Clinicopathologic and Prognostic Features of Pediatric Follicular Cell-derived Thyroid Carcinomas: A Retrospective Study of 222 Patients

Pediatric thyroid carcinomas (TCs) are rare and mainly approached based on data extrapolated from adults. We retrospectively reviewed 222 pediatric TCs (patient age less than or equal to 21 y). Lymph node (LN) disease volume at presentation was considered high if the largest positive LN measured ≥1 cm and/or >5 LNs were positive. High-grade follicular cell-derived thyroid carcinoma (HGFCTC) were defined by the presence of marked mitotic count and/or tumor necrosis and considered as high-risk histology along with papillary thyroid carcinomas (PTC) diffuse sclerosing variant (DSV). Disease-free survival (DFS) was analyzed. LN involvement at presentation was significantly associated with male sex, larger tumor size, lymphatic invasion, positive surgical margins, and distant metastases at presentation. Five- and 10-year DFS was 84% and 77%, respectively. Only 1 patient with HGFCTC died of disease. Within PTC variants, PTC-DSV was associated with adverse histopathologic parameters and higher regional disease spread, unlike PTC tall cell variant which did not portend worse behavior. The presence of necrosis conferred worse DFS ( P =0.006), while increased mitotic activity did not. While the entire HGFCTC group did not correlate with outcome ( P =0.071), HGFCTC with necrosis imparted worse DFS ( P =0.006). When restricted to PTC-DSV and HGFCTC with necrosis, high-risk histologic classification emerged as an independent prognostic parameter of DFS ( P =0.020). The excellent prognosis of pediatric TCs differs from that of adult TCs showing similar histologic features. While neither increased mitotic activity nor PTC tall cell variant histology predict adverse outcome, PTC-DSV and tumors with necrosis constitute high-risk histologic variants with an increased risk of protracted disease.

NATIONAL SURVEY OF ENDOCRINOLOGISTS AND SURGEONS REGARDING ACTIVE SURVEILLANCE FOR LOW-RISK PAPILLARY THYROID CANCER

OBJECTIVE

Active surveillance for low-risk papillary thyroid cancer (PTC) was endorsed by the American Thyroid Association guidelines in 2015. The attitudes and beliefs of physicians treating thyroid cancer regarding the active surveillance approach are not known.

METHODS

A national survey of endocrinologists and surgeons treating thyroid cancer was conducted from August to September 2017 via professional society emails. This mixed-methods analysis reported attitudes toward potential factors impacting decision-making regarding active surveillance, beliefs about barriers and facilitators of its use, and reasons why physicians would pick a given management strategy for themselves if they were diagnosed with a low-risk PTC. Survey items about attitudes and beliefs were derived from the Cabana model of barriers to guideline adherence and theoretical domains framework of behavior change.

RESULTS

Among 345 respondents, 324 (94%) agreed that active surveillance was appropriate for at least some patients, 81% agreed that active surveillance was at least somewhat underused, and 76% said that they would choose surgery for themselves if diagnosed with a PTC of ≤1 cm. Majority of the respondents believed that the guidelines supporting active surveillance were too vague and that the current supporting evidence was too weak. Malpractice and financial concerns were identified as additional barriers to offering active surveillance. The respondents endorsed improved information resources and evidence as possible facilitators to offering active surveillance.

CONCLUSION

Although there is general support among physicians who treat low-risk PTC for the active surveillance approach, there is reluctance to offer it because of the lack of robust evidence, guidelines, and protocols.

The Delphian Node Revisited: An Uncommon Site of Recurrence

The Delphian nodes (DNs) are frequently involved in cancers of the head and neck, including laryngeal and thyroid malignancies. Positivity in the DN has been considered a predictor of recurrence as well as an overall aggressive tumor biology. However, little has been written regarding the consequences of recurrence at the site of the DN. We present two case reports regarding recurrence in the DN and the unique challenges associated with DN metastases. In addition, we discuss our surgical approach to disease at the prelaryngeal space, including workup, imaging, and resection.

Surgical considerations for papillary thyroid microcarcinomas

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

Current Management of Low Risk Differentiated Thyroid Cancer and Papillary Microcarcinoma

Each year, the proportion of thyroid cancer patients presenting with low risk disease is increasing. Moreover, the definition of low risk thyroid cancer is expanding and several histological subtypes beyond papillary microcarcinomas are now classified as low risk disease. This shift in the landscape of thyroid cancer presentation is forcing clinicians to critically re-evaluate whether or not traditional management paradigms that were effective in treating intermediate and high risk disease are applicable to these low risk patients. Here we review the definition of low risk disease, examine the various histological subtypes that are considered low risk in the 2015 American Thyroid Association guidelines for the management of thyroid nodules and thyroid cancer, and review our current approach to the management of these low risk tumours.

Patients with high-risk differentiated thyroid cancer have a lower I-131 ablation success rate than low-risk ones in spite of a high ablation activity

OBJECTIVE

To examine success rates in strictly defined high-risk differentiated thyroid cancer (DTC) patients who received a high-activity (≥5550 MBq) adjuvant postoperative I-131 therapy and compare these to the rates found in highest risk and low-risk patients.

DESIGN

Retrospective database study.

PATIENTS

We examined 377 patients with DTC who received I-131 ablation. Patients with distant metastases were classified as very high risk. Patients with primary tumours >4 cm, extensive extrathyroidal invasion (pT4a or pT4b in accordance with the 7th edition of the TNM system), and patients with ≥5 lymph node metastases or any lateral compartment lymph node metastases were considered high risk. All other patients were considered low risk.

MEASUREMENTS

Ablation success rate at first TSH-stimulated follow-up.

RESULTS

The ablation success rate was 72·6% in low-risk patients, 51·7% in high-risk patients and 13·8% in highest risk patients (all differences P < 0·001). In none of the groups, a significant difference in the initial I-131 activity was found between patients with successful and unsuccessful ablation (low risk: P = 0·16, high risk: P = 0·91 and highest risk: P = 0·48). Furthermore, there was no difference in ablation success between patients who received <5550 MBq and those who received ≥5550 Mbq (low risk: P = 0·31, high risk: P = 0·69 and highest risk: P = 0·22).

CONCLUSIONS

Patients with high-risk DTC have a significantly reduced I-131 ablation success rate compared to low-risk ones in spite of high initial I-131 activities. As successful ablation is prognostically important, efforts should be made to improve outcome in these patients.

Outcomes for patients with papillary thyroid cancer who do not undergo prophylactic central neck dissection

BACKGROUND

The role of prophylactic central neck dissection (CND) in the management of papillary thyroid cancer (PTC) is controversial. This report describes outcomes of an observational approach in patients without clinical evidence of nodal disease in PTC.

METHODS

All patients who had surgery between 1986 and 2010 without CND for PTC were identified. All patients had careful clinical assessment of the central neck during preoperative and perioperative evaluation, with any suspicious nodal tissue excised for analysis. The cohort included patients in whom lymph nodes had been removed, but no patient had undergone a formal neck dissection. Recurrence-free survival (RFS), central neck RFS and disease-specific survival (DSS) were calculated using the Kaplan-Meier method.

RESULTS

Of 1798 patients, 397 (22.1 per cent) were men, 1088 (60.5 per cent) were aged 45 years or more, and 539 (30.0 per cent) had pT3 or pT4 disease. Some 742 patients (41.3 per cent) received adjuvant treatment with radioactive iodine. At a median follow-up of 46 months the 5-year DSS rate was 100 per cent. Five-year RFS and central neck RFS rates were 96.6 and 99.1 per cent respectively.

CONCLUSION

Observation of the central neck is safe and should be recommended for all patients with PTC considered before and during surgery to be free of central neck metastasis.

LEADER 2: baseline calcitonin in 9340 people with type 2 diabetes enrolled in the Liraglutide Effect and Action in Diabetes: Evaluation of cardiovascular outcome Results (LEADER) trial: preliminary observations

AIMS

To report preliminary data on baseline serum calcitonin concentrations and associated clinical characteristics in a global population with type 2 diabetes before liraglutide or placebo randomization.

