Prospective multicenter study of thyroiscarcinoma treatment: initial analysis of staging and outcome. National Thyroid Cancer Treatment Cooperative Study Registry Group

Geriatric Importance of Histopathological Parameters Evaluated in Thyroidectomy Specimens: A Single Center Retrospective Analysis

Nowadays, the aging human population exerts a notable influence on the treatment of thyroid diseases. The most appropriate approach for the treatment of benign and malignant thyroid diseases in older adults has not yet been determined. The aim of our study is to evaluate the effect of thyroidectomies in geriatric patients considering age, sex and histopathological parameters and to determine the importance of thyroidectomy as a treatment option in the geriatric population. A total of 910 cases from all age groups were included, for which thyroidectomies were examined and reported. In accordance with the College of American Pathologists Cancer Protocol for thyroid reporting, considering geriatric patients, the rate of Thyroid Follicular Nodular Disease was significantly higher among the tumor types in the benign tumor group (p = 0.033), while Anaplastic Thyroid Carcinoma rate was higher in the malignant tumor group. The diagnosis rate of malignant tumors was higher in males, reflecting a more advanced pT stage (p < 0.001), larger tumor size (p < 0.001) and increased lymph node involvement rate (p = 0.039). Given that increasing age is associated with a heightened incidence of thyroid disease, the safety of surgery for geriatric patients is an important issue. Thyroidectomy should be considered in the treatment of these patients, especially in males, as the rate of malignant diagnosis and worse histopathological parameters are seen with increasing age.

PAFAH1B3 Regulates Papillary Thyroid Carcinoma Cell Proliferation and Metastasis by Affecting the EMT

INTRODUCTION

Thyroid carcinoma (TC) is currently the prevalent type of endocrine malignancy worldwide, having an incidence of around 15.5 per 100,000 people. However, the underlying mechanisms of TC tumorigenesis remain to be further elucidated.

METHODS

Performing the database analyses, Platelet-activating factor acetylhydrolase 1B3 (PAFAH1B3) was found to be dysregulated in several carcinomas and might trigger tumor occurrence as well as the progression of TC. Clinicopathological information of patients from our local validated cohort and The Cancer Genome Atlas (TCGA) cohort also confirmed this hypothesis.

RESULTS

Our present research showed that elevated expression of PAFAH1B3 has a close association with worse behavior in papillary thyroid carcinoma (PTC). We utilized the small interfering RNA to obtain the PAFAH1B3-transfected PTC cell lines, including BCPAP, FTC-133, and TPC-1, and then further examined their biological function in vitro. Furthermore, gene set enrichment analysis suggested that PAFAH1B3 is implicated with epithelial-mesenchymal transition (EMT). Afterward, the western blotting assays aimed at EMT-related proteins were performed.

CONCLUSION

In short, our results revealed that silencing PAFAH1B3 could hinder the capabilities of proliferation, migration, and invasion of PTC cells. Increasing expression of PAFAH1B3 might be of quintessence with lymph node metastasis by triggering EMT in PTC patients.

Radiomics Analysis of Gray-Scale Ultrasonographic Images of Papillary Thyroid Carcinoma > 1 cm: Potential Biomarker for the Prediction of Lymph Node Metastasis

Purpose

This study aimed to investigate radiomics analysis of ultrasonographic images to develop a potential biomarker for predicting lymph node metastasis in papillary thyroid carcinoma (PTC) patients.

Materials and Methods

This study included 431 PTC patients from August 2013 to May 2014 and classified them into the training and validation sets. A total of 730 radiomics features, including texture matrices of gray-level co-occurrence matrix and gray-level run-length matrix and single-level discrete two-dimensional wavelet transform and other functions, were obtained. The least absolute shrinkage and selection operator method was used for selecting the most predictive features in the training data set.

Results

Lymph node metastasis was associated with the radiomics score (p < 0.001). It was also associated with other clinical variables such as young age (p = 0.007) and large tumor size (p = 0.007). The area under the receiver operating characteristic curve was 0.687 (95% confidence interval: 0.616-0.759) for the training set and 0.650 (95% confidence interval: 0.575-0.726) for the validation set.

Conclusion

This study showed the potential of ultrasonography-based radiomics to predict cervical lymph node metastasis in patients with PTC; thus, ultrasonography-based radiomics can act as a biomarker for PTC.

Scoring system and a simple nomogram for predicting radioiodine refractory differentiated thyroid cancer: a retrospective study

Background

Differentiated thyroid carcinoma (DTC) originates from abnormal follicular cells and accounts for approximately 90–95% of thyroid malignancies. The diagnosis of radioiodine refractory DTC (RR-DTC) is based on clinical evolution and iodine uptake characteristics rather than pathological characteristics. Thus, it takes a long time to become apparent, and the definition of RR-DTC covers multiple aspects. We aimed to analyze the clinical and molecular imaging characteristics of patients with RR-DTC and identify independent predictors to develop an RR-DTC scoring system and a simple nomogram for predicting the probability of RR-DTC. We reviewed the data of 404 patients with metastatic DTC who underwent both post-RAI WB therapy scintigraphy and ¹⁸F-fluorodeoxyglucose (¹⁸F-FDG) positron emission tomography/computed tomography. Data on the clinical features and molecular characteristics of RR-DTC and non-RR-DTC cases were obtained from medical records. We screened for predictors using univariate analyses, obtained independent predictors through multivariate analyses, and then established a scoring system and a simple nomogram for predicting RR-DTC according to the corresponding odds ratio (OR) values.

Results

Diagnosis at age ≥ 48 years (OR, 1.037; 95% confidence interval [CI], 1.007–1.069), recurrence between the operation and iodine-131 treatment (OR, 7.362; 95% CI 2.388–22.698), uptake of ¹⁸F-FDG (OR, 39.534; 95% CI 18.590–84.076), and the metastasis site (OR, 4.365; 95% CI 1.593–11.965) were highly independently associated with RR-DTC. We established a scoring system for predicting RR-DTC, showing that the area under the receiver operating characteristic curve (AUC) with a cutoff value of 10 points (AUC = 0.898) had a higher discernibility than any other single independent predictor. The risk factors of RR-DTC in nomogram modeling include diagnosis at age ≥ 48 years, recurrence between the operation and iodine-131 treatment, uptake of ¹⁸F-FDG, and the site of metastasis. The concordance index (c-Index) of the nomogram was 0.9.

Conclusions

We demonstrated that a predictive model based on four factors has a good ability to predict RR-DTC. An index score ≥ 10 points was found to be the optimal index point for predicting RR-DTC. Moreover, this nomogram model has good predictive ability and stability. This model may help establish an active surveillance or appropriate treatment strategy for RR-DTC cases.

Role of STAT3 Expression in Thyroid Cancer: A Meta-Analysis and Systematic Review Based on the Chinese Population

Background

Signal transduction and activator of transcription 3 (STAT3) is an oncogene with transcriptional activity. In recent years, there have been several studies concerning the clinicopathological significance of the expression of the STAT3 protein in thyroid cancer. However, the results are still inconsistent. In this study, we conducted a meta-analysis to evaluate the relationship between the expression of STAT3 protein and thyroid cancer susceptibility and its clinicopathological characteristics.

Methods

We searched the China National Knowledge Infrastructure (CNKI) database, Chinese Biomedical Literature Database (CBM), Chinese Scientific and Journal Database (VIP), Wanfang, PubMed, and EMBASE. The time frame of the publication search was from the establishment of each of the databases until December 2021. We performed a meta-analysis to quantitatively evaluate the relationship between the expression of the STAT3 protein in thyroid cancer and its clinicopathological characteristics.

Results

A total of eight articles were included in the meta-analysis, covering 448 thyroid cancer patients and 227 controls. Results indicated that the expression of STAT3 protein in thyroid cancer tissue is highly expressed (OR = 14.41, 95% CI (6.94, 29.91), p < 0.001). Besides, we also discovered that STAT3 protein is negatively correlated with thyroid cancer tumor diameter and TNM stage (OR = 0.13, 95% CI (0.05, 0.33), p < 0.001; OR = 0.40, 95% CI (0.24, 0.67), p < 0.001) and positively correlated with lymph node metastasis (OR = 2.83, 95% CI (1.08, 7.46), p = 0.035). However, STAT3 expression is not related to gender (OR = 0.88, 95% CI (0.54, 1.44), p = 0.609), age (OR = 0.54, 95% CI (0.21, 1.36), p = 0.191), capsular invasion (OR = 2.98, 95% CI (0.23, 38.29), p = 0.403), or tumor multiplicity (OR = 0.25, 95% CI (0.003, 19.28), p = 0.533).

Conclusions

This study reveals that STAT3 protein expression is significantly related to the susceptibility and clinicopathological characteristics of thyroid cancer. It also suggests that STAT3 may be a potential predictor of the clinical progression of thyroid cancer.

Stereotactic radiotherapy (SRT) for differentiated thyroid cancer (DTC) oligometastases: an AIRO (Italian association of radiotherapy and clinical oncology) systematic review

PURPOSE

The aim of this systematic review was to examine efficacy of stereotactic radiotherapy (SRT) in patients with oligometastatic thyroid cancer.

MATERIALS AND METHODS

A systematic search was conducted by means of PubMed, Scopus, and Cochrane library.

CLINICALTRIALS

gov was searched for ongoing or recently completed trials, and PROSPERO was searched for ongoing or recently completed systematic reviews. We analyzed only clinical studies as full text carried out on patients with oligometastatic thyroid cancer treated with SRT. Conference papers, surveys, letters, editorials, book chapters, and reviews were excluded. Time of publication was restricted to the years 1990-2021.

