Increasing thyroid cancer incidence in Canada, 1970-1996: time trends and age-period-cohort effects

Impact of thyroid hormone replacement on the risk of second cancer after thyroidectomy: a Korean National Cohort Study

We aimed to investigate the effect of thyroid hormone administration on the risk of second primary cancer in patients who underwent thyroidectomy for differentiated thyroid cancer. Data were extracted from the medical billing data of the Health Insurance Review and Assessment Service in South Korea. Patients between 19 and 80 years old who underwent thyroid surgery at least once between January 2009 and June 2020 were included. Data of patients with second primary cancer and control patients with matched age, sex, operation date, and follow-up duration were extracted at a ratio of 1:4. A nested case-control analysis was performed to exclude length bias to confirm the correlation between the duration of thyroid hormone administration, dose, and incidence of second primary cancer. Of the 261,598 patients who underwent surgery for thyroid cancer included in the study, 11,790 with second primary cancer and 47,160 without second primary cancer were matched. The average dose of thyroid hormone increased the adjusted odds ratio (OR) for both low (≤ 50 μg, OR 1.29, confidence interval (CI) 1.12-1.48) and high (< 100 μg, OR 1.24, CI 1.12-1.37) doses. Analyzing over time, the adjusted OR of second primary cancer increased, especially in short (≤ 1 year) (OR 1.19; CI 1.06-1.34) and long (> 5 years) duration (OR 1.25; CI 1.10-1.41). In conclusion, insufficient and excessive thyroid hormone replacement might be linked to increased second primary cancer in patients who underwent thyroidectomy for differentiated thyroid cancer.

Impact of thyroid cancer on the cancer risk in patients with non-alcoholic fatty liver disease or dyslipidemia

The raised prevalence of obesity has increased the incidence of obesity-related metabolic diseases such as dyslipidemia (DL) and non-alcoholic fatty liver disease (NAFLD), along with the development and progression of various types of cancer, including thyroid cancer. In this study, we investigated whether thyroid cancer in patients with DL and NAFLD could be a risk factor for other cancers. To achieve our goal, we generated two independent cohorts from our institution and from the National Health Insurance System in South Korea. Based on the ICD-10 code, we conducted exact matching (1:5 matching) and estimated the overall risk of thyroid cancer for other cancers in patients with DL or NAFLD. Univariate and multivariate analyses showed that the hazard ratio (HR) of thyroid cancer was 2.007 (95% Confidence Interval [CI], 1.597-2.522) and 2.092 (95% CI, 1.546-2.829), respectively in the institutional cohort and 1.329 (95% CI, 1.153-1.533) and 1.301 (95% CI, 1.115-1.517), respectively in the nationwide cohort. Risk analysis revealed a significant increase in the HR in lip, tongue, mouth, lung, bone, joint, soft tissue, skin, brain, male cancers and lymphoma after thyroid cancer occurred. Thyroid cancer in patients with DL or NAFLD might be a valuable factor for predicting the development of other cancers.

Access to diagnostic imaging and incidental detection of differentiated thyroid cancer in Ontario: A population-based retrospective cohort study

Global increases in thyroid cancer incidence (≥90% differentiated thyroid cancers; DTC) are hypothesized to be related to increased use of pre-diagnostic imaging. These procedures can detect DTC during imaging for conditions unrelated to the thyroid (incidental detection). The objectives were to evaluate incidental detection of DTC associated with standardized, regional imaging capacity and drivetime from patient residence to imaging facility (the exposures). We conducted a population-based retrospective cohort study of 32,097 DTC patients in Ontario, 2003-2017. We employed sex-specific spatial Bayesian hierarchical models to evaluate the exposures and examine the adjusted odds of incidental detection by administrative regions. Regional capacities of computed tomography and magnetic resonance imaging scanners are positively associated with incidental detection, but vary by sex. Contrary to hypothesis, drivetimes in urban areas are positively associated with incidental detection. Access to primary care may play a role in several administrative regions with higher adjusted odds of incidental detection.

Hashimoto's Thyroiditis and Papillary Cancer Thyroid Coexistence Exerts a Protective Effect: a Single Centre Experience

Papillary thyroid carcinoma (PTC) is the most common malignant tumour of the thyroid and it is often found in association with Hashimoto's thyroiditis (HT). This concomitance is still under debate. The aim of this study is to investigate the influence of Hashimoto's thyroiditis in patients with papillary thyroid carcinoma. Two thousand two hundred eighteen patients underwent thyroidectomy in our department between January 2015 and January 2020. Of these, 435 patients had surgery for papillary thyroid carcinoma and form the basis of our studies. The association between PTC and HT was found in 180 patients (41.4%), mostly represented in the female group (78.9%), with a lower median age than patients with PTC without HT. In comparison to patients with PTC alone, the PTC-HT group had less invasive and smaller tumours, as well as less lymph node involvement. Moreover, tumours of patients with PTC-HT were diagnosed earlier. Our data showed that Hashimoto's thyroiditis may be considered a protective factor when PTC develops. Furthermore, we concluded that patients with PTC and HT had a better prognosis and a lower risk of recurrence than those that did not have HT.

Incidence and prognosis of thyroid cancer in children: based on the SEER database

OBJECTIVE

To update the recognition of the trends in the incidence of childhood thyroid cancer (TC) and its prognosis.

METHODS

A large-scale sample based on long time-line public database was recruited. Join-point regression model was used to analyze the incidence trend of childhood TC. Univariable and multivariable Cox regression model analyses were applied to explore the survival situation and prognostic factors.

RESULTS

The incidence rate of childhood TC increased between 1975 and 2016 from 3.8/million (95% CI 2.6-5.5) to 11.5/million (95% CI 9.2-14.1), AAPC = 2.38% (95% CI 1.98-9.65) and could be divided into two stages of increasing trends. The incidence rate of Trend1 (1975-2005) increased slowly (APC = 1.08%, 95% CI 0.38-1.82) while Trend2 (2005-2016) increased dramatically (APC = 6.77%, 95% CI 4.30-9.28). Annual incidence rate of small size tumor (< 4 cm) and local stage childhood TC increased significantly. The overall cumulative survival rate for childhood TC was high up to 97-99%. Males, black race, MTC type, distant metastasis, tumor size ≥ 4 cm, non-primary cancer were the independent risk factors of childhood TC prognosis.

CONCLUSION

A contribution of overdetection to rising pediatric TC rates might not be able to rule out. For clinical implications, screening TC in children with potential specific risk factors is feasible. Over-treatment to small size and local stage TC in children should be avoided.

The comparison of microbial communities in thyroid tissues from thyroid carcinoma patients

Thyroid carcinoma is a common endocrine organ cancer associated with abnormal hormone secretion, leading to the disorder of metabolism. The intestinal microbiota is vital to maintain digestive and immunologic homeostasis. The relevant information of the microbial community in the gut and thyroid, including composition, structure, and relationship, is unclear in thyroid carcinoma patients. A total of 93 samples from 25 patients were included in this study. The results showed that microbial communities existed in thyroid tissue; gut and thyroid had high abundance of facultative anaerobes from the Proteobacteria phyla. The microbial metabolism from the thyroid and gut may be affected by the thyroid carcinoma cells. The cooccurrence network showed that the margins of different thyroid tissues were unique areas with more competition; the stabilization of microcommunities from tissue and stool may be maintained by several clusters of species that may execute different vital metabolism processes dominantly that are attributed to the microenvironment of cancer.

Changing incidence and projections of thyroid cancer in mainland China, 1983-2032: evidence from Cancer Incidence in Five Continents

PURPOSE

An increasing incidence of thyroid cancer has been seen in China during the past several decades. The aim of this study was to analyze potential age, period, and cohort effects on the incidence of thyroid cancer in mainland China and to predict new cases up to 2032.

METHODS

We calculated age-adjusted and age-specific incidence rates of thyroid cancer, conducted an age-period-cohort analysis of 35,037 thyroid cancer incidence cases reported to Cancer Incidence in Five Continents from 1983 to 2012 in mainland China, and predicted incidence up to 2032 using the Bayesian age-period-cohort method.

RESULTS

The age-adjusted overall incidence rate of thyroid cancer increased from 1.93/100,000 in 1983-1987 to 12.18/100,000 in 2008-2012 among females and from 0.77/100,000 in 1983-1987 to 3.89/100,000 in 2008-2012 among males, with a female-to-male ratio of approximately 3.0 during the three decades. Strong birth cohort and period effects on the incidence of thyroid cancer were observed for both sexes, and such an increasing trend is predicted to continue for at least the next 20 years. More than 3.7 million new cases are projected in the 2028-2032 period.

CONCLUSION

The increasing trend of thyroid cancer in mainland China will cause a great burden in the future. In addition to the potential impact of improvement in medical diagnostics, potential exposure to risk factors have played a role in the observed rising trend. Further population-based epidemiologic studies are required to identify risk factors to aid in thyroid cancer prevention and control.

Management of thyroid cancer: results from a German and French patient survey

OBJECTIVE

Various national and international guidelines for the management of thyroid cancer exist. The aim of this survey was to evaluate whether patients experience differences regarding the management of thyroid cancer in Germany and in France.

