18F-FDG-PET/CT in Patients with Advanced, Radioiodine Refractory Thyroid Cancer Treated with Lenvatinib

Association of 18F- fluorodeoxyglucose uptake with the expression of metabolism-related molecules in papillary thyroid cancer

OBJECTIVES

18F-fluorodeoxyglucose positron emission tomography-computed tomography (18F-FDG-PET/CT) is a diagnostic imaging method that is based on the Warburg effect, which is the increased uptake of glucose through aerobic glycolysis in cancer cells. The diagnostic value of 18F-FDG-PET/CT for thyroid cancer is controversial. However, uptake of 18F-FDG and the corresponding maximum standardized uptake value (SUVmax) is expected to reflect the metabolic status of cancer cells. In the present study, we sought to determine the relationship between 18F-FDG uptake and tumor metabolism- associated factors.

METHODS

This was a single-center retrospective study. In the present study, SUVmax was compared with the expression of hexokinase 2 (HK2), glucose transporter 1 (GLUT1), vascular endothelial growth factor (VEGF), and glutaminase 1 (GLS1) in 41 patients with thyroid cancer.

RESULTS

GLS1 expression was found to be moderately correlated with SUVmax (p < 0.001, r = 0.51), whereas HK2 and VEGF expression were weakly correlated (p = 0.011, r = 0.28, p = 0.008, r = 0.29, respectively) and GLUT1 did not correlate with SUVmax (p = 0.62, r = 0.06).

CONCLUSION

Our findings suggest 18F-FDG PET/CT reflects GLS1 expression in thyroid cancer and could be used to select suitable candidates for GLS1 inhibitor treatment.

Early Structural, Biochemical, and Metabolic Responses to Anlotinib in Patients With Progressive Radioactive Iodine Refractory Differentiated Thyroid Cancer

OBJECTIVE

We aimed to assess the early efficacy of anlotinib in patients with progressive radioactive iodine refractory differentiated thyroid cancer at the structural, biochemical, and metabolic levels.

METHODS

Ten eligible patients were prospectively enrolled to receive anlotinib. Their responses were assessed at 6 weeks. Apart from the structural response according to Response Evaluation Criteria in Solid Tumors version 1.1, the biochemical response was assessed by serum thyroglobulin (Tg), and the metabolic response was assessed by 2-deoxy-2-[18F] fluoro-D-glucose positron emission tomography/computed tomography (18F-FDG PET/CT) according to the European Organization for Research and Treatment of Cancer criteria. A safety profile was recorded.

RESULTS

Structurally controlled disease (20% partial response + 80% stable disease) was observed in all patients. The median longest diameter of target lesions shrank from 20.8 mm (IQR, 14.9-27.5) to 17.0 mm (IQR, 14.1-23.7) (P < .001), and the average shrinkage rate was -15.1 ± 14.1%. Sharp serum Tg reduction by 72.8 ± 16.4% was observed in 8 measurable patients. The 18F-FDG PET/CT-mapped glucose metabolic response was not quite comparable to the structural response, with 90% of the patients having controlled disease (30% partial metabolic response + 60% stable metabolic disease), whereas 10% presented progressive metabolic disease. The most common treatment-emergent adverse events (AEs) were hypertension (100%) and proteinuria (70%). Most AEs were grade 1 or 2, whereas grade 3 AEs occurred only in hypertension.

CONCLUSION

Anlotinib is generally well tolerated and can bring early disease control within the initial 6 weeks of treatment. The sharp biochemical response suggests Tg to be an early sensitive biomarker to anlotinib, whereas the heterogeneous metabolic response might play a complementary role.

Positron Emission Tomography/Computed Tomography in Thyroid Cancer: An Updated Review

PET/computed tomography (CT) is a valuable hybrid imaging modality for the evaluation of thyroid cancer, potentially impacting management decisions. 18F-fluorodeoxyglucose (FDG) PET/CT has proven utility for recurrence evaluation in differentiated thyroid cancer (DTC) patients having thyroglobulin elevation with negative iodine scintigraphy. Aggressive histologic subtypes such as anaplastic thyroid cancer shower higher FDG uptake. 18F-FDOPA is the preferred PET tracer for medullary thyroid cancer. Fibroblast activation protein inhibitor and arginylglycylaspartic acid -based radiotracers have emerged as promising PET agents for radioiodine refractory DTC patients with the potential for theranostic application.

