Prognosis and prognostic factors of differentiated thyroid carcinoma after the appearance of metastasis refractory to radioactive iodine therapy

Radioactive iodine refractoriness in Middle Eastern differentiated thyroid cancer: clinical outcome and risk factor analysis

Background

Radioactive iodine refractory differentiated thyroid cancer (RAIR-DTC) has received increasing attention due to its poor prognosis. However, outcomes may vary among patients with RAIR-DTC. The role of clinico-pathological and molecular prognostic factors in survival remains controversial, resulting in difficulty in selecting patients for new targeted therapies. We assessed mortality rate and DTC-specific survival in Middle Eastern RAIR-DTC to identify prognostic factors associated with survival.

Methods

This single center, retrospective study enrolled 268 patients with RAIR-DTC. Mortality rate and DTC-specific survival were analyzed to identify prognostic factors related to survival. Univariate and multivariate analysis were performed using Cox proportional hazards model.

Results

Of the 268 cases of RAIR-DTC, 40.3% (108/268) had absent 131I uptake (either on diagnostic or post-therapy whole body scan), 15.3% (41/268) had progressive disease (PD) despite 131I, 7.5% (20/268) had persistent disease despite cumulative activity of I131 of >600 mCi and 36.9% (n=99/268) developed distant metastasis. On multivariate analysis, age (more than 45 years), presence of metastatic disease and tumors harboring telomerase reverse transcriptase (TERT) promoter mutations were independent prognostic factors for poor DTC-specific survival. Subjects were divided into 3 groups according to the number of risk factors; low risk (no risk factors); intermediate (≤ 2 risk factors); and high risk (all the 3 risk factors). Ten-year DTC-specific survival rates in low, intermediate and high-risk groups were 100.0%, 92.9% and 53.6%, respectively.

Conclusions

The contribution of age greater than 45 years to RAIR-DTC mortality is impactful. Older age, presence of distant metastasis and TERT mutations could be used as early predictors of RAIR-DTC cases. The identification of prognostic factors for poor survival in RAIR-DTC may improve the selection of patients for more personalized surveillance and therapeutic modalities.

Neutrophil-To-Lymphocyte Ratio is Associated With the Proportion of Poorly Differentiated Components in Papillary Thyroid Carcinoma

INTRODUCTION

Diagnosis of poorly differentiated thyroid cancer (PDTC) requires ≥ 50% of poorly differentiated components (PDC) in Japan. However, the optimal cutoff percentage of PDC for PDTC diagnosis remains controversial. Although high neutrophil-to-lymphocyte ratio (NLR) correlates with the aggressiveness of papillary thyroid cancer (PTC), whether NLR is associated with the proportion of PDC in PTC remains unstudied.

MATERIALS AND METHODS

Patients with the pure PTC (n = 664), PTC with < 50% PDC (n = 19), or PTC with ≥ 50% PDC (n = 26) who underwent surgery were retrospectively analyzed. Twelve-year disease-specific survival and preoperative NLR were compared among these groups.

RESULTS

Twenty seven patients died from thyroid cancer. The PTC with ≥ 50% PDC group (80.7%) showed significantly worse 12-year disease-specific survival than the pure PTC group (97.2%) (P < 0.001); however, the < 50% PDC group (94.7%) did not (P = 0.91). The PTC with ≥ 50% PDC group had a significantly higher NLR than the pure PTC (P < 0.001) and the PTC with < 50% PDC groups (P < 0.001), whereas there was no significant difference in the NLR between the pure PTC and the PTC with < 50% PDC groups (P = 0.48).

CONCLUSIONS

PTC with ≥ 50% PDC is more aggressive than either pure PTC or PTC with < 50% PDC, and NLR potentially reflects the PDC proportion. These results support the validity of 50% PDC as a cut-off for PDTC diagnosis and indicate the utility of NLR as a biomarker for PDC proportion.

