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

SKI-606, an Src inhibitor, reduces tumor growth, invasion, and distant metastasis in a mouse model of thyroid cancer

PURPOSE

Src is overexpressed or hyperactivated in a variety of human cancers, including thyroid carcinoma. Src is a central mediator in multiple signaling pathways that are important in oncogenesis and cancer progression. In this study, we evaluated the effects of an Src inhibitor, SKI-606 (bosutinib), in a spontaneous metastatic thyroid cancer model with constitutively activated Src (Thrb(PV/PV)Pten(+/-) mice).

EXPERIMENTAL DESIGN

Thrb(PV/PV)Pten(+/-) mice were treated with SKI-606 or vehicle controls, beginning at 6 weeks of age until the mice succumbed to thyroid cancer. We assessed the effects of SKI-606 on thyroid cancer progression and analyzed the impact of SKI-606 on aberrant Src-mediated signaling.

RESULTS

SKI-606 effectively inhibited aberrant activation of Src and its downstream targets to markedly inhibit the growth of thyroid tumor, thereby prolonging the survival of treated mice. While Src inhibition did not induce cell apoptosis, it decreased cell proliferation by affecting the expression of key regulators of cell-cycle progression. Importantly, SKI-606 dramatically prevented dedifferentiation, vascular invasion, and lung metastasis of thyroid cancer cells. These responses were meditated by downregulation of mitogen-activated protein kinase pathways and inhibition of the epithelial-mesenchymal transition.

CONCLUSIONS

Our findings suggest that Src is critical in the progression of thyroid cancer, making oral SKI-606 a promising treatment strategy for refractory thyroid cancer.

Metastases to the thyroid: a review of the literature from the last decade

BACKGROUND

Although clinically evident metastases of nonthyroid malignancies (NTMs) to the thyroid gland are uncommon, it is important to suspect them in patients who present with a new thyroid mass and a history, however far back, of prior malignancy. In fact, metastases from NTMs to the thyroid gland have been reported in 1.4%-3% of all patients who have surgery for suspected cancer in the thyroid gland. Here we review the literature over the last decade regarding this topic.

SUMMARY

Based on recent literature, the most common NTMs that metastasize to the thyroid gland are renal cell (48.1%), colorectal (10.4%), lung (8.3%), and breast carcinoma (7.8%), and sarcoma (4.0%). Metastases of NTMs to the thyroid are more common in women than men (female to male ratio=1.4 to 1) and in nodular thyroid glands (44.2%). The mean and median intervals between diagnosing NTMs and their metastases to thyroid gland are 69.9 and 53 months, respectively. In 20% of cases the diagnosis of the NTM and its metastases to the thyroid was synchronous. Recent reports indicate that there is a higher frequency of sarcoma metastasizing to the thyroid gland than reported in prior years. Fine-needle aspiration biopsy (FNAB) of thyroid masses is useful in diagnosis of thyroid metastases. However, this requires information about the NTM so that the proper antibodies can be used for immunohistochemical analysis; therefore it is of lesser utility if the NTM is occult. In patients with preexisting thyroid pathology the FNAB diagnosis can be more difficult due to more than one lesion being present.

CONCLUSIONS

It is important to keep in mind that the thyroid gland can be a site of metastases for a variety of tumors when evaluating a thyroid nodule, especially in a patient with a prior history of malignancy. In patients with thyroid lesions and a history of malignant disease, regardless of time elapsed since the initial diagnosis of the primary neoplasm, disease recurrence or progression of malignancy must be considered until proven otherwise.

BMI, diet and female reproductive factors as risks for thyroid cancer: a systematic review

Background

Thyroid cancer incidence rates have been increasing worldwide but the reason behind this is unclear. Both the increasing use of diagnostic technologies allowing the detection of thyroid cancer and a true increase in thyroid cancer incidence have been proposed. This review assesses the role of body mass index (BMI), diet, and reproductive factors on the thyroid cancer trend.

Methods

Epidemiologic studies of the selected risk factors up to June 2010 were reviewed and critically assessed.

Results

Among the thirty-seven studies reviewed and despite variation in the risk estimates, most papers supported a small but positive association for BMI (risk estimate range: 1.1–2.3 in males and 1.0–7.4 in females.). Among specific dietary components, there was no consistent association of thyroid cancer risk with iodine intake through fortification (risk estimate range: 0.49–1.6) or fish consumption (risk estimate range 0.6–2.2), nor with diets high in cruciferous vegetables (risk estimate range 0.6–1.9). A small number of studies showed a consistent protective effect of diets high in non-cruciferous vegetable (risk estimate range: 0.71–0.92). Among reproductive factors (pregnancy, parity, number of live births, use of prescription hormones, menstrual cycle regularity, and menopausal status), none were consistently associated with higher thyroid cancer risk.

Conclusions

BMI had the strongest link to thyroid cancer risk among those examined. Detailed examinations of population-level risk factors can help identify and support prevention efforts to reduce the burden of thyroid cancer.

HIF-1α and HSP90: target molecules selected from a tumorigenic papillary thyroid carcinoma cell line

It is important to properly identify aggressive tumors among differentiated thyroid cancers that are most often indolent. By comparison of a tumorigenic clone with an originally less tumorigenic papillary thyroid carcinoma (PTC) cell line, we looked for markers involved in the aggressive biology of thyroid cancer. Human PTC cell lines BHP10-3 and its tumorigenic subclone BHP10-3SC(mice) were compared using microarray analysis. Upregulated genes in the tumorigenic clone were selected for RT-PCR, immunoblot analysis and immunohistochemistry in human tissue. Hypoxia-inducible factor (HIF)-1α and its chaperone protein heat shock protein (HSP)90 showed significantly increased expression in BHP10-3SC(mice) and human PTC tissue. These two genes, HIF-1α and HSP90, were further validated using siRNA gene knockdown, pharmacological inhibition using 17-N-allylamino-17-demethoxygeldanamycin (17-AAG), an inhibitor of both HSP90 and HIF-1α and in vivo orthotopic animal model. Invasiveness of BHP10-3SC(mice) was abrogated by blockade of HIF-1αin vitro by both siRNA and 17-AAG. The same finding was demonstrated in the orthotopic animal model. These findings support that HIF-1α is important in tumorigenesis of PTC and that it may serve to be an important target for identification and treatment of aggressive tumors.

