Low-Risk Papillary Thyroid Cancer: Treatment De-Escalation and Cost Implications

METTL3-mediated m6A modification of MT1G inhibits papillary thyroid carcinoma cell growth and metastasis via Wnt/β-catenin pathway

BACKGROUND

Downregulation of metallothionein 1 G (MT1G) has been demonstrated in papillary thyroid carcinoma (PTC) tissues. However, the underlying molecular mechanisms of MT1G in PTC progression need to be further explored.

METHODS

MT1G and methyltransferase-like 3 (METTL3) mRNA levels were tested by quantitative real-time PCR. The protein levels of MT1G, METTL3, Wnt3A and β-catenin were measured by western blot. Cell proliferation, apoptosis, invasion and migration were measured by cell counting kit 8 assay, colony formation assay, EdU assay, flow cytometry, transwell assay and wound healing assay. MeRIP analysis was used to detect the MT1G methylation. The interaction between METTL3 and MT1G was evaluated using RIP assay and dual-luciferase reporter assay. A mouse xenograft model was also constructed to explore the roles of METTL3 and MT1G in vivo.

RESULTS

MT1G expression was downregulated in PTC, and its overexpression suppressed PTC cell growth, invasion and migration. METTL3-regulated m6A modification enhanced MT1G mRNA stability. Overexpression of METTL3 repressed PTC cell growth and metastasis, and this effect was reversed by MT1G knockdown. Besides, METTL3/MT1G axis could inhibit the activity of Wnt/β-catenin pathway. Meanwhile, METTL3 enhanced MT1G expression to suppress PTC tumor growth through Wnt/β-catenin pathway in vivo.

CONCLUSION

METTL3-mediated m6A modification of MT1G inhibited PTC cell growth and metastasis via inactivating the Wnt/β-catenin pathway.

Thyroid Cancer Staging: Historical Evolution and Analysis From Macrocarcinoma to Microcarcinoma

The classification of thyroid cancer diagnosis and treatment has evolved dramatically since the Union for International Cancer Control (UICC) published the first staging system in 1968. A careful review of the eight published editions of well-differentiated thyroid cancer (WDTC) staging by the UICC and the American Joint Committee on Cancer (AJCC) was performed. Each edition was analyzed to clearly understand which development published and accepted by specialists treating thyroid cancer justified considering a new updated edition. This study presents a comprehensive review of the remarkable evolution of thyroid cancer staging, highlighting the various changes in several areas throughout the years and editions. There were surprising changes within the eight publications: the tumor size was progressively reduced from 4 cm in the first AJCC volume to less than 1 cm in the seventh and eighth UICC and AJCC editions, classifying these small, WDTCs known up to now as "microcarcinomas." Extrathyroidal extension was accepted after the third edition; this description certainly plays a key role in today's decisions to manage this tumor as a prognostic factor. The age specification of 45 years prevailed for seven consecutive publications until it was raised to 55 years in the eighth thyroid cancer staging system. Without a doubt, this iconic change allowed physicians around the world to give their 45-year-old thyroid cancer patients a more encouraging panorama of the disease with the new classification. Over the course of nearly 57 years, thyroid cancer staging has undergone remarkable changes, reaching a level of certainty that not only provides recommendations for safer treatments with less surgery and adjunctive measures but also improves survival rates and patient safety.

A comprehensive analysis and comparative study of the trends in thyroid cancer burden in China and globally from 1990 to 2021, with projections for the next 15 Years

Objective

This study aims to analyze the trends in incidence, prevalence, mortality, and disability-adjusted life years (DALYs) of thyroid cancer across gender and age groups in China and globally from 1990 to 2021, using data from the Global Burden of Disease (GBD) database. Additionally, it projects the trends in thyroid cancer burden for the next 15 years for both China and the global population.

Materials and methods

Thyroid cancer-related data were extracted from the 2021 GBD dataset. The average annual percentage change (AAPC) and the corresponding 95% confidence intervals (95% CI) were calculated using Joinpoint regression to reflect trends in the thyroid cancer burden. R software was used to perform a gender- and age-specific analysis and visualize the trends in thyroid cancer burden for both China and the global population. Furthermore, the Autoregressive Integrated Moving Average (ARIMA) model was employed to project the trends in thyroid cancer burden over the next 15 years.