Nomogram incorporating preoperative clinical and ultrasound indicators to predict aggressiveness of solitary papillary thyroid carcinoma

Objective

To construct a nomogram based on preoperative clinical and ultrasound indicators to predict aggressiveness of solitary papillary thyroid carcinoma (PTC).

Methods

Preoperative clinical and ultrasound data from 709 patients diagnosed with solitary PTC between January 2017 and December 2020 were analyzed retrospectively. Univariate and multivariate logistic regression analyses were performed to identify the factors associated with PTC aggressiveness, and these factors were used to construct a predictive nomogram. The nomogram's performance was evaluated in the primary and validation cohorts.

Results

The 709 patients were separated into a primary cohort (n = 424) and a validation cohort (n = 285). Univariate analysis in the primary cohort showed 13 variables to be associated with aggressive PTC. In multivariate logistic regression analysis, the independent predictors of aggressive behavior were age (OR, 2.08; 95% CI, 1.30-3.35), tumor size (OR, 4.0; 95% CI, 2.17-7.37), capsule abutment (OR, 2.53; 95% CI, 1.50-4.26), and suspected cervical lymph nodes metastasis (OR, 2.50; 95% CI, 1.20-5.21). The nomogram incorporating these four predictors showed good discrimination and calibration in both the primary cohort (area under the curve, 0.77; 95% CI, 0.72-0.81; Hosmer-Lemeshow test, P = 0.967 and the validation cohort (area under the curve, 0.72; 95% CI, 0.66-0.78; Hosmer-Lemeshow test, P = 0.251).

Conclusion

The proposed nomogram shows good ability to predict PTC aggressiveness and could be useful during treatment decision making.

Advances in knowledge

Our nomogram-based on four indicators-provides comprehensive assessment of aggressive behavior of PTC and could be a useful tool in the clinic.

Strategies for Radioiodine Treatment: What’s New

Radioiodine treatment (RAI) represents the most widespread and effective therapy for differentiated thyroid cancer (DTC). RAI goals encompass ablative (destruction of thyroid remnants, to enhance thyroglobulin predictive value), adjuvant (destruction of microscopic disease to reduce recurrences), and therapeutic (in case of macroscopic iodine avid lesions) purposes, but its use has evolved over time. Randomized trial results have enabled the refinement of RAI indications, moving from a standardized practice to a tailored approach. In most cases, low-risk patients may safely avoid RAI, but where necessary, a simplified protocol, based on lower iodine activities and human recombinant TSH preparation, proved to be just as effective, reducing overtreatment or useless impairment of quality of life. In pediatric DTC, RAI treatments may allow tumor healing even at the advanced stages. Finally, new challenges have arisen with the advancement in redifferentiation protocols, through which RAI still represents a leading therapy, even in former iodine refractory cases. RAI therapy is usually well-tolerated at low activities rates, but some concerns exist concerning higher cumulative doses and long-term outcomes. Despite these achievements, several issues still need to be addressed in terms of RAI indications and protocols, heading toward the RAI strategy of the future.

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.

Upregulated SLC27A2/FATP2 in differentiated thyroid carcinoma promotes tumor proliferation and migration

Background

Differentiated thyroid carcinoma (DTC) accounts for the vast majority of thyroid cancer (TC) cases. The rapidly increasing incidence of TC requires the urgent identification of new diagnostic and therapeutic targets. Solute carrier family 27 member 2 (SLC27A2/FATP2) plays an essential role in lipid biosynthesis and fatty acid transport. Recent studies have confirmed its involvement in a variety of diseases, including cancer.

Methods

In this study, the expression of SLC27A2 was analyzed in cancer and paracancerous tissue samples from 98 thyroid cancer patients, and we performed ROC analysis to confirm the diagnostic value. CCK8, Transwell, and other methods were used to study its effect on DTC, and the mechanism of SLC27A2 was investigated by RNA sequencing and Western blot.