Natural History and Prognostic Model of Untreated Papillary Thyroid Cancer: A SEER Database Analysis

PURPOSE

This investigation leveraged the SEER database to delve into the progression patterns of PTC when left untreated. Furthermore, it aimed to devise and authenticate a nomogram for prognosis prediction for such patients.

METHODS

We extracted data from the SEER database, focusing on PTC-diagnosed individuals from 2004-2020. To discern disease progression intervals, median survival times across stages were gauged, and the disease progression time was estimated by subtracting the median survival time of a more severe stage from its preceding stage. Prognostic determinants in the training set were pinpointed using both univariate and multivariate Cox regression. Using these determinants, a prognostic nomogram was crafted.

RESULTS

In untreated PTC patients, those in stages I and II had a favorable prognosis, with 10-year overall survival rates of 86.34% and 66.03%, respectively. Patients in stages III and IV had a relatively poorer prognosis. The median survival time of stage III, stage IVA, stage IVB and stage IVC patients was 108months, 43 months, 20 months and 8 months, respectively. The deduced progression intervals from stages III-IVC were 65, 23, and 12 months. In the training set, age, tumor stage, gender, and marital status were identified as independent risk factors influencing the prognosis of untreated PTC, and a nomogram was constructed using these variables.

CONCLUSION

In the absence of treatment intervention, early-stage PTC progressed slowly with an overall favorable prognosis. However, in mid to advanced-stage PTC, as tumor stage increased, disease progression accelerated, and prognosis gradually worsened. Age, tumor stage, marital status, and gender were independent risk factors influencing the prognosis of untreated PTC, and the nomogram based on these factors demonstrated good prognostic capability.

Early Reduction of Glucose Consumption Is a Biomarker of Kinase Inhibitor Efficacy Which Can Be Reversed with GLUT1 Overexpression in Lung Cancer Cells

PURPOSE

Small molecule inhibitors that target oncogenic driver kinases are an important class of therapies for non-small cell lung cancer (NSCLC) and other malignancies. However, these therapies are not without their challenges. Each inhibitor works on only a subset of patients, the pharmacokinetics of these inhibitors is variable, and these inhibitors are associated with significant side effects. Many of these inhibitors lack non-invasive biomarkers to confirm pharmacodynamic efficacy, and our understanding of how these inhibitors block cancer cell growth remains incomplete. Limited clinical studies suggest that early (< 2 weeks after start of therapy) changes in tumor glucose consumption, measured by [18F]FDG PET imaging, can predict therapeutic efficacy, but the scope of this strategy and functional relevance of this inhibition of glucose consumption remains understudied. Here we demonstrate that early inhibition of glucose consumption as can be measured clinically with [18F]FDG PET is a consistent phenotype of efficacious targeted kinase inhibitors and is necessary for the subsequent inhibition of growth across models of NSCLC.

METHODS

We tested nine NSCLC cell lines (A549, H1129, H1734, H1993, H2228, H3122, H460, HCC827, and PC9 cells) and ten targeted therapies (afatinib, buparlisib, ceritinib, cabozantinib, crizotinib, dovitinib, erlotinib, ponatinib, trametinib, and vemurafenib) across concentrations ranging from 1.6 nM to 5 µM to evaluate whether these inhibitors block glucose consumption at 24-h post-drug treatment and cell growth at 72-h post-drug treatment. We overexpressed the facilitative glucose transporter SLC2A1 (GLUT1) to test the functional connection between blocked glucose consumption and cell growth after treatment with a kinase inhibitor. A subset of these inhibitors and cell lines were studied in vivo.

RESULTS

Across the nine NSCLC cell lines, ten targeted therapies, and a range of inhibitor concentrations, whether a kinase inhibitor blocked glucose consumption at 24-h post-drug treatment strongly correlated with whether that inhibitor blocked cell growth at 72-h post-drug treatment in cell culture. These results were confirmed in vivo with [18F]FDG PET imaging. GLUT1 overexpression blocked the kinase inhibitors from limiting glucose consumption and cell growth.

CONCLUSIONS

Our results demonstrate that the early inhibition of lung cancer glucose consumption in response to a kinase inhibitor is a strong biomarker of and is often required for the subsequent inhibition of cell growth. Early inhibition of glucose consumption may provide complementary information to other biomarkers in determining whether a drug will effectively limit tumor growth.