Changes in the incidence of thyroid cancer between 1991 and 2005 in Italy: a geographical analysis

BACKGROUND

The incidence of thyroid cancer (TC) has been increasing over the last 30 years in several countries, with some of the worldwide highest TC incidence rates (IRs) reported in Italy. The objectives of this study were to evaluate by histological subtypes the geographical heterogeneity of the incidence of TC in Italy and to analyze recent time trends for papillary thyroid carcinoma (PTC) in different cancer registries (CRs).

METHODS

The study included cases of TC (<85 years of age) reported to 25 Italian CRs between 1991 and 2005. Age-standardized IRs were computed for all histological subtypes of TC according to CRs. Estimated annual percent change and joinpoint regression analysis were used for analysis of PTC.

RESULTS

In women, IRs of PTC ranged between 3.5/100,000 in Latina and 8.5/100,000 in Sassari for the period 1991-1995 (a 2.4-fold difference) and between 7.3/100,000 in Alto Adige and 37.5/100,000 in Ferrara for 2001-2005 (a 5.1-fold difference). In men, IRs ranged between 0.7/100,000 in Latina and 3.4/100,000 in Sassari for the period 1991-1995 (a 4.9-fold difference) and between 2.0/100,000 (Alto Adige, Trento) and 10.6/100,000 in Ferrara for 2001-2005 (a 5.3-fold difference). In both sexes, IRs significantly higher than the pooled estimates emerged for the most recent period in the majority of CRs located within the Po River plain and in Latina, but they were lower in the Alpine belt. For women, CRs reported higher IRs than pool estimates showed, between 1991 to 2005, a significantly more marked annual percent change (+12%) than other CRs (+7%). For men the corresponding estimates were +11% and +8%.

CONCLUSIONS

The distribution of PTC does not lend support to a role of environmental radiation exposure due to the Chernobyl fallout, iodine deficiency, or (volcanic) soils. Between 1991 and 2005, wide geographic variations in the incidence of PTC and heterogeneous upward trends emerged, suggesting that the heterogeneity was a relatively recent phenomenon; this appeared to be mainly explained by variations, at a local level, in medical surveillance.

Epigenetics modifications and therapeutic prospects in human thyroid cancer

At present no successful treatment is available for advanced thyroid cancer, which comprises poorly differentiated, anaplastic, and metastatic or recurrent differentiated thyroid cancer not responding to radioiodine. In the last few years, biologically targeted therapies for advanced thyroid carcinomas have been proposed on the basis of the recognition of key oncogenic mutations. Although the results of several phase II trials look promising, none of the patients treated had a complete response, and only a minority of them had a partial response, suggesting that the treatment is, at best, effective in stabilizing patients with progressive disease. "Epigenetic" refers to the study of heritable changes in gene expression that occur without any alteration in the primary DNA sequence. The epigenetic processes establish and maintain the global and local chromatin states that determine gene expression. Epigenetic abnormalities are present in almost all cancers and, together with genetic changes, drive tumor progression. Various genes involved in the control of cell proliferation and invasion (p16INK4A, RASSF1A, PTEN, Rap1GAP, TIMP3, DAPK, RARβ2, E-cadherin, and CITED1) as well as genes specific of thyroid differentiation (Na+/I- symport, TSH receptor, pendrin, SL5A8, and TTF-1) present aberrant methylation in thyroid cancer. This review deals with the most frequent epigenetic alterations in thyroid cancer and focuses on epigenetic therapy, whose goal is to target the chromatin in rapidly dividing tumor cells and potentially restore normal cell functions. Experimental data and clinical trials, especially using deacetylase inhibitors and demethylating agents, are discussed.

Managing thyroid microcarcinomas

Papillary thyroid microcarcinomas (PTMCs) are the most common form of classic papillary thyroid carcinoma (PTC). PTMCs are typically discovered by fine-needle- aspiration biopsy (FNAB), usually with sensitive imaging studies, or are found during thyroid surgery in a patient without a previously known history of thyroid carcinoma. However, the definition of PTMC has not always been universally accepted, thus creating controversy concerning the diagnosis and treatment of PTMC. The aim of this review is to summarize the clinical features of PTMC and identify the widely differing opinions concerning the diagnosis and management of these small ubiquitous thyroid tumors.

Nativity and papillary thyroid cancer incidence rates among Hispanic women in California

BACKGROUND

Overall, the incidence of papillary thyroid cancer in Hispanic women residing in the United States (US) is similar to that of non-Hispanic white women. However, little is known as to whether rates in Hispanic women vary by nativity, which may influence exposure to important risk factors.

METHODS

Nativity-specific incidence rates among Hispanic women were calculated for papillary thyroid cancer using data from the California Cancer Registry (CCR) for the period 1988-2004. For the 35% of cases for whom birthplace information was not available from the CCR, nativity was statistically imputed based on age at Social Security number issuance. Population estimates were extracted based on US Census data. Incidence rate ratios (IRRs) and 95% confidence intervals (CIs) were also estimated.

RESULTS

In young (age <55 years) Hispanic women, the incidence of papillary thyroid cancer among US-born women (10.65 per 100,000) was significantly greater than that for foreign-born women (6.67 per 100,000; IRR, 1.60 [95% CI, 1.44-1.77]). The opposite pattern was observed in older women. The age-specific patterns showed marked differences by nativity: among foreign-born women, rates increased slowly until age 70 years, whereas among US-born women, incidence rates peaked during the reproductive years. Incidence rates increased over the study period in all subgroups.

