International patterns and trends in thyroid cancer incidence, 1973-2002

Obesity and Cancer: Evidence, Impact, and Future Directions

BACKGROUND

Mounting evidence, particularly from prospective epidemiologic studies but with additional support from animal models and mechanistic studies, supported conclusions in 2016 by the International Agency for Research on Cancer (IARC) in their review of the preventive effects of weight control on cancer risk.

CONTENT

The workgroup concluded that obesity is causally related to cancer at 13 anatomic sites (esophagus: adenocarcinoma; gastric cardia; colon and rectum; liver; gallbladder; pancreas; breast: postmenopausal; uterine endometrial; ovary; kidney: renal cell; meningioma; thyroid; and multiple myeloma). Further, avoiding weight gain and excess body fat will prevent cancer. Evidence on weight loss and reduction in risk of cancer is more limited. Ongoing clinical trials address the benefits of weight loss interventions after diagnosis.

SUMMARY

Here, we review the evidence from the 2016 IARC that obesity is causally related to cancer at 13 anatomic sites and identify areas for future research, including the consequences of childhood adiposity, the relation between velocity of weight gain and cancer risk, and improved methods for analysis of life-course adiposity and cancer risk. Refining understanding of mechanisms may further inform prevention strategies.

The Radioprotective Effects of Curcumin and Trehalose Against Genetic Damage Caused By I-131

Background:

Thyroid cancer has been growing rapidly during the last decades. Radioiodine-131 (I-131) as an appropriate therapy modality is currently using in the treatment of cancer and hyperthyroidism diseases. This radiotracer is considered as a cause of oxidative DNA damage in nontarget cells and tissues. The aim of this study was to investigate the effects of curcumin and trehalose on the level of DNA double-strand breaks (DSBs) caused by I-131 in human lymphocytes.

Materials and Methods:

First, 6-mL blood samples were taken from each of the five volunteers. After 1 h of preincubation with the antioxidants, a total of 20 μCi I-131/2 mL (blood + NaCl) was added to each sample, and then, the samples were reincubated for 1 h. Lymphocytes were separated and the mean DSB levels were measured for each sample through γ-H2AX assay to evaluate the effects of antioxidants.

Results:

After 1-h incubation with I-131, the DSBs increased by 102.9% compared to the control group (0.343 vs. 0.169 DSB/cell; P = 0.00). Furthermore, compared to the control + I-131 group, curcumin and trehalose reduced the DSBs by 42% and 38%, respectively. There was a significant decrement (P = 0.00) in the levels of DSBs of the curcumin + I-131 and trehalose + I-131 subgroups compared to the control + I-131 subgroup. Furthermore, there was no significant relationship between the radioprotective effect of curcumin and trehalose (P = 0.95).

Conclusion:

The use of curcumin and trehalose as antioxidant can reduce the numbers of DSBs caused by I-131. Meanwhile, the radioprotective effect of curcumin was more than trehalose.

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.

Heavy metals in the volcanic environment and thyroid cancer

In the last two decades thyroid cancer incidence has increased worldwide more than any other cancer. Overdiagnosis of subclinical microcarcinomas has certainly contributed to this increase but many evidences indicate that a true increase, possibly due to environmental factors, has also occurred. Thyroid cancer incidence is markedly increased in volcanic areas. Thus, the volcanic environment is a good model to investigate the possible factors favoring thyroid cancer. In the volcanic area of Mt. Etna in Sicily, as well as in other volcanic areas, a non-anthropogenic pollution with heavy metals has been documented, a consequence of gas, ash and lava emission. Soil, water and atmosphere contamination, via the food chain, biocontaminate the residents as documented by high levels in the urines and the scalp hair compared to individuals living in adjacent non-volcanic areas. Trace amounts of metals are essential nutrients but, at higher concentrations, can be toxic for living cells. Metals can behave both as endocrine disruptors, perturbing the hormonal system, and as carcinogens, promoting malignant transformation. Similarly to other carcinogens, the transforming effect of heavy metals is higher in developing organisms as the fetus (contaminated via the mother) and individuals in early childhood. In the last decades environment metal pollution has greatly increased in industrialized countries. Although still within the "normal" limits for each single metal the hormesis effect (heavy metal activity at very low concentration because of biphasic, non linear cell response) and the possible potentiation effect resulting from the mixture of different metals acting synergistically can explain cell damage at very low concentrations. The effect of metals on the human thyroid is poorly studied: for some heavy metals no data are available. The scarce studies that have been performed mainly focus on metal effect as thyroid endocrine disruptors. The metal concentration in tissues has been rarely measured in the thyroid. Heavy metal accumulation and metabolism in the thyroid or the carcinogenic activity of different doses and different speciation of metals has not been investigated. These studies are now warranted to better understand thyroid biology and heavy metal role in human thyroid carcinogenesis.

A predictive model to distinguish malignant and benign thyroid nodules based on age, gender and ultrasonographic features

Introduction

A discussion in literature about a standardized decision support tool for the management of thyroid nodules remains.

Objective

The purpose of this study was to create a statistical prediction model for thyroid nodules management.

Methods

Two hundred and four benign and 57 malignant thyroid nodules were selected for a retrospective study. The variables age, gender and ultrasonographic features were examined using univariate and multivariate models. A statistical formula was used to calculate the risk of cancer of each case.

Results

In multivariate analysis, irregular shape, absence of halo, lower mean age, homogeneous echotexture, microcalcifications and solid content were associated with cancer. After applying the formula, 20 cases (7.6%) with a calculated risk for malignancy ≤3.0% were found, all of them benign. Setting the calculated risk in ≥80%, 21 (8.0%) cases were selected, and in 85.7% of them cancer was confirmed in histopathology. Internal accuracy of the prediction formula was 92.5%.

Conclusions

The prediction formula reached high accuracy and may be an alternative to other decision support tools for thyroid nodule management.

The relationship between RASSF1A promoter methylation and thyroid carcinoma: A meta-analysis of 14 articles and a bioinformatics of 2 databases (PRISMA)

BACKGROUND

DNA promoter methylation can suppresses gene expression and shows an important role in the biological functions of Ras association domain family 1A (RASSF1A). Many studies have performed to elucidate the role of RASSF1A promoter methylation in thyroid carcinoma, while the results were conflicting and heterogeneous. Here, we analyzed the data of databases to determine the relationship between RASSF1A promoter methylation and thyroid carcinoma.

METHODS

We used the data from 14 cancer-normal studies and Gene Expression Omnibus (GEO) database to analyze RASSF1A promoter methylation in thyroid carcinoma susceptibility. The data from the Cancer Genome Atlas project (TCGA) database was used to analyze the relationship between RASSF1A promoter methylation and thyroid carcinoma susceptibility, clinical characteristics, prognosis. Odds ratios were estimated for thyroid carcinoma susceptibility and hazard ratios were estimated for thyroid carcinoma prognosis. The heterogeneity between studies of meta-analysis was explored using H, I values, and meta-regression. We adopted quality criteria to classify the studies of meta-analysis. Subgroup analyses were done for thyroid carcinoma susceptibility according to ethnicity, methods, and primers.

RESULTS

Result of meta-analysis indicated that RASSF1A promoter methylation is associated with higher susceptibility to thyroid carcinoma with small heterogeneity. Similarly, the result from GEO database also showed that a significant association between RASSF1A gene promoter methylation and thyroid carcinoma susceptibility. For the results of TCGA database, we found that RASSF1A promoter methylation is associated with susceptibility and poor disease-free survival (DFS) of thyroid carcinoma. In addition, we also found a close association between RASSF1A promoter methylation and patient tumor stage and age, but not in patients of different genders.