RESULTS

The number of evaluated patients was 146 (267 lesions), and the median age was 58 years. The median 1-year local control (LC) was 82% (range 67.0%-97.1%); the median disease-free survival (DFS) was 12 months (range 4-53); the median 1-year overall survival was 72% (range 66.6%-85.0%); the 3-year cancer-specific survival was 75.0%; and the 4-year cancer-specific survival was 37.5%. No grade 3-5 acute toxicity was reported. No late effects were recorded.

CONCLUSIONS

SRT for oligometastases from thyroid cancer as salvage therapy is well tolerated and yields high rates of LC and prolonged DFS.

The deubiquitinating enzyme ATXN3 promotes the progression of anaplastic thyroid carcinoma by stabilizing EIF5A2

Ataxin-3 (ATXN3) is a ubiquitous deubiquitinating enzyme that plays an essential role in the carcinogenesis of numerous tumors and stabilizes the expression of substrates by deubiquitination. However, the functional role of ATXN3 in anaplastic thyroid carcinoma (ATC) remains unknown. In this research, we report that ATXN3 was overexpressed in ATC compared to that in paracancerous samples. Moreover, various gain/loss functional assays were performed to indicate that ATXN3 overexpression enhanced ATC cell proliferation and metastasis. We also found that ATXN3 and eukaryotic translation initiation factor 5A2 (EIF5A2) protein levels in ATC tissues are positively correlated, and ATXN3 promotes the proliferation and metastasis of ATC cells through EIF5A2. Mechanistically, ATXN3 promotes EIF5A2 expression by directly binding to EIF5A2 to reduce its ubiquitination and degradation. Therefore, for the first time, we clarified the role of ATXN3 in the carcinogenesis of ATC cells, which provides novel insights into potential therapeutic targets for ATC progression.

Comparison of the abilities of staging and risk stratification systems to predict the long-term structural recurrence in patients with differentiated thyroid carcinoma after total thyroidectomy and radioactive iodine remnant ablation

Background

In patients with differentiated thyroid carcinoma (DTC), various staging and risk stratification systems have been applied to estimate long-term recurrence, which is a major issue during the postoperative follow-up period. However, the efficacy of these systems remains unclear in this context.

Methods

The present historical cohort study included 510 patients with DTC who underwent a total thyroidectomy followed by radioactive iodine (RAI) remnant ablation. Enrolled patients were categorized according to the 8^th edition of American Joint Committee on Cancer/Union for International Cancer Control (AJCC/UICC) Tumor Node Metastasis (TNM) staging system, the 2015 American Thyroid Association (ATA) initial risk stratification system, and the dynamic risk stratification (DRS) system. The ability of each system to predict long-term structural recurrence was compared using proportion of variance explained (PVE) by logistic regression models.

Results

The median follow-up period was 108 months. Structural recurrence occurred in 7.6% of the patients (n=39/510). Disease-free survival (DFS) curves of the patients within each category in the TNM staging system, the ATA initial risk stratification system, and the DRS system were significantly different (P<0.001). The PVE of the DRS system (20.7%) was higher than those of the TNM staging system and the ATA initial risk estimates.

Conclusions

The DRS system may effectively predict long-term structural recurrence and guide long-term management and follow-up strategies in patients with DTC undergoing total thyroidectomy and RAI remnant ablation.

Association of Low Serum 25OHD Levels with Abnormal Bone Microarchitecture in Well-Differentiated Thyroid Cancer

The association of low levels of 25 hydroxyvitamin D (25OHD) with papillary thyroid cancer (PTC) is being studied, as to whether it is a risk factor or as a coincidental one. This study aimed to evaluate serum levels of deficiency, insufficiency, and sufficiency of 25OHD in PTC and its relationship with the trabecular bone score (TBS) and bone mineral density (BMD). This study includes 134 postmenopausal women with PTC, followed for 10 years. BMD was measured with DXA Hologic QDR 4500, and TBS with Med-Imaps iNsight2.0 Software. Mean serum 25OHD was 23.09 ± 7.9 ng/mL and deficiency, insufficiency, and sufficiency levels were 15.64 ± 2.9, 25.27 ± 2.7, and 34.7 ng/mL, respectively. Parathyroid hormone (PTH) and bone alkaline phosphatase (BAP) were higher in deficiency (57.65 ± 22.6 ng/mL; 29.5 ± 14 U/L) and in insufficiency (45.88 ± 19.8 ng/mL; 23.47 ± 8.8 U/L) compared with sufficiency of 25OHD (47.13 ± 16 and 22.14± 9.7 ng/mL) (p = 0.062 and p = 0.0440, respectively). TBS was lower in patients with 25OHD < 20 ng/mL (1.24 ± 0.13) compared with between 20-29 (1.27 ± 0.13, p < 0.05) and 30 ng/mL (1.31 ± 0.11, p < 0.01). We found low TBS in patients with PTC and long-term follow-up associated with low serum 25OHD levels, not associated with cancer stage, or accumulative iodine radioactive dose. Low 25OHD associated with deleterious bone quality in patients with PTC should be restored for the prevention of fractures.

Course and Predictive Factors of Incomplete Response to Therapy in Low- and Intermediate-Risk Thyroid Cancer

Context

Controversy surrounds the extent and intensity of the management of American Thyroid Association (ATA) intermediate- and low-risk patients with differentiated thyroid cancer (DTC). Understanding the natural history and factors that predict outcome is important for properly tailoring the management of these patients.

Objective

This work aims to study the natural course and predictive factors of incomplete response to therapy in low- and intermediate-risk DTC.

Patients and Methods

We studied a cohort of 506 consecutive patients [418 women (82.6%) and 88 men (17.4%)] with low and intermediate risk with a median age of 35 years (interquartile range [IQR], 27-46 years). We analyzed the natural course and the predictive factors of biochemically or structurally incomplete response.

Results

Of 506 patients studied, 297 (58.7%) patients were in the low-risk group and 209 (41.3%) were in the intermediate-risk group. Over a median follow-up of 102 months (IQR, 66-130 months), 458 (90.5%) patients achieved an excellent response, 17 (3.4%) had a biochemically incomplete status, and 31 (6.1%) had a structurally incomplete status. In univariable and multivariable analyses, age (≥ 33 years) (P < .0001, odds ratio 1.06 [1.04-1.08]) and lateral lymph node metastasis (LNM; P < .0001, odds ratio 3.2 [1.7-5.9]) were strong predictive factors for biochemically and structurally incomplete response to therapy. Sex, tumor size, multifocality, extrathyroidal extension, and lymphovascular invasion did not predict incomplete response to therapy.

Conclusions

Patients with low- and intermediate-risk DTC have favorable outcomes. Age and lateral LNM are strong predictors of an incomplete response to therapy. This suggests that older patients and those with LNM should be managed and followed up more actively than younger patients and those without LNM.

The De Novo Detection of Anti-Thyroglobulin Antibodies and Differentiated Thyroid Cancer Recurrence

Background: The prevalence and clinical significance of de novo detection of anti-thyroglobulin antibodies (TgAbs) during the follow-up of patients with differentiated thyroid cancer (DTC) is unknown. Methods: We utilized the National Thyroid Cancer Treatment Cooperative Study registry (1987-2012). Patients registered after 1996 (n = 3318) were analyzed. We identified 1545 subjects who had available TgAb status (TgAb cohort) between years 1996 and 2012, of whom 1325 were TgAb negative at first postoperative follow-up testing. From this initial TgAb-negative group, we excluded 513 patients: 423 patients who had less than 3 years of follow-up and/or fewer than three follow-up visits, 86 patients with persistent disease after initial treatment, and 4 patients with data entry errors. The remaining 812 patients were included for analysis, comprising the TgAb persistently negative group (defined as TgAb negative for at least 3 consecutive follow-up visits and at least 3 years of follow-up) (n = 772) and the de novo TgAb-positive group in whom TgAbs became detectable (n = 40). We then assessed whether de novo appearance of TgAb was associated with DTC structural recurrence by using the Kaplan-Meier method. Results: The de novo detection of TgAb occurred in 5% of DTC patients. Recurrence of DTC in the TgAb persistently negative group compared with the de novo TgAb-positive group did not differ significantly (9.6% vs. 15.0%, p = 0.23). Baseline characteristics, histology, history of radiation exposure, staging, and median duration of follow-up were similar between the two groups. Interestingly, in all six patients who suffered a recurrence in the de novo TgAb-positive group, the TgAbs were negative at the time of recurrence detection and became positive at a median of 2.1 (0.7-8.7) years after the structural recurrence. Conclusions: Utilizing a large North American DTC registry, we found the prevalence of de novo TgAb detection to be 5% among initially TgAb-negative patients. We did not find a statistically significant association between de novo TgAb development and DTC structural recurrence. Larger prospective studies are required to confirm these findings and further assess the significance of de novo TgAb detection in the follow-up of DTC.