METHODS

An online survey addressing diagnosis, treatment, aftercare, and information needs of thyroid cancer survivors was set up by the German and the French nationwide thyroid cancer self-help organizations. The survey consisted of up to 70 questions depending on the given answers. Descriptive statistics and univariate comparisons, if appropriate, for comparing thyroid cancer survivors in Germany and France were performed.

RESULTS

In total, 1254 thyroid cancer survivors took part in the survey, of whom 1005 were included in the analysis, 618 from Germany and 387 from France. Remarkable differences between the two countries were observed regarding waiting times, diagnostics, surgical complications, radioiodine treatment, and aftercare of the patients. A high disease burden and lack of information regarding the condition and its treatment were reported in both countries.

CONCLUSION

This large survey showed that despite various guidelines for the management of thyroid cancer, thyroid cancer survivors' experiences are noticeably different between two big European countries. Lack of information and unmet needs are still tasks to be addressed in order to optimize thyroid cancer care.

Trend dynamics of thyroid cancer incidence among China and the U.S. adult population from 1990 to 2017: a joinpoint and age-period-cohort analysis

BACKGROUND

Thyroid cancer (TC) is the most common malignant disease of the endocrine system. Based on the previously published reports, the incidence of TC has been increasing in the past 25 years, and the reason for the increase is not yet clear. The present study aims to reveal the long-term trends and age-period-cohort effects for the incidence of TC in China and the U.S. from 1990 to 2017.

METHODS

We examined the trends of TC incidence and the average annual percentage change (AAPC) of rate using the Joinpoint regression analysis in the two countries, for the different genders (men/women) in the Global Burden of Disease (GBD 2017). We further used an age-period-cohort model to analyze age-period-cohort effects on TC incidence.

RESULTS

The ASIR of China increased markedly with AAPC of 4.5% (95% confidence interval (CI): 4.0, 5.0%) and 1.8% (1.6, 2.0%) for men and women during 1990-2017. The ASIR of the U. S increased by 1.4% (1.0, 1.8%) and 1.3% (0.9, 1.7%) for men and women from 1990 to 2017.TC increased with the age and period. Aging was one of the most influential factors of TC in China. The age effect increased markedly in the U.S. compared with China. The period effect showed an increase in China while that tended to grow steadily during 1990-2017 in the U.S. The cohort effect peaked in 1963-1967 birth cohorts for men and women in China and declined consistently in the birth cohort in the U.S.

CONCLUSION

From 1990 to 2017, due to ionizing radiation and over-diagnosis, age-standardized TC incidence rates in both genders rose in China and the U.S. The standardized incidence rate of women is higher than that of men. It is necessary to provide women with reasonable prevention and protection measures for TC. We need to apply for health services and screening to reduce ionizing radiation.

Impact of Dyslipidemia on the Risk of Second Cancer in Thyroid Cancer Patients: A Korean National Cohort Study

BACKGROUND

Studies have shown that radioactive iodine therapy (RAIT) affects the development of second cancer in thyroid cancer patients. The impact of other factors, such as dyslipidemia are not clear.

METHODS

A retrospective analysis of thyroid cancer patients with a 1,251,913 person-year follow-up was conducted using data from the Health Insurance Review and Assessment database in South Korea from January 2008 to December 2018. We investigated factors related to second cancer development using a nested case-control analysis to avoid length bias.

RESULTS

The overall risk of developing second cancer was higher in thyroid cancer patients than in the general population [standardized incidence ratio, 3.34; 95% confidence interval (CI) 3.30-3.39]. Second cancer incidence was higher in patients who received RAIT than in those who did not [odds ratio (OR) 1.130; 95% CI 1.094-1.169]. Moreover, the risk of second cancer was higher in patients with dyslipidemia than in those without dyslipidemia (OR 1.265; 95% CI 1.223-1.309). After adjustment for RAIT, the incidence of a second cancer was higher in patients with dyslipidemia than in those without dyslipidemia (OR 1.262; 95% CI 1.221-1.306).

CONCLUSIONS

The risk of second cancer development in patients with thyroid cancer appears to be high. Dyslipidemia may be associated with an increased risk of several types of second cancers.

Genetic Landscape of Papillary Thyroid Carcinoma and Nuclear Architecture: An Overview Comparing Pediatric and Adult Populations

Thyroid cancer is a rare malignancy in the pediatric population that is highly associated with disease aggressiveness and advanced disease stages when compared to adult population. The biological and molecular features underlying pediatric and adult thyroid cancer pathogenesis could be responsible for differences in the clinical presentation and prognosis. Despite this, the clinical assessment and treatments used in pediatric thyroid cancer are the same as those implemented for adults and specific personalized target treatments are not used in clinical practice. In this review, we focus on papillary thyroid carcinoma (PTC), which represents 80-90% of all differentiated thyroid carcinomas. PTC has a high rate of gene fusions and mutations, which can influence the histologic subtypes in both children and adults. This review also highlights telomere-related genomic instability and changes in nuclear organization as novel biomarkers for thyroid cancers.

Incidental detection, imaging modalities and temporal trends of differentiated thyroid cancer in Ontario: a population-based retrospective cohort study

BACKGROUND

Incidence rates of thyroid cancer in Ontario have increased more rapidly than those of any other cancer, whereas mortality rates have remained relatively stable. We evaluated the extent to which incidental detection of differentiated thyroid cancer during unrelated prediagnostic imaging procedures contributed to Ontario's incidence rates.

METHODS

We conducted a retrospective cohort study involving Ontarians who received a diagnosis of differentiated thyroid cancer from 1998 to 2017 using linked health care administrative databases. We classified cases as incidentally detected if a nonthyroid diagnostic imaging test (e.g., computed tomography [CT]) preceded an index event (e.g., prediagnostic fine-needle aspiration biopsy); all other cases were nonincidentally detected cases. We used Joinpoint and negative binomial regressions to characterize sex-specific rates of differentiated thyroid cancer by incidentally detected status and to quantify potential age, diagnosis period and birth cohort effects.

RESULTS

The study included 36 531 patients with differentiated thyroid cancer, of which 78.7% were female. Incidentally detected cases increased from 7.0% to 11.0% of female patients and from 13.5% to 18.2% of male patients over the study period. Age-standardized incidence rates increased more rapidly for incidentally detected cases (4.2-fold for female and 3.7-fold for male patients) than for nonincidentally detected cases (2.6-fold for female and 3.0-fold for male patients; p < 0.001). Diagnosis period was the primary factor associated with increased incidence rates of differentiated thyroid cancer, adjusting for other factors. Within each period, incidentally detected rates increased faster than nonincidentally detected rates, adjusting for age. Our results showed that CT was the most common imaging procedure preceding incidentally detected diagnoses.

INTERPRETATION

Incidentally detected cases represent a large and increasing component of the observed increases in differentiated thyroid cancer in Ontario over the past 20 years, and CT scans are primarily associated with these cases despite the modality having similar, increasing rates of use compared with magnetic resonance imaging (1993-2004). Recent increases in rates of differentiated thyroid cancer among males and incidentally detected cases among females in Ontario appear to be unrelated to birth cohort effects.

Changes in the Demographic and Clinicopathological Characteristics of Thyroid Cancer: A Population-Based Investigation in Algeria, 1993-2013

Over the last three decades, the incidence of thyroid cancer has increased worldwide. The reasons for this increase remain controversial. In Algeria, however, to date, information on thyroid cancer has been limited to a hospital-based case series. We analyzed data from a population-based cohort study in Oran District, Algeria, to describe demographic and clinicopathological characteristics of patients diagnosed with thyroid cancer between 1993 and 2013. Medical records and pathology reports of thyroid cancer patients who had surgery were reviewed. Changes in demographic and clinicopathological features over the 21-year period are described. During the study period, thyroid cancer was diagnosed in 1248 women (86.5%, mean age 43.7 ± 15.2 years) and 195 men (23.4%, mean age 48.1 ± 15.9 years). Most cases (83.1% for women and 69.8% for men) sought a diagnosis following a self-neck check. The most common histologic types were papillary (58.3%), follicular (29.7%), anaplastic (4.1%), and medullary (0.8%) carcinomas. The incidence of papillary carcinomas significantly increased (p < 0.001) while the incidence of other histologic types significantly decreased over time. Tumor size overall significantly decreased (p < 0.001) while the frequency of small (≤20 mm) and larger (>20 mm) carcinomas significantly increased (p < 0.05). The frequency of thyroid cancers with capsular effractions and angioinvasions also decreased over time. Thyroid cancer incidence in Algeria has increased substantially in line with international trends with changes in clinical practice being a possible contributing factor. However, the increasing papillary-to-follicular cancer ratio may be due to changes in iodine nutrition status in Algeria. Further research, including exploration of biological and molecular features of thyroid cancer, will enable a better understanding of risk factors and etiopathogenetic mechanisms.