CONCLUSION

Incidence rates of papillary thyroid cancer vary by nativity and age among Hispanic women residing in California. These patterns can provide insight for future etiologic investigations of modifiable risk factors for this increasingly common and understudied cancer.

Pathways to the diagnosis of thyroid cancer in New South Wales: a population-based cross-sectional study

BACKGROUND

Over the past few decades, an increase in the incidence of thyroid cancer has been recorded in many countries around the world including Australia. Heightened medical surveillance and increased technological sensitivity could be contributing to greater detection of asymptomatic disease.

OBJECTIVES

To describe the pathways to diagnosis of thyroid cancer for a cohort of newly diagnosed patients in New South Wales (NSW), Australia, and compare these pathways by age, sex, place of residence, ethnic background, medical insurance status, and disease characteristics.

METHODS

A total of 452 newly diagnosed cases of thyroid cancer were recruited through the population-based NSW Central Cancer Registry. Participants completed a questionnaire and diary of doctor visits and investigations that led to their diagnosis. Tumor characteristics were obtained from pathology reports.

RESULTS

Forty percent of patients initially presented to their doctor with a lump or symptom specific to thyroid cancer and 60% had their cancer detected incidentally during a medical encounter. Men were more likely than women to be diagnosed after imaging for another health concern versus reporting a thyroid lump or symptom (p = 0.001). Thyroid cancer diagnosis after imaging for another health concern increased with age (p = 0.023), and larger tumors were less likely to be diagnosed after treatment for a benign thyroid disease (p = 0.040).

CONCLUSION

As the majority of participants had incidental diagnoses, the reported incidence of thyroid cancer is likely to be influenced by diagnostic technology and medical surveillance practices. This, however, probably only partly explains the observed rise in the incidence of thyroid cancer in NSW.

Diabetes and thyroid cancer risk in the National Institutes of Health-AARP Diet and Health Study

BACKGROUND

We hypothesized that diabetes may play a role in thyroid cancer risk due to the parallel secular rise in diabetes prevalence and morbidity in the United States, the higher prevalence of thyroid disorders among diabetics compared with the general population, and the potential roles of metabolic syndrome, obesity, and diabetes as precipitating factors in cancer development.

METHODS

We assessed the association between self-reported diabetes and the risk of differentiated thyroid cancer in the NIH-AARP Diet and Health Study, a prospective cohort of 200,556 women and 295,992 men, 50-71 years of age, in 1995-1996. Diabetes status and information on potential confounders was ascertained using a self-administered questionnaire. During an average of 10 years of follow-up, 585 thyroid cancer cases were identified. Cox proportional hazards models were used to estimate hazard ratios (HR) and 95% confidence intervals (CI) for thyroid cancer and thyroid cancer subtypes in men and women according to diabetes status.

RESULTS

Nine percent of the total baseline cohort reported a history of diabetes (7% of women, 10% of men). A nonsignificant 25% increase in thyroid cancer risk (HR = 1.25; 95% CI: 0.95-1.64) was associated with diabetes. Among women, the risk was significantly increased (HR = 1.46, 95% CI: 1.01-2.10). The risk was not elevated among men (HR = 1.04, 95% CI: 0.69-1.58). In this cohort, diabetic women with differentiated thyroid cancer were at somewhat higher risk of follicular thyroid cancer (HR = 1.92; 95% CI: 0.86-4.27) than papillary thyroid cancer (HR = 1.25; 95% CI: 0.80-1.97).

CONCLUSION

This study lends support to the hypothesis that diabetes increases the risk of differentiated thyroid cancer.

Rationale and design of decision: a double-blind, randomized, placebo-controlled phase III trial evaluating the efficacy and safety of sorafenib in patients with locally advanced or metastatic radioactive iodine (RAI)-refractory, differentiated thyroid cancer

Background

The incidence of thyroid cancer and the number of patients who die from this disease are increasing globally. Differentiated thyroid cancer (DTC) is the histologic subtype present in most patients and is primarily responsible for the increased overall incidence of thyroid cancer. Sorafenib is a multikinase inhibitor that targets several molecular signals believed to be involved in the pathogenesis of thyroid cancer, including those implicated in DTC. In phase II studies of patients with DTC, sorafenib treatment has yielded a median progression-free survival (PFS) of 58 to 84 weeks and disease control rates of 59% to 100%. The DECISION trial was designed to assess the ability of sorafenib to improve PFS in patients with locally advanced or metastatic, radioactive iodine (RAI)-refractory DTC.

Methods/design

DECISION is a multicenter, double-blind, randomized, placebo-controlled phase III study in patients with locally advanced/metastatic RAI-refractory DTC. Study treatment will continue until radiographically documented disease progression, unacceptable toxicity, noncompliance, or withdrawal of consent. Efficacy will be evaluated every 56 days (2 cycles), whereas safety will be evaluated every 28 days (1 cycle) for the first 8 months and every 56 days thereafter. Following disease progression, patients may continue or start sorafenib, depending on whether they were randomized to receive sorafenib or placebo, at investigator discretion. Patients originally randomized to receive sorafenib will be followed up every 3 months for overall survival (OS); patients originally randomized to receive placebo will be followed up every month for 8 months after cross-over to sorafenib. The duration of the trial is expected to be 30 months from the time the first patient is randomized until the planned number of PFS events is attained. The primary endpoint is PFS; secondary endpoints include OS, time to disease progression, disease control rate, response rate, duration of response, safety, and pharmacokinetic analysis.

Discussion

The DECISION study has been designed to test whether sorafenib improves PFS in patients with locally advanced or metastatic RAI-refractory DTC.

Trial Registration

ClinicalTrials.gov Identifier: NCT00984282; EudraCT: 2009-012007-25.