Results

The expression of SLC27A2 was upregulated in both DTC tissues and cell lines and was correlated with clinical progression. In vitro studies further confirmed that SLC27A2 knockdown attenuated the proliferation and invasion of DTC cells. Through RNA sequence analysis and gene set enrichment analysis, we found that the MAPK pathway is the main downstream signaling pathway for the regulation by SLC27A2. SLC27A2 affects cell proliferation and differentiation by inducing changes in the proto‐oncogene C‐FOS.

Conclusions

Our results show that SLC27A2 plays an important role in tumor proliferation and migration, providing a new putative target for the diagnosis and treatment of TC.

Comparative efficacy and safety of tyrosine kinase inhibitors for thyroid cancer: a systematic review and meta-analysis

The tyrosine kinase inhibitors (TKIs) sorafenib, lenvatinib, vandetanib, and cabozantinib are currently used for thyroid cancer treatment; however, the differences in their clinical efficacy and toxicity remain unclear. This meta-analysis assessed the efficacy and toxicity of these four TKIs based on 34 studies. The pooled incidence of partial response (PR), stable disease (SD), TKI-related adverse events (AEs), and pooled median progression-free survival (PFS) were calculated with 95% confidence intervals (CI). Complete response to TKIs was extremely rare (0.3%). The highest PR rate and longest PFS were observed for lenvatinib in differentiated thyroid cancer (69%, 95% CI: 57-81 and 19 months, 95% CI: 9-29, respectively) and vandetanib in medullary thyroid cancer (40%, 95% CI: 25-56 and 31 months, 95% CI: 19-43, respectively). Although the discontinuation rate due to AEs was similar for each TKI, there was a difference in the most frequently observed AE for each TKI (hand-foot syndrome for sorafenib, hypertension and proteinuria for lenvatinib, and QTc prolongation for vandetanib). The identified differences in the TKI efficacy and AE profiles may provide a better understanding of thyroid cancer treatment. Although TKIs are promising agents for thyroid cancer treatment, they are unlikely to lead to a cure. Thus, even in the TKI era, a multimodal treatment including surgery, radioiodine therapy, external beam radiotherapy, and TKIs is required to optimize patient chances of improved survival.

VCAM-1 Upregulation Contributes to Insensitivity of Vemurafenib in BRAF-Mutant Thyroid Cancer

Vemurafenib, an inhibitor of mutant BRAF activity, is a promising anticancer agent for patients with BRAF-mutant metastatic melanoma. However, it is less effective in BRAF-mutant thyroid cancer, and the reason for this discrepancy is not yet fully elucidated. By RNA sequencing analysis, we identified vascular cell adhesion molecular-1 (VCAM-1) to be highly upregulated in both time- and dose-dependent manners during BRAF inhibition (BRAFi) in a BRAF-mutant papillary thyroid cancer cell line (BCPAP). Cell cytotoxicity and apoptosis assays showed that knockdown of the induced VCAM-1 in BCPAP cells augmented the antitumor effects of vemurafenib, with decreased IC50 values of 1.4 to 0.8 μM. Meanwhile, overexpression of VCAM-1 in a BRAF-mutant anaplastic thyroid cancer cell line (FRO) reduced the sensitivity to vemurafenib, with increased IC50 values of 1.9 to 5.8 μM. Further investigation showed that PI3K-Akt-mTOR pathway was activated during BRAFi. Co-treatment with Akt signaling inhibitor MK2206 decreased the induced expression of VCAM-1 during BRAFi. This combination further improved the efficacy of vemurafenib. Moreover, VCAM-1 promoted migration and invasion in thyroid cancer cells in vitro, which was also indicated in thyroid cancer patients. The present study is the first to demonstrate that VCAM-1 is upregulated in thyroid cancer cells treated with vemurafenib and contributes to vemurafenib resistance in BRAF-mutant thyroid cancer cells. Targeting the PI3K-Akt-mTOR pathway–mediated VCAM-1 response may be an alternative strategy to sensitize BRAF-mutant thyroid cancers to vemurafenib.