Long non-coding RNA DLEUI promotes papillary thyroid carcinoma progression by sponging miR-421 and increasing ROCK1 expression

We investigated the role of long non-coding RNA DLEU1 (deleted in lymphocytic leukemia 1) in the progression of papillary thyroid carcinoma (PTC). DLEU1 levels were higher in PTC cell lines (BHP5-16, TPC-1,8505C, and SW1736) and patient tissues (n=54) than in a human thyroid follicular epithelial cell line (Nthy-ori3-1) or adjacent normal thyroid tissues. High DLEU1 expression correlated positively with lymph node metastasis and advanced clinical stages in PTC patients. Bioinformatics, dual luciferase reporter, and RNA pulldown assays confirmed that DLEU1 directly binds to miR-421. Moreover, bioinformatics and dual luciferase reporter assays showed that miR-421 directly binds to the 3'untranslated region of the rho-related coiled-coil kinase 1 (ROCK1) in TPC-1 cells. PTC patient tissues and cell lines showed high ROCK1 mRNA and protein levels as well as low miR-421 levels. CCK-8, flow cytometry, wound healing, and Transwell invasion assays demonstrated that DLEU1 silencing decreases TPC-1 cell proliferation, survival and progression, but they can be rescued by miR-421 knockdown or ROCK1 overexpression. DLEU1 knockdown in TPC-1 cells decreased in vivo xenograft tumor size and weight compared to controls in nude mice. These findings demonstrate that DLEU1 promotes PTC progression by sponging miR-421 and increasing ROCK1 expression.

A rapidly increasing trend of thyroid cancer incidence in selected East Asian countries: Joinpoint regression and age-period-cohort analyses

BACKGROUND

This study described the incidence and mortality trends and analyzed age-period-cohort effects on incidences in China, Japan, and Korea.

METHODS

Data were extracted from the Cancer Incidence in Five Continents series and the World Health Organization Cancer Mortality Database, and the age-standardized incidence and mortality rates by Segi's world population were calculated. Joinpoint regression analysis was used to evaluate the time trend of age-standardized incidence and mortality rates and the age-period-cohort model with intrinsic estimator was applied for estimating the effects of age, period, and cohort on thyroid cancer (TC) incidence in individuals between 20 and 84 years of age.

RESULTS

An increasing trend in TC incidence rates was observed among males from China (10.3%), Japan (4.7%), and Korea (20.8%) and among females from China (9.4%), Japan (3.5%), and Korea (20.5%). TC incidence rates in females were much higher than those in males. A downward trend of TC mortality rates was observed, especially in both sexes of Japan and Chinese females. The slope of the age effect curve peaked at an earlier age in females than males in Japan and Korea. A strong period effect and remarkedly increasing rate ratios were observed in all regions and for both sexes. The cohort effect had a declining tendency on TC incidence in males and females in these areas.

CONCLUSIONS

The rapidly upward incidence trend and strong period effect suggest that overdiagnosis caused by higher diagnostic intensity might be an explanation for the upward trend, and some environmental risk factor exposures are also not excluded. In addition, the discrepant trends of TC incidence and mortality reveal the need to identify the few high-risk patients who needed further treatment from those patients who may not need treatment.

Incidental versus clinically diagnosed differentiated thyroid cancer in both adult and elderly subjects: histological characteristics and follow-up in a retrospective analysis from a single institution

PURPOSE

Most thyroid cancer are incidentally diagnosed. However, little is known on the different modalities of incidental diagnosis in adult versus older patients.

METHODS

We retrospectively analyzed data from 440 patients consecutively diagnosed with differentiated thyroid cancer (DTC) in a single institution. Modalities of diagnosis were categorized as follows: (A) clinically diagnosed, nonincidental cases; (B) incidental during carotid power-duplex (CPD); (C) incidental during neck imaging other than carotid power-duplex; (D) incidental during imaging workup of thyroid dysfunction or at histological examination after thyroidectomy for benign lesions. Demographics, histology and follow-up were compared between adult (<65 years) and older (≥65 years) patients according to the different modalities of diagnosis.

RESULTS

A total of 363 and 67 cases were recorded in adult and older patients, respectively with incidental proportions of 79% and 85%, respectively. A P < 0.001 significant difference in the modality of diagnosis was found between adult and older subjects, the latter presenting with a higher prevalence of Group B. In the nonincidental group, papillary histotype, larger size, and extrathyroidal invasion were more frequently observed in older subjects. Disease-free survival was comparable between adult and older subjects in the incidental cases, whereas it was reduced, though not significantly, in older subjects.

CONCLUSION

Incidental cases of DTC are more frequently diagnosed in the old subjects and are mainly due to CPD. Disease-free survival is comparable between adult and older subjects in both incidental and nonincidental cases, although it may be slightly reduced in nonincidentally diagnosed older patients.

Bounding Analyses of Age-Period-Cohort Effects

For more than a century, researchers from a wide range of disciplines have sought to estimate the unique contributions of age, period, and cohort (APC) effects on a variety of outcomes. A key obstacle to these efforts is the linear dependence among the three time scales. Various methods have been proposed to address this issue, but they have suffered from either ad hoc assumptions or extreme sensitivity to small differences in model specification. After briefly reviewing past work, we outline a new approach for identifying temporal effects in population-level data. Fundamental to our framework is the recognition that it is only the slopes of an APC model that are unidentified, not the nonlinearities or particular combinations of the linear effects. One can thus use constraints implied by the data along with explicit theoretical claims to bound one or more of the APC effects. Bounds on these parameters may be nearly as informative as point estimates, even with relatively weak assumptions. To demonstrate the usefulness of our approach, we examine temporal effects in prostate cancer incidence and homicide rates. We conclude with a discussion of guidelines for further research on APC effects.

Thyroid cancer: incidence and mortality trends in China, 2005-2015

PURPOSE

Understanding secular trends of thyroid cancer is critical to plan strategies for cancer prevention and control. Our aim was to estimate the incidence and mortality trends of thyroid cancer in China during 2005-2015.

METHODS

A retrospective cohort evaluation of thyroid cancer cases and deaths during 2005-2015 was performed using population-based data from the Chinese Cancer Registry Annual Report. The incidence and mortality rates of thyroid cancer were stratified by gender, age group (0, 1-4, 5-9, 10-14…80-84, 85-), and area (urban or rural). A Joinpoint regression model was used to examine secular trends.

RESULTS

In China, the age-standardized incidence was 3.21/10⁵ in 2005, and increased to 9.61/10⁵ in 2015. Besides, a significant increase incidence rate was observed with the average annual percent change (AAPC) of 12.4% (95% CI: 10.5%-14.4%) in the period 2005-2015. The age-standardized mortality was 0.30/10⁵ in 2005 and 0.35/10⁵ in 2015, and the AAPC was 2.9% (95% CI: 1.3%-4.5%). For both incidence and mortality, the rates of thyroid cancer were much higher in females than in males, and in urban areas rather than rural areas; however, the rates of increasing trends showed no significant differences. With respect to the highest age-specific rates, it appeared in the age group of 50-54 years old for incidence and in the age group of 80-84 years old for mortality. Notably, the rate of increasing incidence trend was lower in older age groups, especially for people aged 70-79 years old.

CONCLUSION

A rapid increase in incidence and a moderate increase in mortality of thyroid cancer were observed from 2005 to 2015 in our study. Effective measures and tailored programs should be taken to curb the growth trend and reduce the disease burden.

Microscopic Positive Tumor Margin Increases Risk for Disease Persistence but Not Recurrence in Patients with Stage T1-T2 Differentiated Thyroid Cancer

Introduction

Differentiated thyroid cancer (DTC) has an overall excellent prognosis. Patients who develop recurrent disease have a more unfavorable disease course than those with no recurrence. Higher recurrence rates are seen with incomplete surgical resection and gross positive margins. It is unclear whether microscopic positive margin affects disease recurrence rates as much as grossly positive margin. Aim of the Study. To assess whether microscopic positive margin is an independent predictor of disease recurrence in patients with overall low-risk DTC. Patients and Methods. We conducted a retrospective single-center institutional review of 1,583 consecutive patients' charts from 1995–2013 using the Canadian Thyroid Cancer Consortium Registry. We included adult patients with nonmetastasizing T1 and T2 DTC with a minimum of three years follow-up. Univariate and multivariate analyses were used to study factors that may influence the risk of persistent/recurrent disease. Strict definitions of persistent versus recurrent disease were applied.

Results

963 patients (152 men and 811 women) were included in the study with a mean age of 46 years. Microscopic positive margins were present in 12% of the specimens and were associated with an increased rate of persistent disease (8% versus 2% in the controls) but not with an increased risk of recurrent disease (1% in both groups). T2 tumors had a significantly higher incidence of positive margins than T1 tumors (48% versus 36%) and significantly higher nodal staging.

Conclusions

Microscopic positive margin in the histopathology report in patients with low-risk DTC was associated with a higher rate of persistent disease but did not increase the risk of disease recurrence. A close follow-up of biomarkers and occult residual cancerous lesions is needed, especially in the first year. Further studies are needed to determine whether additional therapeutic measures to prevent recurrence are indicated in T1 and T2 DTC with positive microscopic surgical margins.