Cardiac metastasis from thyroid carcinoma

Cardiac metastasis from epithelial thyroid cancer is a very rare and potentially serious complication. We have identified only 54 reported cases over a 130-year period. Here we review this literature. Cardiac metastases are frequently asymptomatic, but when symptoms develop these tend to be severe and often fatal. The prognosis of cardiac metastases from thyroid cancer is unclear as survival data are often missing or absent in reported cases. However, as many patients died suddenly from cardiac complications, the prognosis seems poor. Of those patients who survived, all underwent surgical intervention. Trans-thoracic echocardiography is the diagnostic modality of choice as it allows dynamic evaluation of intracardiac masses. Metastatic involvement of the heart from thyroid cancer is uncommon. Left untreated this complication seems likely to be fatal. Therefore, in patients with established thyroid malignancy who develop cardiac arrhythmias, new murmurs, or signs of cardiac decompensation, we suggest that cardiac metastases be considered. Echocardiography should be performed in patients with advanced thyroid cancer and cardiac symptoms or signs. If a cardiac metastasis is present, we recommend surgical intervention if possible.

Epidemiology of thyroid diseases in Africa

BACKGROUND

Thyroid disorders are common endocrine disorders encountered in the African continent. Environmental and nutritional factors are often implicated in the occurrence of some thyroid disorders that occur in this part of the world. This is a narrative review that seeks to document the pattern, prevalence, and management of thyroid disorders in the continent.

MATERIALS AND METHODS

The search engine used for this review were PubMed and Google scholar. All available articles on thyroid disorders from the sub-African continent, published until May 2011, were included.

RESULTS

Iodine deficiency disorders (IDD) which top the list of thyroid disorders and remain the commonest cause of thyroid disorders in the continent is often affected not only by the iodine status in the region but sometimes also by selenium deficiency and thiocyanate toxicity. The reported prevalence rates of endemic goiter range from 1% to 90% depending on the area of study with myxedematous cretinism still a prominent feature of IDD in only a few regions of the continent. The extent of autoimmune thyroid disorders remains unknown because of underdiagnosis and underreporting but the few available studies note a prevalence rate of 1.2% to 9.9% of which Graves diseases is the commonest of these groups of disorders. Rarer causes of thyroid dysfunction such as thyroid tuberculosis and amiodarone related causes are also documented in this review. The onset of new thyroid diseases following amiodarone usage was documented in 27.6% of persons treated for arrhythmia. Reports on thyroid malignancies (CA) in Africa abound and differentiated thyroid malignancies are noted to occur more commonly than the other forms of thyroid CA. The documented prevalence rates of thyroid CA in the African continent are as follows (papillary: 6.7-72.1%, follicular: 4.9-68%, anaplastic: 5-21.4%, and medullary: 2.6%-13.8%). For the differentiated thyroid CA, there is a changing trend toward the more frequent occurrence of papillary CA compared to follicular CA and this may be attributable to widespread iodization programs. Our review shows that diagnosis and evaluation of thyroid disorders are reliant in most regions of the continent on clinical acumen and suboptimal diagnostic facilities and expertise are what obtain in many practices. The frequently employed management options of thyroid disorders in the continent are pharmacological and surgical treatment modalities.

CONCLUSION

Diagnosis and management of thyroid disorders in the African continent remain suboptimal. Thyroid registries may be helpful to determine the scope of the burden of thyroid disorders since this knowledge may help change policies on the approach to the management of these disorders.

Risks and benefits of dietary isoflavones for cancer

A high intake of fruits and vegetables is associated with a lower risk of cancer. In this context, considerable attention is paid to Asian populations who consume high amounts of soy and soy-derived isoflavones, and have a lower risk for several cancer types such as breast and prostate cancers than populations in Western countries. Hence, interest focuses on soyfoods, soy products, and soy ingredients such as isoflavones with regard to their possible beneficial effects that were observed in numerous experiments and studies. The outcomes of the studies are not always conclusive, are often contradictory depending on the experimental conditions, and are, therefore, difficult to interpret. Isoflavone research revealed not only beneficial but also adverse effects, for instance, on the reproductive system. This is also the case with tumor-promoting effects on, for example, breast tissue. Isoflavone extracts and supplements are often used for the treatment of menopausal symptoms and for the prevention of age-associated conditions such as cardiovascular diseases and osteoporosis in postmenopausal women. In relation to this, questions about the effectiveness and safety of isoflavones have to be clarified. Moreover, there are concerns about the maternal consumption of isoflavones due to the development of leukemia in infants. In contrast, men may benefit from the intake of isoflavones with regard to reducing the risk of prostate cancer. Therefore, this review examines the risks but also the benefits of isoflavones with regard to various kinds of cancer, which can be derived from animal and human studies as well as from in vitro experiments.

[Epidemiology of thyroid carcinoma over the world]

Thyroid cancer (TC) incidence, in France and over the world, has dramatically increased over the last two decades. The temporal and geographical incidence trends in France and in the world are analysed. The increased incidence of TC is actual, mainly due to an increase of papillary microcarcinomas. The spread of ultrasonographic and cytological procedures, the extensiveness of thyroidectomies lead to diagnostic advance, to a better preoperative selection of patients and to the discovery of occult microcarcinomas. Nevertheless, the impact of the risk factors of thyroid cancer on the increase of incidence is not excluded. These risk factors are analysed, especially environmental chemicals agents that disrupt thyroid function.