Radioiodine refractoriness score: A multivariable prediction model for postoperative radioiodine-refractory differentiated thyroid carcinomas

OBJECTIVE

The purpose of the present study was to evaluate the clinical features of patients with radioiodine refractory (RAIR) differentiated thyroid carcinoma (DTC) and establish an effective risk score for postoperative radioiodine refractoriness.

SUBJECTS AND METHODS

Data were retrospectively collected from 5163 patients admitted to our center after thyroid surgery. Radioiodine refractoriness was defined according to criteria used in the 2015 American Thyroid Association guidelines. The scoring system was established by independent risk factors identified by univariate and multivariate analyses. The optimal index points for predicting the prevalence of radioiodine refractoriness and the model discriminatory power were assessed by receiver operating characteristic (ROC) curves.

RESULTS

One hundred and twelve (2.2%) patients developed RAIR DTC. Smoking, tumor type (follicular thyroid cancer), extrathyroid extension, lymph node metastasis number (≥4), lymph node metastasis rate (≥53%), and pN stage (N1) were highly positively correlated with the prevalence of RAIR DTC. The cutoff value of seven points was found to be the best for predicting the prevalence of RAIR DTC, and the scoring system presented better discrimination than other single independent predictors.

CONCLUSIONS

Based on our multivariable prediction model, patients with ≥7 index points may need to undergo more active surveillance or aggressive treatment due to the high risk of RAIR DTC.

Whole-Exome Sequencing Identifies Two Discrete Druggable Signaling Pathways in Follicular Thyroid Cancer

BACKGROUND

Thyroid cancer is the most common endocrine malignancy, with continuously increasing incidence. Follicular thyroid cancer (FTC) accounts for approximately 10% to 15% of these cases and is known to be associated with several gene mutations. The purpose of this study was to identify novel therapeutic targets in FTC using whole-exome sequencing (WES) and bioinformatics analysis.

STUDY DESIGN

Whole-exome sequencing was performed on 6 established FTC cell lines. Stringent false-proof filtering and exclusion of synonymous and known polymorphisms yielded novel missense, nonsense, and splice-site single nucleotide variants (SNV). Gene variants were analyzed for structural, functional, and evolutionary properties using GO (Gene Ontology), Pfam (Protein Families), and KEGG (Kyoto Encyclopedia of Genes and Genomes) searches by STRING (Search Tool for the Retrieval of Interacting Genes/Proteins) and GORILLA (Gene Ontology enRIchment anaLysis and visuaLizAtion tool) analyses. A false discovery rate of <0.5 was used to denote significantly enriched signaling pathways.

RESULTS

An average of 657 (range 366 to 1,158) SNVs including 31 (range 12 to 53) known cancer driver genes were identified in FTC cell line exomes. The SNV burden, distribution, frequency, and signature followed the known thyroid mutation profiles, without chromosomal bias. Recurrently mutated cancer driver genes included FRG1 (6/6), CDC27, NCOR1, PRSS1 (5/6), AHCTF1, MUC20, PABPC1, and PABPC3 (4/6). Pathway analysis using bioinformatics tools STRING and GORILLA segregated FTC cell lines into 2 druggable signaling groups showing dominant RAS/ERK1-2/AKT and CDK1/CyclinB signaling pathway targets.

CONCLUSIONS

Next-generation sequencing tools can be used to identify druggable signaling targets for precision treatment of FTCs.

Prognostic indicators of outcomes in patients with lung metastases from differentiated thyroid carcinoma during long-term follow-up

BACKGROUND

Distant metastases, although uncommon, represent maximum disease-related mortality in differentiated thyroid carcinoma (DTC). Lungs are the most frequent sites of metastases. We aimed to evaluate long-term outcomes and identify prognostic factors in metastatic DTC limited to the lungs.

