OUP accepted manuscript

Metabolomics reveals the implication of acetoacetate and ketogenic diet therapy in radioiodine-refractory differentiated thyroid carcinoma

OBJECTIVE

Patients with radioiodine-refractory (RAIR) differentiated thyroid carcinoma (DTC; RAIR-DTC) have a poor prognosis. The aim of this study was to provide new insights and possibilities for the diagnosis and treatment of RAIR-DTC.

METHODS

The metabolomics of 24 RAIR-DTC and 18 non-radioiodine-refractory (NonRAIR) DTC patients samples were analyzed by liquid chromatograph-mass spectrometry. Cellular radioiodine uptake was detected with γ counter. Sodium iodide symporter (NIS) expression and thyroid stimulating hormone receptor (TSHR) were measured by Western blot analysis. CCK8 and colony formation assays were used to measure cellular proliferation. Scratch and transwell assays were performed to assess cell migration and invasion. Annexin V/PI staining was used to detect cell apoptosis. Cell growth in vivo was evaluated by a tumor xenograft model. The acetoacetate (AcAc) level was measured by ELISA. Pathological changes, Ki67, NIS, and TSHR expression were investigated by immunohistochemistry.

RESULTS

The metabolite profiles of RAIR could be distinguished from those of NonRAIR, with AcAc significantly lower in RAIR. The significantly different metabolic pathway was ketone body metabolism. AcAc increased NIS and TSHR expression and improved radioiodine uptake. AcAc inhibited cell proliferation, migration, and invasion, and as well promoted cell apoptosis. Ketogenic diet (KD) elevated AcAc levels and significantly suppressed tumor growth, as well as improved NIS and TSHR expression.

CONCLUSION

Significant metabolic differences were observed between RAIR and NonRAIR, and ketone body metabolism might play an important role in RAIR-DTC. AcAc improved cellular iodine uptake and had antitumor effects for thyroid carcinoma. KD might be a new therapeutic strategy for RAIR-DTC.

The potential of lenvatinib in breast cancer therapy

Breast cancer, as a highly prevalent cancer among women, is one of the main causes of female mortality due to cancer. There is a need for more treatment options to improve the survival time of breast cancer patients. Metastasis to distant organs is a standard indicator of advanced breast cancer and a primary cause of breast cancer mortality, making the control of breast cancer metastasis crucial. Targeted therapy, with its advantages of precision, high effectiveness, and minimal side effects, has garnered significant attention as a hot research topic in breast cancer treatment. Among these therapies, anti-angiogenic therapy aim to inhibit tumor angiogenesis, control tumor growth, and reduce metastasis. Additionally, anti-angiogenic therapy can restructure the tumor vasculature, enhancing the effectiveness of other anti-cancer drugs. Lenvatinib, an orally available small molecule multi-targeted tyrosine kinase inhibitor, exerts its anti-tumor effects mainly by inhibiting tumor angiogenesis and tumor cell proliferation. It has been approved for the treatment of thyroid cancer, renal cell carcinoma, and hepatocellular carcinoma. Due to its multi-targeted nature, lenvatinib not only has direct anti-tumor effects but also possesses immunomodulatory activity, which can enhance the tumor immune response. This makes it a promising candidate for a broad range of cancers. Recent studies have explored the role of lenvatinib in breast cancer, including its various mechanisms of action and its use as a monotherapy or in combination to control breast cancer progression. This review will summarize the molecular mechanisms and research progress of lenvatinib in breast cancer treatment, discussing its potential applications and therapeutic prospects in managing breast cancer.

Development of TSHR-CAR NK-92 cells for Differentiated Thyroid Cancer

Differentiated thyroid cancer (DTC) is the predominant type of thyroid cancer, with some patients experiencing relapse, distant metastases, or refractoriness, revealing limited treatment options. Chimeric antigen receptor (CAR)-modified Natural Killer (NK) cells are revolutionary therapeutic agents effective against various resistant cancers. Thyroid-stimulating hormone receptor (TSHR) expression in DTC provides a unique tumor-specific target for CAR therapy. Here, we developed an innovative strategy for treating DTC using modified NK-92 cells armed with a TSHR-targeted CAR. The modified cells showed enhanced cytotoxicity against TSHR-positive DTC cell lines and exhibited elevated degranulation and cytokine release. After undergoing irradiation, the cells effectively halted their proliferative capacity while maintaining potent targeted killing ability. Transfer of these irradiation-treated cells into NSG mice with DTC tumors resulted in profound tumor suppression. NK-92 cells modified with TSHR-CAR offer a promising, off-the-shelf option for advancing DTC immunotherapy.