CONCLUSIONS

The methylation status of RASSF1A promoter is strongly associated with thyroid carcinoma susceptibility and DFS. The RASSF1A promoter methylation test can be applied in the clinical diagnosis of thyroid carcinoma.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Anaplastic thyroid carcinoma: from clinicopathology to genetics and advanced therapies

Anaplastic thyroid carcinoma (ATC) is a rare malignancy, accounting for 1-2% of all thyroid cancers. Although rare, ATC accounts for the majority of deaths from thyroid carcinoma. ATC often originates in a pre-existing thyroid cancer lesion, as suggested by the simultaneous presence of areas of differentiated or poorly differentiated thyroid carcinoma. ATC is characterized by the accumulation of several oncogenic alterations, and studies have shown that an increased number of oncogenic alterations equates to an increased level of dedifferentiation and aggressiveness. The clinical management of ATC requires a multidisciplinary approach; according to recent American Thyroid Association guidelines, surgery, radiotherapy and/or chemotherapy should be considered. In addition to conventional therapies, novel molecular targeted therapies are the most promising emerging treatment modalities. These drugs are often multiple receptor tyrosine kinase inhibitors, several of which have been tested in clinical trials with encouraging results so far. Accordingly, clinical trials are ongoing to evaluate the safety, efficacy and effectiveness of these new agents. This Review describes the updated clinical and pathological features of ATC and provides insight into the molecular biology of this disease. The most recent literature regarding conventional, newly available and future therapies for ATC is also discussed.

The distribution of cancer cases in Somalia

OBJECTIVE

The aim of this study was to investigate the frequency and distribution of cancer cases in a defined time period in Somalia.

MATERIALS AND METHODS

A total of 403 cancer cases were diagnosed between January 01, 2016 and March 01, 2017 in the Department of Pathology at the Somalia Mogadishu-Turkey Education and Research Hospital or the Department of Oncology at Uniso Hospital, Somalia University. Data on cancer type, patient age, and gender were obtained from pathology reports and hospital records.

RESULTS

Female patients totaled 49.6% (n = 200) and 50.4% of patients were male (n = 203). The youngest patient was 18 years of age, the oldest was 97, and the average age was 53.4 years. The 10 most common types of cancer were esophageal (n = 130, 32.3%), non-Hodgkin lymphoma (n = 35, 8.7%), liver (n = 26, 6.5%), breast (n = 24, 6.0%), skin (n = 17, 4.2%), thyroid (n = 13, 3.2%), brain (n = 12, 3.0%), bone (n = 11, 2.7%), colorectal (n = 11, 2.7%), and soft tissue (n = 11, 2.7%). The most common site of cancer in both males and females was the esophagus.

CONCLUSION

These results show a high incidence of esophageal cancer in Somalia, and strongly suggest that environmental risk factors and nutritional habits have a strong impact in this population. Serious and extensive research on the etiology of esophageal cancer is required.

Patterns of Thyroid Cancers in Southeastern Nigeria: A 15 Year Histopathologic Review (2000-2014)

INTRODUCTION

Thyroid Cancer (TC) continues to be the most common endocrine cancer with a worldwide increase in incidence over the last three decades. This trend has been reported in all continents except Africa, where detection is adjudged to be insufficient, making it imperative for us to re-evaluate the patterns in our environment.

AIM

To determine the patterns of TCs in Southeastern Nigeria.

MATERIALS AND METHODS

This was a 15-year retrospective review of all thyroidectomy specimens received at the Depart-ment of Morbid Anatomy, University of Nigeria, Enugu Campus, Enugu, Nigeria. The age, sex and histologic subtypes of diagnosed TCs were analysed using Predictive Analytics Software (PASW) Statistics for Windows, Version 18 (Chicago: SPSS Inc.) and the results were expressed in descriptive statistics.

RESULTS

Sixty one cases of TCs were identified in this study constituting 10.8% of thyroid biopsies received at our centre during the period under review. There were 51 (83.6%) females and 10 (16.4%) males giving a ratio of 5.1:1, and a mean age of 45.9 years. The commonest histologic type was Papillary Thyroid Carcinoma (PTC) (42.6%), followed by; follicular thyroid carcinoma (37.7%), medullary thyroid carcinoma (4.9%), anaplastic carcinomas (3.3%), Non-Hodgkin lymphoma (1.6%) and metastatic squamous cell carcinoma (3.3%). Mixed papillary/ follicular carcinoma (4.9%) and mixed papillary/ anaplastic carcinoma (1.6%) were also identified.

CONCLUSION

TC continues to predominate amongst females, occurring mainly in early middle age group in Southeastern Nigeria. PTC is now the commonest histologic type.

A Pragmatic Approach to the Indeterminate Thyroid Nodule

Thyroid nodules are prevalent in upto 68% of randomly selected individuals in whom high resolution ultrasound is performed. The majority of nodules are benign. The use of ultrasound coupled with FNAC has dramatically reduced the number of patients who undergo surgery for nodules. The six tier Bethesda scoring system has reduced variability and increased the ability to clinicians to guide patients with thyroid nodules. There is good correlation between cytology and histopathologic outcomes. A significant proportion of patients will however fall into an indeterminate category. The availability of molecular markers enhanced with next generation sequencing technology and the expression classifier are added diagnostic aids that can help in management. However these are not available in many countries and in resource limited settings. A pragmatic approach to the diagnosis of indeterminate nodules includes utilising pre and post test probability, clinical acumen, correlation of ultrasound findings and expert opinion in some settings. Using this approach high risk patients can be appropriately chosen for surgery while relegating patients with lower risk to watchful followup.

Thyrotropin Suppressive Therapy for Low-Risk Small Thyroid Cancer: A Propensity Score-Matched Cohort Study

BACKGROUND

Thyrotropin (TSH) suppression has improved the clinical outcomes of patients with differentiated thyroid cancer (DTC). However, the efficacy of TSH suppressive therapy (TST) is unclear in patients with low-risk DTC. This study aimed to evaluate the efficacy of TST and optimal TSH levels of patients with low-risk DTC.

METHODS

This retrospective propensity score-matched cohort study included DTC patients (n = 446) who underwent lobectomy from 2002 to 2008 with or without TST (TST group and No-TST group). Disease-free survival (DFS) and dynamic risk stratification were compared between both groups using serum TSH levels.

RESULTS

Approximately 74% of TST patients and 11% of No-TST patients had suppressed serum TSH levels (<2 mIU/L). The median follow-up period was 8.6 years. During follow-up, the disease recurred in 10 (2.7%) patients, with no significant difference in DFS between the groups (p = 0.63). The proportion of patients with excellent treatment response was similar between the TST (65.2%) and No-TST (64.4%) groups. Incomplete biochemical response was noted in 17.2% of the TST group patients and 9.4% of the No-TST group patients. No significant difference was observed in the DFS between both groups by comparing serum TSH level (p = 0.57).

CONCLUSIONS

TST did not improve clinical outcomes, and serum TSH levels were not associated with recurrence in patients with low-risk small DTC. No clinical benefits were shown for TSH suppression in low-risk patients who underwent lobectomy. Thus, levothyroxine is not necessary for patients without evidence of hypothyroidism.

GABRB2 plays an important role in the lymph node metastasis of papillary thyroid cancer

BACKGROUND

Thyroid cancer is a common malignant tumor of the endocrine system. Its incidence has increased continuously worldwide for the past three decades. With advanced sequencing technology, we discovered that GABRB2 gene is overexpressed in tumor tissues and closely associated with vertebrate nervous systems. However, its role in cancer remains unclear.

METHODS

We conducted a massively parallel whole transcriptome resequencing and a comprehensive analysis of matched papillary thyroid carcinoma (PTC) tumors and normal tissues in 19 patients. Results showed that GABRB2 expression was significantly upregulated in thyroid cancer. Forty-five pairs of tumors and normal tissues were subjected to reverse transcription polymerase chain reaction to validate previous findings. The specific functions of GABRB2 in PTC cell lines (BCPAP, TPC1, and KTC-1) transfected with small interfering RNA were determined through cell colony formation, Cell Counting Kit-8, Transwell migration, Transwell invasion, and apoptosis assays. The effect of DNA demethylation on this gene was also examined.