Effect of the m6ARNA gene on the prognosis of thyroid cancer, immune infiltration, and promising immunotherapy

BACKGROUND

Accumulating evidence suggests that N6-methyladenosine (m6A) RNA methylation plays an important role in tumor proliferation and growth. However, its effect on the clinical prognosis, immune infiltration, and immunotherapy response of thyroid cancer patients has not been investigated in detail.

METHODS

Clinical data and RNA expression profiles of thyroid cancer were extracted from the Cancer Genome Atlas-thyroid carcinoma (TCGA-THCA) and preprocessed for consensus clustering. The risk model was constructed based on differentially expressed genes (DEGs) using Least Absolute Shrinkage and Selection Operator (LASSO) and Cox regression analyses. The associations between risk score and clinical traits, immune infiltration, Gene Ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG), Gene Set Enrichment Analysis (GSEA), immune infiltration, and immunotherapy were assessed. Immunohistochemistry was used to substantiate the clinical traits of our samples.

RESULTS

Gene expression analysis showed that 17 genes, except YHTDF2, had significant differences (vs healthy control, P<0.001). Consensus clustering yielded 2 clusters according to their clinical features and estimated a poorer prognosis for Cluster 1 (P=0.03). The heatmap between the 2 clusters showed differences in T (P<0.01), N (P<0.001) and stage (P<0.01). Based on univariate Cox and LASSO regression, a risk model consisting of three high-risk genes (KIAA1429, RBM15, FTO) was established, and the expression difference between normal and tumor tissues of three genes was confirmed by immunohistochemical results of our clinical tissues. KEGG and GSEA analyses showed that the risk DEGs were related mainly to proteolysis, immune response, and cancer pathways. The levels of immune infiltration in the high- and low-risk groups were different mainly in iDCs (P<0.05), NK cells (P<0.05), and type-INF-II (P<0.001). Immunotherapy analysis yielded 30 drugs associated with the expression of each gene and 20 drugs associated with the risk score.

CONCLUSIONS

Our risk model can act as an independent marker for thyroid cancer and provides promising immunotherapy targets for its treatment.

Advanced imaging and theranostics in thyroid cancer

PURPOSE OF REVIEW

Thyroid cancers are endocrine neoplasms with diverse gene expression and behavior, for which constantly evolving anatomic and functional imaging/theranostic agents have an essential role for diagnosis, staging, and treatment.

RECENT FINDINGS

To achieve definitive diagnosis, neck ultrasound and associated risk stratification systems, notably Thyroid Imaging Reporting and Data System (TI-RADS), allow improved thyroid nodule characterization and management guidance. Radioactive iodine-131 (RAI) has long played a role in management of differentiated thyroid cancer (DTC), with recent literature emphasizing its effectiveness for intermediate-high risk cancers, exploring use of dosimetry for personalized medicine, and potential for retreatment with RAI following tumor redifferentiation. Iodine-124 positron emission tomography/computed tomography (PET/CT) has promising application for DTC staging and dosimetry. F18-fluorodeoxyglucose (FDG) PET/CT is used for staging of high risk DTC and identification of noniodine-avid disease recurrences, with metabolic uptake consistently portending poor prognosis. Poorly differentiated and anaplastic thyroid cancers are best assessed with anatomic imaging and F18-FDG PET/ CT, though recent studies show a potential theranostic role for Ga68/Lu177-prostate-specific membrane antigen. Medullary thyroid cancers are evaluated with ultrasound, CT, magnetic resonance imaging, and various positron-emitting radiotracers for PET imaging (F18-DOPA, F18-FDG, and recently Ga68-1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid (DOTA)-octreotate (DOTATATE)); the latter may enable treatment with Lu177-DOTATATE.

SUMMARY

Multidisciplinary collaboration is essential to streamline appropriate management, given the wide array of available imaging and new therapies for metabolic and genetically complex cancers.

Assessment of Treatment Response to Lenvatinib in Thyroid Cancer Monitored by F-18 FDG PET/CT Using PERCIST 1.0, Modified PERCIST and EORTC Criteria-Which One Is Most Suitable?