Improving the response to lenvatinib in partial responders using a Constrained-Disorder-Principle-based second-generation artificial intelligence-therapeutic regimen: a proof-of-concept open-labeled clinical trial

Introduction

The main obstacle in treating cancer patients is drug resistance. Lenvatinib treatment poses challenges due to loss of response and the common dose-limiting adverse events (AEs). The Constrained-disorder-principle (CDP)-based second-generation artificial intelligence (AI) systems introduce variability into treatment regimens and offer a potential strategy for enhancing treatment efficacy. This proof-of-concept clinical trial aimed to assess the impact of a personalized algorithm-controlled therapeutic regimen on lenvatinib effectiveness and tolerability.

Methods

A 14-week open-label, non-randomized trial was conducted with five cancer patients receiving lenvatinib-an AI-assisted application tailored to a personalized therapeutic regimen for each patient, which the treating physician approved. The study assessed changes in tumor response through FDG-PET-CT and tumor markers and quality of life via the EORTC QLQ-THY34 questionnaire, AEs, and laboratory evaluations. The app monitored treatment adherence.

Results

At 14 weeks of follow-up, the disease control rate (including the following outcomes: complete response, partial response, stable disease) was 80%. The FDG-PET-CT scan-based RECIST v1.1 and PERCIST criteria showed partial response in 40% of patients and stable disease in an additional 40% of patients. One patient experienced a progressing disease. Of the participants with thyroid cancer, 75% showed a reduction in thyroglobulin levels, and 60% of all the participants showed a decrease in neutrophil-to-lymphocyte ratio during treatment. Improvement in the median social support score among patients utilizing the system supports an ancillary benefit of the intervention. No grade 4 AEs or functional deteriorations were recorded.

Summary

The results of this proof-of-concept open-labeled clinical trial suggest that the CDP-based second-generation AI system-generated personalized therapeutic recommendations may improve the response to lenvatinib with manageable AEs. Prospective controlled studies are needed to determine the efficacy of this approach.

Current Advances in Radioactive Iodine-Refractory Differentiated Thyroid Cancer

BACKGROUND

Differentiated thyroid cancer (DTC) patients have an outstanding overall long-term survival rate, and certain subsets of DTC patients have a very high likelihood of disease recurrence. Radioactive iodine (RAI) therapy is a cornerstone in DTC management, but cancer cells can eventually develop resistance to RAI. Radioactive iodine-refractory DTC (RAIR-DTC) is a condition defined by ATA 2015 guidelines when DTC cannot concentrate RAI ab initio or loses RAI uptake ability after the initial therapy. The RAIR condition implies that RAI cannot reveal new met-astatic foci, so RAIR-DTC metabolic imaging needs new tracers. 18F-FDG PET/CT has been widely used and has demonstrated prognostic value, but 18F-FDG DTC avidity may remain low. Fibroblast activation protein inhibitors (FA-Pi)s, prostatic-specific membrane antigen (PSMA), and somatostatin receptor (SSTR) tracers have been proposed as theragnostic agents in experimental settings and Arg-Gly-Asp (RGD) peptides in the diagnostic trial field. Multi-targeted tyrosine kinase inhibitors are relatively new drugs approved in RAIR-DTC therapy. Despite the promising targeted setting, they relate to frequent adverse-event onset. Sorafenib and trametinib have been included in re-differentiation protocols aimed at re-inducing RAI accumulation in DTC cells. Results appear promising, but not excellent.