Targeted therapies for thyroid tumors

Systemic chemotherapies for advanced or metastatic thyroid carcinomas have been of only limited effectiveness. For patients with differentiated or medullary carcinomas unresponsive to conventional treatments, novel therapies are needed to improve disease outcomes. Multiple novel therapies primarily targeting angiogenesis have entered clinical trials for metastatic thyroid carcinoma. Partial response rates up to 30% have been reported in single-agent studies, but prolonged disease stabilization is more commonly observed. The most successful agents target the vascular endothelial growth factor receptors, with potential targets including the mutant kinases associated with papillary and medullary oncogenesis. Two drugs approved for other malignancies, sorafenib and sunitinib, have had promising preliminary results reported, and are being used selectively for patients who do not qualify for clinical trials. At least one randomized, placebo-controlled phase III trial has been successfully completed, showing improved progression-free survival in patients with advanced or metastatic medullary thyroid carcinoma treated with vandetanib. Randomized trials for other agents are currently underway. Treatment for patients with metastatic or advanced thyroid carcinoma now emphasizes clinical trial opportunities for novel agents with considerable promise. Alternative options now exist for use of tyrosine kinase inhibitors that are well tolerated and may prove worthy of regulatory approval for this disease.

Role of the XRCC5/XRCC6 dimer in carcinogenesis and pharmacogenomics

Over the past few decades, the incidence of cancer has rapidly increased all over the world and cancer remains a major threat to public health. It is believed that cancer results from a series of genetic alterations that lead to the progressive disorder of the normal mechanisms controlling cell proliferation, differentiation, death and/or genomic stability. The response of the cell to genetic injury and its ability to maintain genomic stability by means of a variety of DNA repair mechanisms are therefore essential in preventing tumor initiation and progression. From the same viewpoint, the relative role of DNA repair as a biomarker for prognosis, predictor of drug and therapy responses or indeed as a target for novel gene therapy, is very promising. In this article, we have summarized the studies investigating the association between the XRCC5/XRCC6 dimer and the susceptibility to multiple cancers and discuss its role in carcinogenesis and its potential application to anticancer drug discovery.

Higher rate of BRAF mutation in papillary thyroid cancer over time: a single-institution study

BACKGROUND

The incidence of thyroid cancer has doubled over the past decade. The reason for this dramatic increase in incidence is controversial. Some investigators have suggested that the increased incidence is because of increased detection of small primary tumors as a result of diagnostic scrutiny. Conversely, some investigators have demonstrated an increased incidence across all tumor sizes, suggesting that other factors may play a role. This study was undertaken to investigate the clinical, pathologic, and molecular changes present in papillary thyroid cancer over a 15-year period during which the incidence of papillary thyroid cancer doubled.

METHODS

A total of 628 patients with conventional papillary thyroid cancer and 228 tumor samples from a single institution were analyzed from 1991 to 2005. Time-trend analyses of demographic, clinical, pathologic, and tumor genotype were performed over three 5-year time periods: group I (1991-1995), group II (1996-2000), and group III (2001-2005).

RESULTS

The authors found no differences in age, sex, ethnicity, primary tumor size, rate of extrathyroidal invasion, or overall TNM cancer stage among the 3 time groups. The rate of BRAF V600E mutation was significantly higher in group III (88% BRAF V600E positive) as compared with groups I and II (51% and 43%, respectively) (P < .001). The rate of all the common somatic mutations was also significantly higher in group III (92% positive) as compared with groups I and II (68% and 64%, respectively) (P < .002).

CONCLUSIONS

The rate of BRAF V600E mutation increased significantly over a 15-year period at the authors' institution. The findings suggest that a higher rate of BRAF mutation in papillary thyroid cancer may contribute to the increasing incidence of thyroid cancer.

Risks of papillary and follicular thyroid cancer among immigrants to Sweden

Previous studies have indicated that ionizing radiation, particularly during childhood, is the main established risk factor for thyroid cancer. History of benign nodules/adenoma, goiter, iodine deficiency or high-iodine intake might be other associated factors. We wanted to define the histology-specific thyroid cancer risk in the first-generation immigrants to Sweden. We used the 2010 update of the nation-wide Swedish Family-Cancer Database (>12 million individuals; 1.8 million immigrants; histology code in force since 1958) to calculate standardized incidence ratios (SIRs) for histology-specific thyroid cancer among immigrants compared to the native Swedes. The patient series covered 2,604 male and 6,406 female Swedes, and 247 and 863 immigrants. The median age at immigration was 29 years, and the median age at thyroid cancer diagnosis was 46 years. Increased risks for female papillary carcinoma were observed for Finns (SIR = 1.63), former Yugoslavians (2.36), Russians (2.34), other East Europeans (2.14), Turks (3.16), Iranians (2.68), Iraqis (2.77), East and Southeast Asians (2.92), other Asians (1.69) and South Americans (2.23). Male Iranians (2.85), East and Southeast Asians (3.57) and other Asians (2.26) had an increased risk for papillary carcinoma. Only male East and Southeast Asians (2.93) had an increased risk for follicular carcinoma. The data might suggest that immigrant populations in Sweden from areas of low or high-iodine intake are at risk of papillary carcinoma, implicating iodine imbalance as a contributing factor to our findings. The increased risk of thyroid cancer among Asian immigrants may confirm the role of childhood-ionizing radiation on thyroid cancer risk.

Cystic lymph nodes in the lateral neck as indicators of metastatic papillary thyroid cancer

OBJECTIVE

To determine whether radiographic findings portend to metastatic disease in patients with papillary thyroid carcinoma (PTC) and whether cystic lymph node metastasis can be recognized by preoperative, ultrasound-guided fine-needle aspiration (FNA).

METHODS

We performed a retrospective review of patients with cystic lymph nodes in the lateral neck identified on preoperative ultrasonography between March 1996 and December 2009. Factors examined included demographic information; stage; cytologic and final pathologic findings; and imaging characteristics including location, size, and presence of vascularity and calcifications. Time of cystic node identification in relationship to initial diagnosis was also recorded.