EIF5A2 Is Highly Expressed in Anaplastic Thyroid Carcinoma and Is Associated With Tumor Growth by Modulating TGF- Signals

Anaplastic thyroid carcinoma (ATC) is resistant to standard therapies and has no effective treatment. Eukaryotic translation initiation factor 5A2 (EIF5A2) has shown to be upregulated in many malignant tumors and proposed to be a critical gene involved in tumor metastasis. In this study, we aimed to investigate the expression status of EIF5A2 in human ATC tissues and to study the role and mechanisms of EIF5A2 in ATC tumorigenesis in vitro and in vivo. Expression of EIF5A2 protein was analyzed in paraffin-embedded human ATC tissues and adjacent nontumorous tissues (ANCT) (n=24) by immunochemistry. Expressions of EIF5A2 mRNA and protein were analyzed in fresh-matched ATC and ANCT (n=23) and ATC cell lines by real-time polymerase chain reaction (PCR) and Western blotting. The effect of targeting EIF5A2 with short hairpin RNA (shRNA) or EIF5A2 overexpression on the ATC tumorigenesis and TGF-/Smad2/3 signals in vitro and in vivo was investigated. Expression of EIF5A2 was significantly upregulated in ATC tissues and cell lines compared with ANCT and normal follicular epithelial cell line. Functional studies found that targeting EIF5A2 induced SW1736 cell death in vitro and in vivo, followed by significantly downregulated phosphorylation of Smad2/3 (p-Smad2/3) in SW1736 cells at the protein level. Ectopic expression of EIF5A2 could promote 8505C cell growth in vitro and in vivo, followed by significantly upregulated p-Smad3 at the protein level. Recombinant human TGF-1 (hTGF-1) treatment decreased the antiproliferative activity of the EIF5A2 downexpressing 8505C cells through reversing pSmad2/3. Using the specific inhibitor SB431542 to block TGF- pathway or Smad3 siRNA to knock down Smad3 increased the antiproliferative activity of the EIF5A2-overexpressing 8505C cells through inhibiting pSmad2/3. Our findings indicated that EIF5A2 controled cell growth in ATC cells, and EIF5A/TGF-/Smad2/3 signal may be a potential therapeutic target for ATC treatment.

ZEB1-AS1/miR-133a-3p/LPAR3/EGFR axis promotes the progression of thyroid cancer by regulating PI3K/AKT/mTOR pathway

Background

Thyroid cancer (TC) is a member of common malignant tumors in endocrine system. To develop effective treatment, further comprehension of understanding molecular mechanism in TC is necessary. In this research, we attempted to search the underlying molecular mechanism in TC.

Methods

ZEB1-AS1 expression was analyzed via qRT-PCR analysis. CCK-8, colony formation, flow cytometry and TUNEL assays were used to evaluate TC cell growth. The interaction between miR-133a-3p and LPAR3, EGFR and ZEB1-AS1 was testified through using RNA pull down and luciferase reporter assays.

Results

LPAR3 and EGFR were expressed at high levels in TC tissues and cell lines. Besides, both LPAR3 and EGFR could promote TC cell growth. Later, miR-133a-3p was searched as an upstream gene of LPAR3 and EGFR, and LPAR3 could partially rescue the suppressive effect of miR-133a-3p overexpression on TC progression, whereas the co-transfection of LPAR3 and EGFR completely restored the inhibition. Next, ZEB1-AS1 was confirmed as a sponge of miR-133a-3p. ZEB1-AS1 has a negative correlation with miR-133a-3p and a positive association with LPAR3 and EGFR through ceRNA analysis. Importantly, ZEB1-AS1 boosted the proliferation and suppressed the apoptosis in TC cells. Through restoration assays, we discovered that ZEB1-AS1 regulated LPAR3 and EGFR expression to mediate TC cell proliferation and apoptosis by sponging miR-133a-3p. Further investigation also indicated the oncogenic role of ZEB1-AS1 by mediating PI3K/AKT/mTOR pathway.

Conclusions

ZEB1-AS1 could be an underlying biomarker in TC.

LINC00311 promotes cancer stem-like properties by targeting miR-330-5p/TLR4 pathway in human papillary thyroid cancer

Growing evidence has suggested that long noncoding RNAs (lncRNAs) play an essential role in the progression of papillary thyroid cancer (PTC). LncRNA LINC00311 was found to be able to regulate many cellular process in several diseases. However, the function and regulatory mechanism of LINC00311 remains unclear in PTC. In the present study, the results showed that the expression of LINC00311 was upregulated in PTC tissues and cells. Furthermore, knockdown of LINC00311 dramatically suppressed spheroid formation, proliferation, migration, and invasion in PTC cells in vitro. Mechanistic investigations revealed that LINC00311 was negatively correlated with the expression of miR‐330‐5p, meanwhile, TLR4 was a direct target of miR‐330‐5p. In addition, rescue assays further determined that LINC00311 contributed to the progression of PTC through regulating TLR4 expression. Taken together, these findings indicated that LINC00311 could promote cancer stem‐like properties by targeting miR‐330‐5p/TLR4 pathway in PTC.

A Predictive Model to Distinguish Papillary Thyroid Carcinomas from Benign Thyroid Nodules Using Ultrasonographic Features: A Single-Center, Retrospective Analysis

Background

We developed a model based on ultrasound (US) features of thyroid nodules and cervical lymph nodes to distinguish papillary thyroid carcinomas (PTC) from benign thyroid nodules.

Material/Methods

We retrospectively collected data on preoperative ultrasonographic characteristics and postoperative histological data from 1119 patients who underwent thyroidectomy in our center from January 2017 to January 2018. Variables of age, sex, and US features of thyroid nodule and lymph nodes features were analyzed. A logistic regression model was established for PTC prediction.

Results

Logistic regression analysis confirmed that age under 45 years (OR=2.22, p=0.00), hypoechogenicity (OR=3.70, p=0.00), irregular shape (OR=2.13, p=0.004), ill-defined margin (OR=2.26, p=0.08), spiculate margin (OR=3.30, p=0.00), indefinite border (OR=2.45, p=0.00), capsular invasion (OR=7.76, p=0.006), taller-than-wide shape (OR=2.94, p=0.00), solid structure (OR=2.46, p=0.001), microcalcifications (OR=3.92, p=0.00), coexistence of microcalcifications and macrocalcifications (OR=5.84, p=0.006), and central vascularity (OR=2.10, p=0.001) were independently associated with increased risks for PTC, as well as lymph nodes metastasis features (absence of an echogenic hilum [OR=3.74, p=0.027] and increased vascularization [OR=3.55, p=0.086]). The area under the curve (AUC) for the risk score diagnosis system was 0.916.

Conclusions

This predictive model is a reliable, simple, and cost-effective diagnostic tool for PTC.

Prognostic Parameters in Differentiated Thyroid Carcinomas

Differentiated thyroid carcinomas make up most thyroid malignancies. The AJCC staging system and the ATA risk prediction system are the best predictors of mortality and recurrence, respectively. Key factors to be identified and reported by pathologists are reviewed in this article and include: (1) aggressive histologic variants of papillary thyroid carcinoma (including tall cell, columnar cell, and hobnail variants); (2) presence of gross extrathyroidal extension (into skeletal muscle or adjacent organs); (3) angioinvasion (including number of foci); (4) number, anatomic level, and size of lymph node metastases; (4) extranodal extension; (5) genetics (especially BRAF V600E or TERT promoter mutation).

The extent of extrathyroidal extension is a key determinant of prognosis in T4a papillary thyroid cancer

BACKGROUND AND OBJECTIVES

In papillary thyroid cancer (PTC), the adverse prognostic impact of extrathyroidal extension (macro-ETE) invading the subcutaneous soft tissues, larynx, trachea, esophagus, or recurrent laryngeal nerve (T4a disease) is well established. We investigated whether the extent of macro-ETE, defined as "limited" with single structure involvement (lim-ETE) and "extensive" with multiple structures involved (ext-ETE), influences prognosis in T4a PTC.

METHODS

A retrospective analysis of 610 patients with PTC identified 39 with T4a disease, including 26 with lim-ETE and 13 with ext-ETE. Univariate Cox regression was used to assess the relationship between the extent of macro-ETE and recurrence-free survival (RFS).

RESULTS

Ext-ETE was associated with a five times increased risk of recurrence compared to lim-ETE (HR 5.0, P < .030), with or without adjustment for radioactive iodine administration and after adjustment for margin status (HR 4.7; P = .041). A low-risk subset of T4a disease comprising of patients aged less than 55 years with lim-ETE and clear margins accounted for one-third of the cohort and demonstrated an excellent 5-year RFS of 92%.

CONCLUSIONS

The extent of macro-ETE appears to be an important determinant of prognosis in T4a PTC. A low-risk subset of T4a disease exists with an excellent prognosis.

Predictive Factors of Recurrence in Patients with Differentiated Thyroid Carcinoma: A Retrospective Analysis on 579 Patients

Differentiated thyroid carcinoma (DTC) is usually associated with a favorable prognosis. Nevertheless, up to 30% of patients present a local or distant recurrence. The aim of this study was to assess the incidence of recurrence after surgery for DTC and to identify predictive factors of recurrence. We included in this retrospective study 579 consecutive patients who underwent thyroidectomy for DTC from 2011 to 2016 at our institution. We observed biochemical or structural recurrent disease in 36 (6.2%) patients; five-year disease-free survival was 94.1%. On univariate analysis, male sex, histotype, lymph node yield, lymph node metastasis, extrathyroidal invasion and multicentricity were associated with significantly higher risk of recurrence, while microcarcinoma was correlated with significantly lower risk of recurrence. On multivariate analysis, only lymph node metastases (OR 4.724, p = 0.012) and microcarcinoma (OR 0.328, p = 0.034) were detected as independent predictive factors of recurrence. Postoperative management should be individualized and commensurate with the risk of recurrence: Patients with high-risk carcinoma should undergo strict follow-up and aggressive treatment. Furthermore, assessment of the risk should be repeated over time, considering individual response to therapy.

Long non-coding RNA MIAT promotes papillary thyroid cancer progression through upregulating LASP1

Background

Accumulating evidences indicate that long non-coding RNAs (lncRNAs) play an important role in initiation and development of thyroid cancer. However, the underlying molecular mechanism remains elusive.