METHODS

The ongoing LEADER trial has enrolled 9340 people with type 2 diabetes and at high risk of cardiovascular disease at 410 centres worldwide. People with baseline serum calcitonin ≤ 50 ng/l were randomized to liraglutide once daily or placebo and will be followed for up to 5 years. Serum calcitonin was measured at baseline and will be measured annually thereafter. An independent committee of thyroid experts will oversee calcitonin monitoring throughout the trial and will review all calcitonin concentrations ≥ 20 ng/l.

RESULTS

The mean age of participants was 64.3 ± 7.2 years, 64.3% were men, and mean the body mass index was 32.5 ± 6.3 kg/m(2). The median (interquartile range) baseline serum calcitonin values were 3.9 (1.0 to >7.6) ng/l in men and 1.0 (1.0 to >1) ng/l in women. Serum calcitonin was >10 ng/l in 14.6% of men and in 0.96% of women. In sex-specific multivariable linear analysis of covariance models, a reduced glomerular filtration rate (GFR) was associated with higher serum calcitonin concentrations that were statistically significant. A 20 ml/min/1.73 m(2) decrease in estimated GFR (eGFR) was associated with a 14% increase in serum calcitonin in women and an 11% increase in men.

CONCLUSIONS

In the LEADER population, the prevalence of elevated serum calcitonin concentrations at baseline was high, and there was an inverse association between eGFR and serum calcitonin concentrations.

Undetectable Thyroglobulin Levels in Poorly Differentiated Thyroid Carcinoma Patients Free of Macroscopic Disease After Initial Treatment: Are They Useful?

BACKGROUND

Predictive role of undetectable thyroglobulin (Tg) in patients with poorly differentiated thyroid carcinoma (PDTC) is unclear. Our goal was to report on Tg levels following total thyroidectomy and adjuvant RAI in PDTC patients and to correlate Tg levels with recurrence.

METHODS

Forty patients with PDTC with no distant metastases at presentation (M0) and managed by total thyroidectomy and adjuvant RAI were identified from a database of 91 PDTC patients. Of these, 31 patients had Tg values recorded and formed the basis of our analysis. A nonstimulated Tg level <1 ng/ml was used as a cutoff point for undetectable Tg levels. Association of patient and tumor characteristics with Tg levels was examined by χ (2) test. Recurrence-free survival (RFS) stratified by postop Tg level was calculated by Kaplan-Meier method and compared by log-rank test.

RESULTS

Twenty patients had undetectable Tg (<1 ng/ml) and 11 had detectable Tg (≥1 ng/ml; range 2-129 ng/ml) following surgery. After adjuvant RAI, 24 patients had undetectable Tg (<1 ng/ml) and 7 had detectable Tg (≥1 ng/ml; range 1-57 ng/ml). Patients with undetectable Tg were less likely to have pathologically positive margins compared to those with detectable Tg (33 vs. 72 % respectively; p = 0.03). Patients with undetectable Tg levels had better 5-year regional control and distant control than patients with detectable Tg level (5-year regional recurrence-free survival 96 vs. 69 %; p = 0.03; 5-year distant recurrence-free survival 96 vs. 46 %, p = 0.11).

CONCLUSION

Postoperative thyroglobulin levels in subset of patients with PDTC appear to have predictive value for recurrence. Patients with undetectable Tg have a low rate of recurrence.

Outcomes in patients with poorly differentiated thyroid carcinoma

BACKGROUND

Poorly differentiated thyroid cancer (PDTC) accounts for only 1-15% of all thyroid cancers. Our objective is to report outcomes in a large series of patients with PDTC treated at a single tertiary care cancer center.

METHODS

A total of 91 patients with primary PDTC were treated by initial surgery with or without adjuvant therapy at Memorial Sloan-Kettering Cancer Center from 1986 to 2009. Outcomes were calculated by the Kaplan-Meier method. Clinicopathological characteristics were compared for PDTC patients who died of disease to those who did not by the χ(2) test. Factors predictive of disease-specific survival (DSS) were calculated by univariate and multivariate analysis using the log rank and Cox proportional hazards method, respectively.

RESULTS

With a median follow-up of 50 months, the 5-year overall survival and DSS were 62 and 66%, respectively. The 5-year locoregional and distant control were 81 and 59%, respectively. Of 27 disease-specific deaths, 23 (85%) were due to distant disease. Age ≥ 45 years, pathological tumor size >4 cm, extrathyroidal extension, higher pathological T stage, positive margins, and distant metastases (M1) were predictive of worse DSS on univariate analysis. Multivariate analysis showed that only pT4a stage and M1 were independent predictors of worse DSS.

CONCLUSIONS

With appropriate surgery and adjuvant therapy, excellent locoregional control can be achieved in PDTC. Disease-specific deaths occurred due to distant metastases and rarely due to uncontrolled locoregional recurrence in this series.

Clinical outcomes and molecular profile of differentiated thyroid cancers with radioiodine-avid distant metastases

BACKGROUND

Radioiodine (RAI) remains the mainstay of therapy for RAI-avid (RAIA) distant metastatic thyroid carcinoma. We previously demonstrated that RAI-refractory distant metastatic thyroid cancers commonly harbor BRAF mutations. However, the molecular profile of RAIA metastatic thyroid cancer is unknown. Here we describe the mutational profile of thyroid tumors from follicular cell-derived cancer (FCDTC) patients presenting with RAIA distant metastases. In addition, we aimed to correlate clinical outcomes of RAI therapy with clinicopathological factors and tumor mutational status.

METHODS

We retrospectively identified 43 patients with FCDTC who had RAI uptake in the lungs and/or bones on their initial ¹³¹I postablation scan. Primary tumors were genotyped for known mutations in thyroid cancer genes. Structural response to RAI was assessed 6-18 months after each administered RAI activity and at the end of follow-up.

RESULTS

RAS, BRAF, RET/PTC, and PIK3CA mutations were found in 42, 23, 10, and 2% of tumors, respectively, and the remaining 23% were wild type. None of these patients achieved cure after repeat RAI therapies, and most patients (54%) experienced disease progression despite repeated RAI administration. There was an increased prevalence of RAS mutations in these RAIA tumors. RAS-mutant cancers were more likely to concentrate iodine on diagnostic whole body scans. Despite this, structural response to RAI was not influenced by tumor genotype.

CONCLUSIONS

RAIA metastatic FCDTC are overrepresented with RAS mutations, whereas RAI refractory metastatic thyroid cancers are enriched with BRAF mutations. Despite a seemingly preserved ability to concentrate iodine, RAI therapy is ineffective in achieving cure in most patients with RAIA metastatic FCDTC, even in RAS-mutant disease. These poor outcomes may be improved based on recent evidence that pretreatment with MAPK kinase 1/2 inhibitors enhances responses to RAI, particularly in patients with RAS-mutant tumors.

Suspicious cervical lymph nodes detected after thyroidectomy for papillary thyroid cancer usually remain stable over years in properly selected patients

CONTEXT

The risk of loco-regional recurrence in papillary thyroid cancer (PTC) patients ranges from 15-30%. However, the clinical significance of small-volume loco-regional recurrence detected by highly sensitive ultrasonography is unclear.

OBJECTIVE

Our objective was to describe the natural history of abnormal cervical lymph nodes (LN) diagnosed after initial treatment.

DESIGN

We conducted a retrospective cohort study.

PATIENTS

166 PTC with patients who had at least one abnormal LN outside the thyroid be on ultrasound and selected for active surveillance were included.

MAIN OUTCOME MEASURE

LN growth during a period of active surveillance was the primary outcome.