RESULTS

GABRB2 was remarkably overexpressed in primarily sequenced PTC tumors and validation cohort (T: N = 4.94 ± 3.43:0.83 ± 1.71, P < 0.001), and this observation was consistent with that in the TCGA cohort (T: N = 38.92 ± 35.53:0.30 ± 0.55, P < 0.001). GABRB2 overexpression was correlated with lymph node metastasis in both cohorts (P < 0.01). In vitro experiments revealed that GABRB2 downregulation significantly inhibited the colony formation, migration, and invasion of the three PTC cell lines.

CONCLUSION

GABRB2 plays important tumorigenic functions and acts as a novel oncogene in PTC.

Is nitric oxide level affected in postmenopausal women with hypothyroidism?

AIM

To analyze serum levels of nitric oxide (NO), an indicator of cardiovascular health, in post-menopausal females with and without hypothyroidism.

METHODS

NO was analyzed colorimetrically in 30 newly diagnosed hypothyroid postmenopausal females and 30 postmenopausal females with normal thyroid profile. Results were compared and subjected to appropriate statistical analysis.

RESULTS

The levels of serum NO were found to be significantly decreased in postmenopausal females with hypothyroidism as compared to the levels in those with normal thyroid profile (P value < 0.05). A negative correlation of NO was observed with thyroid stimulating hormone whereas a positive correlation of NO was observed with free T3 (FT3), free T4 (FT4), T3 and T4 though it was statistically significant only for FT4 among postmenopausal females with hypothyroidism.

CONCLUSION

Postmenopausal hypothyroid females may be at a risk of compromised cardiovascular health as indicated by low NO levels. Regular monitoring and risk assessment is essential for timely intervention.

Prognostic impact of vascular invasion in differentiated thyroid carcinoma: a systematic review and meta-analysis

BACKGROUND

The role of vascular invasion (VI) as a prognostic marker in thyroid cancer is continuously debated among investigators. In this systematic review and meta-analysis, we aimed to investigate the association of VI with tumor recurrence and patient mortality in differentiated thyroid cancers (DTCs).

METHODS

We searched five electronic databases for cases of DTC matching our criteria. Data of tumor persistence, locoregional recurrence (LRR), distant recurrence (DR) and overall recurrence/persistence (RP) were extracted and pooled into odds ratios (OR) and corresponding 95% confidence intervals (CIs) using random effect model. Pooled hazard ratio (HR) for disease-specific survival (DSS) was calculated using random effect model weighted by inverse variance method. Publication bias was examined by using Egger's test and funnel plot.

RESULTS

From 1650 studies, we included 26 studies comprising 11 961 DTCs for meta-analyses. In DTC patients, we found significant associations of VI with tumor persistence (OR = 2.75; 95% CI = 1.46-5.18), LRR (OR = 4.44; 95% CI = 2.94-6.71), DR (OR = 5.08; 95% CI = 2.95-8.75), overall RP (OR = 3.53; 95% CI = 2.09-5.96) and worse DSS (HR = 2.47; 95% CI = 1.45-4.21). Our results also demonstrated that the presence of extensive VI is associated with a significantly higher risk for DR in follicular thyroid carcinomas as compared with focal VI.

CONCLUSION

Our study demonstrated a significant impact of VI on tumor recurrence and patient survival in DTC patients. The presence and extent of VI should be considered an adverse prognostic factor in DTCs.

Unusual Presentation of Differentiated Thyroid Cancer Metastasis

Introduction  The rates of thyroid cancers are on a rise, especially well-differentiated thyroid cancers. This could be partly due to newer diagnostic modalities, like high-resolution ultrasound, that can pick up smaller lesions. Differentiated thyroid cancers with distant metastases are not common, and even rarer is the initial presentation with complaints not related to the neck.

Objectives  The objective of this series was to study and report the unusual cases of patients with differentiated thyroid cancer with distant metastasis. There is a lack of data in the literature on these cases, and due to the rarity of such metastases, no definite treatment protocol has been defined.

Methods  A retrospective chart review of 1,200 cases of thyroid surgeries was performed. A total of 10 cases of well-differentiated thyroid cancer on the final histopathology exam that had initially presented with usual complaints to departments other than the Otolaryngology Department were identified.

Results  A total of 6 patients had papillary carcinoma, whereas 4 patients had follicular carcinoma on final the histopathology exam. Two patients presented with iliac crest lesions, 2 with vertebral lesions one each with parapharyngeal mass, supraclavicular mass, labia majora swelling and bleeding, lung, rib and neck of femur lesion.

Conclusion  There are still no specific guidelines on how to address these patients with differentiated thyroid cancer with distant metastasis (except for the cases of bone and lung lesions) and on which treatment should be offered in case of recurrence. More studies on the subject are required.

Are dietary reports in a case-control study on thyroid cancer biased by risk perception of Chernobyl fallout?

BACKGROUND

In retrospective case-control studies performed following nuclear tests or nuclear accidents, individual thyroid radiation dose reconstructions are based on fallout and meteorological data from the residential area, demographic characteristics, and lifestyle as well as dietary information. Collecting the latter is a controversial step, as dietary declarations may be affected by the subjects' beliefs about their risk behavior. This report analyses the potential for such bias in a case-control study performed in eastern France.

METHODS

The study included 765 cases of differentiated thyroid carcinoma matched with 831 controls. Risk perceptions and beliefs of cases and controls were compared using Chi² tests and differences in dietary reports were analyzed using a two-way ANOVA.

RESULTS

In general, atmospheric pollution and living near a nuclear power plant were the two major risks that may influence thyroid cancer occurrence cited by cases and controls. When focusing in particular on the consequences of the Chernobyl accident, cases were more likely to think that the consequences were responsible for thyroid cancer occurrence than controls. Vegetable consumption during the two months after the Chernobyl accident was correlated with the status of subjects, but not to their beliefs. Conversely, consumption of fresh dairy products was not correlated with the status or beliefs of subjects.

CONCLUSION

We found no evidence of systematic bias in dietary reports according to the status or beliefs held by subjects about the link between thyroid cancer occurrence and Chernobyl fallout. As such, these dietary reports may be used in further studies involving individual dosimetric reconstructions.

Trends of Second Primary Malignancy in Patients with Thyroid Cancer: A Population-Based Cohort Study in Israel

BACKGROUND

Thyroid cancer (TC) is the most common endocrine malignancy. TC patients have a good prognosis and a low disease-related mortality rate. Since such patients are often young, they may be at a higher risk for a second primary malignancy (SPM). This study sought to determine the incidence, risk, and types of SPM between 1980 and 2011, and to assess SPM trends over time among Israeli TC patients.

METHODS

Data were derived from the Israel National Cancer Registry. Primary TC patients diagnosed during 1980-2009 were followed up for SPM incidence until December 31, 2011. Standardized incidence ratios (SIRs) of observed to expected SPM (based on the general population rates) were calculated using Poisson regression. Analyses were stratified by time period of initial TC diagnosis (1980-1995 and 1996-2009).

RESULTS

A total of 11,538 TC patients were identified. After exclusion of 107 duplicate cases, records of 1032 patients with SPM were analyzed (an SPM incidence of 8.9%). SIRs for all-site SPMs were 1.23 [confidence interval 1.08-1.35] for males and 1.19 [confidence interval 1.10-1.27] for females. SIRs for tumors of the urinary system and prostate were significantly elevated in males, as were SIRs for tumors of the brain, urinary system, breast, and lung in females. Variables associated with increased risk of developing SPMs included a younger age at TC diagnosis, a shorter latency period, being born in Asia/Africa for both sexes, and being born in Israel for females. Compared with the general population, a subanalysis by TC diagnosis during 1980-1995 and 1996-2009 disclosed a higher SPM incidence for the latter time period in males and for both time periods, with a slightly higher SIR for the latter time period in females.

CONCLUSIONS

The overall risk of SPM in Israeli TC patients was significantly greater for both sexes compared with the general population, thus identifying TC patients as a high-risk group and calling for caretakers to apply specific follow-up guidelines.