Methods

To explore potential oncogenic and tumor suppressive lncRNAs in papillary thyroid cancer (PTC), we performed RNA sequencing to discover differentially expression lncRNAs between PTC tissues and matched normal tissues. RT-qPCR was used to validate differentially expressed lncRNAs. Bioinformatic analysis was performed to predicted potential miRNA and gene which might be regulated by MIAT. Cell proliferation, invasion and cycle assay were conducted to study the function of MIAT and LASP1 in PTC.

Results

Through analysis of RNA sequencing, we observed that lncRNA-MIAT was overexpressed in PTC tissues. The upregulation of MIAT was further confirmed in 40 pairs of PTC tissues and normal tissues we collected. In the function assays, results suggested that MIAT silencing led to inhibition of cell proliferation, invasion and disruption of cell cycle progression in PTC cells. Mechanistically, MIAT directly bound to miR-324-3p and upregulated LASP1 expression in PTC cells. In addition, expression of MIAT was positively correlated with LASP1 mRNA expression in samples collected from patients with PTC. More importantly, transfection of recombinant LASP1 attenuated MIAT silencing induced inhibition of cell proliferation, invasion and disruption of cell cycle progression in PTC cells.

Conclusions

In conclusion, the findings suggest that lncRNA-MIAT may promote PTC proliferation and invasion through physically binding miR-324-3p and upregulation of LASP1.

Electronic supplementary material

The online version of this article (10.1186/s12935-019-0913-z) contains supplementary material, which is available to authorized users.

Impact of the change from the seventh to eighth edition of the AJCC TNM classification of malignant tumours and comparison with the MACIS prognostic scoring system in non-medullary thyroid cancer

Background

In 2018, AJCC TNM staging changed for differentiated (DTC) and anaplastic (ATC) thyroid carcinoma. The impact of this change on mortality rates was investigated and compared with the MACIS prognostic score.

Methods

Analysis of a prospective database of DTC/ATC was undertaken. Patients were staged according to TNM7 and TNM8 criteria, and MACIS scores calculated. Five‐year disease‐specific mortality rates were determined. Proportions were compared with Fisher's exact and χ² goodness‐of‐fit tests.

Results

Between August 2002 and December 2016, 310 patients had primary surgery for thyroid cancer. After exclusions, 159 patients (154 DTC, 5 ATC) remained to be studied. The MACIS score was less than 6 in 105 patients (66·0 per cent), 6–6·99 in 19 (11·9 per cent), 7–7·99 in 14 (8·8 per cent) and 8 or more in 21 (13·2 per cent), with corresponding disease‐specific 5‐year mortality rates of 0, 5, 14 and 86 per cent. For TNM7 the distribution was stage I in 53·5 per cent (85 patients), stage II in 10·1 per cent (16), stage III in 14·5 per cent (23) and stage IV in 22·0 per cent (35), and differed from that for TNM8: 76·7 per cent (122), 10·7 per cent (17), 4·4 per cent (7) and 8·2 per cent (13) respectively (P < 0·001). Overall disease‐specific 5‐year mortality rates by stage for TNM7 versus TNM8 were: stage I, 0 of 85 versus 3 of 100 (P = 0·251); stage II, 0 of 16 versus 6 of 16 (P = 0·018); stage III, 3 of 23 versus 2 of 7 (P = 0·565); stage IV, 20 of 32 versus 11 of 11 (P = 0·020).

Conclusion

Compared with TNM7, TNM8 downstaged more patients to stage I and accurately reflected worse prognosis for stage IV disease. TNM8 is an inferior predictor of mortality compared with MACIS.

Clinical features and therapeutic outcomes of patients with papillary thyroid microcarcinomas and larger tumors

OBJECTIVE

The aim of this study was to identify clinical features and therapeutic outcomes of patients with papillary thyroid cancer (PTC) according to tumor diameter and evaluate the correlation of neck lymph node (LN) involvement of papillary thyroid microcarcinoma (PTMC) according to patients' age.

PATIENTS AND METHODS

We divided 467 patients into two groups according to tumor diameter: PTMC group (≤1 cm) and non-PTMC group (>1 cm). The clinical data were analyzed retrospectively. Thereafter, we divided the PTMC patients into three subgroups according to age: young subgroup (<45 years), middle subgroup (45-54 years), and old subgroup (≥55 years). A further study about clinical features, especially the neck LN involvement in three subgroups, was analyzed.

RESULTS

All patients received radioiodine ablation at least once. There were more patients with a single cancer lesion and cancer in the unilateral lobe, less number of neck LN involvement, fewer patients with neck lymph node metastasis (LNM), and more patients with Hashimoto's thyroiditis in PTMC group than in non-PTMC group. At the further evaluation, 58.03% patients maintained clinical remission, which was more in the PTMC group than in non-PTMC group. There was no significant difference in recurrence, but the disease-free survival rate of patients in the PTMC group was higher than in the non-PTMC group. In the PTMC group, the radioactive iodine curative ratio in younger patients is lower than that in the other two subgroups. Both the LNM and central LNM (CLNM) rates were significantly higher in young patients compared with older patients. In addition, the LNM-positive group had more male patients, larger tumor size, and higher thyroglobulin antibody level. Both LNM and the CLNM rates were significantly higher in the young subgroup than in the older subgroup. Young and middle age and extrathyroid extension were independent risk factors for neck LNM. Unlike LNM, young age, extrathyroid extension, and male sex were independent risk factors for CLNM.

CONCLUSION

Some PTMCs were less aggressive and the therapeutic outcomes of them were better than non-PTMC. Moreover, PTMCs in young patients were more aggressive, especially in LNM. Hence, clinicians should consider an individualized treatment according to tumor characteristics and age to achieve better therapeutic efficacy.

Clinical Assessment and Risk Stratification in Differentiated Thyroid Cancer

Thyroid cancer management is rapidly evolving to a personalized management approach. Risk stratification systems are designed to assist in personalized management. Differentiating patients who may benefit from aggressive therapy and intense follow-up as opposed to those who can be successfully treated with minimalized initial management options and follow-up is crucial to the development of the right treatment plan for the right patient in order to optimize initial therapy and follow-up testing. This article aims to describe and discuss the risk stratification systems currently recommended for differentiated thyroid cancer.

Impact of tumor-associated macrophages and BRAFV600E mutation on clinical outcomes in patients with various thyroid cancers

BACKGROUND

Tumor-associated macrophages (TAMs) play a role in thyroid cancer tumor progression and metastasis. This study aimed to investigate the association of TAM density and cluster of differentiation 68 (CD68) expression with thyroid tumors as a prognostic marker and the relationship of these factors with BRAF^V600E mutations.

METHODS

This study included 275 thyroid specimen tissues, including benign and malignant lesions. We compared the clinicopathological features according to thyroid tumor types and evaluated the presence of CD68 expression and BRAF^V600E mutations.

RESULTS

CD68 positive expression increased with aggressiveness of thyroid tumor histologic grades (P < 0.001). In patients with poorly differentiated thyroid cancer (PDTC) and anaplastic thyroid cancer (ATC), CD68 positivity was associated with aggressive adverse clinical outcomes such as extrathyroidal extension, cervical lymph node metastases, and distant metastases (P < 0.05).

CONCLUSIONS

CD68 positivity was more frequent in advanced and aggressive thyroid cancer types such as PDTC/ATC.

Eighth edition of tumor-node-metastasis staging system improve survival predictability for papillary, but not follicular thyroid carcinoma: A multicenter cohort study

OBJECTIVES

This study aimed to evaluate the proposed changes in the eighth edition of the tumor-node-metastasis staging system (TNM-8) compared with the seventh edition (TNM-7) in terms of pathologic subtypes, using a large multicenter thyroid cancer cohort.

MATERIALS AND METHODS

We retrospectively reviewed 7717 patients with papillary (PTC) and 273 with follicular thyroid carcinoma (FTC) who underwent thyroid surgery between 1996 and 2005. We assessed the proportion of variation explained (PVE) to compare the predictive accuracy of disease-specific survival (DSS).

RESULTS

During a median 11.3 years of follow-up, 169 (2%) disease-specific deaths were recorded. In patients with PTC, the 10-year DSS rates of stages I, II, III, and IV disease in TNM-8 were 99.6%, 95.7%, 81.5%, and 54.8%, respectively; the corresponding rates in TNM-7 were 99.6%, 98.4%, 98.4%, and 90.1%, respectively. In patients with FTC, the 10-year DSS rates of stages I, II, III, and IV disease in TNM-8 were 97.2%, 69.8%, 50.0%, and 45.5%, respectively; the corresponding rates in TNM-7 were 98.3%, 90.0%, 92.3%, and 42.1%, respectively. Comparing TNM-7 and TNM-8, the PVE values increased from 3.4% to 4.7% in the PTC group, whereas they decreased from 17.5% to 14.5% in the FTC group.

CONCLUSION

Our study suggests that the changes in TNM-8 have improved the clinical usefulness of the TNM staging system in terms of predicting DSS in patients with PTC but not FTC. Further studies to establish a more predictable TNM staging system that focuses on patients with FTC are necessary.

Prognostic Value of FDG-PET/CT Metabolic Parameters in Metastatic Radioiodine-Refractory Differentiated Thyroid Cancer

PURPOSE

There are no standardized prognostication algorithms for metastatic radioiodine-refractory (RAI-R) differentiated thyroid cancer (DTC). We hypothesize that [F]-FDG PET/CT may predict progression versus stability of disease based on quantitative analysis of metabolic tumor volume (MTV) and total lesion glycolysis (TLG).

METHODS

Retrospective study of 62 patients with metastatic RAI-R DTC to determine clinical outcomes with median follow-up from initial diagnosis of 11.1 years (8.38, 14.1) (range, 1.2-20 years). Baseline [F]-FDG PET/CT scans were evaluated qualitatively for regional and distant metastases and quantitatively for tumor burden based on MTV and TLG obtained using gradient segmentation method.