RESULTS

Most patients had classical PTC (85%) and an intermediate risk of recurrence (77%). The median LN size at the start of the observation period was 1.3 cm (range, 0.5-2.7 cm) in largest diameter, with all nodes having at least one abnormal sonographic characteristic (70% of patients had LN with at least two abnormal features). In almost all patients, the LN were in the lateral neck, primarily in levels 3 (43%) and 4 (58%). After a median follow-up of 3.5 yr, only 20% (33 of 166) grew at least 3 mm, 9% (15 of 166) grew at least 5 mm, and 14% (23 of 166) resolved. None of the clinical or sonographic features were predictive of LN growth (positive predictive value range = 0.21-0.57). There were no local complications (nerve damage or local invasion) related to the abnormal nodes and no disease-related mortality.

CONCLUSIONS

Suspicious cervical LN in the lateral neck usually remain stable for long periods of time in properly selected PTC patients and can be safely followed with serial ultrasounds.

Five-year survival is similar in thyroid cancer patients with distant metastases prepared for radioactive iodine therapy with either thyroid hormone withdrawal or recombinant human TSH

CONTEXT

Elevated levels of TSH markedly enhance the effectiveness of radioiodine (RAI) therapy in metastatic thyroid cancer.

OBJECTIVE

The objective of the study was to compare short-term overall survival in thyroid cancer patients with RAI-avid distant metastases prepared for RAI therapy with either traditional thyroid hormone withdrawal (THW) or recombinant human TSH (rhTSH) stimulation.

DESIGN

This was a retrospective chart review.

SETTING

The study was conducted at a tertiary care comprehensive cancer center.

PATIENTS

Patients included 175 patients with RAI avid metastatic disease to lung and/or bone.

INTERVENTIONS

In 58 patients, all RAI treatments (remnant ablation and therapy of metastatic disease) were done with rhTSH stimulation. In 35 patients, all RAI treatments were done after THW. In 82 patients, THW was used for initial RAI treatment(s) with subsequent administered activities given after rhTSH stimulation.

MAIN OUTCOME MEASURE

Overall survival was measured.

RESULTS

After a median follow-up of 5.5 yr, there were no significant differences in overall survival between patients prepared for RAI therapy with rhTSH alone, THW alone, or THW followed by rhTSH (Kaplan-Meier analysis, P = 0.80). In a multivariate analysis that included clinicopathological features and method of preparation (rhTSH or TWH), only age at diagnosis was an independent predictor of overall survival.

CONCLUSIONS

Preparation for RAI therapy using either THW or rhTSH stimulation was associated with similar 5-yr overall survival rates in patients with RAI avid thyroid cancer metastases to lung or bone.

Clinical presentation and clinical outcomes in Chernobyl-related paediatric thyroid cancers: what do we know now? What can we expect in the future?

Over the last 20 years, nearly 5000 cases of differentiated thyroid cancer have been diagnosed and treated in the regions of Russia, Ukraine and Belarus in young people previously exposed to the Chernobyl radioactive fallout during childhood. At diagnosis, 60-70% of the Chernobyl-related paediatric thyroid cancers had clinically evident cervical lymph node metastases (N1) and 10-15% had distant metastases (M1). Despite early reports suggesting that the paediatric thyroid cancer cases that developed after exposure to Chernobyl fallout were particularly aggressive, it now seems that the initial presentation and early clinical course of most of these cases are very similar to both non-radiation-associated paediatric thyroid cancers and thyroid cancers that arise after exposure to external beam irradiation. Over an average clinical follow-up period of about 10 years, the disease-specific mortality rate in these paediatric thyroid cancer cases that developed after the Chernobyl accident is quite low (1% or less). As would be expected in paediatric thyroid cancer, short-term recurrence rates range from 7 to 28% in published reports (mean 17%). However, long-term studies of paediatric thyroid cancer suggest that although the 30 year disease-specific mortality rate should be about 1%, the risk of developing structural disease recurrence is nearly 30% (of which 80% are expected to be locoregional recurrences and 20% are probably new distant metastases). Projected over 30 years of follow-up, a 1% disease-specific mortality in this cohort of 5000 patients would equate to about 50 deaths directly attributable to thyroid cancer. However, a 30% recurrence rate would also mean that about 1500 patients may develop a clinically meaningful recurrence that would need to be diagnosed and treated. It is imperative that we continue to work with our colleagues in Belarus, Ukraine and Russia to ensure that this large volume of patients destined to develop clinically significant recurrences are diagnosed and treated in a timely manner. Ready access to modern disease detection tools (serum thyroglobulin, postoperative neck ultrasonography, cytology/pathology support, and radioactive iodine scanning) and treatments (surgery for recurrent disease, radioactive iodine therapy) in their major academic centres are mandatory if we expect to achieve the excellent clinical outcomes that should be seen when paediatric thyroid cancer recurrence is diagnosed early and treated appropriately.

Prognostic factors of recurrence in encapsulated Hurthle cell carcinoma of the thyroid gland: a clinicopathologic study of 50 cases

BACKGROUND

Follicular carcinomas of the thyroid gland, including its oncocytic variant (so-called Hurthle cell carcinoma), are subdivided into the indolent encapsulated ("minimally invasive") and the clinically aggressive widely invasive tumors. There are, however, cases of encapsulated follicular carcinoma that recur and metastasize. Identifying these cases at the time of diagnosis is crucial for prognostic and therapeutic considerations. Because to the authors' knowledge most studies do not focus exclusively on the encapsulated Hurthle cell carcinoma (EHC), the current study attempted to identify predictors of recurrence in EHC.

METHODS

A tumor was defined as EHC if it was encapsulated, macroscopically well defined with microscopic but no macroscopic evidence of vascular or capsular invasion, and composed of > 75% follicular oncocytic cells. Retrospective chart review and microscopic examination identified 50 primary tumors meeting the above criteria at the Memorial Sloan-Kettering Cancer Center between 1967 and 2005. The cases were analyzed for various histologic and clinical parameters. Each parameter was correlated with recurrence-free survival (RFS).

RESULTS

Seven of 50 (14%) patients developed disease recurrence. All patients who developed recurrence were found to have a high number of foci of vascular invasion (> or = 4). In univariate analysis, > or = 4 foci of vascular invasion (P <.0001), tumor size > 4 cm (P = .049), the presence of mitosis (P = .018), and a solid/trabecular growth pattern (P = .009) were found to be correlated with a decreased RFS. Extensive capsular invasion, gender, and age did not confer a statistically higher recurrence rate. The finding of a solid/trabecular growth and mitosis correlated with the presence of numerous foci (> or = 4) of vascular invasion (P = .01 and P = .005, respectively).

CONCLUSIONS

A diligent search for vascular invasion is recommended in EHC that display mitosis or a solid/trabecular growth pattern. The presence of > or = 4 foci of vascular invasion should alert the pathologist and the clinician to a significantly higher risk of recurrence in EHC.

Erythropoietin in thyroid cancer

Erythropoietin (Epo) and the epo-receptor (EpoR) have been implicated in tumor growth, invasion and metastasis. We previously demonstrated Epo and EpoR expression in a small group of archived papillary thyroid cancers (PTC), but were unable to examine functional integrity using formalin-fixed tissues. In the present study, we examined the in vitro expression, induction and function of Epo and EpoR in papillary (NPA), follicular (WRO) and anaplastic (ARO-81) thyroid cancer cells. We found that all three cell lines expressed Epo and EpoR mRNA and that the hypoxia-mimetic cobalt induced Epo expression in all cell lines. None of the growth factors we examined (thyrotropin, vascular endothelial growth factor, IGF-I, or human Epo) altered Epo or EpoR gene expression. Importantly, however, administration of Epo to NPA but not WRO cells resulted in significant alterations in the expression of several mitogenic genes including cyclooxygenase-2 (COX-2), beta-casein (CSN2), wild type p53-induced gene-1 (WIG1) and cathepsin D (CTSD). Epo treated ARO-81 cells only had an increase in CSN2 expression. We conclude that Epo and EpoR are expressed by thyroid cancers and that stimulation of the Epo/EpoR signal pathway results in changes that could impact on the clinical behavior of thyroid cancers.