RESULTS

Thirty patients had cystic lymph nodes in the lateral neck on cervical ultrasonography during the study period. Among this group, 28 (93%) had PTC, 1 (3%) had papillary serous carcinoma of the ovary, and 1 (3%) had poorly differentiated thyroid cancer. Median age at initial cancer diagnosis was 41 years (range, 16-64 years). Twenty-one patients (70%) were women, and median lymph node size was 1.8 cm (range, 0.6-4.8 cm). Twenty-three patients (77%) had a solitary cystic lymph node, and the remainder had more than 1 cystic lymph node. Cystic lymph nodes were identified at initial presentation in 11 patients (37%), while cystic lymph nodes were discovered in 19 patients (63%) after the initial operation. FNA was performed on the cystic lymph nodes of 23 patients (77%). Cytologic findings were positive for metastatic disease in 18 of 23 patients (78%). Among the 5 of 23 patients with negative cytologic findings, thyroglobulin aspirate was obtained in 1 patient, confirming metastatic PTC. Final pathologic review after surgical resection of cystic lymph nodes with negative cytologic findings from FNA was consistent with metastatic disease in 4 of 5 patients (80%).

CONCLUSIONS

In patients with PTC, the presence of a cystic lymph node by ultrasonographic examination is highly suggestive of locally metastatic disease. Confirmation of metastatic PTC may sometimes be achieved with thyroglobulin aspirate from cystic lymph nodes when cytologic findings are negative. Clinicians should strongly consider surgical lymph node resection of cystic lymph nodes regardless of the preoperative cytologic findings by FNA.

Clinical and pathological implications of concurrent autoimmune thyroid disorders and papillary thyroid cancer

Cooccurrences of chronic lymphocytic thyroiditis (CLT) and thyroid cancer (DTC) have been repeatedly reported. Both CLT and DTC, mainly papillary thyroid carcinoma (PTC), share some epidemiological and molecular features. In fact, thyroid lymphocytic inflammatory reaction has been observed in association with PTC at variable frequency, although the precise relationship between the two diseases is still debated. It also remains a matter of debate whether the association with a CLT or even an autoimmune disorder could influence the prognosis of PTC. A better understanding about clinical implications of autoimmunity in concurrent thyroid cancer could raise new insights of thyroid cancer immunotherapy. In addition, elucidating the molecular mechanisms involved in autoimmune disease and concurrent cancer allowed us to identify new therapeutic strategies against thyroid cancer. The objective of this article was to review recent literature on the association of these disorders and its potential significance.

Medical exposure to radiation and thyroid cancer

In 2008, the worldwide estimated age-standardised incidence rates for thyroid cancer incidence were 4.7 and 1.5 per 100,000 women and men, respectively. Thyroid cancer's overall contribution to the worldwide cancer burden is relatively small, but incidence rates have increased over the last three decades throughout the world. This trend has been hypothesised to reflect a combination of technological advances enabling increased detection, but also changes in environmental factors, including population exposure to ionising radiation from fallout, diagnostic tests and treatment for benign and malignant conditions. Studies of the atomic bomb survivors and populations treated with radiotherapy have established radiation as a risk factor for thyroid cancer, particularly from early life exposure. About 0.62 mSv (20%) of the global annual per caput effective radiation dose comes from diagnostic medical and dental radiation for the period of 1997-2007, increased from 0.4 mSv for the years 1991-1996. This international trend of increasing population exposure to medical diagnostic sources of radiation, attributed in large part to the growing use of computed tomography scans, but also interventional radiology procedures, has raised concerns about exposure to radiosensitive organs such as the thyroid. Worldwide, medical and dental X-rays constitute the most common type of diagnostic medical exposures, but their contribution to the cumulative effective dose is relatively low, whereas computed tomography scans account for 7.9% of diagnostic radiology examinations but 47% of the collective effective dose from diagnostic radiation procedures in parts of the world. Although the radiation exposure from computed tomography scans is substantially lower than that from radiotherapy, multiple computed tomography scans could result in non-trivial cumulative doses to the thyroid. Studies are currently underway to assess the incidence of cancer in large cohorts of children who received computed tomography scans. National and international efforts have been developed to raise awareness and to standardise procedures for use of computed tomography and interventional radiology procedures in paediatric and general populations.

Thyroid cancer incidence patterns in the United States by histologic type, 1992-2006

BACKGROUND

The increasing incidence of thyroid cancer in the United States is well documented. In this study, we assessed the incidence patterns by histologic type according to demographic and tumor characteristics to further our understanding of these cancers.

METHODS

We used the National Cancer Institute's Surveillance, Epidemiology, and End Results (SEER) program for cases diagnosed during 1992-2006 to investigate patterns for the four major histologic types of thyroid cancer by gender, race/ethnicity, and age as well as registry, tumor stage, and size.

RESULTS

Among women, papillary thyroid cancer rates were highest among Asians (10.96 per 100,000 woman-years) and lowest among blacks (4.90 per 100,000 woman-years); follicular cancer rates did not vary substantially by race/ethnicity (p-values >0.05), medullary cancer rates were highest among Hispanics (0.21 per 100,000 woman-years) and whites (0.22 per 100,000 woman-years), and anaplastic rates were highest among Hispanics (0.17 per 100,000 woman-years). Among men, both papillary and follicular thyroid cancer rates were highest among whites (3.58 and 0.58 per 100,000 man-years, respectively), medullary cancer rates were highest among Hispanics (0.18 per 100,000 man-years), and anaplastic rates were highest among Asians (0.11 per 100,000 man-years). Racial/ethnic-specific rates did not vary notably across registries. In contrast to age-specific rates of papillary thyroid cancer that peaked in midlife (age 50), especially pronounced among women, rates for follicular, medullary, and anaplastic types continued to rise across virtually the entire age range, especially for anaplastic carcinomas. Female-to-male incidence rate ratios among whites decreased with age most steeply for the follicular type and least steeply for the medullary type; it was <1 until the very oldest ages for the anaplastic type.

CONCLUSION

We conclude that the similar age-specific patterns and lack of geographical variation across the SEER racial/ethnic groups indicate that detection effects cannot completely explain the observed thyroid cancer incidence patterns as variation in the amount or quality of healthcare provided has been shown to vary by SEER racial/ethnic groups, gender, and age. We find that the variations in age-specific patterns by gender and across histologic types are intriguing and recommend that future etiologic investigation focus on exogenous and endogenous exposures that are experienced similarly by racial/ethnic groups, more strongly among women, and distinctively by age.