RESULTS

After diagnosis of metastatic RAI-R disease was established, the 5-year overall survival (OS) probability was 34%, and median OS was 3.56 years (2.87, infinity). The 5-year progression-free survival (PFS) probability was 19%, and median PFS was 1.31 years (1.03, 2.38). TSH-suppressed thyroglobulin (Tg) levels greater than 100 ng/mL and Tg doubling time (Tg-DT) less than 6 months were significantly associated with worse OS and PFS. Higher than median values of MTV and TLG were associated with worse OS (P = 0.06) and PFS (P = 0.007). Higher hazard of death was noted for higher values of log-MTV and log-TLG (HR, 1.17 [95% confidence interval, 0.99-1.39], P = 0.05, and HR, 1.14 [95% confidence interval, 1.00-1.31], P = 0.05, respectively).

CONCLUSIONS

[F]-FDG PET/CT metabolic parameters can help define the volume and biologic variations of metastatic tumor burden. Metabolic tumor volume and TLG can be used for dynamic risk stratification of patients with metastatic RAI-R DTC regarding PFS and complement Tg-DT for prognosis of clinical disease course.

Capsaicin inhibits the metastasis of human papillary thyroid carcinoma BCPAP cells through the modulation of the TRPV1 channel

Capsaicin (CAP), a potent transient receptor potential vanilloid type 1 (TRPV1) agonist, is a major ingredient of red pepper. Recently, capsaicin has attracted increasing attention owing to its multiple biological activities. However, the anticancer effects of capsaicin against various types of cancers, especially on thyroid carcinoma, have not been completely elucidated. TRPV1, which can be activated by capsaicin, plays a key role in many biological and physiological processes. In the present study, the anticancer properties of capsaicin against papillary thyroid cancer BCPAP cells were investigated. Our results indicated that TRPV1 and TRPV6 were universally expressed in different types of thyroid cell lines. Capsaicin could inhibit multiple steps of metastasis without affecting the viability of BCPAP cells. The activation of TRPV1 by capsaicin (25-100 μM) significantly suppressed the migration and invasion of BCPAP cells as well as their adhesion. The protein levels of Snail1 and Twist1, two critical EMT transcription factors (EMT-TFs), dramatically decreased in a dose-dependent manner after capsaicin treatment, accompanied by the up-regulation of downstream protein E-cadherin. Subsequently, the activation of TRPV1 by capsaicin also caused significant inhibition of the expression of MMP-2 and MMP-9. Moreover, the inhibitory effects of capsaicin on the metastasis of BCPAP cells were abrogated by the pre-treatment of a specific TRPV1 antagonist (capsazepin). Our results suggest that the activation of TRPV1 by capsaicin is associated with the metastatic inhibition of papillary thyroid cancer BCPAP cells, indicating that targeting of TRPV1 functions remains a feasible strategy for cancer treatment.

Dynamic risk stratification system in post-lobectomy low-risk and intermediate-risk papillary thyroid carcinoma patients

OBJECTIVE

The dynamic risk stratification (DRS) and its current definition of each response-to-therapy category in post-lobectomy papillary thyroid carcinoma (PTC) patients have not been well studied. This study aimed to validate the DRS system and to investigate useful thyroglobulin (Tg) or anti-Tg antibody (Ab)-related parameters in defining each response-to-therapy category.

DESIGN

Retrospective observational study.

PATIENTS

This historical cohort study included 619 patients with PTC treated by thyroid lobectomy.

MEASUREMENTS

All enrolled participants were stratified according to the American Thyroid Association (ATA) initial risk stratification system and DRS system, respectively. The association between these stratifications and structural recurrence was evaluated.

RESULTS

The median follow-up period was 103 months. Structural recurrence occurred in 1.6% of the patients with excellent response, 3.8% of those with indeterminate response, 2.9% of those with biochemical incomplete response, and all patients with structural incomplete response. Five (1.5%) of the low-risk patients and 14 (5.0%) of the intermediate-risk patients had structural recurrence. The disease-free survival curves showed significant differences according to the DRS (P < .001) and ATA initial risk stratification (P = .012), respectively. The proportion of variance explained the DRS system and ATA risk stratification system for structural recurrence was 32.4% and 29.4%, respectively. A thyroid-stimulating hormone (TSH) level >2.75 μU/mL at 1 year after the initial operation (P < .001) was the only valuable risk factor for structural recurrence identified in this study.

CONCLUSION

The long-term postoperative management of PTC patients treated with thyroid lobectomy could be guided based on the DRS.

Evaluation of the dosimetry approaches in ablation treatment of thyroid cancer

In this study, we aimed to evaluate dosimetric approaches in ablation treatment of Differentiated Thyroid Carcinoma (DTC) without interrupting the clinical routine. Prior to therapy, 10.7 MBq ¹³¹I in average was orally given to 24 patients suffering from DTC. MIRD formalism was used for dosimetric calculations. For blood and bone marrow dosimetry, blood samples and whole‐body counts were collected at 2, 24, 72, and 120 h after I‐131 administration. For remnant tissue dosimetry, uptake measurements were performed at the same time intervals. To estimate the remnant volume, anterior and lateral planar gamma camera images were acquired with a reference source within the field of view at 24 h after I‐131 administration. Ultrasound imaging was also performed. Treatment activities determined with the fixed activity method were administered to the patients. Secondary cancer risk relative to applied therapy was evaluated for dosimetric approaches. The average dose to blood and bone marrow were determined as 0.15 ± 0.04 and 0.11 ± 0.04 Gy/GBq, respectively. The average remnant tissue dose was 0.58 ± 0.52 Gy/MBq and the corresponding required activity to ablate the remnant was approximately 1.3 GBq of ¹³¹I. A strong correlation between 24th‐hour uptake and time‐integrated activity coefficient values was obtained. Compared to fixed activity method, approximately five times higher secondary cancer risk was determined in bone marrow dosimetry, while the risk was about three times lower in lesion‐based dosimetry.

The effects of the Union for International Cancer Control/American Joint Committee on Cancer Tumour, Node, Metastasis system version 8 on staging of differentiated thyroid cancer: a comparison to version 7

OBJECTIVE

To assess the changes resulting from the changes from UICC/AJCC TNM version 7 to version 8 and to subsequently determine whether TNM version 8 is an improvement compared to previous iterations of the TNM system and other staging systems for differentiated thyroid cancer (DTC) with regard to prognostic power.

DESIGN

Database study of DTC patients treated in our centre between 1978 up to and including 1 July 2014. Results were compared to our previous comparison of prognostic systems using the same data set.

PATIENTS

2257 DTC patients.

MEASUREMENTS

Staging in accordance with TNM 7 and TNM 8. Thyroid cancer-specific mortality; comparison was based on p-values of univariate Cox regression analyses as well as analysis of the proportion of variance explained (PVE).

RESULTS

There is a redistribution from stage 3 to lower stages affecting 206 (9.1%) patients. DTC-related mortality according to Kaplan-Meier for younger and older patients in TNM 7 had a slightly lower prognostic power than that in accordance with TNM 8 (P = 8.0 10^-16 and P = 1.5 10^-21 , respectively). Overall staging is lower in 627/2257 (27.8%) patients. PVE (TNM 7: 0.29; TNM 8: 0.28) and the P-value of Cox regressions (TNM 7: P = 7.1*10^-52 ; TNM 8: P = 3.9*10^-49 ) for TNM version 8 are marginally lower than that for TNM version 7, but still better than for any other DTC staging system.

CONCLUSION

TNM 8 results in a marked downstaging of patients compared to TNM 7. Although some changes, like the change in age boundary, appear to be associated with an improvement in prognostic power, the overall effect of the changes does not improve the predictive power compared to TNM 7.

The Association of BRAF V600E Mutation With Tissue Inhibitor of Metalloproteinase-3 Expression and Clinicopathological Features in Papillary Thyroid Cancer

BACKGROUND

Papillary thyroid cancer (PTC) is the most common endocrine malignancy. The aim of this study was to investigate the association of tissue inhibitor metalloproteinase-3 (TIMP3) mRNA and protein levels in thyroid tissues, based on BRAF V600E status with the clinicopathologic characteristics of PTC.

METHODS

A total of 60 fresh frozen tissue samples of PTC patients (15 male and 45 female) were collected during thyroidectomy. All clinicopathological information was obtained and samples were reviewed as well as confirmed by a pathologist; exon 15 of the BRAF gene was genotyped by sequencing, TIMP3 mRNA level was assessed using SYBR-Green Real-Time PCR, and TIMP3 protein level was measured using ELISA.

RESULTS

Of 60 cases, BRAF mutation was found in 24 (40%). Larger tumor size and higher lymph node metastasis frequency were observed, significant in BRAF (+), compared to the BRAF (-) PTC group (P = 0.039 and P = 0.03, respectively). No significant difference was seen in the tumoral tissues of the TIMP3 mRNA level in BRAF (+), compared to BRAF (-) PTC samples. However, the mean TIMP3 protein level was significantly lower in tumoral tissues, compared to matched non-tumoral tissues in BRAF (+) PTC (P=0.003); TIMP3 protein level was significantly lower in tumoral tissues compared to matched non-tumoral tissues in BRAF (+), in subjects who had no lymph node metastasis and also in subjects with lymph node metastasis in both BRAF positive and negative PTC cases.

CONCLUSION

Our results showed that BRAF mutation was associated with a larger tumor size, higher frequency of lymph node metastasis, and lower TIMP3 protein levels. Lower TIMP3 protein level was associated with the lymph node metastasis in PTC patients.

Age greater than 60 years portends a worse prognosis in patients with papillary thyroid cancer: should there be three age categories for staging?