Serum thyrotropin (TSH) levels after recombinant human TSH injections in children and teenagers with papillary thyroid cancer

CONTEXT

In preparation for whole body radioactive iodine scanning, recombinant human TSH (rhTSH) is usually administered as 0.9-mg i.m. injections on 2 consecutive days without regard to age, body size, or other comorbid conditions.

OBJECTIVE

Our objective was to determine whether the usual adult rhTSH dosing regimen would result in excessive elevations of serum TSH in children and teenagers with thyroid cancer. DESIGN/SETTING/PATIENTS/INTERVENTIONS: A retrospective review identified 53 children and teenagers with thyroid cancer who underwent whole body radioactive iodine (RAI) scanning over a 12-yr period at two major medical centers (34 after thyroid hormone withdrawal and 19 after rhTSH treatment).

MAIN OUTCOME MEASURES

The dynamic time course of changes in serum TSH after rhTSH administration and/or hypothyroid withdrawal was examined. Peak TSH levels were correlated with age, weight, and body surface area.

RESULTS

The mean serum TSH at the time of RAI administration was similar in patients undergoing hypothyroid preparation (188 +/- 118 mIU/liter; range, 110-452 mIU/liter) and those treated with rhTSH (134 +/- 75 mIU/liter; range, 32-290 mIU/liter; P = 0.07). Serial determinations after rhTSH injections revealed a mean serum TSH of 268 +/- 76 mU/liter (range, 87-628) at 6 h and 130 +/- 58 mU/liter (range, 67-250) at 24 h after the initial injection, and 361 +/- 78 mU/liter (range 161-524) at 6 h and 134 +/- 44 mU/liter (range, 32-290) at 24 h after the second injection.

CONCLUSIONS

The mean TSH levels achieved in children after rhTSH injections are remarkably similar to values previously reported in adults despite marked differences in clinical characteristics between children and adults. These data suggest that dose adjustments are not generally required in children and teenagers undergoing rhTSH stimulation for RAI scanning or serum-stimulated thyroglobulin determinations.

Nitrotyrosine, inducible nitric oxide synthase (iNOS), and endothelial nitric oxide synthase (eNOS) are increased in thyroid tumors from children and adolescents

Nitric oxide (NO) is a reactive cell signal that controls vascular tone and is generated by inducible (iNOS), endothelial (eNOS) and neuronal (nNOS) NO synthase (NOS). We hypothesized that NO could be important for growth of thyroid tumors and tested this hypothesis, by staining 41 papillary thyroid carcinoma (PTC), 9 follicular thyroid carcinoma (FTC), and 15 benign thyroid lesions for iNOS, eNOS and nitrotyrosine (N-TYR). Staining intensity was determined by 2 blinded, independent examiners, and quantified from grade 1 (absent) to grade 4 (intense). Average N-TYR staining of benign adenomas (2.5+/-0.42, p=0.009), PTC (3.10+/-0.12, p=0.001), FTC (2.44+/-0.30, p=0.001), and autoimmune lesions (3.25+/-0.48, p=0.019) were greater than that of multinodular goiter (1.0 for all 3) and surrounding normal thyroid (1.1+/-0.1). Average iNOS staining of benign adenomas (2.6+/-0.37), PTC (2.7+/-0.16), FTC (2.4+/-0.26) and autoimmune lesions (3.5+/-0.29) were all greater than that of surrounding normal thyroid (1.1+/-0.1, p<0.008), but there were too few multinodular goiters to achieve a significant difference (no.=2, 3.0+/-1.0). Average eNOS staining of benign adenomas (2.9+/-0.40), multinodular goiters (3.5+/-0.5), PTC (3.24+/-0.18), FTC (3.5+/-0.50), and autoimmune lesions (2.8+/-0.6) were also greater than that of surrounding normal thyroid (mean=1.4+/-0.2, p<0.001). N-TYR staining correlated with that of vascular endothelial growth factor (VEGF, r=0.36, p=0.007) and the number of lymphocytes/high power field (r=0.39, p=0.004). Recurrent disease developed only from carcinoma with moderate-intense N-TYR staining, but there were too few recurrent tumors to achieve statistical significance (p=0.08). We conclude that NO is produced by benign adenomas, PTC and FTC suggesting that NO could be important in vascularization of thyroid tumors and autoimmune thyroid diseases.

Matrix metalloproteinase (MMP) expression by differentiated thyroid carcinoma of children and adolescents

The factor(s) that control metastasis of thyroid carcinoma are unknown, but the matrix metalloproteinases (MMPs) are excellent candidates. MMP-1, membrane-type-1 MMP (MT1-MMP), and tissue inhibitor of MMP-1 (TIMP-1) have all been implicated, but the site of production and importance are disputed. In vitro, normal thyroid cells secrete TIMP-1, while thyroid cancer cells secrete TIMP-1 and MMP-1. However, previous pathological studies identified MMP-1 and TIMP-1 only in the stroma surrounding thyroid carcinoma. These data suggest that thyroid carcinoma or tumor-associated inflammatory cells might secrete a factor(s) which stimulates MMP-1 or TIMP-1 expression by surrounding tissues. We hypothesized that MMP-1, MT1-MMP, and TIMP-1 would be directly expressed by thyroid carcinoma and might promote invasion or metastasis. We used immunohistochemistry to determine the expression of MMP-1, MT1-MMP, and TIMP-1 in 32 papillary thyroid carcinoma (PTC), 10 follicular thyroid carcinoma (FTC) and 13 benign thyroid lesions from children and adolescents. The intensity of staining was graded from absent (grade 0) to intense (grade 3). Average MMP-1 expression (mean relative intensity units+/-SE) was significantly greater among PTC (1.97+/-0.15; p=0.004) and FTC (2.2+/-0.25; p=0.006) compared to benign lesions (1.30+/-0.15); but there was no relationship between MMP-1 expression and invasion, metastasis, or recurrence. Expression of MT1-MMP and TIMP-1 was similar for benign and malignant lesions; but recurrent PTC expressed lower levels of TIMP-1 when compared to non-recurrent PTC (p=0.049). Only the expression of TIMP-1 correlated with the presence of tumor-associated lymphocytes (r=0.35, p=0.032). We conclude that MMP-1, MT1-MMP and TIMP-1 are all expressed by thyroid carcinoma and could be important in promoting recurrence.

Thyroid carcinomas that express telomerase follow a more aggressive clinical course in children and adolescents

With each cell division, DNA is lost from the telomeres, limiting the number of divisions, and leading to senescence. Malignant tumors maintain immortality by expressing a specific DNA repair enzyme, telomerase, that replaces this DNA. We hypothesized that tumors which express telomerase would have the highest recurrence risk and we tested this by determining telomerase expression in 27 papillary thyroid carcinomas (PTC), 5 follicular thyroid carcinomas (FTC) and 13 benign thyroid lesions from children and adolescents. Patients were 6-21 yr of age (mean+/-SE=16.6+/-4.1 yr) and followed from 0-14.1 yr (mean+/-SE=4.71+/-3.5 yr). Original tumors were sectioned, and immunostained for telomerase. Telomerase-specific staining was determined by two independent, blind examiners and graded from absent (Grade 0) to intense (Grade 3). Telomerase was detected in a similar majority of benign (11/13, 85%) and malignant tumors (24/32, 75%). However, the intensity of telomerase expression was greater among FTC (mean+/-SE=2.4+/-0.5 relative intensity) followed by PTC (mean+/-SE=1.9+/-1.0 relative intensity) and benign tumors (mean+/-SE=1.8+/-1.0 relative intensity). Autoimmune lesions had lower telomerase expression (mean+/-SE=1.25+/-0.5 relative intensity) compared to FTC (p=0.01), PTC (p=0.06) and benign lesions (p=0.15). Among PTC, 19 (70%) expressed telomerase, and 8 (30%) did not. Direct invasion (no.=4, 21%), distant metastasis (no.=2, 10%) and recurrence (no.=7, 37%) developed exclusively in PTC that expressed telomerase (p=0.02). Disease-free survival was also shorter for PTC that expressed telomerase (p=0.06). Recurrence developed in 1/2 (50%) FTC that expressed telomerase. We conclude that childhood thyroid cancers which express telomerase have an increased risk of tissue invasion, metastasis, and recurrence.