Background: We aimed to compare the established metabolic response criteria PERCIST and EORTC for their applicability and predictive value in terms of clinical response assessment early after the initiation of lenvatinib therapy in patients with metastatic radioiodine-refractory (RAI) thyroid cancer (TC). Methods: In 25 patients treated with lenvatinib, baseline and 4-month follow-up F-18 FDG PET/CT images were analyzed using PERCIST 1.0, modified PERCIST (using SUVpeak or SUVmax) and EORTC criteria. Two groups were defined: disease control (DC) and progressive disease (PD), which were correlated with PFS and OS. Results: PERCIST, mPERCIST, PERCISTmax and EORTC could be applied in 80%, 80%, 88% and 100% of the patients based on the requirements of lesion assessment criteria, respectively. With PERCIST, mPERCIST, PERCISTmax and EORTC, the patients classified as DC and PD ranged from 65 to 68% and from 32 to 35%, respectively. Patients with DC exhibited a longer median PFS than patients with PD for EORTC (p < 0.014) and for PERCIST and mPERCIST (p = 0.037), respectively. Conclusion: EORTC and the different PERCIST criteria performed equally regarding the identification of patients with PD requiring treatment changes. However, the applicability of PERCIST 1.0 using SULpeak seems restricted due to the significant proportion of small tumor lesions.

2-[18F]FDG PET in the Management of Radioiodine Refractory Differentiated Thyroid Cancer in the Era of Thyrosin-Kinases Inhibitors: A Real-Life Retrospective Study

Purpose To evaluate the role of 2-[¹⁸F]FDGPET/CT in the follow-up of radioiodine refractory thyroid cancer (RR-TC). Methods Forty-six 2-[¹⁸F]FDGPET/CT scans from 14 RR-TC patients were considered. Thyroid function tests: thyroglobulin (Tg), levothyroxine (LT4), and tyrosine-kinases inhibitors (TKIs) assumptions were recorded. Metabolic tumour volume (MTV) and total lesion glycolysis (TLG) were calculated from each scan and correlated with clinical parameters and the overall survival (OS). Results Baseline TLG and MTV predicted OS (p = 0.027 and p = 0.035), and negative correlation with OS was also confirmed when the same parameters were measured in follow-up scans (p = 0.015 and p = 0.021). Tg also correlated with the OS; (p = 0.014; p = 0.019 and p = 0.009). However, TLG and MTV were not significantly correlated with Tg levels. MTV and TLG variation in time were reduced during TKI therapy (p = 0.045 and p = 0.013). Conclusions 2-[¹⁸F]FDGPET/CT confirmed its prognostic role at the first assessment and during the follow-up of RR-TC patients. 2-[¹⁸F]FDGPET/CT parameters seem at least partially independent from Tg. TKI therapy resulted in a measurable effect on the variation of 2-[¹⁸F]FDGPET/CT parameters over time.

Risk Stratification Using 18F-FDG PET/CT and Artificial Neural Networks in Head and Neck Cancer Patients Undergoing Radiotherapy

This study retrospectively analyzed the performance of artificial neural networks (ANN) to predict overall survival (OS) or locoregional failure (LRF) in HNSCC patients undergoing radiotherapy, based on 2-[¹⁸F]FDG PET/CT and clinical covariates. We compared predictions relying on three different sets of features, extracted from 230 patients. Specifically, (i) an automated feature selection method independent of expert rating was compared with (ii) clinical variables with proven influence on OS or LRF and (iii) clinical data plus expert-selected SUV metrics. The three sets were given as input to an artificial neural network for outcome prediction, evaluated by Harrell’s concordance index (HCI) and by testing stratification capability. For OS and LRF, the best performance was achieved with expert-based PET-features (0.71 HCI) and clinical variables (0.70 HCI), respectively. For OS stratification, all three feature sets were significant, whereas for LRF only expert-based PET-features successfully classified low vs. high-risk patients. Based on 2-[¹⁸F]FDG PET/CT features, stratification into risk groups using ANN for OS and LRF is possible. Differences in the results for different feature sets confirm the relevance of feature selection, and the key importance of expert knowledge vs. automated selection.