Background

Age is an important prognostic factor in papillary thyroid cancer (PTC), with better survival observed in patients < 45 years of age, regardless of stage. Although the impact of increasing age on PTC-related survival is well-known, previous studies have focused on survival relative to age 45 years only. As the number of patients entering their 7th decade of life increases, PTC-related survival in this demographic becomes increasingly important. Survival in patients ≥ 60 years specifically compared to other groups has not previously been examined. We sought to determine whether age ≥ 60 years is an adverse prognostic factor for disease-specific survival and recurrence in patients with PTC.

Methods

The California Cancer Registry database was linked to inpatient and ambulatory patient records from the Office of Statewide Health Planning and Development for the years 2000–2011. This linked database was queried for patients diagnosed with papillary thyroid cancer and treated with surgery. We then identified prognostic factors related to both 5-year and 10-year disease-specific survival and disease-free survival in patients ≤ 45, 45–59, and ≥ 60 years. Multivariable Cox proportional hazard models were created to test the effect of age ≥ 60 on disease-specific and disease-free survival, controlling for clinical, treatment, and demographic factors.

Results

The final cohort included 15,675 patients. Of the group, 46.3% were between 18 and 44 years of age, 33.6% were 45–59 years, and 20.1% were ≥ 60. Univariate analysis showed that compared to other groups, patients ≥ 60 were more likely to be male (p < 0.001), present with tumors > 5 cm (p < 0.001), more likely to have metastatic disease (p < 0.001), less likely to receive radioactive iodine (p < 0.001), and more likely to receive external beam radiation therapy (p < 0.001). In multivariable Cox proportional hazards models for 5 and 10-year disease-free survival, age ≥ 60 was associated with higher risk of disease at 5 and 10-years (HR 2.3 and 1.9 respectively, p < 0.001). Similar results were observed for 5 and 10-year disease-specific survival (HR 38.0 and 30.0 respectively, p < 0.001) after controlling for gender, race, co-morbidity, stage, surgical procedure, radioactive iodine, insurance, and hospital volume.

Conclusions

Patients ≥ 60 years of age have worse DSS and DFS after a diagnosis of PTC, across all stages of disease. Given that patients over the age of 45 years have progressively worse survival as they age, these data support having three age groups, 18–44 years of age, 45–59 years, and ≥ 60 as an independent predictor of survival and recurrence to current staging guidelines.

Acquired resistance to BRAF inhibition induces epithelial-to-mesenchymal transition in BRAF (V600E) mutant thyroid cancer by c-Met-mediated AKT activation

Previously, the authors have identified that c-Met mediates reactivation of the PI3K/AKT pathway following BRAF inhibitor treatment in BRAF (V600E) mutant anaplastic thyroid cancer, thereby contributing to the acquired drug resistance. Therefore dual inhibition of BRAF and c-Met led to sustained treatment response, thereby maximizing the specific anti-tumor effect of targeted therapy. The present study goes one step further and aims to investigate the effect of acquired resistance of BRAF inhibitor on epithelial-to-mesenchymal transition (EMT) in BRAF mutant thyroid cancer cells and the effect of dual inhibition from combinatorial therapy. Two thyroid cancer cell lines, 8505C and BCPAP were selected and treated with BRAF inhibitor, PLX4032 and its effect on EMT were examined and compared. Further investigation was carried out in orthotopic xenograft mouse models. Unlike BCPAP cells, the BRAF inhibitor resistant 8505C cells showed increased expressions of EMT related markers such as vimentin, β-catenin, and CD44. The combinatorial treatment of PLX4032 and PHA665752, a c-Met inhibitor reversed EMT. Similar results were confirmed in vivo. c-Met-mediated reactivation of the PI3K/AKT pathway contributes to the drug resistance to PLX4032 in BRAF (V600E) mutant anaplastic thyroid cancer cells and further promotes tumor cell migration and invasion by upregulated EMT mechanism. Dual inhibition of BRAF and c-Met leads to reversal of EMT, suggesting a maximal therapeutic response.

EGFR inhibition enhances the antitumor efficacy of a selective BRAF V600E inhibitor in thyroid cancer cell lines

BRAF V600E is the most common genetic alteration in thyroid cancer and is indicative of a relatively poor prognosis. A selective inhibitor of BRAF V600E has been proposed as a novel treatment for patients with thyroid cancer exhibiting BRAF V600E mutations. However, this inhibitor has demonstrated a limited therapeutic effect. In the present study, possible adaptive mechanisms of resistance of thyroid cancer cells to the specific BRAF V600E inhibitor, PLX4032, were investigated. MTT assays were performed to determine the anti-proliferative efficiencies and half maximal inhibitory concentration (IC₅₀) of inhibitory treatments. The level of phosphorylated ERK was used to evaluate the activity of the mitogen assisted protein kinase (MAPK) pathway. Flow cytometry was performed to evaluate the rate of apoptosis. The IC₅₀ measurements of PLX4032 in K1 and BCPAP cells were 0.550 and 1.772 µM, respectively. Co-treatment with an endothelial growth factor receptor (EGFR) inhibitor decreased the IC₅₀ of PLX4032 to 0.206 µM, and prolonged the inhibitory effect of PLX4032 in K1 cells. In cells treated with PLX4032 alone, the MAPK pathway was reactivated after 24 h. However, the addition of an EGFR inhibitor suppressed this reactivation and increased the rate of apoptosis. In summary, the present study demonstrated that thyroid cancer harboring the BRAF V600E mutation was resistant to a selective BRAF inhibitor due to reactivation of the MAPK pathway. Co-treatment with an EGFR inhibitor increased antitumor efficacy and suppressed resistance to the BRAF V600E inhibitor.

Effect of Age on Response to Therapy and Mortality in Patients With Thyroid Cancer at High Risk of Recurrence

CONTEXT

Age at diagnosis has been identified as a major determinant of thyroid cancer-specific survival, with older patients being at higher risk for mortality, but the association of age with risk of recurrence has not been studied to date.

OBJECTIVE

To examine the effect of a patient's age on response to therapy and disease-specific mortality in a cohort of thyroid cancer patients at high risk of recurrence, as defined by the American Thyroid Association (ATA) risk stratification system.

DESIGN

Retrospective cohort study of 320 patients, median age 49.3 years, with follicular cell-derived thyroid carcinoma classified at ATA high risk and followed for a median of 7 years.

MAIN OUTCOME MEASURES

Association of age with response to therapy, overall mortality, disease-specific mortality, and timing of metastases.

RESULTS

Age was a major determinant of response to therapy. There was a significantly larger percentage of excellent responders among young patients (age <55) than among old patients (age ≥55), 40.3% vs 27.5%, P = 0.002, respectively, whereas the proportion of structural incomplete responders was higher in the old group compared with the young group, 53% vs 33%, P = 0.002, respectively. ATA high-risk young patients with a structural incomplete response to therapy had a significantly better disease-specific survival than old patients (74% vs 12%, P < 0.001, respectively).

CONCLUSIONS

Age was a key predictor of response to therapy and disease-specific survival in ATA high-risk thyroid cancer patients. Its incorporation as a variable in the ATA risk stratification system would improve its power to predict response to therapy as well as mortality.

Disease-free survival in papillary and follicular thyroid carcinoma

T stage was redefined for patients with differentiated thyroid carcinoma (DTC) between the 5th and 7th versions of the UICC tumour classification system. Patients, methods: 636 patients (486 women, 150 men; mean age 49.1 ± 15.6 years, mean follow-up 4.6 years) who had been treated with ablative radioiodine therapy after thyroidectomy for papillary (PTC) or follicular thyroid carcinomas (FTC) were retrospectively assessed on occurrence of locoregional recurrent disease, or cervical lymph node or distant metastases. Disease-free survival was calculated from initial T stage, classified according to both versions of the UICC staging system and compared with the prognostic value of primary tumour size. Kaplan-Meier method and two measures of explained variation, (1) R2 based on the (partial) likelihood ratio statistic of the Cox proportional hazards model and (2) a model-free variant of a distance measure proposed by Schemper had the aim to detect the most advantageous classification. Results: Of the 508 patients with PTC, 11 (2.2%) developed a local recurrence, 37 (7.3%) cervical lymph node and 23 (4.5%) distant metastases, 3 (2.3%), 8 (6.3%), and 18 (14.1%) were the numbers for the 128 FTC patients respectively. The two classification systems yielded an equal count of statistically significant differences regarding disease-free survival in patients with PTC while UICC 7th classification appeared slightly advantageous in patients with FTC. Regarding explained variation the UICC 7th classification tended to be superior to the UICC 5th classification, both in PTC and FTC, however statistical significance was not reached. Conclusion: The primary tumour size significantly added to the prognosis regarding local cervical and distant metastases.

Subpopulations of cancer stem cells found in papillary thyroid carcinoma

Papillary thyroid carcinoma (PTC) is the most common form of thyroid cancer and while it has a generally good prognosis, tumor recurrence remains a major clinical challenge. Studying laboratory cell lines as well as clinical specimens indicate that PTC may follow the cancer stem cell (CSC) model. However, CSC characteristics relevant in PTC initiation and progression remain largely unknown. Here we studied a population of sphere-growing tumor cells isolated from primary cultures of clinical PTC. These sphere-growing cells consisted of aldehyde dehydrogenase positive (ALDH⁺) and ALDH negative (ALDH^-) cell subpopulations and demonstrated a hierarchical pattern of cell division. Using combinations of selective depletion, specific inhibition and cell sorting, we found that both subpopulations of the sphere cells were able to self-renew and initiate xenograft tumors independently, and fulfilled the definition of CSC. Importantly, when the subpopulations functioned together, the cancer-initiation efficiency and the xenograft tumor progression were significantly enhanced compared to either subpopulation alone. These data revealed crucial roles of ALDH^- CSC in PTC biology and suggested that CSC subpopulations function cooperatively to control PTC initiation and progression. Together, our study indicates that CSC subpopulations isolated from clinical specimens offer unprecedented opportunities for investigating PTC pathogenesis and developing effective therapies.