Dietary nitrate and nitrite and the risk of thyroid cancer in the NIH-AARP Diet and Health Study

During the past several decades, an increasing incidence of thyroid cancer has been observed worldwide. Nitrate inhibits iodide uptake by the thyroid, potentially disrupting thyroid function. An increased risk of thyroid cancer associated with nitrate intake was recently reported in a cohort study of older women in Iowa. We evaluated dietary nitrate and nitrite intake and thyroid cancer risk overall and for subtypes in the National Institutes of Health-American Association of Retired Persons (NIH-AARP) Diet and Health Study, a large prospective cohort of 490,194 men and women, ages 50-71 years in 1995-1996. Dietary intakes were assessed using a 124-item food frequency questionnaire. During an average of 7 years of follow-up we identified 370 incident thyroid cancer cases (170 men, 200 women) with complete dietary information. Among men, increasing nitrate intake was positively associated with thyroid cancer risk (relative risk [RR] for the highest quintile versus lowest quintile RR = 2.28, 95% confidence interval [CI]: 1.29-4.041; p-trend <0.001); however, we observed no trend with intake among women (p-trend = 0.61). Nitrite intake was not associated with risk of thyroid cancer for either men or women. We evaluated risk for the two main types of thyroid cancer. We found positive associations for nitrate intake and both papillary (RR = 2.10; 95% CI: 1.09-4.05; p-trend = 0.05) and follicular thyroid cancer (RR = 3.42; 95% CI: 1.03-11.4; p-trend = 0.01) among men. Nitrite intake was associated with increased risk of follicular thyroid cancer (RR = 2.74; 95%CI: 0.86-8.77; p-trend = 0.04) among men. Our results support a role of nitrate in thyroid cancer risk and suggest that further studies to investigate these exposures are warranted.

Increasing incidence of differentiated thyroid cancer in South East England: 1987-2006

There has been a worldwide increase in the incidence of thyroid cancer (TC). Documenting these recent trends is of immense value to cancer control measures, monitoring policies, improving clinical outcomes, resource allocation and stimulating research. Hence this study aimed to analyse the changes in incidence, staging and morphologic types of TC in South East England (1987-2006) by means of a retrospective, descriptive epidemiological study using anonymized data obtained from the Thames Cancer Registry (TCR) of all patients registered with TC in the period 1987-2006. Ethical approval was obtained from the Kent Research Ethics Committee. 4,880 anonymized datasets using the ICD-10 code for thyroid cancer (C73) were analyzed using SPSS v.17. TC was commoner amongst females 3,560 (73%) than males 1,320 (27%) with a 2.7:1 ratio. Mean age at diagnosis was 53 years (Range 5-99) years. An increasing incidence trend was observed in early stage disease (p < 0.001), in young adults aged ≤ 49 years (p < 0.001) and in well-differentiated TC (papillary p < 0.001 and follicular p = 0.03). The results showed that TC is commoner in females than males in SE England with a 2.7:1 ratio. The results also indicate that TC incidence has increased in SE England over the 20 years studied, with the greatest increase occurring in early stage disease, in females, young adults and well-differentiated types (papillary and follicular). This may be due to widespread usage of ultrasound with detection of incidental nodules. Further studies are required to explain the trend.

Incidence of thyroid cancer in Italy, 1991-2005: time trends and age-period-cohort effects

BACKGROUND

In Italy, some of the highest incidence rates (IRs) of thyroid cancer (TC) worldwide have been reported.

PATIENTS AND METHODS

TC cases <85 years of age reported to Italian cancer registries during 1991-2005 were included. Age-standardized IRs were computed for all TC and age-period-cohort effects were estimated for papillary TC.

RESULTS

IRs of TC were twofold higher in 2001-2005 than in 1991-1995 (18 and 8 per 100,000 women, 6 and 3 per 100,000 men, respectively). Increases were similar in the two sexes and nearly exclusively due to papillary TC. Increases of papillary TC by birth cohort were found in both sexes and among all age groups between 20 and 79 years. Age-period-cohort models showed a strong period effect in both sexes (rate ratio for 2001-2009 versus 1991-1995 = 2.5 in women and 2.3 in men), although IRs peaked at an earlier age in women (45-49 years) than men (65-69 years).

CONCLUSION

The strength of the period effect in both sexes and the earlier onset in women than men strongly implicated increased medical surveillance in the upward trends of papillary TC incidence in Italy. The consequences of the current intense search for TC on morbidity and possible overtreatment, especially among young women, should be carefully evaluated.

Thyroid cancer epidemiology and prognostic variables

Thyroid cancer comprises a broad spectrum of diseases with variable prognoses. Although most patients with this disease have excellent overall survival, there are some who do not fare so well. With the worldwide increase in incidence, the need to identify which tumours pose the greatest risk to patients is more acute than ever. This paper will discuss this rising trend in incidence with an analysis of the possible reasons for the increase. In addition, the paper will explore the factors that portend a worse prognosis for the individual patient. Finally, the limitations of the current staging systems will be discussed, with particular emphasis on why they are not as informative in the management of patients with thyroid cancer.

Trends in survival of patients diagnosed with cancers of the brain and nervous system, thyroid, eye, bone, and soft tissues in the Nordic countries 1964-2003 followed up until the end of 2006

BACKGROUND

Diagnoses of cancer of the brain, thyroid, eye, bone, and soft tissues are categorised by heterogeneity in disease frequency, survival, aetiology and prospects for curative therapy. In this paper, temporal trends in patient survival in the Nordic countries are considered.

MATERIAL AND METHODS

Age-standardised incidence and mortality rates, 5-year relative survival, and excess mortality rates for varying follow-up periods are presented, as are age-specific 5-year relative survival by country, sex and 5-year diagnostic period.