Differentiated thyroid carcinoma: a 5-years survival study at a referral hospital in Brazil

BACKGROUND

Although the prognosis of differentiated thyroid carcinoma (DTC) therapy is considered excellent over time, some cases have a poorer prognosis and evolve into death.

OBJECTIVE

This study aimed to estimate the 5-year specific survival and to identify prognosis factors in a cohort of DTC adult subjects.

METHODS

Survival probability was estimated by Kaplan-Meier's method in a retrospective hospital-based cohort study. Comparisons were made by log-rank test. Prognosis factors were identified using Cox risk modeling and crude and adjusted Hazard Ratio measures were obtained. Two models were estimated, considering age grouping of the 7th and 8th editions of TNM.

RESULTS

Specific 5-year survival in the cohort was 98.5% (95%CI: 94.2 - 97.5). Considering TNM 7th edition, the risk estimates were 9.88 (95%CI: 1.67 - 58.33) for age group ≥ 55 years, 18.87 (95%CI: 7.38 - 48.29) for individuals with distant metastasis, 6.36 (95%CI: 2.26 - 17.91) for patients who underwent lymphadenectomy and 0.16 (95%CI: 0.06 - 0.43) for those who received radioiodine therapy. For TNM 8th edition, the risk estimates were 10.12 (95%CI: 2.05 - 50.09) for age group ≥ 55 years, 12.43 (95%CI: 4.58 - 33.77) for individuals with distant metastasis, 5.06 (95%CI: 1.82 - 14.05) for patients who underwent lymphadenectomy and 0.19 (95%CI: 0.07 - 0.51) for those who received radioiodine therapy.

CONCLUSIONS

This cohort had a very high survival over a 5-year period. The prognosis was negatively influenced by age, distant metastasis and lymphadenectomy, whereas radioiodine therapy was found to be protective.

Ku80 gene knockdown by the CRISPR/Cas9 technique affects the biological functions of human thyroid carcinoma cells

In the present study, to evaluate the role of Ku80 in thyroid carcinoma (TC), 86 thyroid tissue samples from patients with a spectrum of thyroid disorders were examined for protein levels of Ku80, nuclear factor-κB (NF-κB) and RET/TC by immunohistochemistry. Furthermore, in TC cells, Ku80 mRNA was detected by reverse transcription-quantitative PCR analysis and silenced using the clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR-associated protein 9 (Cas9) technique to assess its role. An antibody array was used to identify Ku80-related regulatory genes. The protein levels of Ku80 in the TC tissues were significantly higher than those in non-neoplastic adjacent tissue samples (P<0.01). The activation of NF-kB and expression of RET/TC in the TC group were significantly increased (P<0.05) and were correlated with the protein expression of Ku80 (P<0.05). In papillary TC cells, the mRNA levels of Ku80 were high; Ku80 knockdown resulted in reductions in proliferation, invasion and colony formation, increased apoptosis, and reduced levels of proteins involved in MAPK signaling, cell proliferation and apoptosis. The high expression of Ku80 in TC was found to be associated with the expression of RET/TC and activation of NF-κB, and Ku80 knockdown decreased the malignancy of TC cells.

Primary versus Tertiary Care Follow-Up of Low-Risk Differentiated Thyroid Cancer: Real-World Comparison of Outcomes and Costs for Patients and Health Care Systems

BACKGROUND

An unprecedented rise in the prevalence of low-risk well-differentiated thyroid cancer (TC) has been reported in several countries, which is partly due to an increased utility of sensitive imaging techniques. The outcome of these cancers has generally remained excellent and the overall 5-year survival is almost 100%. However, the extended follow-up strategy for these patients remains unclear and while the initial management is done in specialist centres some experts opt to follow them on a long-term basis while others discharge them to primary care after the initial management. The effectiveness of one strategy versus the other has not been studied.

METHODS

We conducted a real-world comparison to assess the outcome of low-risk TC (AJCC stage I) with undetectable thyroglobulin (TG) 2 years after radio-iodine (I-131) therapy. The outcome from Halifax (NS, Canada) and London (ON, Canada), where all TC patients are routinely followed by the tertiary care team, was compared with that from Edmonton (AB, Canada), where patients are routinely discharged to primary care.

RESULTS

All patients were diagnosed between January 1, 2006, and December 31, 2011. The mean follow-up in primary care after discharge was 62.2 months and in tertiary care it was 64.6 months (p = 0.43). Rates of recurrence were similar in both groups, i.e., 1.1% in primary care and 1.3% in tertiary care (p = 0.69). Ultrasound surveillance was conducted in 56.5% of the patients in primary care and 52.6% of the tertiary care group (p = 0.26). The rate of annual unstimulated TG testing per patient was 0.58 (range 0-14) in primary care and 0.96 (range 0-6) in tertiary care (p = 0.06). More patients in primary care (86%) than in tertiary care (29.9%) consistently had thyroid-stimulating hormone levels within the target range (p < 0.001). The mean healthcare cost, based on a single follow-up visit with a blood test and ultrasound in the primary care group was CAD 118.01 and in the tertiary care group it was CAD 164.12.

CONCLUSION

Our study shows that extended follow-up of low-risk TC patients is perfectly feasible in primary care and provides significant economic benefit for the healthcare system.

MicroRNA‑873 inhibits the progression of thyroid cancer by directly targeting ZEB1

Recent evidence has revealed that certain microRNAs (miRNAs) are dysregulated in thyroid cancer (TC), which has been associated with the pathogenesis and development of TC. Therefore, improved understanding of the detailed roles of miRNAs that are aberrantly expressed in TC may aid the development of valuable therapeutic methods for the management of patients with this malignancy. In this study, miRNA‑873‑5p (miR‑873) expression in TC tissues and cell lines was detected by reverse‑transcription quantitative polymerase chain reaction (RT‑qPCR). MTT and cell invasion assays were performed to investigate the effects of miR‑873 overexpression on TC cell proliferation and invasion in vitro. Bioinformatics analysis, luciferase reporter assay, RT‑qPCR and western blot analysis were employed to evaluate whether zinc finger E‑box‑binding homeobox 1 (ZEB1) is a direct target of miR‑873 in TC cells. The present study reported that miR‑873 was weakly expressed in human TC tissues and cell lines. Functionally, miR‑873 overexpression suppressed TC cell proliferation and invasion in vitro. Mechanistically, ZEB1 was predicted to be a putative target of miR‑873. In addition, miR‑873 was proposed to directly bind to the 3'‑untranslated region of ZEB1 and decrease its expression in TC cells at the mRNA and protein levels. Furthermore, ZEB1 expression was significantly upregulated in TC tissues and negatively correlated with miR‑873 expression. Furthermore, ZEB1 restoration partially reversed the suppressive effects of miR‑873 overexpression on TC cell proliferation and invasion. These results demonstrated that miR‑873 may serve tumour‑suppressive roles in the progression of TC, and its suppressive effects could be mediated by the inhibition of ZEB1. Therefore, miR‑873 may be a valuable therapeutic target in the management of patients with TC.

MicroRNA‑744 suppresses cell proliferation and invasion of papillary thyroid cancer by directly targeting NOB1

MicroRNAs (miRs) serve important roles in the formation and progression of papillary thyroid cancer (PTC) by regulating numerous physiological and pathological behaviours. Thus, investigating the functional roles of specific miRNAs in PTC may contribute in identifying effective therapeutic targets for the management of patients with PTC. miR‑744 is emerging as a cancer‑associated miRNA in numerous types of human cancers; however, the expression and specific functions of miR‑744 in PTC are yet to be determined, and the mechanism underlying the regulatory roles of miR‑744 in PTC remains unknown. In the present study, miR‑744 expression was significantly decreased in PTC tissues and cell lines, as detected by reverse transcription‑quantitative polymerase chain reaction. miR‑744 restoration inhibited cell proliferation and invasion in PTC. Bioinformatics analysis predicted NIN1 (RPN12) binding protein 1 homolog (NOB1) as a potential target of miR‑744. Subsequent experiments validated NOB1 as a direct target gene of miR‑744 in PTC. Furthermore, NOB1 was upregulated in PTC tissues and negatively correlated with miR‑744 expression. NOB1 overexpression could counteract miR‑744‑mediated antitumor effects on PTC cells. In summary, these findings indicated that miR‑744 may inhibit the progression of PTC by directly targeting NOB1. The identification of the miR‑744/NOB1 axis may provide insight into potential targets for the treatment of patients with PTC and improve their prognosis.

An 18-year study of thyroid carcinoma in the western region of Saudi Arabia: a retrospective single-center study in a community hospital

BACKGROUND

Thyroid carcinoma (TC) is the ninth most common site of all cancers in women in the world and the second most common malignancy in Saudi Arabia. This reports updates data on the epidemiology of the disease in Saudi Arabia.

OBJECTIVE

Describe and interpret changes in the frequency of TC to compare with other populations and determine proportions of certain histological types of TC.

DESIGN

Medical record review.

SETTING

Military hospital in Jeddah, Saudi Arabia.

PATIENTS AND METHODS

We reviewed the pathological and clinical records from January 2000 to December 2017 of patients with TC.