Prognostic value of putative cancer stem cell markers (CD24, CD44, CD133, and ALDH1) in human papillary thyroid carcinoma

We hypothesized that cancer stem cells (CSCs) are responsible for the poor outcome and aggressive clinicopathological factors. We surveyed the expression of selected CSC markers that are specifically expressed in thyroid papillary carcinoma (PTC). A total of 80 patients with PTC from 2011 to 2012 were enrolled. We selected CD24, CD44, CD133, and dehydrogenase 1 (ALDH1), as they have been suggested to be candidate CSC markers. Expression of these markers was investigated by immunohistochemical (IHC) staining. IHC staining for CD24, CD44, CD133 and ALDH1 was evaluated according to staining intensity and proportion. The intensity and proportion scores were multiplied together for a total score, which was either 0-2 (negative) or 3-7 (positive). IHC for CD133 in PTC was positive in 49 (61.3%) patients, and CD24 was positive in 28 (35.0%). Seventy-eight (97.5%) patients were CD44 positive and 79 (98.8%) were ALDH1 positive. When we assessed the relationship between CSC markers and clinicopathological factors in PTC, CD24 expression was inversely correlated with multifocality (p=0.045; odds ratio [OR], 0.370; 95% confidence interval [CI], 0.138-0.991) and CD44 expression was significantly correlated with a BRAF mutation (p=0.001; OR, 7.091; 95% CI, 4.101-12.262). However, CD133 and ALDH1 were not associated with any of the clinicopathological parameters. CD24 expression was inversely correlated with multifocality, and CD44 expression was significantly correlated with a BRAF mutation. Therefore, CD24 and CD44 are related to clinicopathological aggressive features and important for determining surgical extent in patients with PTC.

Clinicopathological characteristics of thyroid cancer in the federal state of Salzburg

OBJECTIVE

The aim of our investigation was to evaluate the clinicopathological characteristics and mutation patterns in newly diagnosed cases of thyroid cancer in the federal state of Salzburg, Austria, in the year 2013.

METHODS

The medical records of all patients newly diagnosed with thyroid cancer in 2013 in the federal state of Salzburg were retrospectively reviewed. The clinicopathological characteristics and mutations of thyroid cancers were analyzed.

RESULTS

63 patients (mean age: 51.0 years, range: 21-81 years; female 75%, male 25%) were identified. 53 patients had papillary (12 follicular variant), 4 patients follicular (1 oxyphilic variant), 3 patients medullary, and 3 patients anaplastic thyroid cancer. T1 tumors were found in 34 patients (pT1a, 20 patients; pT1b, 14 patients), T2 tumors in 10 patients, T3 tumors in 16 patients, and T4 tumors in 3 patients. Lymph node involvement was seen in 15 patients and metastatic disease in 1 patient. Mutations of BRAF (B-type Raf kinase) were detected in 23 and mutation of NRAS (Neuroblastoma RAS Viral Oncogene Homolog) in 2 papillary thyroid cancers. No concomitant mutations of BRAF and NRAS were found.

CONCLUSION

Females accounted for 75% of the patients with newly diagnosed thyroid cancer and the incidence peaked at a younger age than in males. Papillary thyroid cancer was the most frequent tumor type, accounting for 84% of the cases. A high frequency of T1 tumors and cancers with no lymph node involvement was found. Males had a higher proportion of large tumors and more aggressive forms of thyroid cancer than females. Mutations (mostly of BRAF) were found in 47% of the cases. Neither mutations of KRAS (Kirsten rat sarcoma viral oncogene homologue) nor concomitant mutations of BRAF and NRAS were found.

Perioperative practices in thyroid surgery: An international survey

BACKGROUND

Perioperative practices in thyroid surgery vary from one specialty, institution, or country to the next. We evaluated the preoperative, intraoperative, and postoperative practices of thyroid surgeons focusing on preoperative ultrasound, vocal cord evaluation, wound drains, and hospitalization duration, among others.

METHODS

A survey was sent to 7 different otolaryngology and endocrine/general surgery associations.

RESULTS

There were 965 respondents from 52 countries. Surgeon-performed ultrasound is practiced by more than one third of respondents. Otolaryngologists perform preoperative and postoperative vocal cord evaluation more often than endocrine/general surgeons (p < .001). Sixty percent of respondents either never place drains or place drains <50% of the time in thyroid lobectomies (43% for total thyroidectomies). Outpatient thyroid surgery is most frequently performed by surgeons in the United States (63%).

CONCLUSION

This epidemiologic study is the first global thyroid survey of its kind and clearly demonstrates the variability and evolving trends in thyroid surgery. © 2017 Wiley Periodicals, Inc. Head Neck 39: 1296-1305, 2017.

Anti-cancer activity of myricetin against human papillary thyroid cancer cells involves mitochondrial dysfunction-mediated apoptosis

Thyroid cancer is the most common endocrine malignancy and can range in severity from relatively slow-growing occult differentiated thyroid cancer to uniformly aggressive and fatal anaplastic thyroid cancer. A subset of patients with papillary thyroid cancer present with aggressive disease that is refractory to conventional treatment. Myricetin is a flavonol compound found in a variety of berries as well as walnuts and herbs. Previous studies have demonstrated that myricetin exhibits anti-cancer activity against several tumor types. However, an anti-cancer effect of myricetin against human papillary thyroid cancer (HPTC) cells has not been established. The present investigation was undertaken to gain insights into the molecular mechanism of the anti-cancer activity of myricetin against HPTC cells. We examined the cytotoxicity, DNA damaging, and cell cycle arresting activities of myricetin using SNU-790 HPTC cells. We found that myricetin exhibited cytotoxicity and induced DNA condensation in SNU-790 HPTC cells in a dose-dependent manner. Moreover, myricetin up-regulated the activation of caspase cascades and the Bax:Bcl-2 expression ratio. In addition, myricetin induced the release of apoptosis-inducing factor (AIF) and altered the mitochondrial membrane potential. Our results suggest that myricetin induces the death of SNU-790 HPTC cells and thus may prove useful in the development of therapeutic agents for human thyroid cancers.

Use of Dietary Vitamin Supplements and Risk of Thyroid Cancer: A Population-Based Case-Control Study in Connecticut

Certain dietary supplements have been reported to increase the risk of some cancers. Over half of the US population regularly uses dietary supplements. Thyroid cancer incidence has increased over the past several decades. However, few studies have investigated the association between dietary supplements and thyroid cancer. Thus, it is essential to clarify any association between dietary supplements and risk of thyroid cancer.

MATERIALS AND METHODS

A population-based case-control study in Connecticut was conducted during 2010-2011 among 462 histologically confi rmed incident thyroid cancer cases and 498 population-based controls. Dietary supplement intake was ascertained through in-person interviews and a food frequency questionnaire. Multivariate unconditional logistic regression models were used to estimate the risk of thyroid cancer and dietary supplement use.

RESULTS

Overall, no statistically signifi cant associations were observed between dietary supplementation and thyroid cancer risk. Stratifi ed analyses revealed a suggestive protective effect on risk of papillary microcarcinoma among longterm (> 10 years) use of multivitamins (OR = 0.59, 95 % CI: 0.33, 1.04) and calcium supplementation (OR = 0.45, 95 % CI: 0.22, 0.93). An increased risk of large papillary thyroid cancers (tumor size > 1 cm) was observed among short-term (< 5 years) users of calcium supplements (OR = 2.24, 95 % CI: 1.30, 3.88).

DISCUSSION

No signifi cant associations were observed between supplementation and overall thyroid cancer risk. The different associations between calcium supplements and risk of papillary thyroid cancer by tumor size warrant further investigation.