Serum vascular endothelial growth factor levels are elevated in metastatic differentiated thyroid cancer but not increased by short-term TSH stimulation

Solid tumor formation requires the development of a blood supply adequate to meet the metabolic demands of the enlarging tumor mass that cannot be sustained by simple diffusion. One principal stimulant to endothelial cell growth and migration, vascular endothelial growth factor (VEGF), is synthesized and secreted by thyroid cancer cells. Furthermore, VEGF overexpression is associated with an aggressive thyroid cancer phenotype in both animal models and clinical-pathological studies. In other malignancies, elevated serum levels of VEGF often correlate with stage of disease and other poor prognostic clinical features. Therefore, we hypothesized that serum VEGF levels would be significantly higher in patients with persistent or recurrent thyroid cancer than in those cured of the disease. Because TSH stimulates both normal and neoplastic thyroid cells, we also proposed that serum VEGF would be further increased by TSH stimulation. Sixty-nine patients with either papillary or follicular thyroid cancer, status post total thyroidectomy, and prior radioactive iodine ablation, who had undergone routine recombinant human TSH (rhTSH, Thyrogen, Genzyme Transgenics Corp., Cambridge, MA) assisted whole-body radioactive iodine scanning, were included in this study. This cohort (mean age 53 +/- 16 yr, 51% female) included 21 patients with no evidence of disease and 48 patients with local or distant metastases. Stored serum samples obtained for standard Tg determinations before and 72 h following standard rhTSH stimulation were identified and assayed for VEGF 165 (R \[amp ]\ D Systems, Minneapolis, MN). Baseline serum VEGF levels obtained at a time of TSH suppression were significantly higher in patients with known metastatic disease than in those with no evidence of disease (416 +/- 62 pg/ml vs. 185 +/- 25 pg/ml, P = 0.001). Patients with distant metastases had baseline serum VEGF levels that did not differ significantly from patients with only cervical recurrences (455 +/- 90 pg/ml in distant metastases vs. 330 +/- 44 pg/ml for local cervical recurrences). Short-term TSH stimulation, although causing a significant rise in serum Tg, resulted in no significant increase in serum VEGF measured 72 h after rhTSH injection in either the patients with known metastatic disease (416 +/- 62 pg/ml baseline vs. 419 +/- 71 pg/ml after TSH stimulation) or in cured patients (185 +/- 25 pg/ml baseline vs. 191 +/- 33 pg/ml after TSH stimulation). Subgroup analysis revealed that patients with metastatic disease arising from well differentiated primary thyroid cancers had significantly higher serum VEGF levels than patients with metastatic disease arising from poorly differentiated thyroid cancer primaries (485 +/- 74 pg/ml vs. 167 +/- 32 pg/ml, P = 0.003 by ANOVA). Poorly differentiated metastatic thyroid cancers had serum VEGF levels indistinguishable from patients cured of disease (167 +/- 32 pg/ml vs. 186 +/- 25 pg/ml). In summary, serum VEGF is significantly elevated in patients with metastatic differentiated thyroid cancer but not in those with poorly differentiated thyroid cancer metastases. No measurable increase in serum VEGF levels can be detected 72 h after short-term TSH stimulation with rhTSH. We conclude that serum VEGF may serve as a clinical useful marker of residual differentiated thyroid cancer.

Resistance of [18f]-fluorodeoxyglucose-avid metastatic thyroid cancer lesions to treatment with high-dose radioactive iodine

Radioactive iodine (131I) is an important therapeutic option for the treatment of metastatic thyroid carcinoma. Survival in patients with metastases that concentrate radioiodine is better than those whose metastatic lesions do not take up radioiodine. Survival is markedly reduced in patients who have metastatic lesions that concentrate 18F-fluorodeoxyglucose (FDG) on positron emission tomography (PET). In this retrospective study, we evaluated the ability of 131I to destroy FDG-avid metastatic lesions in thyroid cancer patients. Twenty-five patients with positive FDG-PET scans received at least one dose of 131I treatment before a second FDG-PET was performed. The average interval between the two PET scans was 12.9 months. The average interval between the 131I treatment and the follow-up FDG-PET was 10.1 months. We measured posttherapy changes in lesional volume, in standard uptake values (SUV) of FDG, and in serum thyroglobulin (Tg) levels. The total volume of FDG-avid metastases rose significantly (p = 0.036) from a mean of 159 mL to 235 mL after 131I therapy, the maximum SUV rose from 9.3 to 11.9, the median Tg at the time of the second PET scan was 132% of that at baseline. Statistical analyses demonstrated no significant changes in maximum SUV, or serum Tg levels after 131I in the FDG-PET-positive group. In a control group of FDG-PET-negative patients, the serum Tg decreased to 38% of baseline after 131I therapy (p < 0.001). We conclude that high-dose 131I therapy appears to have little or no effect on the viability of metastatic FDG-avid thyroid cancer lesions.

Radioiodine ablation of thyroid remnants after preparation with recombinant human thyrotropin

Radioiodine ablation (RA) of normal thyroid remnants after thyroidectomy for differentiated thyroid carcinoma improves the sensitivity of subsequent radioiodine scans and serum thyroglobulin measurements for detection of residual thyroid carcinoma. Local cancer recurrences are also lower after RA. One standard preparation for RA involves rendering the patient hypothyroid in order to stimulate endogenous thyrotropin (TSH) secretion and sodium iodide symporter (NIS) activity. An alternative approach is to prescribe thyroxine after thyroidectomy and to stimulate NIS with exogenous recombinant human thyrotropin (rhTSH). This latter approach was used in 10 patients at our medical center. Complete resolution of all visible 131I thyroid bed uptake was achieved in all when follow-up scans were performed 5 to 13 months later. This approach has the potential to successfully ablate thyroid remnants without the need to induce hypothyroidism.

Nuclear localization of thyroid transcription factor-1 correlates with serum thyrotropin activity and may be increased in differentiated thyroid carcinomas with aggressive clinical course

Thyroid transcription factor 1 (TTF-1) is essential for thyroid differentiation and regulates expression of thyroglobulin, thyroid peroxidase, sodium/iodide symporter, and thyrotropin receptor (TSH-R) genes. Because thyrotropin (TSH) upregulates these same genes, we hypothesized TSH-R activation might increase TTF-1 and that TTF-1 might be differentially expressed in benign and malignant thyroid disease. TTF-1 expression and sub-cellular localization were determined by immunohistochemistry in 62 thyroid carcinomas, 15 benign lesions, and 2 normal thyroids. Nuclear TTF-1 was detected in benign (77%) and malignant lesions (69%), with similar intensity in both (1.1+/-0.19 versus 1.0+/-0.10). Nuclear TTF-1 staining correlated with the effective serum TSH level (p = 0.02) and patient age (p < 0.05). Nuclear TTF-1 was detected in 35 papillary thyroid carcinomas (PTC), of which 23% developed recurrent or persistent disease, and was absent from 18 PTC, of which only 6% recurred (p = 0.06). We conclude that nuclear TTF-1 correlates with serum TSH activity, increases with age, and may be increased in persistent or recurrent PTC.

Intensity of vascular endothelial growth factor expression is associated with increased risk of recurrence and decreased disease-free survival in papillary thyroid cancer

BACKGROUND

Vascular endothelial growth factor (VEGF) induces proliferation of endothelial cells, stimulates angiogenesis, and increases vascular permeability. Increased VEGF expression has been associated with poor clinical outcomes in many malignancies. Several recent reports have documented over expression of VEGF in papillary thyroid cancer. We hypothesized that increased expression of VEGF would be associated with either an increased risk of recurrence or a decreased recurrence-free survival in papillary thyroid cancer.