MAIN OUTCOME MEASURES

Frequency and types of TC.

SAMPLE SIZE

347 patients.

RESULTS

Over the 18-year period, out of 456 patients with TC, 347 patients had sufficiently complete records: 275 (79.3%) were female and 72 (20.7%) were male for a female to male ratio of 3.8:1. The mean (SD) age at surgery of all patients was 45.2 (16.0) years. There were 287 (82.7%) cases of papillary TC. The next common malignancy was follicular TC with 32 (9.2%) cases followed by Hurthle cell cancer with 11 (3.2%) cases. Lymphoma was found in only 7 (2%) cases. All TC types occurred at a younger age in females than males except for lymphoma. All TC types occurred with the greatest frequency in the fourth and fifth decades. There was a 2.3-fold increase in the number of TCs from 8 (2.3%) in 2000 to 26 (7.5%) in 2017. The rate per 100000 residents of Jeddah increased for the period from 2000 to 2002 from 1.6 to 3.4 for 2015-2017. Papillary TC cases in females accounted for most of the increase.

CONCLUSION

Our findings are consistent with similar studies worldwide. Etiological factors promoting the rise in TC must be investigated and may provide insight in developing suitable management strategies for the Saudi population.

LIMITATION

Small sample size and retrospective over a long period.

CONFLICT OF INTEREST

None.

Incidence and Survival of Thyroid Cancer in Children, Adolescents, and Young Adults in Denmark: A Nationwide Study from 1980 to 2014

BACKGROUND

Thyroid cancer constitutes a major and increasing proportion of head and neck cancers in children and adolescents. The purpose of this study was to determine the incidence and survival of thyroid cancer in Danish patients aged 0-24 years from 1980 to 2014.

METHODS

Patients aged 0-24 years registered with primary thyroid cancer in the Danish Cancer Registry or the Danish Pathology Data Bank during 1980-2014 were included. Crude incidence rates and age-adjusted incidence rates (AAIR) per 100,000, average annual percent change (AAPC), and overall survival (OS) were evaluated in relation to sex, histopathological tumor type, age at diagnosis, and year of diagnosis.

RESULTS

A total of 297 thyroid cancer patients (72% female, 72% papillary carcinoma) were identified. The AAIR per 100,000 increased significantly from 0.36 in 1980 to 0.97 in 2014, with an AAPC of 2.9%. There was no significant increase in incidence among children and adolescents (0-17 years). However, among young adults (18-24 years), a significant increase in incidence was observed (AAPC 3.7%). The incidence of thyroid cancer increased with age from 0.05 among infants aged 0 years to 1.73 among young adults aged 24 years. Female patients and papillary carcinoma showed significant increase in incidence (AAPC 3.3% and 3.2%), whereas male patients and other histopathological tumor types showed no change. The 15-year OS was 99%. The lowest 15-year OS was observed among patients with medullary carcinomas at 96%. There was no significant difference in OS between groups based on histopathological tumor type, and there was no significant change in OS over time.

CONCLUSION

In this nationwide study, no change in OS was observed, but a significant increase was seen in the incidence of thyroid cancer among young adults (aged 18-24 years), mainly attributed to an increase among females and patients with papillary carcinoma. No increase in incidence was seen among children and adolescents. These findings demonstrate the excellent prognosis for children and adolescents diagnosed with thyroid cancer.

Thyroid Cancer Incidences From Selected South America Population-Based Cancer Registries: An Age-Period-Cohort Study

PURPOSE

The incidence of thyroid cancer (TC) has increased substantially worldwide. However, there is a lack of knowledge about age-period-cohort (APC) effects on incidence rates in South American countries. This study describes the TC incidence trends and analyzes APC effects in Cali, Colombia; Costa Rica; Goiânia, Brazil; and Quito, Ecuador.

MATERIALS AND METHODS

Data were obtained from the Cancer Incidence in Five Continents series, and the crude and age-standardized incidence rates were calculated. Trends were assessed using the estimated annual percentage change, and APC models were estimated using Poisson regression for individuals between age 20 and 79 years.

RESULTS

An increasing trend in age-standardized incidence rates was observed among women from Goiânia (9.2%), Costa Rica (5.7%), Quito (4.0%), and Cali (3.4%), and in men from Goiânia (10.0%) and Costa Rica (3.4%). The APC modeling showed that there was a period effect in all regions and for both sexes. Increasing rate ratios were observed among women over the periods. The best fit model was the APC model in women from all regions and in men from Quito, whereas the age-cohort model showed a better fit in men from Cali and Costa Rica, and the age-drift model showed a better fit among men from Goiânia.

CONCLUSION

These findings suggest that overdiagnosis is a possible explanation for the observed increasing pattern of TC incidence. However, some environmental exposures may also have contributed to the observed increase.

Risk stratification of 282 differentiated thyroid cancers found incidentally in 1369 total thyroidectomies according to the 2015 ATA guidelines; implications for management and treatment

Introduction The purpose of this study was to evaluate the incidence of incidental differentiated thyroid carcinoma in thyroid operations for a benign preoperative diagnosis, to identify the risk factors involved and to risk stratify the cancer patients according to the 2015 American Thyroid Association (ATA) guidelines. Materials and methods The study was a retrospective review of all thyroidectomy operations performed in a single institution (January 2004 to January 2009). We excluded patients with a preoperative diagnosis of thyroid malignancy. Results Incidental differentiated thyroid carcinoma was diagnosed in 282/1369 patients (21%). The incidental group had a significantly higher number of males (19% vs 14%, P = 0.033) and a higher number of patients with histopathological evidence of thyroiditis (35% vs 25%, P = 0.004). There was a higher number of lymph nodes present in the incidental group but numbers did not reach statistical significance (17% vs 13%, P = 0.079). There were 270 cases in the ATA low-risk group (96%) and 12 cases in the ATA intermediate-risk group (4%). Patients with an ATA intermediate risk had a statistically higher number of capsule invasion, extrathyroidal extension and angioinvasion (P < 0.001, P < 0.001 and P < 0.001, respectively). Overall, 22% of patients with an incidental differentiated thyroid carcinoma should be considered for radioactive iodine 131I treatment. 29 of the 191 patients in American Joint Committee on Cancer stage I should be considered for radioactive iodine treatment (15%). Conclusions Males and patients with thyroiditis are at a higher risk for an incidental differentiated thyroid carcinoma. One of every five of patients diagnosed with cancer will need radioactive iodine treatment, even some patients with stage I disease.

miR-622 suppresses tumor formation by directly targeting VEGFA in papillary thyroid carcinoma

Background

MicroRNAs (miRNAs) were reportedly to play crucial roles in papillary thyroid carcinoma (PTC) tumorigenesis and development. Therefore, the discovery of miRNAs may provide a new and powerful tool for diagnosis and treatment of PTC.

Purpose

The aim of this study was to investigate the biological function and underlying mechanism of miR-622 in PTC.

Materials and methods

The expression levels of miR-622 in PTC patient tissues and cell lines were determined by quantitative RT-PCR (qRT-PCR). The biological function including cell proliferation, colony formation, migration and invasion, as well as underling mechanism of miR-622 in PTC, were also evaluated by a series of in vitro and in vivo experiments.

Results

miR-622 expression level was significantly downregulated in PTC tissues and cell lines. Decreased miR-622 expression was associated with advanced clinical stage and lymph node metastasis (P<0.01). The overexpression of miR-622 in TPC-1 cells inhibited cell proliferation, migration and invasion in vitro, as well as suppress tumor growth in vivo. Moreover, we also demonstrated that miR-622 specifically targeted the 3'-UTR regions of vascular endothelial growth factor A (VEGFA) and inhibited its expression both mRNA level and protein levels. Overexpression of VEGFA reversed miR-622-mediated inhibition effect on cell proliferation, migration and invasion in thyroid cancer cells. More importantly, VEGFA expression was significantly increased and inversely correlated with the levels of miR-622 in PTC tissues.

Conclusion

These results show that miR-622 acts as a tumor suppressor in thyroid cancer, at least in part, via targeting VEGFA, and suggest that miR-622 may serves as a potential target for treatment of thyroid cancer patients.

Thyroid cancer: trends in incidence, mortality and clinical-pathological patterns in Zhejiang Province, Southeast China

Background

Thyroid cancer is the most common malignant disease of the endocrine system. Previous studies indicate a rapid increase in the incidence of thyroid cancer in recent decades, and this increase has aroused the great public concern. The aim of this study was to analyze the trends in incidence, mortality and clinical-pathological patterns of thyroid cancer in Zhejiang province.

Methods

Population-based incidence and mortality rates of thyroid cancer were collected from eight cancer registries in Zhejiang from 2000 to 2012. The incidence and mortality rates were age-standardized to Segi’s world population. A Joinpoint model was used to examine secular trends in age-adjusted thyroid cancer rates with the Joinpoint Regression Program Version 4.0.0. Thyroid cancer patients were recruited from Zhejiang Cancer Hospital from 1972 to 2014. Patient demographics, tumor histology and tumor size were compared among the different periods of 1972–1985, 1986–1999 and 2000–2014.