Hormonal and reproductive risk factors of papillary thyroid cancer: A population-based case-control study in France

The three times higher incidence of thyroid cancer in women compared to men points to a role of female sex hormones in its etiology. However the effects of these factors are poorly understood. We analyzed the association between thyroid cancer and hormonal and reproductive factors among women enrolled in CATHY, a population-based case-control study conducted in France. The study included 430 cases of papillary thyroid cancer and 505 controls frequency-matched on age and area of residence. The odds ratios for thyroid cancer increased with age at menarche (p trend 0.05). Postmenopausal women were at increased risk, as compared to premenopausal women, particularly if menopause followed an ovariectomy, and for women with age at menopause <55years. In addition, use of oral contraceptives and menopausal hormone therapy reduced the association with thyroid cancer by about one third, and breastfeeding by 27%. Overall, these findings provide evidence that the risk of thyroid cancer increases with later age at menarche and after menopause, and decreases with use of oral contraceptives and menopausal hormone therapy. These findings confirm an implication of hormonal factors in papillary thyroid cancer risk, whose mechanisms need to be elucidated.

Combined MEK and Pi3'-kinase inhibition reveals synergy in targeting thyroid cancer in vitro and in vivo

Anaplastic thyroid cancers and radioiodine resistant thyroid cancer are posing a major treat since surgery combined with Iodine131 therapy is ineffective on them. Small-molecule inhibitors are presenting a new hope for patients, but often lead to drug resistance in many cancers. Based on the major mutations found in thyroid cancer, we propose the combination of a MEK inhibitor and a Pi3'-kinase inhibitor in pre-clinical models. We used human thyroid cancer cell lines and genetically engineered double mutant BRAFV600E PIK3CAH1047R mice to evaluate the effect of both inhibitors separately or in combination in terms of proliferation and signaling in vitro; tumor burden, histology, cell death induction and tumor markers expression in vivo. The combination of MEK and Pi'3-kinase inhibition shows a synergistic effect in term of proliferation and apoptosis induction through Survivin down-regulation in vitro. We show for the first time the effects of the combination of a MEK inhibitor and Pi3'-kinase inhibitor in a genetically engineered mouse model of aggressively lethal thyroid cancer. In fine, the two drugs cooperate to promote tumor shrinkage by inducing a proliferation arrest and an elevation of apoptosis in vivo. Moreover, a phenotypic reversion is also observed with a partial restoration of normal thyroid marker transcription, and thyroid cancer marker expression reduction.In conclusion, combination therapy of MEK and Pi3'-kinase inhibition synergizes to target double mutant thyroid cancer in vitro and in vivo. This multidrug approach could readily be translated into clinical practice and bring new perspectives for the treatment of incurable thyroid carcinoma.

Clinical Features of Early and Late Postoperative Hypothyroidism After Lobectomy

CONTEXT

Lobectomy is preferred in thyroid cancer to decrease surgical complications and avoid lifelong thyroid-hormone replacement. However, postoperative hypothyroidism, requiring thyroid-hormone replacement, may occur.

OBJECTIVE

We aimed to identify the incidence and risk factors of postoperative hypothyroidism to develop a surveillance strategy after lobectomy for papillary thyroid microcarcinoma (PTMC).

METHODS

This historical cohort study involved 335 patients with PTMC treated by lobectomy. Postoperative thyroid functions were measured regularly, and patients were prescribed levothyroxine according to specific criteria. Patients not satisfying hormone-replacement criteria were closely followed up.

RESULTS

Postoperative hypothyroidism occurred in 215 patients (64.2%) including 5 (1.5%) with overt hypothyroidism and 210 (62.7%) with subclinical hypothyroidism. Forty patients (11.9%) were required thyroid hormone replacement. One hundred nineteen patients (33.5%) experienced temporary hypothyroidism and spontaneously recovered to euthyroid state. High preoperative thyroid-stimulating hormone (TSH) was the most important factor predicting postoperative hypothyroidism and failure of recover from hypothyroidism (odds ratio [OR], 2.82 and 1.77; 95% confidence interval [CI], 2.07 to 3.95 and 1.22 to 2.63; P < 0.001 and 0.002, respectively). Of the 215 patients eventually developing postoperative hypothyroidism, 70 (32.6%) developed hypothyroidism after the first postoperative year. Postoperative 1-year TSH levels were able to differentiate patients developing late hypothyroidism or euthyroidism (OR, 2.29; 95% CI, 1.68 to 3.26; P < 0.001).

CONCLUSIONS

Preoperative and postoperative TSH levels might be predictive for patients who develop postlobectomy hypothyroidism and identify those requiring long-term surveillance for hypothyroidism. Additionally, mild postoperative hypothyroidism cases should be followed up without immediate levothyroxine replacement with the expectation of spontaneous recovery.

Dynamic Risk Stratification for Predicting Recurrence in Patients with Differentiated Thyroid Cancer Treated Without Radioactive Iodine Remnant Ablation Therapy

BACKGROUND

Increased incidence of small differentiated thyroid cancer (DTC) has emphasized the need for risk stratification and individualized disease management for these low risk DTCs. The aim of this study was to validate a new dynamic risk stratification (DRS) system for the prediction of structural recurrent/persistent disease in patients with DTC treated without radioactive iodine (RAI) remnant ablation therapy.

METHODS

This historical cohort study included 357 patients with DTC treated with lobectomy or total thyroidectomy without RAI therapy. We stratified patient response to initial treatment as excellent, indeterminate, biochemical incomplete, and structural incomplete according to the DRS system.

RESULTS

During a median follow-up of 8.6 years, 3.6% patients had structural recurrent DTC. The response was excellent in 71.7% patients, indeterminate in 18.5%, biochemical incomplete in 8.4%, and structural incomplete in 1.4%. There were significant differences in DFS among the DRS groups (p < 0.001). The hazard ratio (HR) of recurrent/persistent disease was significantly higher in the biochemical incomplete group (HR = 20.8, p < 0.001) and structural incomplete group (HR = 243.3, p < 0.001) compared with the excellent group. However, the Tumor Node Metastasis staging system and the American Thyroid Association initial risk classification did not effectively predict recurrence of DTC.

CONCLUSIONS

The new DRS system was effective for predicting risk of recurrent/persistent disease in patients with DTC who underwent lobectomy or total thyroidectomy without RAI remnant ablation.

More surprises in the global greenhouse: Human health impacts from recent toxic marine aerosol formations, due to centennial alterations of world-wide coastal food webs

Reductions of zooplankton biomasses and grazing pressures were observed during overfishing-induced trophic cascades and concurrent oil spills at global scales. Recent phytoplankton increments followed, once Fe-, P-, and N-nutrient limitations of commensal diazotrophs and dinoflagellates were also eliminated by respective human desertification, deforestation, and eutrophication during climate changes. Si-limitation of diatoms instead ensued during these last anthropogenic perturbations of agricultural effluents and sewage loadings. Consequently, ~15% of total world-wide annual asthma trigger responses, i.e. amounting to ~45 million adjacent humans during 2004, resulted from brevetoxin and palytoxin poisons in aerosol forms of western boundary current origins. They were denoted by greater global harmful algal bloom [HAB] abundances and breathing attacks among sea-side children during prior decadal surveys of asthma prevalence, compiled here in ten paired shelf ecosystems of western and eutrophied boundary currents. Since 1965, such inferred onshore fluxes of aerosolized DOC poisons of HABs may have served as additional wind-borne organic carriers of toxic marine MeHg, phthalate, and DDT/DDE vectors, traced by radio-iodine isotopes to potentially elicit carcinomas. During these exchanges, as much as 40% of mercury poisonings may instead have been effected by inhalation of collateral HAB-carried marine neurotoxic aerosols of MeHg, not just from eating marine fish. Health impacts in some areas were additional asthma and pneumonia episodes, as well as endocrine disruptions among the same adjacent humans, with known large local rates of thyroid cancers, physician-diagnosed pulmonary problems, and ubiquitous high indices of mercury in hair, pesticides in breast milk, and phthalates in urine.