Results

The results indicate a rising trend in the incidence and prevalence of thyroid cancer both in China and globally. Conversely, the mortality rate and DALYs show a declining trend over the same period. Age-specific analysis revealed that thyroid cancer is most prevalent among individuals aged 50-64. Gender-specific analysis indicated that the incidence rate is higher in females than in males. Projections for the next 15 years show that the age-standardized incidence rates for both males and females are expected to continue rising in China and globally. While the age-standardized mortality rate for females is projected to decline significantly, the mortality rate for males is predicted to stabilize.

Conclusion

Between 1990 and 2021, the number of thyroid cancer cases has increased both in China and globally, while the mortality rate has shown a marked decline. This trend is expected to persist over the next 15 years. The growing population affected by thyroid cancer reflects a substantial disease burden, making thyroid cancer a significant global public health concern. The formulation of proactive and effective health policies is urgently needed.

Revisiting the Relationship Between Tumor Size and Risk in Well-Differentiated Thyroid Cancer

Introduction: Large tumor size is associated with poorer outcomes in well-differentiated thyroid cancer, yet it remains unclear whether size >4 cm alone confers increased risk, independent of other markers of aggressive disease. The goal of this study was to assess the relationship between tumor size, other high-risk histopathological features, and survival in well-differentiated thyroid cancer and to evaluate the significance of 4 cm as a cutoff for management decisions. Methods: Patients with well-differentiated thyroid cancer were identified from the National Cancer Database (2010-2015) and categorized by tumor size (i.e., small [≤4 cm] or large [>4 cm]) and presence of high-risk histopathological features (e.g., extrathyroidal extension). First, propensity score matching was used to identify patients who were similar across all other observed characteristics except for small versus large tumor size, and a multivariable Cox proportional hazards model was used to estimate the relationship between tumor size and survival. Second, we assessed whether the presence of high-risk features demonstrates conditional effects on survival based on the presence of tumor size >4 cm using an interaction term. Finally, additional models assessed the relationship between incremental 1 cm increases in tumor size and survival. Analyses were repeated using a validation cohort from the Surveillance, Epidemiology, and End Results Program (2008-2013). Results: Of 193,133 patients in the primary cohort, 7.9% had tumors >4 cm, and 30% had at least one high-risk feature. After matching, tumor size >4 cm was independently associated with worse survival (HR 1.63, p < 0.001). However, tumor size >4 cm and one or more other high-risk features together yielded worse survival than either size >4 cm alone (MMD: 0.70, p < 0.001) or other high-risk features alone (MMD: 0.49, p < 0.001). When assessed in 1 cm increments, the largest increases in hazard of death occurred at 2 cm and 5 cm, not 4 cm. Results from the validation cohort were largely consistent with our primary findings. Conclusions: Concomitant high-risk features confer worse survival than large tumor size alone, and a 4 cm cutoff is not associated with the greatest increase in risk. These findings support a more nuanced approach to tumor size in the management of well-differentiated thyroid cancer.

Which Ultrasound Characteristics Predict Lymphatic Spread of Papillary Thyroid Cancer?

INTRODUCTION

The 2015 American Thyroid Association guidelines recommend lymph node mapping US in patients with definitive cytological evidence of thyroid cancer. Suspicious lymph node features on imaging including enlarged size (>1 cm in any dimension), architectural distortion, loss of fatty hilum, and microcalcifications often prompt evaluation with fine needle aspiration. There is no universally agreed upon model for determining which ultrasound characteristics most strongly correlate with metastatic disease.

METHODS

A retrospective review of patients with confirmed papillary thyroid cancer (PTC) undergoing lymph node mapping ultrasound from 2013 to 2019 was performed. Sensitivity, specificity, positive predictive value (PPV), and negative predictive value were calculated for each individual ultrasound characteristic as well as for characteristic combinations.

RESULTS

Data from 119 lymph nodes were included. Malignant lymph nodes were more likely to be enlarged (71% versus 61%, P < 0.001) and to have each individual suspicious feature. Loss of fatty hilum had the highest sensitivity (89%) but was not specific (19%) for metastatic disease. Architectural distortion was found to have the highest specificity (87%). A combination of the four features was found to have higher specificity (97%) and PPV (88%) than any individual feature or combination of two/three features.

CONCLUSIONS

A combination of four sonographic features correlates with metastatic PTC to lymph nodes and has the highest specificity and PPV for malignancy. A risk stratification model based on these features may lead to better classification of ultrasound findings in PTC patients with concern for nodal metastases.

Could Oxidative Stress Play a Role in the Development and Clinical Management of Differentiated Thyroid Cancer?