Results

The age-standardized incidence rate of thyroid cancer in Zhejiang cancer registries was 2.75/10⁵ in 2000, and increased to 19.42/10⁵ in 2012. Additionally, we observed significantly increasing incidence rates with the Annual Percent Change (APC) of 22.86% (95%CI, 19.2%–26.7%). The age-standardized mortality of thyroid cancer in Zhejiang cancer registries was 0.23/10⁵ in 2000 and 0.25/10⁵ in 2012. No significant change in mortality rate was found. We observed a rapid increase in the proportions of papillary thyroid carcinoma (PTC) in 12,508 patients with thyroid carcinoma identified in the Zhejiang Cancer Hospital from 1972 to 2014 while the proportions of poorly differentiated thyroid cancer (PDTC), medullary thyroid carcinoma (MTC) and follicular thyroid carcinoma (FTC) decreased over the decades. In the PTC cases, the proportion of patients with maximum tumor diameter (MTD) < 1 cm dramatically and significantly increased from 0 in 1972–1985 to 32.1% in 2000–2014.

Conclusions

A rapid increase in incidence and a stable trend in mortality of thyroid cancer were found in the distribution of thyroid cancer. Most of the increased incidence was PTC, especially the papillary thyroid microcarcinoma (PTMC) with MTD < 1 cm. This increase in incidence might be due to increased diagnosis with advanced technology.

MiR-574-5p mediates the cell cycle and apoptosis in thyroid cancer cells via Wnt/β-catenin signaling by repressing the expression of Quaking proteins

Thyroid cancer is the most frequently occurring type of endocrine tumor, with a rapidly increasing incidence rate. MicroRNA (miR)-574-5p is a candidate oncogene in various types of cancer. The present study identified that miR-574-5p affected the cell cycle distribution and apoptosis of BCPAP and FTC133 thyroid cancer cells via β-catenin/Wnt signaling by targeting Quaking proteins (QKIs). An MTT assay demonstrated that the knockdown of miR-574-5p suppressed the proliferation of the thyroid cancer cells. Fluorescence-activated cell sorting analysis demonstrated that the inhibition of miR-574-5p induced the G₁/S phase arrest and apoptosis of the cells. Reverse transcription-quantitative polymerase chain reaction and western blot analyses revealed that the knockdown of miR-574-5p significantly upregulated the mRNA and protein expression levels of QKIs. Furthermore, western blot analysis identified that the knockdown of miR-574-5p also repressed the Wnt/β-catenin pathway via downregulating the expression of β-catenin, cyclin D1 and survivin, and upregulating the phosphorylation of β-catenin. The further depletion of QKIs in combination with the knockdown of miR-574-5p not only increased the expression of β-catenin, cyclin D1 and survivin, but also rescued the apoptosis of thyroid cancer cells induced by the miR-574-5p knockdown. In conclusion, these findings indicated that the aberrant upregulation of miR-574-5p may be oncogenic, through regulating the Wnt/β-catenin pathway by targeting QKIs.

Incidence and histological patterns of thyroid cancer in Sri Lanka 2001-2010: an analysis of national cancer registry data

BACKGROUND

An increasing incidence of thyroid cancer is observed in many developed countries. Increasing incidence may also reflect better reporting or increased diagnostic scrutiny. We conducted this study to examine trends in thyroid cancer incidence and histological patterns in Sri Lanka.

METHODS

A retrospective cohort evaluation of patients with thyroid cancer during 2001-2010 was performed using population based data published from the Sri Lanka National Cancer Registry. Trends in incidence and histological patterns were analysed by age and gender.

RESULTS

The age-standardized incidence of thyroid cancer increased from 2.44 per 100,000 in 2001 (95% confidence interval [95% CI]: 2.21-2.67) to 5.16 per 100,000 in 2010 (95% CI: 4.85-5.47); a 2.1-fold increase (p < 0.05 for trend). A greater part of this increase is attributable to increase in incidence of papillary thyroid cancer, which increased from 1.64 to 3.61 per 100,000; a 2.2-fold increase (p < 0.05 for trend). Follicular cancer showed lesser, yet a significant increase from 0.56 to 0.95 per 100,000 (p < 0.05). Other varieties of thyroid cancer showed no significant increases in incidence. Trends in the increases in incidence of papillary cancer in females showed a much greater increase compared with males (from 2.45 to 5.60 per 100,000, a 2.28-fold increase in females compared with from 0.82 to 1.55; a 1.89-fold increase in males, p < 0.001). Highest incidence of papillary cancer was observed in 30-39-year age group, which has increased from 5.56 to 12.9 per 100,000; a 2.32-fold increase (p < 0.001).

CONCLUSIONS

The increasing incidence of thyroid cancer in Sri Lanka is predominantly due to the increasing incidence of papillary cancers. These trends may reflect increased detection and better reporting, although an inherent increase in the incidence is the likely main contributor. Further studies including tumour stage and mortality may help answer these questions.

MicroRNA-613 inhibits cell growth, migration and invasion of papillary thyroid carcinoma by regulating SphK2

MicroRNAs (miRNAs) have emerged as important gene regulators and are recognized as key players in carcinogenesis. In this study, we investigated the biological function and mechanism of miR-613 in the regulation of papillary thyroid cancer (PTC) development. We found that miR-613 was downregulated in PTC cell lines and tissues, and overexpression of miR-613 significantly suppressed PTC cell growth, migration and invasion in vitro and inhibited tumor growth in vivo. We identified the gene for sphingosine kinase 2 (SphK2) as a direct target of miR-613. Overexpression of miR-613 significantly repressed SphK2 expression by directly targeting its 3'-untranslated regions (3'-UTR) and restoration of SphK2 reversed the inhibitory effects of miR-613 on PTC cell growth and invasion. Taken together, our results indicated that miR-613 functions as a tumor suppressor in PTC and its suppressive effect is mediated by repressing SphK2 expression.

Growing incidence of thyroid carcinoma in recent years: Factors underlying overdiagnosis

There is an increasing incidence of well-differentiated thyroid cancer worldwide. Much of the increase is secondary to increased detection of small, low-risk tumors, with questionable clinical significance. This review addresses the factors that contribute to the increasing incidence and considers environmental, and patient-based and clinician-led influences. Articles addressing the causes of the increased incidence were critically reviewed. A complex interplay of environmental, medical, and social pressures has resulted in increased awareness of the thyroid disease risk, increased screening of thyroid cancers, and increased diagnosis of thyroid cancers. Although there is evidence to suggest that the true disease incidence may be changing slightly, most of the increase is related to factors that promote early diagnosis of low-risk lesions, which is resulting in a significant phenomenon of overdiagnosis. An improved understanding of these pressures at a global level will enable healthcare policymakers to react appropriately to this challenge in the future.

How Many Contralateral Carcinomas in Patients with Unilateral Papillary Thyroid Microcarcinoma are Preoperatively Misdiagnosed as Benign?

BACKGROUND

The decision to perform a total thyroidectomy (TT) for unilateral papillary thyroid microcarcinoma (PTMC) with nodules in the contralateral lobe remains controversial. The aim of this study was to investigate the rate of contralateral carcinomas that are preoperatively misdiagnosed as benign.

METHODS

From October 2011 to October 2015, a total of 347 patients with unilateral PTMC and contralateral benign nodules who were treated with a TT at a single institution were enrolled. All patients underwent preoperative fine needle aspiration and ultrasonography (US). Clinicopathological features such as age, sex, laterality, tumor size, central lymph node metastases, capsular invasion, TgAb and TPOAb levels, Hashimoto's thyroiditis, nodule number in both lobes according to preoperative US, and primary carcinoma number in the final postoperative pathology report were all analyzed to investigate the rate and predictive factors of contralateral carcinoma.

RESULTS

A total of 100 patients (28.9 %) were diagnosed with papillary thyroid carcinoma in the contralateral lobe. A multivariate analysis showed that tumor size, nodule number in the contralateral lobe, and multifocality of the primary tumor were all independent predictive factors of contralateral carcinoma in patients with unilateral PTMC and contralateral benign nodules.

CONCLUSIONS

According to our findings, the rate at which contralateral carcinomas are preoperatively misdiagnosed as benign is 28.9 %. A TT is essential for unilateral PTMC with a primary tumor size >5 mm, multifocal primary carcinomas or multifocal benign nodules in the contralateral lobe.

miR-217 inhibits proliferation, migration, and invasion via targeting AKT3 in thyroid cancer

PURPOSE

The aims of this study were to test the influence of miR-217 on the proliferation, invasion, migration of thyroid cancer and the relevant mechanism.

METHOD

miR-217 expression levels in thyroid cancer tissues and cell lines were detected by quantitative real-time PCR (qRT-PCR).Cell Counting Kit-8, flow cytometer, wound healing, transwell invasion assays were applied to evaluate the effect of miR-217 on proliferation, apoptosis, migration and invasion of thyroid cells. The luciferase reporter assay, qRT-PCR, and western blot were used to identify target of miR-217. Relative relationship of expression level between miR-217 and AKT3 was analyzed in thyroid cancer tissues. Xenograft transplantation was performed to test effect of miR-217 in vivo.