Iodine intake as a risk factor for BRAF mutations in papillary thyroid cancer patients from an iodine-replete area

PURPOSE

Both deficient and excessive iodine intake leads to thyroid disease, which shows U-shaped curves. Our previous study showed that a relatively low [urinary iodine concentration (UIC) <300 μg/L] and extremely excessive (UIC ≥ 2500 μg/L) iodine intake were associated with thyroid cancer in Korea, an iodine-replete area. Papillary thyroid cancer (PTC) accounts for more than 97 % of thyroid cancer and 80% or more PTC cases harbor the BRAF mutation in Korea. We aimed to investigate the relationship between iodine intake and the prevalence of the BRAF mutation in PTC in Korea.

METHODS

UIC was measured by inductively coupled plasma mass spectrometry. The BRAF mutation was detected using both allele-specific polymerase chain reaction and mutant enrichment with 3'-modified oligonucleotide sequencing. Risk factors for the occurrence of BRAF mutations in PTC were evaluated using multivariate logistic regression models.

RESULTS

The median UIC in all patients with PTC was 287 μg/L (range from 7 to 7, 426 μg/L). Nearly half of the patients (102/215, 47%) belonged to the excessive iodine intake category (UIC ≥ 300 μg/L) according to the WHO iodine recommendations. The frequency of BRAF mutations was lowest in the 300-499 μg/L UIC group; it was significantly different compared to the relatively low (UIC < 300 μg/L) and more than excessive (UIC ≥ 500 μg/L) iodine intake groups. UIC was an independent predictor for BRAF mutations in PTC. The multivariate-adjusted odds ratios (95% confidence intervals) in the relatively low and more than excessive iodine intake groups for the BRAF mutation were 4.761 (1.764-12.850) and 6.240 (2.080-18.726), respectively, compared to the 300-499 μg/L UIC group.

CONCLUSION

Relatively low iodine intake and more than excessive iodine intake seem to be significant risk factors for the occurrence of BRAF mutations in the thyroid and, therefore, may be risk factors for the development of PTC in an iodine-replete area.

Expression characteristics of proteins of IGF-1R, p-Akt, and survivin in papillary thyroid carcinoma patients with type 2 diabetes mellitus

Type 2 diabetes mellitus (T2DM) is related to increased risk of papillary thyroid carcinoma (PTC). Insulin-like growth factor-1 receptor (IGF-1R) is increased in patients with T2DM. The increased IGF-1R may be responsible for the development of PTC. In this study, we investigated the expression of phosphorylation of Akt (p-Akt)/survivin pathway activated by IGF-1R in PTC subjects with and without diabetes.Clinicopathological data of 20 PTC patients with T2DM were retrospectively analyzed and compared with those of 21 PTC subjects without diabetes. Meanwhile, IGF-1R, p-Akt, and survivin expressions of PTC tissues were detected by immunohistochemical staining.The immunohistochemical results found that the expression level of IGF-1R was significantly higher in diabetic PTC patients than that in nondiabetic PTC patients (P < 0.05). However, no significant differences of p-Akt and survivin expression were found between PTC patients with T2DM and PTC patients without T2DM. In addition, among 20 PTC patients with T2DM, subgroup analysis showed that the ratio of tumor size >10 mm was significantly higher in IGF-1R moderate to strong expression group than that in IGF-1R negative to weak expression group (P < 0.05).IGF-1R expression level was higher in PTC patients with T2DM, and the increased IGF-1R expression was associated with lager tumor size. IGF-1R may play an important role in carcinogenesis and tumor growth in PTC patients with T2DM.

LMTK3 knockdown retards cell growth and invasion and promotes apoptosis in thyroid cancer

Lemur tyrosine kinase-3 (LMTK3) is a member of the serine/threonine tyrosine kinase family, which is thought to be involved in tumor progression and prognosis. The purpose of the present study was to determine the diagnostic significance and therapeutic targets in thyroid cancer. ELISA assay was used to detect the protein expression of serum LMTK3. Immunohistochemistry and reverse transcription-quantitative polymerase chain reaction were employed to measure the expression of LMTK3. Flow cytometry was used to determine the cell cycle. Transwell assay was used to measure the invasion and migration of SW579 cells and terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) assay to detect cell apoptosis. The LMTK3 level was positively associated with disease stage and pathological type, whereas there was no correlation between LMTK3 level and gender, age, tumor size or lymph node metastasis. The serum LMTK3 level was significantly increased in 102 thyroid carcinoma patients compared with 52 benign thyroid tumor patients and 50 healthy volunteers (P=0.001). The protein and mRNA expression of LMTK3 was markedly higher in thyroid cancer patients compared with patients with benign thyroid tumors. Notably, LMTK3 knockdown retarded proliferation, invasion and migration in SW579 cells. In addition, downregulation of LMTK3 promoted apoptosis in SW579 cells. These findings indicated that LMTK3 knockdown retards the growth of thyroid cancer cells partly through inhibiting proliferation, invasion, migration and inducing apoptosis in SW579 cells. It may serve as a useful diagnostic biomarker and a novel therapeutic target for patients with thyroid cancer.

Detection of BRAF mutation in the cytocentrifugation supernatant fluid from fine-needle aspiration of thyroid lesions may enhance the diagnostic yield

Objective:

BRAF mutations using cellular DNA from fine-needle aspiration (FNA) specimens are commonly used to support the diagnosis of papillary thyroid carcinoma (PTC). The goal of this study was to preliminarily evaluate the diagnostic utility of detecting BRAF mutations in the routinely discarded FNA specimen supernatant fluid.

Materials and Methods:

Seventy-eight FNAs of thyroid lesions were evaluated for BRAF mutations using both cellular and supernatant DNA. BRAF mutation data were correlated with cytology and surgical pathology.

Results:

Of the 78 samples evaluated, 68 (87%) had amplifiable DNA in the supernatant with 2 (3%) positive for BRAF mutations. These two samples showed no mutations in the cellular counterpart. Among the 11 samples showing morphologic findings (FNA/surgical pathology) suspicious/diagnostic of PTC, 6 (55%) samples (one supernatant and five cellulars) were positive for BRAF mutations. This suggests that testing supernatant DNA in FNA specimens may increase the diagnostic yield by 1/11 (9%) in this setting.

Conclusions:

The vast majority of routinely discarded FNA supernatants contain amplifiable DNA. In addition, profiling the mutations of BRAF and other genes using supernatant DNA may provide valuable diagnostic information to assist the diagnosis of PTC in patients with clinical/morphologic findings suspicious for malignancies and cellular DNA showing no mutations.

Evaluation of Diagnostic Performance of Screening Thyroid Ultrasonography and Imaging Findings of Screening-Detected Thyroid Cancer

Purpose

The purpose of this study was to evaluate the diagnostic performance and cost of screening thyroid ultrasonography (US) in an asymptomatic population and determine the US features of screening-detected thyroid cancer.

Materials and Methods

This study included 1,845 asymptomatic participants who underwent screening thyroid US between March and August 2012 at the screening center in our hospital. We evaluated the diagnostic performance of screening thyroid US for thyroid cancer and the average cost of diagnosis for each patient. We also determined the characteristic US features of screening-detected thyroid cancer.

Results

Of the 1,845 subjects, 661 showed no abnormalities, 1,155 exhibited benign thyroid nodules, and 29 exhibited thyroid cancer. Imaging features such as solid composition, hypoechogenicity, taller-than-wide axis, and ill-defined or spiculated margins of nodules were suggestive of malignancy. The rate of detection of cancer was 1.6% (29/1,845), and the sensitivity, specificity, and positive and negative predictive values were 100% (18/18), 98.7% (1,051/1,065), 56.3% (18/32), and 100% (1,051/1,051), respectively. Of 18 patients who underwent thyroidectomy, three (16.7%) had a pathological tumor staging of T3, and four (22.2%) had a pathological nodal staging of N1a. The average cost of diagnosis for each patient with cancer was $7,319.