METHODS

Immunohistochemistry was used to detect VEGF expression in archival paraffin-embedded surgical thyroid specimens from 96 subjects with papillary thyroid cancer.

RESULTS

VEGF expression was detected in 98% (94/96) of the samples, predominantly of slight-to-moderate intensity in the majority of malignant cells. However, the specific finding of a diffuse pattern of intense immunostaining for VEGF was detected significantly more often than less intense, patchy immunostaining patterns in subjects with distant metastasis at diagnosis (63% versus 15%, P =.005), local recurrence (58% versus 13%, P =.001), and distant recurrence (83% versus 14%, P =.001). Furthermore, this specific pattern of diffuse, intense VEGF expression was associated with a significantly shorter recurrence-free survival than other staining patterns (P =.007).

CONCLUSIONS

These data demonstrate that the immunohistochemical pattern of VEGF staining in the initial surgical specimen is strongly associated with the incidence of local and distant metastasis in papillary thyroid cancer.

Advances in the detection of residual thyroid carcinoma

The challenge of detecting and anatomically localizing metastatic thyroid cancer deposits has become less daunting with the recent developments in radionuclide technology. The use of serum Tg measurements and the whole body radioiodine scan remain the mainstays of the diagnostic evaluation. The advent of recombinant human TSH makes the preparation for a diagnostic scan much less burdensome and appears to have excellent sensitivity for serious metastatic lesions. The dilemma of an elevated serum Tg associated with a negative DxWBS has been ameliorated somewhat with the newly discovered ability of FDG-PET scanning to localize these less well-differentiated lesions. The real challenge lies in the development of new therapeutic agents to treat metastatic lesions that do not concentrate radioiodine.

Expression of the sodium iodide symporter and thyroglobulin genes are reduced in papillary thyroid cancer

Altered expression of the gene encoding the sodium iodine symporter (NIS) may be an important factor that leads to the reduced iodine accumulation characteristic of most benign and malignant thyroid nodules. Both up- and down-regulation of NIS gene expression have been reported in thyroid cancer using several different methods. The goal of the present study was to accurately identify alterations in NIS gene expression in benign and malignant thyroid nodules using an accurate real-time quantitative RT-PCR assay system. Total RNA was prepared from 18 benign thyroid nodules, 20 papillary thyroid cancers, and 23 normal thyroid samples from 38 subjects. Quantitative RT-PCR was used to measure NIS and thyroglobulin (TG) mRNA expression in normal thyroid tissue and in each nodular tissue sample. Papillary thyroid cancer samples had significantly lower NIS mRNA expression (72 +/- 41 picogram equivalents [pg Eq]), than did benign nodules (829 +/- 385 pg Eq), or normal tissues (1907 +/- 868 pg Eq, P = 0.04). Most important, in the paired samples, NIS gene expression was decreased in each papillary thyroid cancer compared with normal tissue (69% median decrease; range, 40-96%; P = .013). Eleven of the 12 benign nodules also demonstrated lower NIS gene expression than the normal tissue (49% decrease; range, 2-96%; P = .04). Analysis of the paired samples demonstrated that Tg mRNA expression was significantly lower in each of the thyroid cancer samples than in corresponding normal tissue (759 +/- 245 pg Eq vs. 1854 +/- 542 pg Eq, P = .03). We have demonstrated a significant decrement in NIS gene expression in all papillary thyroid cancers and in over 90% of benign nodules examined compared with adjacent normal thyroid tissue, using a highly accurate quantitative RT-PCR technique. Similarly, thyroid cancers demonstrated significantly lower TG mRNA expression than corresponding normal thyroid. Reduced NIS expression may be an important factor in the impairment of iodine-concentrating ability of neoplastic thyroid tissues.

Infiltration of differentiated thyroid carcinoma by proliferating lymphocytes is associated with improved disease-free survival for children and young adults

An immune response directed against thyroid cancer might be important in preventing metastasis and recurrence. This idea is supported by previous observations showing that adults with autoimmune thyroiditis or lymphocytic infiltration surrounding papillary thyroid carcinoma (PTC) have improved disease-free survival. The long-term outcome for differentiated thyroid cancer is even more favorable for children and young adults. If the immune response is important, we hypothesized that tumor-associated lymphocytes with a high proliferation index would be found in thyroid cancers from children and young adults and would be associated with improved disease-free survival. Using immunohistochemistry, we examined 39 childhood PTC, 9 follicular thyroid carcinomas, 2 medullary thyroid carcinomas, 11 benign thyroid lesions, and 2 normal thyroid glands for the presence of lymphocytes (leukocyte common antigen) and lymphocyte proliferation (proliferating cell nuclear antigen, Ki-67). The majority of PTC (65%) and follicular thyroid carcinomas (75%) from children and young adults contained lymphocytes in the immediate vicinity of thyroid cancers, but only 7 (18%) patients with PTC also had a diagnosis of autoimmune thyroiditis. Disease-free survival did not correlate with the presence or number of lymphocytes per high power field. In contrast, disease-free survival was significantly improved (P = 0.01) for thyroid cancers with the greatest number of Ki-67-positive lymphocytes per high power field. The number of lymphocytes per high powered field was greater for multifocal PTC (P: = 0.023), and the number of proliferating lymphocytes was greatest for PTC with regional lymph node involvement (30.5 +/- 12.3 vs. 6.8 +/- 5.0; P = 0.047). We conclude that proliferation of tumor-associated lymphocytes is associated with improved disease-free survival for children and young adults with thyroid cancer.

Thyroglobulin messenger ribonucleic acid levels in the peripheral blood of children with benign and malignant thyroid disease

Reverse transcriptase-PCR has identified thyroglobulin mRNA (Tg mRNA) in peripheral blood of normal adults and adults with thyroid cancer. However, no children were studied. The primary objective of this study was to determine whether whole blood Tg mRNA levels differ between benign and malignant thyroid disease in children. The secondary goals were to determine whether whole blood Tg mRNA levels vary with age or pubertal development among children with thyroid disease. Whole blood Tg mRNA levels were determined in 38 children (29 girls, nine boys; median age, 14.5 y; range, 4.8-20.4 y) with benign and malignant thyroid disease and correlated with diagnosis, age, pubertal status, thyroid size, and serum levels of free thyroxine, TSH, and Tg protein. Tg mRNA levels ranged from 3.3 to 104 pg Eq/microg total thyroid RNA (mean, 28 +/- 20.2 pg Eq/microg total thyroid RNA) and were similar in benign and malignant disorders (p = 0.67). However, in children with previously treated papillary thyroid cancer, Tg mRNA levels directly correlated with total body (131)I uptake (p = 0.026) and serum Tg protein (p = 0.037). There was no difference between boys and girls, and no change with pubertal maturation. In children with benign thyroid disease, Tg mRNA levels correlated with serum TSH (p = 0.031), but not with diagnosis, age, Tanner stage, or thyroid size. We conclude that Tg mRNA levels are similar in children with benign and malignant thyroid disease and unchanged by age or pubertal status, but correlated with tumor burden in previously treated papillary thyroid cancer.