CONCLUSIONS

RAIR-DTC remains a challenging nosological entity. There are still controversies on RAIR-DTC definition and post-RAI therapy evaluation, with post-therapy whole-body scan (PT-WBS) the only validated criterion of response. The recent introduction of multiple diagnostic and therapeutic agents obliges physicians to pursue a multidisciplinary approach aiming to correct drug introduction and timing choice.

[Thyroid carcinomas: the role of systemic therapies in internal medicine]

The molecular pathogenesis of thyroid carcinoma is well studied and of importance for the treatment of advanced stages. Differentiated, poorly differentiated and anaplastic carcinomas originate in the follicular cells, while medullary carcinomas derive from the C‑cells. The prognosis of differentiated thyroid carcinoma is generally very favourable after surgery and radioiodine therapy. Where tumours progress and lose the ability to enrich iodine, curative treatment is usually not possible. A strategy of watchful waiting is often appropriate. Activating mutations in BRAF or gene fusions of RET and NTRK provide opportunities for targeted therapies. These may be applied with the aim of restoring iodine uptake (redifferentiation). In the absence of molecular therapy targets, multityrosine kinase inhibitors (MKI) are the therapy of choice. If anaplastic thyroid carcinoma is suspected, rapid diagnostic workup including molecular pathology is warranted. Surgery where possible and radiochemotherapy are essential components of therapy. In the presence of a BRAF mutation, inhibition of BRAF and MEK is effective, even if it is not approved in Germany. Where molecular targets are lacking, combination therapy with the MKI lenvatinib and immune checkpoint inhibition is highly effective. Mutations in RET are present in the vast majority of cases of medullary thyroid carcinoma. In aggressive advanced disease, selective RET inhibition has recently been approved as first-line therapy and often leads to an objective response and long-lasting disease stabilisation. In summary, thyroid carcinomas are among the tumour entities for which molecularly targeted therapies can be used most frequently. The involvement of specialised centres is advisable.

Causal relationship between gut microbiota and differentiated thyroid cancer: a two-sample Mendelian randomization study

Background

The gut microbiota has been significantly associated with differentiated thyroid cancer (DTC). However, the causal relationship between the gut microbiota and DTC remains unexplored.

Methods

Genome-wide association study (GWAS) summary databases were utilized to select exposures and outcomes. The Mendelian randomization (MR) method was employed to investigate the causal relationship between the gut microbiota and DTC. A sensitivity analysis was performed to assess the reliability of the findings.

Results

Four bacterial traits were associated with the risk of DTC: Class Mollicutes [odds ratio (OR) = 10.953, 95% confidence interval (95% CI): 2.333-51.428, p = 0.002], Phylum Tenericutes (OR = 10.953, 95% CI: 2.333-51.428, p = 0.002), Genus Eggerthella (OR = 3.219, 95% CI: 1.033-10.024, p = 0.044), and Order Rhodospirillales (OR = 2.829, 95% CI: 1.096-7.299, p = 0.032). The large 95% CI range for the Class Mollicutes and the Phylum Tenericutes may be attributed to the small sample size. Additionally, four other bacterial traits were negatively associated with DTC: Genus Eubacterium fissicatena group (OR = 0.381, 95% CI: 0.148-0.979, p = 0.045), Genus Lachnospiraceae UCG008 (OR = 0.317, 95% CI: 0.125-0.801, p = 0.015), Genus Christensenellaceae R-7 group (OR = 0.134, 95% CI: 0.020-0.886, p = 0.037), and Genus Escherichia Shigella (OR = 0.170, 95% CI: 0.037-0.769, p = 0.021).

Conclusion

These findings contribute to our understanding of the pathological mechanisms underlying DTC and provide novel insights for the clinical treatment of DTC.

Clinicopathological features of differentiated thyroid carcinoma as predictors of the effects of radioactive iodine therapy

BACKGROUND

Patients with differentiated thyroid cancer (DTC) usually have an excellent prognosis; however, 5 %-15 % develop radioactive iodine-refractory (RAIR) DTC (RAIR-DTC), which has a poor prognosis and limited treatment options. The aim of the present study was to investigate the clinicopathological characteristics of RAIR-DTC in order to provide clinical evidence for timely prediction of the effects of iodine therapy.