Conclusion

Screening thyroid US exhibited a good diagnostic performance, with a feasible social cost of use. This modality demonstrated significant differences in sonographic features between screening-detected cancer and benign nodules.

Occupational exposure to pesticides and other biocides and risk of thyroid cancer

OBJECTIVES

To assess the associations between occupational exposure to biocides and pesticides and risk of thyroid cancer.

METHODS

Using data from a population-based case-control study involving 462 incident thyroid cancer cases and 498 controls in Connecticut collected in 2010-2011, we examined the association with occupational exposure to biocides and pesticides through a job-exposure matrix. We used unconditional logistic regression models to estimate OR and 95% CI, adjusting for potential confounders.

RESULTS

Individuals who were occupationally ever exposed to biocides had an increased risk of thyroid cancer (OR=1.65, 95% CI 1.16 to 2.35), and the highest risk was observed for the high cumulative probability of exposure (OR=2.18, 95% CI 1.28 to 3.73). The observed associations were similar when we restricted to papillary thyroid cancer and well-differentiated thyroid cancer. Stronger associations were observed for thyroid microcarcinomas (tumour size ≤1 cm). No significant association was observed for occupational exposure to pesticides.

CONCLUSIONS

Our study provides the first evidence linking occupational exposure to biocides and risk of thyroid cancer. The results warrant further investigation.

The changing characteristics and molecular profiles of papillary thyroid carcinoma over time: a systematic review

BACKGROUND

The genetic alterations of papillary thyroid carcinoma (PTC) have been reported to change over the past few decades. We performed this systematic review to further examine the trends and modifications of patient demographic, clinicopathological features and molecular profiles of PTC over time.

METHODS

A literature search was performed within six electronic databases to identify relevant articles. The inclusion criteria were published studies investigating BRAF mutations, RET/PTC rearrangements or RAS mutations in PTCs or classical PTCs. Two teams of reviewers independently screened titles and abstracts of all articles. Full texts of potential articles were read and extracted data were listed and stratified into an excel file according to country, city, institution, and surgical time period. Student t test and Pearson Chi-square were used to analyze the trends of demographic and clinicopathological features of PTC patients and the prevalence of each genetic alteration in individual institutions.

RESULTS

From 3139 articles, we included 16 articles for final analysis. Our results showed an increasing trend of BRAF and a decreasing trend of RET/PTC prevalence over time in PTCs and classical PTCs, accompanied by an older age of PTC patients, an increase in proportion of PTMC and less aggressive behaviours of tumours.

CONCLUSIONS

The demographic and clinicopathological characteristics and molecular profile of PTCs have been changing over the past few decades. These modifications suggest changes in etiologies and risk factors of thyroid cancer that influence the tumorigenesis of PTCs.

Single Point Mutations in Pediatric Differentiated Thyroid Cancer

PURPOSE

Differentiated thyroid cancer (DTC) is rare in children. Previous studies have suggested that it has different clinicopathologic features and mutation profiles compared with adult DTC. However, those studies focused on a single or limited number of gene mutations. This study comprehensively investigated a large series of pediatric DTC for single point mutations in BRAF, HRAS, KRAS, NRAS, PIK3CA, PTEN, and TERT. It also analyzed associations between clinicopathologic features and the BRAF^V600E mutation.

PATIENTS AND METHODS

Eighty-nine consecutive cases seen in children and adolescents (≤18 years) during 1998-2015 were identified. Rare variants of DTC were excluded, and the study focused on 72 (91.1%) classical papillary thyroid carcinoma (PTC) and seven (8.9%) follicular variant PTC. These included 68 (86.1%) females and 11 (13.9%) males, with a median age of 15.5 years (range 8-18 years). The clinical and histopathological data were obtained from medical records. DNA was extracted from paraffin-embedded tumor tissue, and was PCR-amplified and directly sequenced.

RESULTS

Mutations detected included BRAF^V600E in 19/72 (26.4%) classical PTC samples, and in none of seven follicular variant PTC. Other mutations included: 1/78 (1.3%) successfully amplified tumor samples with TERT^C228T; 2/79 (2.5%) NRAS 61 (c.181C>A and c.182A>G); 1/73 (1.4%) PIK3CA exon 9 (c.1589A>G and c.1598C>T in one tumor); 1/79 (1.3%) PIK3CA exon 20 (c.2951G>A); and 1/74 (1.4%) PTEN exon 5 (c.295G>A). No mutation was found in HRAS, KRAS, NRAS12, PTEN exons 6, 7, and 8, and TERT^C250T. No significant association was found between BRAF^V600E mutation and sex, extrathyroidal invasion, tumor multifocality, vascular invasion, lymph node or distant metastases, and persistent/recurrent disease.

CONCLUSIONS

In pediatric DTC, the prevalence of the BRAF^V600E mutation is significantly less common compared with adult DTC, and there is no association between this mutation and the histopathological features and outcome of PTC. PIK3CA, PTEN, NRAS 61, and TERT^C228T mutations are rare.

Estimation of Second Primary Cancer Risk After Treatment with Radioactive Iodine for Differentiated Thyroid Carcinoma

BACKGROUND

An increase in the incidence of second primary cancers is the late effect of greatest concern that could occur in differentiated thyroid carcinoma (DTC) patients treated with radioactive iodine (RAI). The decision to treat a patient with RAI should therefore incorporate a careful risk-benefit analysis. The objective of this work was to adapt the risk-estimation models developed by the Biological Effects of Ionizing Radiation Committee to local epidemiological characteristics in order to assess the carcinogenesis risk from radiation in a population of Brazilian DTC patients treated with RAI. Absorbed radiation doses in critical organs were also estimated to determine whether they exceeded the thresholds for deterministic effects.

METHODS

A total of 416 DTC patients treated with RAI were retrospectively studied. Four organs were selected for absorbed dose estimation and subsequent calculation of carcinogenic risk: the kidney, stomach, salivary glands, and bone marrow. Absorbed doses were calculated by dose factors (absorbed dose per unit activity administered) previously established and based on standard human models. The lifetime attributable risk (LAR) of incidence of cancer as a function of age, sex, and organ-specific dose was estimated, relating it to the activity of RAI administered in the initial treatment.

RESULTS

The salivary glands received the greatest absorbed doses of radiation, followed by the stomach, kidney, and bone marrow. None of these, however, surpassed the threshold for deterministic effects for a single administration of RAI. Younger patients received the same level of absorbed dose in the critical organs as older patients did. The lifetime attributable risk for stomach cancer incidence was by far the highest, followed in descending order by salivary-gland cancer, leukemia, and kidney cancer.

CONCLUSION

RAI in a single administration is safe in terms of deterministic effects because even high-administered activities do not result in absorbed doses that exceed the thresholds for significant tissue reactions. The Biological Effects of Ionizing Radiation Committee mathematical models are a practical method of quantifying the risks of a second primary cancer, demonstrating a marked decrease in risk for younger patients with the administration of lower RAI activities and suggesting that only the smallest activities necessary to promote an effective ablation should be administered in low-risk DTC patients.

Occupation and Thyroid Cancer: A Population-Based, Case-Control Study in Connecticut

OBJECTIVE

The study aims to explore the associations between various occupations and thyroid cancer risk.

METHODS

A population-based, case-control study involving 462 histologically confirmed incident cases and 498 controls was conducted in Connecticut in 2010 to 2011.

RESULTS

A significantly increased risk of thyroid cancer, particularly papillary microcarcinoma, was observed for those working as the health care practitioners and technical workers, health diagnosing and treating practitioners, and registered nurses. Those working in building and grounds cleaning, maintenance occupations, pest control, retail sales, and customer service also had increased risk for papillary thyroid cancer. Subjects who worked as cooks, janitors, cleaners, and customer service representatives were at an increased risk of papillary thyroid cancer with tumor size more than 1 cm.

CONCLUSION

Certain occupations were associated with an increased risk of thyroid cancer, with some tumor size and subtype specificity.