RESULTS

We found that the expression of miR-217 was significantly decreased in thyroid cancer tissues cell lines. Significantly, decreased miR-217 expression were associated with the clinical stage and lymph node metastasis. Function studies revealed that miR-217 overexpression in thyroid cancer cells inhibited proliferation, migration, and invasion in vitro, as well as suppressed tumor growth in vivo. Subsequently, AKT3 was identified as a target of miR-217 in thyroid cancer. AKT3 expression was upregulated in thyroid cancer tissues, was inversely correlated with miR-217expression. Besides, overexpression of AKT3 efficiently abrogates suppressive effect on proliferation, migration and invasion in thyroid cancer cells caused by overexpression of miR-217.

CONCLUSION

These data demonstrated a tumor suppressor role for miR-217 in thyroid cancer development and progression by targeting AKT3, suggesting miR-217 might be a potential target for thyroid cancer.

Thyroid cancer incidence in Canada: a national cancer registry analysis

BACKGROUND

Thyroid cancer incidence rates are increasing in many developed countries while mortality rates remain stable. International evidence shows that the increase in incidence rates is mostly caused by overdiagnosis of small papillary cancers. We sought to describe how thyroid cancer incidence has changed and how it varies between provinces in Canada.

METHODS

Data were obtained from the National Cancer Incidence Reporting System, causes of death tables and the Canadian Cancer Registry using the 1991 census population structure. We report thyroid cancer incidence by sex, age and province and mortality by sex from 1970 to 2012.

RESULTS

Since 1970, age-standardized thyroid cancer incidence rates have increased in women from 3.9 to 23.4 per 100 000 and in men from 1.5 to 7.2 per 100 000 while mortality rates have remained stable at around 0.5 per 100 000 for both sexes. In 2012, incidence rates for both women and men were highest in Ontario (31.5 and 9.2 per 100 000, respectively) and lowest in British Columbia (13.2 and 4.5 per 100 000, respectively). Age-specific incidence rates were the highest in Ontarian women aged 50-54 years, at 65.2 per 100 000.

INTERPRETATION

The rapid increase in thyroid cancer incidence especially since 1990, the variation among provinces and the peak in middle-aged women does not correspond to any known cause or risk factor for disease, although the lack of change in mortality rates suggests that serious thyroid cancer has not increased. The likely cause of the increase in incidence is an overdiagnosis epidemic for clinically unimportant lesions detected by modern diagnostic imaging. To reduce the harms of overtreatment, overdiagnosis should be reduced, through more judicious use of diagnostic imaging.

Causes of referral to the first endocrine visit of patients with thyroid carcinoma in a mildly iodine-deficient area

To evaluate the causes of the first referral to an endocrine visit of patients with thyroid cancer in a mildly iodine-deficient area and to correlate them with prognostic features. We studied 298 consecutive patients (64 M and 234 F) with thyroid cancer. Of these, 281 had differentiated thyroid cancer. The causes of referral were categorized as follows: (Group A) clinical evidence of a neck lump; (Group B) incidental imaging in subjects without known thyroid diseases; (Group C) incidental imaging during a workup of thyroid disorders. Also, in differentiated thyroid cancer cases, clinical, histomorphologic, and prognostic parameters were compared among the three different groups of referral causes. In both total thyroid cancer and differentiated thyroid cancer cohorts, Group A, B, and C accounted for about 25, 35, and 40 % of causes, respectively. Considering the differentiated thyroid cancer, in Group B, ultrasound accounted for 94 % of cases, with 73 % resulting from screening or serendipitous study. Within a median follow-up of 5.6 [IQR: 2.7-9.5] years, disease-free survival was significantly lower in patients of Group A (Log-Rank test p = 0.030 vs. the other groups of causes). However, at the Cox multivariate analysis only male sex (p = 0.002) and stage (p = 0.005), but not referral cause, resulted independent predictors of events. In patients without known thyroid disease, unjustified thyroid ultrasound represents the main cause of referral of thyroid cancer patients to the first endocrine visit. The fact that this is not related to the disease-free survival strengthens the concept of the uselessness of thyroid cancer screening.

Surgical considerations for papillary thyroid microcarcinomas

We reevaluate current treatment recommendations of papillary thyroid microcarcinomas taking into account the indolent behavior of these tumors, and the potential morbidity that may result from an unnecessary surgery. The goals of this communication are to: 1) provide surgeons and endocrinologists with the most up-to-date evidence on management of microcarcinomas, 2) outline appropriate instances for active surveillance, and 3) describe the role of surgical interventions for microcarcinomas including lobectomy, total thyroidectomy, and central neck dissection.

MicroRNA-338-3p inhibits thyroid cancer progression through targeting AKT3

microRNA-338-3p (miR-338-3p) has been implicated in tumor development and progression in many types of cancers. However, the function and mechanism underlying the action of miR-383-3p in thyroid cancer remain unclear and were therefore investigated in this study by in vitro and in vivo experiments. We found that miR-338-3p was downregulated in thyroid cancer tissues and cell lines. miR-338-3p expression was significantly associated with the clinical stage and lymph node metastasis of thyroid cancer. Forced expression of miR-338-3p suppressed thyroid cancer cell proliferation, clonogenicity, migration, and invasion in vitro and inhibited tumorigenesis in a nude mouse xenograft model system. Moreover, AKT3, a known oncogene, was confirmed as a direct target of miR-383-3p in thyroid cancer cells, as evidenced by the fact that ectopic miR-383 expression suppressed AKT3 expression and its downstream pathway (AKT pathway). In addition, AKT3 silencing by siRNA mimicked the effect of ectopic miR-338-3p on the growth and invasion of thyroid cancer cells. In contrast, AKT3 overexpression attenuated the inhibitory effect induced by miR-338-3p overexpression in thyroid cancer cells. These results suggest that miR-338-3p functions as a novel tumor suppressor that blocks thyroid cancer cell growth through targeting AKT3.

Association between Hashimoto's Thyroiditis and Thyroid Cancer in 64,628 Patients

Background

The incidence of thyroid cancer (TC) is increasing although explanatory causes are lacking. A link between cancer and inflammation is well documented but unclear for autoimmune thyroid diseases and TC. We aimed to systematically review the association between Hashimoto’s thyroiditis (HT) and papillary, follicular, medullary, anaplastic thyroid carcinoma, and thyroid lymphoma (TL).

Methods

PubMed, OVID Medline, Google Scholar, and the Cochrane Library were searched from 1955 to 2016. The inclusion criteria were age >18 years, ≥20 cases of HT or TC. We collectively examined the incidence of HT in TC and of TC in HT.

Results

We identified 36 studies (64,628 subjects) published between 1955 and 2016 from 13 countries. We found a relative risk (RR) of HT among papillary thyroid cancer (PTC) of 2.36 [95% confidence intervals (CIs) 1.55–3.29, p < 0.001], an RR of PTC among HT of 1.40 (95% CI 1.07–1.85, p = 0.016), and an RR of TL among HT of 9.74 (95% CI 3.93–24.13, p < 0.001).

Conclusion

We report an association between HT and PTC and between HT and TL. No association was found between HT and follicular, medullary, or anaplastic thyroid cancer.

Evaluation of the presence of Epstein-Barr virus (EBV) in Iranian patients with thyroid papillary carcinoma

BACKGROUND AND PURPOSE

Papillary thyroid carcinoma (PTC) is the most common thyroid cancer. EBV is one of the most important viruses related to different types of malignancies. This study investigated the relationship between EBV and papillary thyroid carcinoma.

MATERIAL AND METHODS

In this study the presence of Epstein-Barr Nuclear Antigen 1 (EBNA1) gene in papillary thyroid carcinoma tissues were examined by nested-PCR method. Paraffin-embedded tissues (N=41) blocks of thyroid cancer were used. DNA was extracted from all samples and then samples were evaluated for the presence of EBV gene.

RESULTS

In 41 samples, EBNA1 was detected in 65.8% of patients with papillary thyroid carcinoma which was significantly higher in younger ages.

CONCLUSION

The significant presence of EBV genome in papillary thyroid carcinoma suggests that this virus may play a role in this cancer especially in younger ages. As a result, monitoring of patients with EBV latent infection for PTC can be very important.

An Approach to Macroscopic Central Lymph Nodes Detected during Surgery in Patients with Thyroid Micropapillary Carcinoma: Should We Resort to Dissection?

Background. High-resolution ultrasonography and the ability to perform fine-needle aspiration biopsy even for nodules smaller than three millimeters have considerably increased the detection rate of thyroid micropapillary carcinoma (TMPC). Despite favorable prognosis, the prevalence of cervical lymph node metastases in patients with TMPC is approximately 30%. Aim. In this study, we aimed to determine the central lymph node metastasis rate and its relation to the characteristics of the tumor. Methods. One hundred nine patients who underwent surgery due to TMPC between December 2009 and January 2014 were analyzed retrospectively. Patients were divided into two groups according to whether they underwent lymph node dissection and the two groups were then compared with respect to tumor size and multicentricity, age, and presence of lymphocytic thyroiditis. Results. There were no statistically significant differences between the two groups of patients in terms of tumor size, tumor multicentricity, age, and presence of lymphocytic thyroiditis. When the patient group that received lymph node dissection was further analyzed, it was found that patients with lymphocytic thyroiditis had a significantly lower number of metastatic lymph nodes. Conclusion. Central lymph node dissection in TMPC patients with macroscopic lymph node detected intraoperatively would ensure accurate staging without an increase in morbidity.