METHODS

Clinicopathological data for 44 patients with RAIR-DTC and 50 patients with radioiodine-avid DTC (RAIA-DTC) were retrospectively analyzed. The risk factors for RAIR-DTC were evaluated and a RAIR-DTC prediction model was established.

RESULTS

RAIR-DTC showed unique clinicopathological features that differed from those of RAIA-DTC; these included age >55 years, a high-risk histological subtype, a large tumor size, a late TNM stage, calcification, distant metastasis, and more than six metastatic lymph nodes. Patients with RAIR-DTC also developed earlier tumor progression. Binary logistic regression analysis showed that distant metastasis, a high-risk histological subtype, and a maximum tumor diameter of ≥12.5 mm were independent risk factors for RAIR-DTC, and the specificity and sensitivity of a combination of these three parameters for the prediction of RAIR-DTC were 98.0 % and 56.8 %, respectively. Decision curve analysis and the calibration curve revealed that the combined prediction of these three parameters had good repeatability and accuracy.

CONCLUSION

The clinicopathological features of DTC can effectively predict the effects of iodine therapy. A combination of distant metastasis, a high-risk histological subtype, and a maximum tumor diameter of ≥12.5 mm showed significantly higher prediction accuracy.

Neoadjuvant therapy to improve resectability of advanced thyroid cancer: A real-world experience

BACKGROUND

Experience with targeted neoadjuvant treatment for locoregionally advanced thyroid cancer is nascent.

METHODS

Multicenter retrospective case series examining targeted neoadjuvant treatment for locoregionally advanced thyroid cancer. The primary outcome was change in surgical morbidity as measured by two metrics developed for use in clinical trials to characterize surgical complexity and morbidity. Secondary outcomes included percentage of patients proceeding to surgery and percentage receiving an R0/R1 resection.

RESULTS

Seventeen patients with varied molecular alterations, pathologies, and treatment regimens were included. Mean surgical complexity scores decreased between time points for baseline and postneoadjuvant treatment, postneoadjuvant treatment and surgery, and between baseline and surgery. Eleven patients (64.7%) underwent surgical resection, with 10 (58.8%) receiving an R0/R1 resection.

CONCLUSIONS

Neoadjuvant treatment of advanced thyroid cancer improves resectability and decreases the morbidity of required surgical procedures. However, treatment is not uniformly effective.

Genetic landscape of 482 thyroid carcinomas: analysis with the national datacenter for cancer genomic medicine in Japan

PURPOSE

Comprehensive genomic profiling is useful for patients with Thyroid carcinoma (TC) for whom standard treatment has become refractory. We analyzed the clinical and genomic characteristics of patients with TC using the Japanese nationwide Center for Cancer Genomics and Advanced Therapeutics (C-CAT) database.

METHODS

This retrospective observational study used the data obtained from the C-CAT database. Genomic information has been accumulated on representative gene mutations associated with TC.

RESULTS

Among the 482 patients, 212 (44%) were male and 270 (56%) were female. According to histological type, 259 (54%), 46 (10%), 16 (3%), 51 (11%), and 110 (23%) patients had papillary TC (PTC), follicular TC, medullary TC, poorly differentiated TC, and anaplastic TC (ATC), respectively. Among the genomic profiling tests, FoundationOne CDx (n = 388; 80%) was the most frequently performed. The frequencies of BRAF, NRAS, HRAS, KRAS, and RET mutations were 259 (54%), 62 (13%), 13 (3%), 16 (3%), and 12 (2%), respectively. The BRAF V600E mutation (n = 257) was the predominant BRAF mutation. TERT promoter mutations, which are associated with tumor aggressiveness, were detected in 308 patients (64%).

CONCLUSIONS

PTC was the most common histologic type of TC for which genetic profiling was performed in Japan, followed by ATC. Since the most common targetable mutation is the BRAF mutation, practical application of BRAF-targeted therapy can be an important treatment option for Japanese patients with TC.

Thyroid Cancer: A Review

Importance

Approximately 43 720 new cases of thyroid carcinoma are expected to be diagnosed in 2023 in the US. Five-year relative survival is approximately 98.5%. This review summarizes current evidence regarding pathophysiology, diagnosis, and management of early-stage and advanced thyroid cancer.