RESULTS

Brain cancer incidence rates have been rising but mortality has been relatively stable, with 5-year survival uniformly increasing from the early-1970s, particularly in younger patients. Five-year survival from brain cancer among men varies between 45% and 50% for men and 60% to 70% in women, with excess deaths decreasing with time in each of the Nordic populations. Age-standardised incidence rates of thyroid cancer have been mainly increasing during the 1960s and 1970s, although trends thereafter diverge, with 5-year relative survival increasing 20-30 percentage points over the last 40 years to around 80-90%. Thyroid cancer survival is consistently lower in Denmark, particularly in patients diagnosed aged over 60, while there is less geographic variation in excess deaths three months beyond initial diagnosis. Relative survival from eye cancer increased with time from approximately 60% in 1964-1968 to 80% 1999-2003, while for bone sarcoma, incidence rates remained stable, mortality rates declined, and 5-year survival increased slightly to around 55-65%. Soft tissue sarcoma incidence and survival have been slowly increasing since the 1960s, with little variation in survival (around 65%) for the most recent period.

CONCLUSIONS

There have been some notable changes in survival that can be linked to epidemiological and clinical factors in different countries over time. Time-varying proportions of the major histological subtypes might however have affected the survival estimates for a number of the cancer forms reviewed here.

Risk of differentiated thyroid cancer in relation to adult weight, height and body shape over life: the French E3N cohort

The increasing incidence rate of thyroid cancer warrants investigation of potentially modifiable factors, especially overweightness. Few prospective studies have investigated anthropometry from childhood to adulthood in relation to thyroid cancer. We analyzed data from 91,909 women of the E3N study, a cohort of French women insured by a national health scheme mostly covering teachers with the age of 40-65 years at inclusion in 1990. Risk estimates of first primary differentiated thyroid cancer (n = 317) were computed using Cox proportional hazards models. There was a significant dose-effect relationship between thyroid cancer risk and weight or body mass index (BMI) but not height. Compared with women whose BMI was 18.5-22 kg/m(2), women with BMI 22-25 and those with BMI over 30 had a 39% [95% confidence interval (CI) 7-81] and 76% (12-176) higher risk of thyroid cancer, respectively, with a 21% (5-39) increased risk per 5 kg/m(2) increase in BMI. A large body shape from age 35-40 was significantly associated with an increased risk of differentiated thyroid cancer when compared with a lean one, while earlier body shapes were not. The highest risk was observed in women whose body shape increased from lean to large between menarche and adulthood, with a HR of 2.17 (95% CI 1.04-4.53) when compared with women who were lean at both periods. Our study adds to the existing evidence in relation to excess weight to the risk of thyroid cancer, particularly in women whose body shape increased from menarche to adult age.

Stereotactic body radiotherapy for refractory cervical lymph node recurrence of nonanaplastic thyroid cancer

OBJECTIVE

To investigate the feasibility and efficacy of stereotactic body radiotherapy as salvage treatment for cervical node recurrence from nonanaplastic thyroid cancer refractory to other modalities.

STUDY DESIGN

Pilot study.

SETTING

A single institution-based practice.

SUBJECTS AND METHODS

Between August 2002 and November 2007, nine patients with recurrent nonanaplastic thyroid cancer were treated with stereotactic body radiotherapy for nodal metastases. Radiotherapy was delivered in one to three fractions, and the median dose was 36 Gy (range 30-39 Gy).

RESULTS

Twenty-nine nodes in nine patients were treated. Seven patients had papillary carcinoma, and two had medullary carcinoma. These patients developed nodal recurrence after they received salvage surgery and/or radioisotope (RI) treatment for recurrent thyroid cancer. All nodes were in the cervical or supraclavicular areas, excepting one hilar node. Retropharyngeal node metastases were present in five patients. The median follow-up period was 23 months (range 4-63 mo). No local progression was observed in nodes treated by stereotactic body radiotherapy. Four patients developed new metastases in nontarget regional nodes after radiotherapy, and in two of these, regional failure was salvaged by additional stereotactic body radiotherapy. No serious adverse events were observed in any patient.

CONCLUSION

In select patients, stereotactic body radiotherapy may be a feasible option for treating refractory nodal recurrence from nonanaplastic thyroid cancer. Further studies are necessary to define the role of stereotactic body radiotherapy in the management of thyroid cancer.

Gender is an age-specific effect modifier for papillary cancers of the thyroid gland

BACKGROUND

Thyroid cancer incidence rates have increased worldwide for decades, although more for papillary carcinomas than other types and more for females than males. There are few known thyroid cancer risk factors except female gender, and the reasons for the increasing incidence and gender differences are unknown.

METHODS

We used the National Cancer Institute's Surveillance, Epidemiology, and End Results 9 Registries Database for cases diagnosed during 1976-2005 to develop etiological clues regarding gender-related differences in papillary thyroid cancer incidence. Standard descriptive epidemiology was supplemented with age-period-cohort (APC) models, simultaneously adjusted for age, calendar-period and birth-cohort effects.

RESULTS

The papillary thyroid cancer incidence rate among females was 2.6 times that among males (9.2 versus 3.6 per 100,000 person-years, respectively), with a widening gender gap over time. Age-specific rates were higher among women than men across all age groups, and the female-to-male rate ratio declined quite consistently from more than five at ages 20-24 to 3.4 at ages 35-44 and approached one at ages 80+. APC models for papillary thyroid cancers confirmed statistically different age-specific effects among women and men (P < 0.001 for the null hypothesis of no difference by gender), adjusted for calendar-period and birth-cohort effects.

CONCLUSION

Gender was an age-specific effect modifier for papillary thyroid cancer incidence. Future analytic studies attempting to identify the risk factors responsible for rising papillary thyroid cancer incidence should be designed with adequate power to assess this age-specific interaction among females and males.