METHODS

This retrospective study included 89 patients with DTC and metastases limited to the lungs, who were treated between 1996 and 2012 at Samsung Medical Center. Progression-free survival (PFS) and cancer-specific survival (CSS) rates were evaluated according to clinicopathologic factors. Cox regression analysis was used to identify independent factors associated with structural progressive disease (PD) and cancer-specific death.

RESULTS

With a median follow-up of 84 months, the 5- and 10-year CSS rates were 78% and 73%, respectively. Older age at diagnosis (≥55 years), radioactive iodine (RAI) nonavidity, preoperative or late diagnosis of metastasis and macro-nodular metastasis (≥1 cm) were predictive of decreased PFS and CSS. Multivariate analysis identified older age (P = .002), RAI nonavidity (P = .045) and preoperative (P = .030) or late diagnosis (P = .026) as independent predictors of structural PD. RAI avidity was also independent predictor of cancer-specific death (P = .025).

CONCLUSION

Patients with DTC and metastatic disease limited to the lungs had favourable long-term outcomes. Age, RAI avidity and timing of metastasis were found to be major factors for predicting prognosis.

The diagnostic and prognostic values of Ki-67/MIB-1 expression in thyroid cancer: a meta-analysis with 6,051 cases

Background

Growing evidence has demonstrated that Ki-67/MIB-1 has an effect on the clinical progression and prognosis in cancers. However, the diagnostic and prognostic values of Ki-67/MIB-1 in thyroid cancer remain unclear.

Materials and methods

The meta-analysis was conducted in accordance with Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Studies were retrieved from PubMed, EBSCO, EMBASE, ISI Web of Science, China National Knowledge Infrastructure, WanFang and Chinese VIP databases. MetaDiSc and STATA12.0 were used to analyze the meta-analysis. Fixed-effect analysis and random-effect analysis were applied to pool the relative ratio based on heterogeneity in this meta-analysis.

Results

In the meta-analysis, 51 eligible studies were included. The pooled sensitivity of Ki-67/MIB-1 was 0.61 (95% confidence interval [CI]: 0.59–0.63) and specificity was 0.75 (95% CI: 0.74–0.77) in thyroid cancer. The pooled positive likelihood ratio was 3.19 (95% CI: 2.30–4.42) and negative likelihood ratio was 0.43 (95% CI: 0.35–0.54). In the diagnosis of thyroid cancer, the pooled diagnostic odds ratio of Ki-67/MIB-1 was 8.54 (95% CI: 5.03–14.49). The area under the symmetric receiver operating characteristic curve was 0.804 (standard error =0.031). Our results showed that there were statistical associations between Ki-67/MIB-1 and age (odds ratio [OR] =1.71, 95% CI: 1.14–2.57, P=0.010), tumor size (OR =1.86, 95% CI: 1.17–2.96, P=0.008), lymph node metastasis (OR =2.49, 95% CI: 1.42–4.39, P=0.002), metastasis status (OR =6.96, 95% CI: 2.46–19.69, P<0.001), tumor node metastasis stage (OR =6.56, 95% CI: 3.80–11.34, P<0.001) and extrathyroid extension (OR =1.91, 95% CI: 1.27–2.87, P=0.002). Furthermore, thyroid cancer patients with a high level of Ki-67/MIB-1 had a worse disease-free survival as compared to patients with a low level of Ki-67/MIB-1 (hazard ratio =5.19, 95% CI: 3.18–8.46, P<0.001). Also, Ki-67/MIB-1 was found to be associated with increased risk of mortality (hazard ratio =3.56, 95% CI: 1.17–10.83, P=0.025).

Conclusion

Our results demonstrated that Ki-67/MIB-1 might act as a potential factor in diagnosing thyroid cancer in Chinese. Also, the meta-analysis indicated that Ki-67/MIB-1 might have an effect on prognosis in non-Chinese thyroid cancer patients.