Increased oxidative stress (OS) has been implicated as a relevant risk factor for cancer progression. Furthermore, patients diagnosed with differentiated thyroid cancer (DTC) have been characterized by an increased OS status. Therefore, assessing OS status could potentially be considered a useful tool in DTC clinical management. This measurement could be particularly valuable in personalizing treatment protocols and determining new potential medical targets to improve commonly used therapies. A literature review was conducted to gather new information on DTC clinical management, with a particular focus on evaluating the clinical utility of OS. These meta-analyses concentrate on novel approaches that employ the measurement of oxidative-antioxidant status, which could represent the most promising area for implementing clinical management.

American Thyroid Association Guidelines and National Trends in Management of Papillary Thyroid Carcinoma

Importance

Over time, the American Thyroid Association (ATA) guidelines have increasingly promoted more limited treatments for well-differentiated thyroid cancers.

Objective

To determine whether the 2009 and 2015 ATA guidelines were associated with changes in the management of low-risk papillary thyroid carcinomas on a national scale.

Design, Setting, and Participants

This historical cohort study used the National Cancer Database. All papillary thyroid carcinomas diagnosed from 2004 to 2019 in the National Cancer Database were selected. Patients with tumors of greater than 4 cm, metastases, or clinical evidence of nodal disease were excluded. Data were analyzed from August 1, 2021, to September 1, 2022.

Main Outcomes and Measures

The primary aim was to tabulate changes in the rates of thyroid lobectomy (TL), total thyroidectomy (TT), and TT plus radioactive iodine (RAI) therapy after the 2009 and 2015 ATA guidelines. The secondary aim was to determine in which settings (eg, academic vs community) the practice patterns changed the most.

Results

A total of 194 254 patients (155 796 [80.2%] female patients; median [range] age at diagnosis, 51 [18-90] years) who underwent treatment during the study period were identified. Among patients who underwent surgery, rates of TL decreased from 15.1% to 13.7% after the 2009 guidelines but subsequently increased to 22.9% after the 2015 changes. Among patients undergoing TT, rates of adjuvant RAI decreased from 48.7% to 37.1% after 2009 and to 19.3% after the 2015 guidelines. Trends were similar for subgroups based on sex and race and ethnicity. However, academic institutions saw larger increases in TL rates (14.9% to 25.7%) than community hospitals (16.3% to 19.5%). Additionally, greater increases in TL rates were observed for tumors 1 to 2 cm (6.8% to 18.9%) and 2 to 4 cm (6.6% to 16.0%) than tumors less than 1 cm (22.8% to 29.2%).

Conclusions and Relevance

In this cohort study among patients with papillary thyroid carcinomas up to 4 cm, ATA guideline changes corresponded with increased TL and reduced adjuvant RAI. These changes were primarily seen in academic institutions, suggesting an opportunity to expand guideline-based care in the community setting.

The high degree of similarity in histopathological and clinical characteristics between radiogenic and sporadic papillary thyroid microcarcinomas in young patients

The potential overtreatment of patients with papillary thyroid microcarcinoma (MPTC) has been an important clinical problem in endocrine oncology over the past decade. At the same time, current clinical guidelines tend to consider prior radiation exposure as a contraindication to less extensive surgery, even for low-risk thyroid carcinomas, which primarily include microcarcinomas. This study aims to determine whether there are differences in the behavior of MPTC of two etiological forms (radiogenic and sporadic), including invasive properties, clinical data, and recurrence in patients aged up to 30 years. For this purpose, 136 radiogenic (from patients aged up to 18 years at the time of the Chornobyl accident) and 83 sporadic (from patients born after the Chornobyl accident) MPTCs were selected and compared using univariate and multivariate statistical methods in a whole group and in age and tumor size subgroups. No evidence of more aggressive clinical and histopathological behavior of radiogenic MPTCs as compared to sporadic tumors for basic structural, invasive characteristics, treatment options, and postoperative follow-up results was found. Moreover, radiogenic MPTCs were characterized by the lower frequencies of oncocytic changes (OR = 0.392, p = 0.004), nodal disease (OR = 0.509, p = 0.050), and more frequent complete remission (excellent response) after radioiodine therapy (OR = 9.174, p = 0.008). These results strongly suggest that internal irradiation does not affect tumor phenotype, does not associate with more pronounced invasive properties, and does not worsen prognosis in pediatric or young adult patients with MPTC, implying that radiation history may be not a pivotal factor for determining treatment strategy in such patients.