Molecular challenges of neuroendocrine tumors

Neuroendocrine tumors (NETs) are a very heterogeneous group that are thought to originate from the cells of the endocrine and nervous systems. These tumors develop in a number of organs, predominantly in the gastrointestinal and pulmonary systems. Clinical detection and diagnosis are reliable at the late stages when metastatic spread has occurred. However, traditional conventional therapies such as radiation and chemotherapy are not effective. In the majority of cases even surgical resection at that stage is unlikely to produce promising reusults. NETs present a serious clinical challenge, as the survival rates remain low, and as these rare tumors are very difficult to study, novel approaches and therapies are required. This review will highlight the important points of accumulated knowledge covering the molecular aspects of the role of neuroendocrine cells, hormonal peptides, the reasons for ectopic hormone production in NET, neuropeptides and epigenetic regulation as well as the other challenging questions that require further understanding.

Outcome prediction with the revised American joint committee on cancer staging system and American thyroid association guidelines for thyroid cancer

BACKGROUND

Several staging systems have been developed to predict the risk of mortality in patients with differentiated thyroid cancer (DTC). However, none of them have been shown to be clearly superior to the other.

METHODS

We compared the patient outcome predictability of recently revised staging systems predictability of patient outcome using data from The Cancer Genome Atlas. To set a comparison among American Joint Committee on Cancer (AJCC)/Union for International Cancer Control (UICC) staging 7th, 8th editions, American Thyroid Association guidelines 2009 and 2015, concordance index (c-index), Akaike information criterion (AIC), Bayesian information criterion (BIC), and Brier score were applied to quantify the predictive ability of a survival model, to select the statistical model, and to measure the accuracy of probabilistic predictions.

RESULTS

A total of 457 patients with papillary thyroid cancer having a mean age of 45.9 years were included in this study (120 males, 337 females). Among these patients, 43 (9.4%) experienced recurrence/progression during the follow-up (591.2 ± 833.5 months). Among the models used, the AJCC/UICC 8th edition, which showed the highest c-index and lowest AIC, BIC, and Brier score, was identified as the best among the models used.

CONCLUSION

AJCC/UICC 8th edition predicted patient outcome more accurately than the other staging systems.

Dynamic Risk Stratification in Stage I Papillary Thyroid Cancer Patients Younger Than 45 Years of Age

BACKGROUND

This study validated the dynamic risk stratification (DRS) system with regard to its association with structural recurrence and risk factors associated with non-excellent responses in patients <45 years with stage I classical papillary thyroid cancer (PTC).

METHODS

This historical cohort study included 598 patients with stage I classical PTC <45 years of age treated with total thyroidectomy followed by radioactive iodine remnant ablation (n = 440), total thyroidectomy without radioactive iodine remnant ablation (n = 23), and thyroid lobectomy alone (n = 135).

RESULTS

The median follow-up period was 123 months. Structural recurrence occurred in 4.2% (n = 18/432) of the patients with an excellent response, 17.1% (18/105) of patients with an indeterminate response, 44.7% (17/38) of patients with a biochemically incomplete response, and 82.6% (19/23) of patients with a structurally incomplete response (p < 0.001) during the follow-up. The disease-free survival curves of each response showed significant differences (p < 0.001). Extensive extrathyroidal extension and extranodal extension were the independent risk factors associated with non-excellent response (p < 0.05).

CONCLUSIONS

DRS may reduce unnecessary additional treatments by reclassifying initial risk estimates of structural recurrence. Furthermore, applying the risk factors associated with non-excellent response to initial therapy may be a more useful and viable surrogate of the risk for structural recurrence in stage I PTC patients <45 years of age.

Projecting Survival in Papillary Thyroid Cancer: A Comparison of the Seventh and Eighth Editions of the American Joint Commission on Cancer/Union for International Cancer Control Staging Systems in Two Contemporary National Patient Cohorts

BACKGROUND

This study aims to compare the seventh and eighth editions of the American Joint Commission on Cancer/Union for International Cancer Control (AJCC/UICC) tumor, node, metastasis staging system for patients with papillary thyroid cancer (PTC) in two national patient cohorts.

METHODS

Adult PTC patients undergoing surgery were selected from the Surveillance, Epidemiology and End Results (SEER) program (2004-2012) and the National Cancer Database (2004-2012). Staging criteria for the seventh and eighth AJCC/UICC editions were applied separately to each cohort. Survival probabilities were estimated using the Kaplan-Meier method. Multivariable Cox proportional hazards models were used to estimate the association of stage with survival in both settings. The Akaike information criterion was used to assess model performance.

RESULTS

About 23% of patients were downstaged from the seventh to the eighth edition in SEER, while 24% were downstaged in the National Cancer Database. Disease-specific survival (DSS) and overall survival (OS) were significantly related to stage at diagnosis when using both the seventh and eighth editions of the AJCC/UICC staging system (p < 0.001). Patients classified into higher stages (III and IV) in the eighth edition showed a worse prognosis than those classified into similar stages in the seventh edition. After adjustment, PTC stages as defined by both editions were significantly associated with DSS and OS. With respect to both DSS and OS, the eighth edition PTC model appeared to be a better fit to the data (smaller Akaike information criterion values) compared to the seventh edition.

CONCLUSION

Based on these large contemporary national cohorts, the eighth edition AJCC/UICC tumor, node, metastasis classification for PTC is superior to the seventh edition for predicting survival.

Novel biomarker SYT12 may contribute to predicting papillary thyroid cancer outcomes

Aim:

To investigate biomarkers for predicting papillary thyroid cancer outcomes.

Materials & methods:

The expression of biomarkers (ITGA2, SYT12 and CDH3) was studied in a prospective cohort of patients with papillary thyroid cancer. Three outcomes of initial metastases, baseline status and longitudinal status were analyzed and correlated with the biomarkers.

Results:

SYT12 provided the best prediction of initial metastasis (sensitivity: 72%; specificity: 54%). SYT12 had the highest accuracy for predicting longitudinal status (sensitivity: 100%; specificity: 47%). The best performance for longitudinal status resulted from combining SYT12 with American Thyroid Association risk stratification, with sensitivity and specificity of 88 and 73%, respectively.

Conclusion:

SYT12 has some prognostic significance in papillary thyroid cancer. Further validation studies in larger populations are warranted.

Survival and disease recurrence after diagnosis of papillary thyroid cancer is imperfectly predicted by commonly used ‘staging systems’ based mostly on the characteristics of the tumor such as size and location of spread. Also, these staging systems are generally designed to predict survival. Other characteristics, such as gene mutations may be helpful in predicting whether thyroid cancer will behave aggressively or not. This study investigates three genes associated with thyroid tumors and shows that expression of one of them, synaptotagmin 12 (SYT12), tends to predict greater progression of disease in patients with papillary thyroid cancer.

Comparison of the Seventh and Eighth Editions of the American Joint Committee on Cancer/Union for International Cancer Control Tumor-Node-Metastasis Staging System for Differentiated Thyroid Cancer

OBJECTIVE

To evaluate the efficacy and prognostic validity for disease-specific survival (DSS) of the eighth edition American Joint Committee on Cancer/Union for International Cancer Control tumor-node-metastasis (TNM) staging system (TNM-8) compared to the seventh edition (TNM-7) in patients with differentiated thyroid carcinoma (DTC).

METHODS

The seventh and eighth editions of the TNM staging system were applied to 1613 DTC patients who underwent thyroid surgery between 1996 and 2003. The proportion of variation explained and Harrell's c-index were evaluated to compare the predictive capability of DSS.

RESULTS

The mean age of the patients was 44.7 years, and the median follow-up period was 11.2 years. When TNM-8 was applied, 63% of T3 and 3% of N1b DTCs were downgraded to T1/T2 and N1a, respectively. About 38% of patients were downstaged according to TNM-8. The 10-year DSS rates in TNM-7 stages I, II, III, and IV were 99.7%, 98.2%, 98.8%, and 83.2%, respectively. Those in TNM-8 stages I, II, III, and IV were 99.6%, 95.4%, 72.3%, and 48.6%, respectively. The proportion of variation explained values of TNM-7 and TNM-8 were 6.0% and 7.0%, respectively. The Harrell's c-index of TNM-7 was 0.86 and that of TNM-8 was 0.88.

CONCLUSIONS

A significant number of patients were reclassified to lower stages with the application of TNM-8 compared to TNM-7. Applying TNM-8 could improve the accuracy of the staging system for predicting DSS in patients with DTC.

Risk prediction in children and adults less than 45 years old with papillary thyroid cancer

The incidence of papillary thyroid cancer is increasing faster than any other cancer in young patients. The purpose of this review is to discuss the most recent determinants of risk of recurrence and compromised outcomes in this population. Areas covered: This review discusses the most updated data on patient age, including children and young adults, extent of disease and subsequent dynamic staging over time, molecular markers for disease aggressiveness, adequacy of surgical resection and surgeon volume, and novel therapies for advanced non-resectable disease as predictors of patient outcomes. Expert commentary: Young patients enjoy excellent outcomes, with long-term survivorship, but face higher risks of short-term complications and disease recurrence. Thoughtful evaluation of the extent of disease, tumor features associated with more aggressive behavior, the presence of locoregional or distant metastases, and an understanding of molecular changes in their tumors are important areas of consideration. High-volume surgeons should work collaboratively with endocrinologists, radiologists, and pathologists specializing in thyroid cancer to help patients achieve excellent outcomes. Emerging data challenging the status quo regarding the relative importance of patient age, tumor features, and dynamic risk-adjustment for overall prognosis of these patients will likely impact future care and staging systems.

