Locally Advanced Thyroid Carcinoma

Although the focus in the last decades has been on the overdiagnosis of incidentally detected thyroid carcinomas in early stages, the other extreme of the disease is represented by locally advanced tumors with the invasion of neighboring structures. These are infrequent tumors, but they have a high complexity and a poor prognosis. In the absence of effective therapies allowing preoperative tumor reduction, in order to achieve a more restricted surgery, treatment was limited to aggressive surgery with resection of the aerodigestive tract and major vascular structures or palliative treatment. However, due to the increased knowledge of tumor biology and the results that tyrosine kinase inhibitors have achieved in the treatment of radioactive iodine-refractory tumors, neoadjuvant therapy with a curative intent has emerged as a reality to be taken into account when dealing with these patients. This paper presents a narrative review of the current scientific evidence regarding neoadjuvant treatment in locally advanced thyroid cancer.

Neoadjuvant treatment with lenvatinib and pembrolizumab in a BRAF V600E-mutated anaplastic thyroid cancer: a case report

Background

Tyrosine kinase inhibitors (TKIs) and immunotherapy have been proposed for advanced metastatic anaplastic thyroid cancer (ATC). We report a case of BRAF V600E-mutated ATC in which lenvatinib (L) plus pembrolizumab (P) enabled neoadjuvant treatment.

Case presentation

A male patient aged 65 years presented with a rapidly enlarging left latero-cervical mass. Fine needle aspiration was suggestive of ATC. Surgical consultation excluded radical surgery. While awaiting molecular profile analysis and considering the fast evolution of the disease, treatment with L and P was started. L was started at a dose of 14 mg daily, while P was started at the standard regimen (200 mg every 3 weeks). After 1 month, computerized tomography showed a reduction in the mass with almost complete colliquative degeneration, and the carotid artery wall was free from infiltration. Radical surgery was performed. Histology confirmed papillary thyroid cancer (PTC) in the left lobe and ATC with extensive necrosis in the left latero-cervical lymph node metastasis. The margins were free of tumors (R0). A BRAF V600E mutation was present in both PTC and ATC. At the 1-year follow-up, the patient was free of disease.

Conclusion

L and P in combination also appeared to be effective as a neoadjuvant treatment for BRAF V600E-mutated ATC. This combination treatment could be used when there is an opportunity for complete resection of the cancer, and as soon as possible. The intermediate dose of 14 mg of L appeared to be well tolerated and effective.

[Personalized approach to anaplastic thyroid carcinoma]

BACKGROUND

Anaplastic thyroid carcinoma (ATC) represents the rarest but most aggressive tumor entity of the thyroid gland. In this respect, the treatment of advanced ATC has rapidly evolved in recent years. Recently, new personalized forms of treatment that address the somatic mutational status of the tumor have been increasingly used. The aim of this article is to provide an overview of current molecular-based and personalized treatment options for ATC.

METHODS

A current literature search was performed with a focus on personalized molecular-based treatment options for ATC.

RESULTS

The majority of patients suffering from ATC have an advanced tumor disease at the time of initial diagnosis. Despite multimodal treatment approaches consisting of surgery, external beam radiation therapy (EBRT) and chemotherapy (CTX), the prognosis of ATC is still poor. Accordingly, the focus of innovative treatment approaches is on molecular-based, individualized tumor therapy, including in particular BRAFV600E and multikinase inhibitors. The potential of the latter seems to lie particularly in combination therapy with immune checkpoint inhibitors. These treatment options can be used in both adjuvant and neoadjuvant settings. Neoadjuvant treatment of advanced ATC can achieve a potentially resectable treatment setting and improve the poor prognosis of affected patients; however, larger prospective and randomized studies on these combination therapies are currently pending.

CONCLUSION

The focus of future treatment approaches for ATC will be on individualized, molecular-based tumor therapy. In particular, the neoadjuvant use of these therapies may change the paradigm of ATC surgery as locally advanced as well as metastatic carcinomas can be converted to a potentially resectable status and made amenable to surgery.

First effectiveness data of lenvatinib and pembrolizumab as first-line therapy in advanced anaplastic thyroid cancer: a retrospective cohort study

BACKGROUND

Anaplastic thyroid cancer (ATC) is a rare and aggressive neoplasm. We still lack effective treatment options, so survival rates remain very low. Here, we aimed to evaluate the activity of the combination of lenvatinib and pembrolizumab as systemic first-line therapy in ATC.

METHODS

In a retrospective analysis, we investigated the activity and tolerability of combined lenvatinib (starting dose 14 to 24 mg daily) and pembrolizumab (200 mg every three weeks) as first-line therapy in an institutional cohort of ATC patients.

RESULTS

Five patients with metastatic ATC received lenvatinib and pembrolizumab as systemic first-line therapy. The median progression-free survival was 4.7 (range 0.8-5.9) months, and the median overall survival was 6.3 (range 0.8-not reached) months. At the first follow-up, one patient had partial response, three patients had stable disease, and one patient was formally not evaluable due to interference of assessment by concomitant acute infectious thyroiditis. This patient was then stable for more than one year and was still on therapy at the data cutoff without disease progression. Further analyses revealed deficient DNA mismatch repair, high CD8+ lymphocyte infiltration, and low macrophage infiltration in this patient. Of the other patients, two had progressive disease after adverse drug reactions and therapy de-escalation, and two died after the first staging. For all patients, the PD-L1 combined positive score ranged from 12 to 100%.

CONCLUSIONS

The combination of lenvatinib and pembrolizumab was effective and moderately tolerated in treatment-naïve ATC patients with occasional long-lasting response. However, we could not confirm the exceptional responses for this combination therapy reported before in pretreated patients.

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.