Preparation by recombinant human thyrotropin or thyroid hormone withdrawal are comparable for the detection of residual differentiated thyroid carcinoma

Clinical recurrences of differentiated thyroid carcinoma occur in 20% of patients after thyroid surgery. We performed a retrospective analysis of a cohort of patients undergoing routine follow-up testing to detect recurrent thyroid carcinoma over a 2-yr period. One group was prepared for testing by thyroid hormone withdrawal (THW), and the other group remained on thyroid hormone and received injections of recombinant human TSH (rhTSH) before diagnostic whole-body radioiodine scanning (DxWBS). We hypothesized that no differences in the ability to detect residual disease would exist between these 2 groups. Two hundred and eighty-nine patients were examined by both DxWBS and by measurement of the serum thyroglobulin (Tg) response to elevated TSH levels. THW was used for 161 patients, and rhTSH preparation was used for 128 patients. Based on all available testing results, we categorized patients as having metastatic disease, thyroid bed uptake only, or no evidence of disease. We examined the sensitivity, specificity, positive and negative predictive values of the DxWBS, and the stimulated Tg after preparation by THW or rhTSH. Patients with thyroid bed were not considered in accuracy testing. The sensitivity and specificity of the 2 tests were comparable between groups. No significant differences were present in the positive or negative predictive values between groups. The highest negative predictive value (97%) was in patients who had both a negative DxWBS and low stimulated Tg levels after rhTSH. In summary, we were unable to demonstrate a difference in the diagnostic accuracy of DxWBS and/or Tg between patients prepared by either THW or rhTSH. We conclude that preparing patients by rhTSH is diagnostically equivalent to preparing them by THW.

Over-expression of hepatocyte growth factor/scatter factor (HGF/SF) and the HGF/SF receptor (cMET) are associated with a high risk of metastasis and recurrence for children and young adults with papillary thyroid carcinoma

OBJECTIVE

The study determined if hepatocyte growth factor/scatter factor (HGF/SF) or the HGF/SF receptor (cMET) might be important for metastasis in thyroid cancer.

DESIGN

We examined HGF/SF and cMET expression by immunohistochemistry in a retrospective group of benign and malignant thyroid lesions from children and young adults, and correlated the intensity of expression with clinical outcome.

PATIENTS

Patients included 42 children and young adults with papillary thyroid carcinomas (PTC), seven with follicular thyroid carcinomas (FTC), two with medullary thyroid carcinomas (MTC), 14 with benign thyroid disorders, and two with normal thyroids.

MEASUREMENTS

Expression of cMET was graded from 0 (absent) to 4 (intense); and HGF/SF expression was graded from 0 (absent-minimal) to 3 (diffuse and intense).

RESULTS

cMET staining was greater in PTC (mean intensity 2.3 +/- 0.4 vs. 0.8 +/- 0.2, P < 0.005) and FTC (2.4 +/- 0.6 vs. 0.8 +/- 0.2, P = 0.04) than benign lesions (0.8 +/- 0.2) or normal thyroids (0.4 +/- 0.5). PTC with intense cMET staining had shorter disease free survival (P = 0.05) and increased HGF/SF staining (r = 0.39, P = 0.017). HGF/SF correlated with the extent of disease at diagnosis (r = 0.33, P = 0.049). Patients with PTC were stratified into quartiles based on combined cMET and HGF/SF staining. Those with intense cMET and HGF/SF staining were younger (P = 0.05), and had reduced disease free survival (P = 0.03).

CONCLUSIONS

We conclude that increased cMET and HGF/SF expression is associated with a high risk for metastasis and recurrence in children and young adults with papillary thyroid carcinoma.

Autoantibodies to p53 in sera of patients with autoimmune thyroid disease

Mutations in the tumor suppressor gene, p53, lead to intracellular accumulation of abnormal p53 protein and are associated with p53 autoantibodies. p53 also accumulates in autoimmune diseases and Hashimoto's thyroiditis, but it is unknown if p53 autoantibodies occur in the latter. We measured p53 autoantibodies in the sera of 93 patients with thyroid disease and 19 patients without thyroid disease. Anti-p53 antibodies were detected in the sera from 4.2% (2/48) of patients with autoimmune thyroid disease, including one patient with Hashimoto's thyroiditis (3.7%, 1/27) and one with Graves' disease (4.8%, 1/21). A third patient with pseudohypoparathyroidism, but without thyroid disease, was also positive (1/19; 5.2%). None of 19 patients with differentiated thyroid cancer had anti-p53 antibodies. We conclude that anti-p53 antibodies can be detected in the sera from approximately 4% of patients with autoimmune thyroid disease. This finding suggests that increased DNA damage and apoptosis may be associated with autoimmune thyroid disease.

The Chernobyl accident and its consequences: update at the millennium

A marked increase in the incidence of papillary thyroid cancer in children has been documented in regions of the former Soviet Union most heavily contaminated by radioactive fallout from the Chernobyl nuclear power plant accident in April 1986. Accumulation of radioactive iodines by normal iodine trapping mechanisms resulted in significant radiation doses to the thyroid gland. Although it has long been known that thyroidal radiation resulted in nuclear and chromosomal abnormalities visible by light microscopy, modern molecular biology techniques are beginning to identify much smaller alterations in chromosomal coding sequences that are associated with malignant transformation. Although stable chromosomal abnormalities can be detected in Chernobyl-associated thyroid cancers, they are much less prevalent than in thyroid cancers developing after external beam irradiation. However, several unique chromosomal breakpoints have been described in radiation-associated thyroid cancers that are not commonly found in spontaneously occurring thyroid cancer. Furthermore, activation of specific subtypes of the ret/PTC tyrosine kinase oncogene appears to be more common in radiation-associated thyroid cancers than in spontaneous thyroid cancers. In summary, thyroid cancers developing in the aftermath of the Chernobyl accident provide a unique opportunity to search for chromosomal abnormalities that may be specific for radiation-induced thyroid cancer.

The expression of vascular endothelial growth factor and the type 1 vascular endothelial growth factor receptor correlate with the size of papillary thyroid carcinoma in children and young adults

Vascular endothelial growth factor (VEGF) is essential for the growth of many solid tumors, but there are little data regarding VEGH in childhood thyroid cancers. We examined the relationships between VEGF, the type 1 VEGF receptor (FLT-1) and clinical outcome for a group of thyroid cancers in children and young adults. The expression of VEGF and FLT-1 were determined by immunohistochemistry using archival, paraffin-embedded thyroid tissue blocks and compared with the retrospective clinical outcome for each patient. The study included 67 children and young adults with papillary thyroid carcinoma (PTC, n = 42), follicular thyroid carcinoma (FTC, n = 8), benign lesions (n = 15), or controls (n = 2). VEGF expression was greater in PTC (mean intensity 2.23 +/- 0.25, p = 0.002) and FTC (2.8 +/- 0.73, p = 0.01) than benign lesions (1.0 +/- 0.27), and correlated with PTC size (r = 0.42, p = 0.008). FLT-1 expression was greater in PTC (mean intensity 2.8 +/- 0.17) than FTC (1.9 +/- 0.25, p = 0.015) and benign lesions (1.7 +/- 0.32, p = 0.002); and correlated with PTC size (r = 0.41, p = 0.01) as well as VEGF expression (r = 0.52, p = 0.002). Recurrent disease developed exclusively in patients with PTC which expressed VEGF (7/28, 95% CI 10.6%-44.2%). PTC that did not express VEGF (0/8, 95% CI = 0%-31.2%) did not recur; however, the difference was not statistically significant (p = 0.15). We conclude that the expression of VEGF and FLT-1 are directly correlated with the size of PTC in children and young adults.

The ret/PTC mutations are common in sporadic papillary thyroid carcinoma of children and young adults

The ret/PTC rearrangements (PTC-1, PTC-2, and PTC-3) are characteristic of papillary thyroid cancer (PTC). In adults, PTC-1 is common and may be associated with an aggressive clinical course. The incidence and significance of ret/PTC mutations are less well understood in children. We examined spontaneous PTC from 33 patients (23 females and 10 males) with a median age of 18 yr (range, 6-21 yr) and a median follow-up of 3.5 yr (range, 0-13.4 yr). The ret/PTC mutations were identified in 15 tumors (45%), including 8 PTC-1 (8 of 15, 53%), 2 PTC-2 (2 of 15, 13%), 2 PTC-3 (2 of 15, 13%), and 3 (3 of 15, 20%) combined PTC mutations (PTC-1 and PTC-2). This distribution is significantly different (P = 0.001, by chi2 analysis) from that reported for children with radiation-induced PTC. There was no correlation between the presence or type of ret/PTC mutation and patient age, tumor size, focality, extent of disease at diagnosis, or recurrence. We conclude that ret/PTC mutations are 1) common in sporadic childhood PTC, 2) predominantly PTC-1, 3) frequently multiple, and 4) of different distribution than that reported for children with radiation-induced PTC.