MiR-195 Inhibits Tumor Growth and Metastasis in Papillary Thyroid Carcinoma Cell Lines by Targeting CCND1 and FGF2

BACKGROUND

MicroRNA (miRNA) dysregulation was commonly seen in papillary thyroid carcinoma (PTC), and miR-195 was verified to be downregulated in PTC by the large data set analysis from The Cancer Genome Atlas (TCGA). Our study aimed to explore the biological functions and the underlying molecular mechanisms of miR-195 in PTC.

METHODS

The relative expression of miR-195 and its target genes were assessed by quantitative RT-PCR assay in 38 pairs of PTC and the adjacent thyroid tissues. Assays were performed to evaluate the effect of miR-195 on the proliferation, migration, and invasion in PTC cell lines. Moreover, we searched for targets of miR-195 and explored the possible molecular pathway of miR-195 in PTC.

RESULTS

We found that miR-195 was downregulated in PTC cell lines and tissues. Overexpression of miR-195 significantly inhibited cell proliferation, migration, and invasion in K1 and BCPAP cell lines. CCND1 and FGF2, which had inverse correlations with miR-195 in clinical specimens, were found to be the direct targets of miR-195. Furthermore, miR-195 might be involved in PTC tumorigenesis by suppressing the Wnt/β-catenin signaling pathway.

CONCLUSIONS

These results highlight an important role of miR-195 in the initiation and progression of PTC and implicate the potential application of miR-195 in PTC target therapy.

Pretreatment BMI Is Associated with Aggressive Clinicopathological Features of Papillary Thyroid Carcinoma: A Multicenter Study

OBJECTIVES

The aim of the present study was to analyze the association between pretreatment body mass index (BMI) and the aggressiveness of papillary thyroid carcinoma (PTC) along with its clinical outcomes in a Chinese population with BMI classification for Asians.

METHODS

A retrospective, observational study was conducted on patients from two teaching hospitals in China. 1622 classical PTC patients were categorized into four groups according to BMI.

RESULTS

We found that increased BMI was associated with extrathyroidal extension, multifocality, the presence of lymph node (LN) metastasis, and advancing TNM stage in PTC patients. Furthermore, compared to patients with normal weight, those in the overweight and obese group exhibited a significantly increased risk of extrathyroidal extension, multifocality, cervical LN metastasis, and advanced TNM stage. 40 and 37 patients experienced persistent and recurrent disease, respectively. No differences regarding persistent disease or recurrence were observed among the BMI groups.

CONCLUSION

A higher pretreatment BMI has been strongly associated with aggressive features of PTC according to the BMI classification for Asians. Obesity was not found to be associated with a greater risk of recurrence.

Thyroid Cancer in Saudi Arabia: A Histopathological and Outcome Study

Most data on differentiated thyroid cancer (DTC) came from the Western world. We describe its salient characteristics and outcome from a Middle Eastern country. Patients and Methods. We studied all cases of TC seen during a 2-year period (2004-2005) seen at our institution. Results. A total of 600 consecutive cases of DTC with a median age at diagnosis of 39 years (5-85) and the female : male ratio of 459 : 141 (76.5% : 23.5%). The cases included classical papillary thyroid cancer (PTC) in 77%, follicular variant PTC in 13.3%, follicular thyroid cancer in 3.2%, and other rare subtypes 6.5%. Total or near-total thyroidectomy was performed in 93%, central and/or lateral neck dissection in 64.5% of cases, and radioactive iodine ablation in 82% of cases. Additional therapies were administered to 154 patients (25.7%). At a median follow-up period of 7.63 years (0.22-13.1), 318 patients (53.3%) were in excellent response, 147 (24.5%) having an indeterminate response, 55 (9.2%) biochemically incomplete, 33 (5.5%) structurally incomplete, and 27 (4.5%) unclassifiable. Twenty cases died secondary to DTC (disease-specific mortality 3.3%). Conclusions. In Saudi Arabia, DTC is common and occurs at young age and predominantly in females. Although remission is common, persistent disease is also common but disease-specific mortality is low.

Female Reproductive Factors and Differentiated Thyroid Cancer

Differentiated thyroid cancer (DTC) is markedly more common in women than men, the highest female-to-male ratio being recorded during the reproductive period. This evidence has led to the suggestion that female hormonal and reproductive factors may account for the observed DTC gender disparity. This review focuses on current evidence on the risk of DTC in conjunction with major female reproductive factors, including the impact of pregnancy on DTC occurrence and progression/recurrence. Overall, studies exploring the link between the risk of DTC and menstrual and menopausal factors, oral contraceptives and/or hormone replacement therapy, showed these associations, if any, to be generally weak. Nonetheless, there is some evidence that higher levels of exposure to estrogens during reproductive years may confer an increased risk of DTC. As far as pregnancy is concerned, it is unclear whether a potential association between parity and risk of DTC actually exists, and whether it is enhanced in the short-term following delivery. A possible role for pregnancy-related factors in DTC progression has been recently suggested by some reports, the results of which are consistent with a worse outcome in the short-term of women diagnosed with DTC during gestation compared to non-pregnant control patients. Also, some progression of disease has been described in women with structural evidence of disease prior to pregnancy. However, there seems to be no impact from pregnancy in DTC-related death or overall survival. Several in vitro and animal studies have evaluated the influence of estrogens (E) and estrogen receptors (ERs) on thyroid cell proliferation. Presently available data are indicative of a role of E and ERs in thyroid cancer growth, although considerable discrepancies in respect to ER expression patterns in thyroid cancer tissues actually exist. Further studies providing more direct evidence on the possible role of E and of placental hormones and growth factors on thyroid growth may expand our knowledge on the mechanisms beyond the gender disparity of proliferative thyroid diseases.

Insulin Resistance: Any Role in the Changing Epidemiology of Thyroid Cancer?

In the past few decades, the incidence of thyroid cancer (TC), namely of its papillary hystotype (PTC), has shown a steady increase worldwide, which has been attributed at least in part to the increasing diagnosis of early stage tumors. However, some evidence suggests that environmental and lifestyle factors can also play a role. Among the potential risk factors involved in the changing epidemiology of TC, particular attention has been drawn to insulin-resistance and related metabolic disorders, such as obesity, type 2 diabetes, and metabolic syndrome, which have been also rapidly increasing worldwide due to widespread dietary and lifestyle changes. In accordance with this possibility, various epidemiological studies have indeed gathered substantial evidence that insulin resistance-related metabolic disorders might be associated with an increased TC risk either through hyperinsulinemia or by affecting other TC risk factors including iodine deficiency, elevated thyroid stimulating hormone, estrogen-dependent signaling, chronic autoimmune thyroiditis, and others. This review summarizes the current literature evaluating the relationship between metabolic disorders characterized by insulin resistance and the risk for TC as well as the possible underlying mechanisms. The potential implications of such association in TC prevention and therapy are discussed.

Observation versus thyroidectomy for papillary thyroid microcarcinoma in the elderly

OBJECTIVE

To compare the effectiveness of non-surgical versus surgical therapy in elderly patients with papillary thyroid microcarcinoma.

METHODS

The study cohort included 2323 elderly patients (aged 65 years and over) diagnosed with papillary thyroid microcarcinoma between 1988 and 2009, identified in the Surveillance, Epidemiology, and End Results 18 database of the National Cancer Institute.

RESULTS

The five-year overall survival rate was 23 per cent for non-surgical patients compared with 91 per cent for surgical patients (p < 0.0001). Unadjusted analysis revealed significantly improved survival in surgical patients compared with non-surgical patients (hazard ratio = 0.06; p < 0.0001). Propensity score analysis also revealed significantly improved survival in surgical patients compared with non-surgical patients (hazard ratio = 0.11; p < 0.0001).

CONCLUSION

Thyroidectomy appears to provide a survival benefit for elderly patients with papillary thyroid microcarcinoma. High-quality prospective studies are needed to better evaluate the comparative effectiveness of immediate thyroidectomy versus observation for elderly patients with papillary thyroid microcarcinoma.