Observations

Papillary thyroid cancer accounts for approximately 84% of all thyroid cancers. Papillary, follicular (≈4%), and oncocytic (≈2%) forms arise from thyroid follicular cells and are termed well-differentiated thyroid cancer. Aggressive forms of follicular cell-derived thyroid cancer are poorly differentiated thyroid cancer (≈5%) and anaplastic thyroid cancer (≈1%). Medullary thyroid cancer (≈4%) arises from parafollicular C cells. Most cases of well-differentiated thyroid cancer are asymptomatic and detected during physical examination or incidentally found on diagnostic imaging studies. For microcarcinomas (≤1 cm), observation without surgical resection can be considered. For tumors larger than 1 cm with or without lymph node metastases, surgery with or without radioactive iodine is curative in most cases. Surgical resection is the preferred approach for patients with recurrent locoregional disease. For metastatic disease, surgical resection or stereotactic body irradiation is favored over systemic therapy (eg, lenvatinib, dabrafenib). Antiangiogenic multikinase inhibitors (eg, sorafenib, lenvatinib, cabozantinib) are approved for thyroid cancer that does not respond to radioactive iodine, with response rates 12% to 65%. Targeted therapies such as dabrafenib and selpercatinib are directed to genetic mutations (BRAF, RET, NTRK, MEK) that give rise to thyroid cancer and are used in patients with advanced thyroid carcinoma.

Conclusions

Approximately 44 000 new cases of thyroid cancer are diagnosed each year in the US, with a 5-year relative survival of 98.5%. Surgery is curative in most cases of well-differentiated thyroid cancer. Radioactive iodine treatment after surgery improves overall survival in patients at high risk of recurrence. Antiangiogenic multikinase inhibitors and targeted therapies to genetic mutations that give rise to thyroid cancer are increasingly used in the treatment of metastatic disease.

Tyrosine Kinase Inhibitors for Radioactive Iodine Refractory Differentiated Thyroid Cancer

Patients with differentiated thyroid cancer usually present with early-stage disease and undergo surgery followed by adjuvant radioactive iodine ablation, resulting in excellent clinical outcomes and prognosis. However, a minority of patients relapse with metastatic disease, and eventually develop radioactive iodine refractory disease (RAIR). In the past there were limited and ineffective options for systemic therapy for RAIR, but over the last ten to fifteen years the emergence of tyrosine kinase inhibitors (TKIs) has provided important new avenues of treatment for these patients, that are the focus of this review. Currently, Lenvatinib and Sorafenib, multitargeted TKIs, represent the standard first-line systemic treatment options for RAIR thyroid carcinoma, while Cabozantinib is the standard second-line treatment option. Furthermore, targeted therapies for patients with specific targetable molecular abnormalities include Latrectinib or Entrectinib for patients with NTRK gene fusions and Selpercatinib or Pralsetinib for patients with RET gene fusions. Dabrafenib plus Trametinib currently only have tumor agnostic approval in the USA for patients with BRAF V600E mutations, including thyroid cancer. Redifferentiation therapy is an area of active research, with promising initial results, while immunotherapy studies with checkpoint inhibitors in combination with tyrosine kinase inhibitors are underway.

Anlotinib in Locally Advanced or Metastatic Radioiodine-Refractory Differentiated Thyroid Carcinoma: A Randomized, Double-Blind, Multicenter Phase II Trial

PURPOSE

Alhough antiangiogenic agents are the bedrock of treatment for radioiodine-refractory differentiated thyroid carcinoma (RAIR-DTC), novel antiangiogenic agents with optimized features like greater target-binding affinities and more favorable pharmacokinetics profile are needed. This phase II randomized, double-blind, placebo-controlled trial investigated the efficacy and safety of anlotinib, a multikinase inhibitor, for RAIR-DTC.

PATIENTS AND METHODS

Patients (ages between 18 and 70 years) with pathologically confirmed locally advanced or metastatic RAIR-DTC were enrolled and randomly received 12 mg anlotinib once daily or placebo on day 1 to 14 every 3 weeks. Patients on placebo were allowed to receive open-label anlotinib after disease progression. The primary endpoint was progression-free survival (PFS). The secondary endpoints included overall survival (OS) and safety.