Natural history of thyroid cancer [Review]

Thyroid cancers have long been considered to arise in middle age and, after their repeated proliferation, resulting in further damage to the genome, they progress to more aggressive and lethal cancers. However, in 2014, some studies were reported that might lead to a marked change in our understanding of the natural history of thyroid cancer. A high prevalence of papillary carcinoma in the young suggested that the first initiation of thyroid cancer is likely to occur in the infantile period. Such a conclusion was also supported by a very slow growth rate of papillary microcarcinomas (PMCs) in an observation trial. The proliferation rate of PMCs was negatively correlated with the age, and surgery to remove PMCs did not contribute to reduce mortality from thyroid cancer. These findings strongly suggested the existence of self-limiting cancers, which are truly malignant but do not progress to lethal cancers, for the first time in human history. The early detection of self-limiting cancers results in overdiagnosis. Ultrasonographic screening of the thyroid in the young should be avoided. Lethal thyroid cancers, whose origin is still unknown, appear suddenly after middle age. In the elderly, thyroid cancers are a mixture of self-limiting and lethal cancers; thus, when thyroid cancer is detected, careful follow-up with examination of its growth rate is required.

DEATH RELATED TO PULMONARY METASTASIS IN PATIENTS WITH DIFFERENTIATED THYROID CANCER

OBJECTIVE

The purpose of the present study was to investigate the predictive factors for shorter disease-specific survival in patients with pulmonary disease secondary to differentiated thyroid cancer (DTC).

METHODS

This was a retrospective cohort study conducted over a 5-year period that included 54 patients with pulmonary disease secondary to DTC during the follow-up. Among these patients, 13 (24.1%) died from the disease. Dedifferentiation characteristics were identified at pathological examination of the metastatic disease (lymph node or distant metastases) and was defined as the abrupt transformation of a well-differentiated tumor into high-grade morphology lacking the original distinct histologic characteristics.

RESULTS

Tumor dedifferentiation marked by cellular aberrations and radioiodine (RAI) therapy resistance occurred in 5 (9.3%) patients. Four of them died due to pulmonary progression (80.0%), and the median survival of this group was 30 months compared to 279 months in the patients without dedifferentiation. The cumulative disease-specific survival was 20.0% in the patients with dedifferentiation during the follow-up versus 46.1% among the cases without this condition (P = .003, log-rank test). Moreover, dedifferentiation was independently associated with shorter disease-specific survival (hazard ratio [HR] = 31.607; 95% confidence interval [CI]: 4.815-207.478; P<.0001, Cox regression model) as were age over 45 years (HR = 10.904; 95% CI: 1.145-103.853; P = .038) and male sex (HR = 4.210; 95% CI: 1.056-16.783; P = .042).

CONCLUSION

DTC patients with pulmonary disease exhibited shorter disease-specific survival, particularly those who developed tumor dedifferentiation, and these patients require special attention during follow-up.

ABBREVIATIONS

CI = confidence interval DTC = differentiated thyroid cancer FTC = follicular thyroid carcinoma HR = hazard ratio IQR = interquartile range LN = lymph node LR = likelihood ratio PTC = papillary thyroid carcinoma RAI = radioiodine pTNM = pathologic tumor-node-metastasis stage system.