Early Predictive Response to Multi-Tyrosine Kinase Inhibitors in Advanced Refractory Radioactive-Iodine Differentiated Thyroid Cancer: A New Challenge for [18F]FDG PET/CT

Differentiated thyroid cancer (DTC) represents the most common thyroid cancer histotype. Generally, it exhibits a good prognosis after conventional treatments; nevertheless, about 20% of patients can develop a local recurrence and/or distant metastasis. In one-third of advanced DTC, the metastatic lesions lose the ability to take up iodine and become radioactive iodine-refractory (RAI-R) DTC. In this set of patients, the possibility to perform localized treatments should always be taken into consideration before the initiation of systemic therapy. In the last decade, some multi-tyrosine kinase inhibitor (MKI) drugs were approved for advanced DTC, impacting on patient’s survival rate, but at the same time, these therapies have been associated with several adverse events. In this clinical context, the role of 2-deoxy-2-[¹⁸F]fluoro-D-glucose positron emission tomography/computed tomography ([¹⁸F]FDG PET/CT) in the early treatment response to these innovative therapies was investigated, in order to assess the potentiality of this diagnostic tool in the early recognition of non-responders, avoiding unnecessary therapy. Herein, we aimed to present a critical overview about the reliability of [¹⁸F]FDG PET/CT in the early predictive response to MKIs in advanced differentiated thyroid cancer.

Predictors of Response and Survival to Multikinase Inhibitors in Radioiodine Resistant Differentiated Thyroid Cancer

Sorafenib and lenvatinib are the only multikinase inhibitors (MKIs) approved for the treatment of radioactive iodine refractory differentiated thyroid cancer (RR-DTC). Although they have been demonstrated to improve progression free survival and overall response rate, the risk of toxicities is very high, worsening patients’ quality of life. Therefore, predicting MKI treatment outcomes in the setting of RR-DTC is very challenging for optimizing patients’ management. The current review provides an overview of the predictive factors for the response and survival of sorafenib and lenvatinib in RR-DTC. In this setting, a systemic therapy should be considered after conducting a multidisciplinary discussion aimed at evaluating the risk-benefit ratio of the treatment and taking into account several clinical, biochemical, and molecular factors. Age, performance status, and cancer-related symptoms are the most important clinical markers to be considered prior to starting MKI treatment, together with tumor burden. Some tissue and circulating biomarkers have been investigated, those involved in the angiogenic pathways being the most promising. Finally, prospective clinical trials aimed at evaluating predictive markers for therapeutic response are needed for tailoring patient management and allowing more appropriate treatment choices.

Graves disease and metastatic hormonal-active Hürthle cell thyroid cancer: A case report

RATIONALE

A hormone-active metastatic Hürthle cell thyroid carcinoma (HCTC) and Graves disease (GD) present a therapeutic challenge and is rarely reported.

PATIENT CONCERNS

We present a 64-year-old male patient, who had dyspnea and left hip pain lasting 4 months. He had clinical signs of hyperthyroidism and a tumor measuring 9 cm in diameter of the left thyroid lobe, metastatic neck lymph node and metastases in the lungs, mediastinum, and bones.

DIAGNOSIS

Laboratory findings confirmed hyperthyroidism and GD. Fine-needle aspiration biopsy and cytological investigation revealed metastases of HCTC in the skull and in the 8th right rib. A CT examination showed a thyroid tumor, metastatic neck lymph node, metastases in the lungs, mediastinum and in the 8th right rib measuring 20 × 5.6 × 4.5 cm, in the left acetabulum measuring 9 × 9 × 3 cm and parietooccipitally in the skull measuring 5 × 4 × 2 cm. Histology after total thyroidectomy and resection of the 8th right rib confirmed metastatic HCTC.

INTERVENTIONS

The region of the left hip had been irradiated with concomitant doxorubicin 20 mg once weekly. When hyperthyroidism was controlled with thiamazole, a total thyroidectomy was performed. Persistent T3 hyperthyroidism, most likely caused by TSH-R-stimulated T3 production in large metastasis in the 8th right rib, was eliminated by rib resection. Thereafter, the patient was treated with 3 radioactive iodine-131 (RAI) therapies (cumulative dose of 515 mCi). Unfortunately, the tumor rapidly progressed after treatment with RAI and progressed 10 months after therapy with sorafenib.

OUTCOMES

Despite treatment, the disease rapidly progressed and patient died due to distant metastases. He survived for 28 months from diagnosis.

LESSONS

Simultaneous hormone-active HCTC and GD is extremely rare and prognosis is dismal. Concomitant external beam radiotherapy and doxorubicin chemotherapy, followed by RAI therapy, prevented the growth of a large metastasis in the left hip in our patient. However, a large metastasis in the 8th right rib presented an unresolved problem. Treatment with rib resection and RAI did not prevent tumor recurrence. External beam radiotherapy and sorafenib treatment failed to prevent tumor growth.