RESULTS

Between September 2015 and August 2018, 76 and 37 patients randomly received anlotinib and placebo, respectively. Patients receiving anlotinib had a significantly longer median PFS [40.5 months, 95% confidence interval (CI), 28.3-not estimable (NE) versus placebo 8.4 months, 95% CI, 5.6-13.8; HR = 0.21, 95% CI, 0.12-0.37, P < 0.001], meeting the primary endpoint. OS was still immature, with a trend of benefit with anlotinib (HR = 0.57, 95% CI, 0.29-1.12). All patients in the anlotinib group experienced adverse events (AE); 8 (10.5%) discontinued treatment due to AEs.

CONCLUSIONS

Anlotinib demonstrated promising efficacy and favorable tolerance in the treatment of locally advanced or metastatic RAIR-DTC, supporting further research to establish its role in the treatment of this serious disease.

Outcome of initial lenvatinib treatment in patients with unresectable anaplastic thyroid cancer

Anaplastic thyroid cancer (ATC) is a very rare disease with a poor prognosis and with no established effective drug therapy. The present study aimed to report the outcomes of lenvatinib single-agent therapy as an initial drug treatment in ATC, and to investigate its safety and efficacy. This retrospective cohort study included 56 patients with unresectable primary ATC, of whom 36 were treated with lenvatinib and 12 with weekly paclitaxel, and 8 patients who refused any drug treatment who received palliative care. The average survival in the lenvatinib group was 5.8 months, which was significantly longer than 2.0 months in the paclitaxel group (P=0.005). The efficacy of lenvatinib in the 36 patients with ATC, whose primary tumors were unresectable, was evaluated. The response rate was 33% and the median overall survival time was 5.0 months. A safety review indicated that lenvatinib should be used under the careful observation of local findings. Two patients, who showed a reduction with lenvatinib, underwent conversion surgery, which prolonged the prognosis in terms of avoiding events, such as asphyxia, fistula and hemorrhage due to tumor growth; however, the surgical margins were positive, indicating that complete remission was impossible even if surgical resection was performed. Therefore, starting with lenvatinib treatment and identifying a therapeutic drug based on genomic analysis is an acceptable treatment strategy for ATC while halting the disease progression.

Lenvatinib resistance mechanism and potential ways to conquer

Lenvatinib (LVN) has been appoved to treat advanced renal cell carcinoma, differentiated thyroid carcinoma, hepatocellular carcinoma. Further other cancer types also have been tried in pre-clinic and clinic without approvation by FDA. The extensive use of lenvastinib in clinical practice is sufficient to illustrate its important therapeutic role. Although the drug resistance has not arised largely in clinical, the studies focusing on the resistance of LVN increasingly. In order to keep up with the latest progress of resistance caused by LVN, we summerized the latest studies from identify published reports. In this review, we found the latest report about resistance caused by lenvatinib, which were contained the hotspot mechanism such as the epithelial-mesenchymal transition, ferroptosis, RNA modification and so on. The potential ways to conquer the resistance of LVN were embraced by nanotechnology, CRISPR technology and traditional combined strategy. The latest literature review of LVN caused resistance would bring some ways for further study of LVN. We call for more attention to the pharmacological parameters of LVN in clinic, which was rarely and would supply key elements for drug itself in human beings and help to find the resistance target or idea for further study.

Prognostic value of neutrophil-to-lymphocyte ratio in colorectal cancer liver metastasis: A meta-analysis of results from multivariate analysis