A Comprehensive Characterization of Mitochondrial Genome in Papillary Thyroid Cancer

Nuclear genetic alterations have been widely investigated in papillary thyroid cancer (PTC), however, the characteristics of the mitochondrial genome remain uncertain. We sequenced the entire mitochondrial genome of 66 PTCs, 16 normal thyroid tissues and 376 blood samples of healthy individuals. There were 2508 variations (543 sites) detected in PTCs, among which 33 variations were novel. Nearly half of the PTCs (31/66) had heteroplasmic variations. Among the 31 PTCs, 28 specimens harbored a total of 52 somatic mutations distributed in 44 sites. Thirty-three variations including seven nonsense, 11 frameshift and 15 non-synonymous variations selected by bioinformatic software were regarded as pathogenic. These 33 pathogenic mutations were associated with older age (p = 0.0176) and advanced tumor stage (p = 0.0218). In addition, they tended to be novel (p = 0.0003), heteroplasmic (p = 0.0343) and somatic (p = 0.0018). The mtDNA copy number increased in more than two-third (46/66) of PTCs, and the average content in tumors was nearly four times higher than that in adjacent normal tissues (p < 0.0001). Three sub-haplogroups of N (A4, B4a and B4g) and eight single-nucleotide polymorphisms (mtSNPs) (A16164G, C16266T, G5460A, T6680C, G9123A, A14587G, T16362C, and G709A) were associated with the occurrence of PTC. Here we report a comprehensive characterization of the mitochondrial genome and demonstrate its significance in pathogenesis and progression of PTC. This can help to clarify the molecular mechanisms underlying PTC and offer potential biomarkers or therapeutic targets for future clinical practice.

Tyrosine-kinase inhibitors to treat radioiodine-refracted, metastatic, or recurred and progressive differentiated thyroid carcinoma [Review]

Differentiated thyroid carcinoma (DTC) is generally indolent in nature and, even though it metastasizes to distant organs, the prognosis is normally excellent. In contrast, the overall survival (OS) of patients with radioactive iodine (RAI)-refractory and progressive metastases is dire, because no effective therapies have been available to control the metastatic lesions. However, recently, administration of tyrosine-kinase inhibitors (TKIs) has become a new line of therapy for RAI-refractory and progressive metastases. Previous studies have reported significant improvement regarding the progression-free survival rates of patients with metastatic lesions. However, TKIs cause various severe adverse events (AEs) that damage patients' quality of life and can even be life-threatening. Additionally, metastatic lesions may progress significantly after stopping TKI therapy. Therefore, it is difficult to determine who is a candidate for TKI therapy, as well as how and when physicians start and stop the therapy. The present review, created by Committee of pharmacological therapy for thyroid cancer of the Japanese Society of Thyroid Surgery (JSTS) and the Japan Association of Endocrine Surgeons (JAES) describes how to appropriately use TKIs by describing what we do and do not know about treatment using TKIs.

[Treatment of patients with radioiodine refractory, differentiated thyroid carcinoma. A Consensus Statement]

There is no clear standard therapy for patients with radioactive iodine (131I)-refractory locally advanced or metastatic differentiated thyroid cancer. The therapeutic options for this indication have expanded with the recently approved multiple kinase inhibitor sorafenib. Recommendations for the definition and the management of iodine refractory patients were worked up by an interdisciplinary expert panel, consisting of endocrine surgeons, medical oncologists and nuclear medicine specialists.

Static and dynamic prognostic factors of papillary thyroid carcinoma

The two types of prognostic factors of papillary thyroid carcinoma (PTC) are static and dynamic. The following static prognostic factors have been conventionally adopted: age, tumor size, extrathyroid extension, lymph node metastasis, and distant metastasis based on pre-, intra- and post-operative findings. These factors are useful to decide therapeutic strategies for PTC patients, including the extent of surgery and radioactive iodine (RAI) ablation. However, even the combination of these factors evaluated pathologically postoperatively is not good enough at predicting recurrence in clinical settings. The dynamic prognostic factors of changes in serum thyroglobulin (Tg) and thyroglobulin antibody (TgAb) values in patients who have undergone a total thyroidectomy are important to evaluate the progression of carcinoma recurrence and to predict patients' cause-specific survival, regardless of their backgrounds and the clinicopathological features of their PTC. Dynamic prognostic factors are superior to static prognostic factors in terms of expressing the condition of recurrence on a real-time basis.