A novel integrative risk index of papillary thyroid cancer progression combining genomic alterations and clinical factors

Although the majority of papillary thyroid cancer (PTC) is indolent, a subset of PTC behaves aggressively despite the best available treatment. A major clinical challenge is to reliably distinguish early on between those patients who need aggressive treatment from those who do not. Using a large cohort of PTC samples obtained from The Cancer Genome Atlas (TCGA), we analyzed the association between disease progression and multiple forms of genomic data, such as transcriptome, somatic mutations, and somatic copy number alterations, and found that genes related to FOXM1 signaling pathway were significantly associated with PTC progression. Integrative genomic modeling was performed, controlling for demographic and clinical characteristics, which included patient age, gender, TNM stages, histological subtypes, and history of other malignancy, using a leave-one-out elastic net model and 10-fold cross validation. For each subject, the model from the remaining subjects was used to determine the risk index, defined as a linear combination of the clinical and genomic variables from the elastic net model, and the stability of the risk index distribution was assessed through 2,000 bootstrap resampling. We developed a novel approach to combine genomic alterations and patient-related clinical factors that delineates the subset of patients who have more aggressive disease from those whose tumors are indolent and likely will require less aggressive treatment and surveillance (p = 4.62 × 10-10, log-rank test). Our results suggest that risk index modeling that combines genomic alterations with current staging systems provides an opportunity for more effective anticipation of disease prognosis and therefore enhanced precision management of PTC.

Comparison of prognostic scoring systems in follicular thyroid cancer

INTRODUCTION Many studies have addressed the accuracy of prognostic scoring systems in the treatment of differentiated thyroid cancers as a whole but few have addressed this issue in patients with follicular thyroid cancer (FTC) alone. The aim of this study was to establish the accuracy of the various scoring systems in determining the overall and disease free survival of FTC patients in Singapore. METHODS Retrospective review was undertaken of 82 patients with FTC treated at a single tertiary institution between January 2000 and December 2014. Demographic, clinical, pathological and treatment outcomes were analysed. Prognostic scoring systems evaluated for the cohort included TNM (Tumour, Nodes, Metastases), AGES (Age, Grade, Extent, Size), MACIS (Metastases, Age, Completeness of resection, Invasion, Size), AMES (Age, Metastases, Extent, Sex) and EORTC (European Organisation for Research and Treatment of Cancer). Statistical analysis was performed by plotting Kaplan-Meier survival curves and using the Cox proportional hazards model. RESULTS There were 29 male and 53 female patients with a mean age of 48 years. The mean follow-up duration was 88 months and there were 7 deaths (9%). The ten-year overall survival rate was 90%. Factors predictive of survival on univariate analysis were age, size of tumour, invasiveness, completeness of resection, metastasis, external beam radiotherapy, and risk scores using the AGES and MACIS scoring systems (p<0.05). On multivariate analysis, AGES and MACIS provided the best prognostic information. CONCLUSIONS MACIS is the best prognostic scoring system currently available for FTC and it is superior to other scoring systems in term of guiding management. The scoring systems require further development to accommodate variations in clinical practice globally and to improve the prognostic accuracy.

Surgical management for follicular variant of papillary thyroid carcinoma

Background and Aims

For most patients with follicular variant of papillary thyroid carcinoma (FVPTC), surgery is required, while the surgical management remains controversial. We aim to further understanding of treatment of FVPTC and to determine whether specific features could be identified for the decision of surgical strategy.

Materials and Methods

Data were obtained from the Surveillance, Epidemiology, and End Results (SEER) Program database during 2003 and 2013. 26700 patients were eligible and stratified by tumor size or extension. Survival rates were compared using multivariate Cox proportional hazard regressions.

Results

Of the total death of 1041, 136 patients died from thyroid cancer. Most patients (79.1%) underwent total thyroidectomy while only a little part of patients (8.2%) underwent lobectomy. Patients receiving radioisotopes had significantly better overall survival (OS) (HR = 0.659, P < 0.001), but showed no differences on disease-specific survival (DSS). No statistical difference was found between total thyroidectomy and lobectomy in multivariate analysis when controlling for tumor size. While for tumor > 2 cm with extrathyroidal extension, lobectomy had significantly worse OS (aHR = 3.364, P = 0.010) and DSS (aHR = 5.494, P = 0.032) compared to total thyroidectomy. Multivariate analysis demonstrated that advanced age, male, higher grade, extrathyroidal extension, lymph nodes metastases and distant metastases had negative effects on OS and DSS controlling for the remaining variables (each P < 0.05).

Conclusions

The results of our study revealed total thyroidectomy could benefit the survival for patients whose tumors > 2 cm with extrathyroidal extension, total thyroidectomy should be recommended for those patients. Lots of factors should be taken into consideration on the decision of surgical treatment.

Total tumour diameter is superior to unifocal diameter as a predictor of papillary thyroid microcarcinoma prognosis

The current American Joint Committee (AJCC) on Cancer TNM classification does not describe the treatment of multifocal papillary thyroid microcarcinomas (PTMCs) with a total tumour diameter (TTD) >1 cm. Herein, we investigated this PTMC subgroup in terms of extrathyroidal extension (ETE), local infiltration, central lymph node metastasis (LNM), and prognosis. Consecutive patients (n = 1102) were identified and the proportions of LNM, ETE, and local infiltration were similar between PTCs with a unifocal tumour diameter >1 cm and ≤2 cm and PTMCs with a multifocal TTD >1 cm and ≤2 cm. The proportions of LNM, ETE, and local infiltration were also similar between PTMCs with a unifocal diameter ≤1 cm vs. multifocal TTD ≤1 cm. However, when comparing PTMCs with a unifocal diameter ≤1 cm vs. multifocal TTD >1 cm, significant differences were observed. In the Kaplan-Meier analysis, significant differences were observed between PTMCs with a unifocal diameter ≤1 cm vs. multifocal TTD >1 cm and multifocal TTD ≤1 cm vs. multifocal TTD >1 cm. Accordingly, TTD may represent a more accurate criterion for tumour size of PTCs and should be considered in the revised AJCC staging system.

RCAN1-4 is a thyroid cancer growth and metastasis suppressor

Metastasis suppressors are key regulators of tumor growth, invasion, and metastases. Loss of metastasis suppressors has been associated with aggressive tumor behaviors and metastatic progression. We previously showed that regulator of calcineurin 1, isoform 4 (RCAN1-4) was upregulated by the KiSS1 metastatic suppression pathway and could inhibit cell motility when overexpressed in cancer cells. To test the effects of endogenous RCAN1-4 loss on thyroid cancer in vivo, we developed RCAN1-4 knockdown stable cells. Subcutaneous xenograft models demonstrated that RCAN1-4 knockdown promotes tumor growth. Intravenous metastasis models demonstrated that RCAN1-4 loss promotes tumor metastases to the lungs and their subsequent growth. Finally, stable induction of RCAN1-4 expression reduced thyroid cancer cell growth and invasion. Microarray analysis predicted that nuclear factor, erythroid 2-like 3 (NFE2L3) was a pivotal downstream effector of RCAN1-4. NFE2L3 overexpression was shown to be necessary for RCAN1-4-mediated enhanced growth and invasiveness and NEF2L3 overexpression independently increased cell invasion. In human samples, NFE2L3 was overexpressed in TCGA thyroid cancer samples versus normal tissues and NFE2L3 overexpression was demonstrated in distant metastasis samples from thyroid cancer patients. In conclusion, we provide the first evidence to our knowledge that RCAN1-4 is a growth and metastasis suppressor in vivo and that it functions in part through NFE2L3.

Optimal cut-off age in the TNM Staging system of differentiated thyroid cancer: is 55 years better than 45 years?

OBJECTIVE

Age >45 years is included as a variable in the tumor, node, metastases (TNM) staging of differentiated thyroid cancer (DTC), but a higher cut-off value has been suggested to be more clinically relevant and prevent over-staging. We evaluated the optimal age cut-off to predict disease-specific survival (DSS) in patients with DTC.

DESIGN AND PATIENTS

This cohort study included 6333 patients with DTC who underwent thyroid surgery at two tertiary referral centres between 1996 and 2005. The optimal age cut-off value between 45 and 65 years for prediction of DSS was assessed. The proportion of variation explained (PVE) and Harrell's c-index was calculated to compare the predictability of each model.

RESULTS

The median age of patients was 46·0 years (IQR 37·8-54·6), and 5498 (87%) were female. Median follow-up period was 10·0 years, and 10-year DSS rate was 98%. Using TNM staging with 45 years as the cut-off (TNM45), 10-year DSS rates of stage I-IV were 99·4%, 96·1%, 97·7% and 85·9%, respectively (PVE = 3·0%, Harrell's c-index = 0·693); and using 55 years as the cut-off (TNM55), 99·4%, 92·2%, 95·3% and 79·7%, respectively (PVE = 4·3%, Harrell's c-index = 0·776). On receiver operating characteristic curve analysis, the optimal age cut-off for prediction of DSS was 55·4 years (area under the curve = 0·837, P < 0·001). About 20% of patients were down-staged to stage I using TNM55 compared to that using TNM45.

CONCLUSIONS

The cut-off age of 55 years was more appropriate for TNM staging to achieve better predictability for DSS in patients with DTC. This change would prevent over-staging in low-risk patients and prevent over-aggressive treatment.