The changing incidence of thyroid cancer

During the past few decades, the incidence of thyroid cancer has increased substantially in many countries, including the USA. The rise in incidence seems to be attributable both to the growing use of diagnostic imaging and fine-needle aspiration biopsy, which has led to enhanced detection and diagnosis of subclinical thyroid cancers, and environmental factors. The latest American Thyroid Association (ATA) practice guidelines for the management of adult patients with thyroid nodules and differentiated thyroid cancer differ substantially from the previous ATA guidelines published in 2009. Specifically, the problems of overdiagnosis and overtreatment of a disease that is typically indolent, where treatment-related morbidity might not be justified by a survival benefit, now seem to be acknowledged. As few modifiable risk factors for thyroid cancer have been established, the specific environmental factors that have contributed to the rising incidence of thyroid cancer remain speculative. However, the findings of several large, well-designed epidemiological studies have provided new information about exposures (such as obesity) that might influence the development of thyroid cancer. In this Review, we describe the changing incidence of thyroid cancer, suggest potential explanations for these trends, emphasize the implications for patients and highlight ongoing and potential strategies to combat this growing clinical and public health issue.

Thyroid Cancer Screening in South Korea Increases Detection of Papillary Cancers with No Impact on Other Subtypes or Thyroid Cancer Mortality

BACKGROUND

The incidence of thyroid cancer has increased worldwide. The country where the incidence has increased most is South Korea. The goal of this study is to understand the magnitude of association between opportunistic thyroid cancer screening and thyroid cancer incidence, thyroid cancer subtype, and disease-specific mortality.

METHODS

We used the 2010 Korea Community Health Survey, which queried 226,873 individuals if they had been screened for thyroid cancer in the last two years. Thyroid cancer incidence data from 2008 to 2010 were obtained from the Korea Cancer registry data, and mortality data from 2007-2010 were obtained from the Statistics Korea database. The ecological association between thyroid screening and thyroid cancer incidence and mortality by age and sex were examined across Korea's 16 administrative regions by general linear regression models.

RESULTS

Between 2008 and 2010, the incidence of thyroid cancer was 64.1 per 100,000 individuals: the incidence in females was 107.3 and in males was 21.1. There was a strong positive correlation between regional thyroid cancer screening and regional thyroid cancer incidence (r = 0.77, [95% confidence interval 0.70-0.82]). The magnitude of correlation was higher for females (r = 0.88 [CI 0.83-0.92]) than in males (r = 0.76 [CI 0.67-0.84]) in any age group. Thyroid screening was only associated with increased detection of papillary thyroid cancer (r = 0.74 [CI 0.59-0.88]); and not associated with mortality (r = -0.08 [CI -0.59-0.63]) due to thyroid cancer.

CONCLUSIONS

The magnitude of association between thyroid cancer screening in South Korea and the incidence of thyroid cancer strongly suggests that screening is the most important driver of the epidemic of thyroid cancer, particularly among females. Thyroid cancer screening, however, was only associated with the increase of one tumor histology, papillary thyroid cancer, and it did not have any association with thyroid cancer mortality. The extent to which opportunistic thyroid cancer screening is converting thousands of asymptomatic persons to cancer patients without any known benefit to them needs to be examined carefully.

Temporal analysis of thyroid cancer management in a Melbourne tertiary centre

BACKGROUND

The American Thyroid Association (ATA) management guidelines for thyroid cancer were revised in 2009. The aim of this study was to determine if management of thyroid cancer in our institution has changed in accordance with the introduction of the revised ATA guidelines (ATA²⁰⁰⁹ ), and to compare the characteristics and management of thyroid cancer in a Melbourne endocrine surgery unit over a 7-year period.

METHODS

All patients treated by the Monash University Endocrine Surgery Unit for thyroid cancer between 2007 and 2013 were divided into two groups - the pre-ATA²⁰⁰⁹ group (2007-2010) and the post-ATA²⁰⁰⁹ group (2011-2013). Comparisons were made of the demographics, cytology, pathology, surgical outcome and adjuvant therapy using t-test and chi-squared tests.

RESULTS

There were 333 patients in the pre-ATA²⁰⁰⁹ group and 342 patients in the post-ATA²⁰⁰⁹ group. Fewer non-diagnostic fine-needle aspiration cytology results were identified in the post-ATA²⁰⁰⁹ group (4% versus 0.9%; P = 0.01), while the rates of other fine-needle aspiration cytology categories were similar. There was a reduction in the use of radioactive iodine ablation in the post-ATA²⁰⁰⁹ group, both in the proportion of patients being treated (66% versus 48%; P < 0.001) and the dosages used (mean 96 mCi versus 80 mCi; P < 0.01), despite similar tumour size in both groups.

CONCLUSION

The key changes in practice thought to be attributable to the 2009 revised ATA guidelines were the reduction in the use and dosage of radioactive iodine in the management of differentiated thyroid cancer.

Thyroid cancer burden in Central and South America

RATIONALE AND OBJECTIVE

Incidence of thyroid cancer (TC) is rapidly increasing worldwide, but little is known about the TC burden in Central and South America (CSA). We describe the geographic patterns and trends of TC by sex in CSA.

METHODS

We obtained regional- and national-level incidence data from 48 population-based cancer registries in 13 countries and nationwide cancer deaths from the WHO mortality database for 18 countries. We estimated world population age-standardized incidence rates (ASRs) and age-standardized mortality rates (ASMRs) per 100,000 person-years. We calculated ASRs by histological subtype. We estimated the annual percentage change (EAPC) to describe time trends.

RESULTS

Between CSA countries, TC incidence and mortality rates varied from 8-fold to 12-fold and from 2-fold to 5-fold, respectively. In 2003-2007, the highest TC ASRs in females and males were in Ecuador (16.0 and 3.5, respectively), Brazil (14.4 and 3.4), Costa Rica (12.6 and 2.1) and Colombia (10.7 and 2.5). The highest ASMRs were in Ecuador, Colombia, Mexico, Peru and Panama (0.68-0.91 in females and 0.41-0.48 in males). Papillary TC was the most commonly diagnosed histological subtype, following the same incidence pattern as overall TC. In Argentinean, Brazilian, Chilean and Costa Rican females TC incidence increased by 2.2-17.9% annually, and papillary TC increased by 9.1-15.0% annually, while mortality remained stable between 1997 and 2008. In males, trends in TC were stable.

CONCLUSION

TC occurred more frequently in females than in males. The overall high incidence and low mortality of TC suggest identification of subclinical disease due to improved detection methods.

Effect of different iodine concentrations on well-differentiated thyroid cancer cell behavior and its inner mechanism

High iodine intake might be an important factor in the promotion of thyroid cancer and the incidence of thyroid carcinoma has increased obviously these years especially in area of high iodine intake, though the mechanism of which remains unknown. The aim of present study was to gain more insight into the influence of different iodine concentrations on cell behavior, such as proliferation and migration, and to further investigate its molecular mechanism using two well-differentiated thyroid cancer cell lines. Our study evaluated the effect of different iodine concentrations on cell behavior and investigated relevant molecules involved. The results indicated that iodine in vitro could promote the growth of thyroid cancer cells with the increase of iodine concentration in a specific range. Such effect may be related to signaling pathways as Akt and Erk and cytokine VEGF-A.

ACTIVE SURVEILLANCE FOR PAPILLARY THYROID MICROCARCINOMA: NEW CHALLENGES AND OPPORTUNITIES FOR THE HEALTH CARE SYSTEM

OBJECTIVE

The dramatic increase in papillary thyroid carcinoma (PTC) is primarily a result of early diagnosis of small cancers. Active surveillance is a promising management strategy for papillary thyroid microcarcinomas (PTMCs). However, as this management strategy gains traction in the U.S., it is imperative that patients and clinicians be properly educated, patients be followed for life, and appropriate tools be identified to implement the strategy.

METHODS

We review previous active surveillance studies and the parameters used to identify patients who are good candidates for active surveillance. We also review some of the challenges to implementing active surveillance protocols in the U.S. and discuss how these might be addressed.

RESULTS

Trials of active surveillance support nonsurgical management as a viable and safe management strategy. However, numerous challenges exist, including the need for adherence to protocols, education of patients and physicians, and awareness of the impact of this strategy on patient psychology and quality of life. The Thyroid Cancer Care Collaborative (TCCC) is a portable record keeping system that can manage a mobile patient population undergoing active surveillance.

CONCLUSION

With proper patient selection, organization, and patient support, active surveillance has the potential to be a long-term management strategy for select patients with PTMC. In order to address the challenges and opportunities for this approach to be successfully implemented in the U.S., it will be necessary to consider psychological and quality of life, cultural differences, and the patient's clinical status.