We aimed to evaluate the prognostic value of the neutrophil-to-lymphocyte ratio (NLR) in colorectal cancer liver metastasis (CRLM). A comprehensive search was conducted across PubMed, MedLine, and the Cochrane Library databases for articles published from January 1, 2000 to April 30, 2022 that investigated the long-term prognostic value of NLR in CRLM; only studies with multivariate analyses were enrolled. Hazard ratio (HR) with 95% confidence interval (CI) was used to determine the effect size. A total of 2,522 patients in 12 studies were selected; the meta-analysis demonstrated that elevated NLR correlated with poor overall survival (OS) and disease-free survival (DFS) (HR, 1.95, 95%CI, 1.698-2.223, P < 0.01; HR, 1.80, 95%CI, 1.363-2.363, P < 0.01; respectively). The 5-year OS and disease-free survival rates were higher in the patients with normal NLR than in patients with high NLR (47% vs. 27%, P < 0.01; 37% vs. 6%, P < 0.01, respectively). Further analysis of clinicopathological parameters indicated no significant difference between the patients with and without elevated NLR. Begg's and Egger's tests for publication bias revealed no significant publication bias (P = 0.891 and P = 0.926, respectively). Multivariate analysis revealed that NLR had an excellent prognostic ability in CRLM, which can be used in deciding the treatment and predicting the clinical outcomes. Further multicenter randomized controlled trials are required to verify this conclusion.

Management of Progressive Radioiodine-Refractory Thyroid Carcinoma: Current Perspective

Patients with thyroid cancer (TC) usually have an excellent prognosis; however, 5-10% of them develop an advanced disease. The prognosis of this subgroup is still favourable if the lesions respond to radioactive iodine (RAI) treatment. Nearly two-thirds of advanced TC patients become RAI-refractory (RAI-R), and their management is challenging. A multidisciplinary approach in the context of a tumour board is essential to define a personalized strategy. Systemic therapy is not always the best option. In case of slow neoplastic growth and low tumour burden, active surveillance may represent a valuable choice. Local approaches might be considered if the disease progression is limited to a single or few lesions, also in combination and during systemic therapy. Antiresorptive treatment may be started in presence of bone metastases. In case of rapid and/or symptomatic progression involving multiple lesions and/or organs, systemic therapy has to be considered, in absence of contraindications. The multi-kinase inhibitors (MKIs) lenvatinib and sorafenib are currently available as first-line treatment for advanced progressive RAI-R TC. Among second-line options, cabozantinib has been recently approved in RAI-R TC who progressed during MKIs targeting the vascular endothelial growth factor receptor (VEGFR). In the last few years, next-generation sequencing (NGS) assays have been increasingly employed, permitting identification of the genetic alterations harboured by TC, with a significant impact on patients' management. Novel selective targeted therapies have been introduced for the treatment of RAI-R TC in selected cases: REarranged during Transfection (RET) inhibitors (selpercatinib and pralsetinib) and Tropomyosin Receptor Kinase (TRK) inhibitors (larotrectinib and entrectinib) have recently expanded the panorama of the therapeutic options. Moreover, immune checkpoint inhibitors (ICIs) have shown promising results, and they are still under investigation.

Aggressive variants of follicular cell-derived thyroid carcinoma: an overview

PURPOSE

The incidence of thyroid carcinoma has increased globally in the past years. Papillary thyroid carcinoma (PTC) is the most frequent neoplasm of the thyroid gland comprehending the 90% of the thyroid carcinoma and has an indolent clinical behaviour. However, some variants of follicular cell-derived thyroid carcinoma, including variants of classic of PTC, have been identified that show a more aggressive biological behaviour. An accurate diagnosis of these entities is crucial for planning a more aggressive treatment and improving patients' prognosis of patients. The aim of this review is to present the main clinical, histological, and molecular features of aggressive variants of follicular cell-derived thyroid carcinoma, and to provide useful histological parameters for determining the most suitable therapeutic strategy for patients affected by these forms.

RESULTS

Variants of classic PTC such as the diffuse sclerosing variant (DSV), the tall cell variant (TCV), the columnar cell variant (CCV), the solid/trabecular variant (STV) and the hobnail variant (HV), and other variants of follicular cell-derived thyroid carcinoma, such as poorly differentiated thyroid carcinoma (PDTC), and anaplastic thyroid carcinoma (ATC), are associated with aggressive behaviour.

CONCLUSIONS

The correct identification and diagnosis of aggressive variants of follicular cell-derived thyroid carcinoma is important, as they allow the clinician to adopt the most refined therapeutic strategies in order to the survival of the patients.