The ret/PTC mutations are common in sporadic papillary thyroid carcinoma of children and young adults

The ret/PTC rearrangements (PTC-1, PTC-2, and PTC-3) are characteristic of papillary thyroid cancer (PTC). In adults, PTC-1 is common and may be associated with an aggressive clinical course. The incidence and significance of ret/PTC mutations are less well understood in children. We examined spontaneous PTC from 33 patients (23 females and 10 males) with a median age of 18 yr (range, 6-21 yr) and a median follow-up of 3.5 yr (range, 0-13.4 yr). The ret/PTC mutations were identified in 15 tumors (45%), including 8 PTC-1 (8 of 15, 53%), 2 PTC-2 (2 of 15, 13%), 2 PTC-3 (2 of 15, 13%), and 3 (3 of 15, 20%) combined PTC mutations (PTC-1 and PTC-2). This distribution is significantly different (P = 0.001, by chi2 analysis) from that reported for children with radiation-induced PTC. There was no correlation between the presence or type of ret/PTC mutation and patient age, tumor size, focality, extent of disease at diagnosis, or recurrence. We conclude that ret/PTC mutations are 1) common in sporadic childhood PTC, 2) predominantly PTC-1, 3) frequently multiple, and 4) of different distribution than that reported for children with radiation-induced PTC.

Prognostic importance of vascular invasion in papillary thyroid carcinoma

BACKGROUND

The prognostic importance of vascular invasion has not been extensively studied in patients with papillary thyroid cancer.

OBJECTIVE

To determine whether the presence of vascular invasion in papillary thyroid carcinoma, even within the thyroid gland, is associated with more aggressive disease at diagnosis and a higher incidence of tumor recurrence.

PATIENTS AND METHODS

We identified 410 patients who had been diagnosed with papillary thyroid cancer since 1986 who had a follow-up period of longer than 1 year (median follow-up, 5.5 years). Pathology reports were reviewed and patients were separated into 3 groups: no vascular invasion, intrathyroidal vascular invasion, and extrathyroidal vascular invasion.

MAIN OUTCOME MEASURES

Statistical comparison was performed by univariate and multivariate analysis.

RESULTS

Patients with intrathyroidal vascular invasion were more likely to have distant metastasis at the time of diagnosis (26.1% vs 2.2%, P = .001). Similarly, patients with extrathyroidal vascular invasion had a higher incidence of distant metastases at diagnosis (40% vs 4.4%, P = .02). Patients with tumors identified to have intrathyroidal vascular invasion were more likely to develop distant recurrence (20% vs 3%, P = .002).

CONCLUSIONS

These associations were found to be independent by multiple regression analysis. Patient age, sex, palpable or fixed lymph nodes, radiation exposure, and race did not differ between the patient group with and those without vascular invasion. Preliminary analysis of our data suggests that the presence of vascular invasion in papillary, thyroid carcinoma, even within the thyroid gland, is associated with more aggressive disease at diagnosis and with a higher incidence of tumor recurrence.

Tyrosine kinase expression is increased in papillary thyroid carcinoma of children and young adults

Tyrosine kinases (TKs) are important candidate genes for malignant transformation and at least 21 different TKs have been identified in the thyroid gland. We hypothesized that the collective activity of these TKs might be increased in thyroid carcinoma and have association with the clinical behavior of individual tumors. To test this, we determined TK expression by immunohistochemistry in 74 archival thyroid tissue blocks (48 papillary thyroid carcinoma, PTC; 9 follicular thyroid carcinoma, FTC; 17 benign thyroid diseases) from children and young adults. Mean TK expression was greater for PTC (2.1 +/- 0.11) than benign lesions (1.6 +/- 0.2, p = 0.027), and also tended to be greater in FTC (2.1 +/- 0.25, p = 0.12). Recurrence risk was three-fold greater for PTC with intense TK expression (4/15, 27%) than for PTC with minimal - moderate TK expression (3/33, 9.0%). However, this was not statistically significant (p = 0.10). In PTC, TK expression correlated with expression of the receptor for hepatocyte growth factor / scatter factor (cMET, r = 0.31, p = 0.044). In FTC, TK expression did not correlate with cMET, but tended to be greater in young patients (r = -0.59, p = 0.09). We conclude that TK expression is increased in PTC and possibly associated with an increased recurrence risk.

Extensive surgery improves recurrence-free survival for children and young patients with class I papillary thyroid carcinoma

BACKGROUND

Children with papillary thyroid cancer (PTC) rarely die of their disease, but are at high risk for recurrence, particularly with multifocal tumors (which occur in 42% of children with PTC). It is not clear if more extensive surgery, with an increased risk of complications, lessens the risk for recurrence. The authors hypothesized that patients with disease presumed to be confined to the thyroid gland (class I PTC) could have multifocal disease, involving the contralateral lobe, of which the surgeon is unaware. Treatment with less than subtotal thyroidectomy might be associated with a higher risk of recurrence.

METHODS

The charts of 37 patients with Class I PTC diagnosed at < or =21 years of age between 1953 and 1996 were reviewed. The incidence of surgical complications and the risk of recurrence based on the extent of initial surgery ([1] lobectomy with or without isthmusectomy, [2] subtotal, or [3] total thyroidectomy) and adjunctive therapy with thyroid hormone or radioactive iodine (RAI) were examined.

RESULTS

Eight patients had recurrent PTC. Patients treated with lobectomy with or without isthmusectomy were more likely to have recurrence than patients treated with subtotal or total thyroidectomy (Odds ratio, 8.7; 95% CI 1.4 to 54). Although the incidence of complications was statistically similar among the 3 surgical groups, 3 patients, all treated with more extensive surgery, had permanent hypoparathyroidism. There were too few patients to determine whether treatment with thyroid hormone or RAI offered additional benefit.

CONCLUSIONS

In children with Class I PTC, more extensive surgery is associated with a lower risk of recurrence. This finding must be weighed against the risk of complications when determining the optimal treatment for individual patients.

Ras mutations are uncommon in sporadic thyroid cancer in children and young adults

Mutations in the ras genes (H-ras, K-ras, and N-ras) occur in 10-15% of all human cancers, and commonly arise from single base substitutions at codons 12, 13, or 61. Although ras mutations have been found in adult thyroid cancers, they were absent from the two studies which examined childhood thyroid cancers. Both studies included only children with radiation induced thyroid cancer, and it remains unclear if ras mutations occur in children without radiation exposure. To answer this question, we examined archival tissue blocks from 31 children with papillary thyroid cancer (PTC) 4 with follicular thyroid cancer (FTC), 2 with medullary thyroid cancer (MTC), and 1 with lymphoma (LYM). Only 1 patient with PTC had previous radiation exposure. Genomic DNA was extracted and used for PCR amplification of the ras genes. The PCR products were analyzed by oligospecific hybridization for mutations at codons 12, 13, and 61. Two of the PTCs (6.5%) contained ras mutations. Both patients had class II disease and no history of previous radiation exposure. One patient subsequently developed bone and lung metastases. The patient with lymphoma also had a ras mutation (N-61), but ras mutations were absent from all FTC and MTC. These results suggest that ras mutations are uncommon in spontaneous childhood thyroid cancer, but occur with a frequency similar to that found in previous reports of adult differentiated thyroid cancers. The number of subjects was too small to determine if ras mutations are more common in patients with aggressive papillary thyroid cancer.

Quantitative reverse transcription-polymerase chain reaction of circulating thyroglobulin messenger ribonucleic acid for monitoring patients with thyroid carcinoma

Patients with thyroid cancer are monitored for disease recurrence by measurement of serum thyroglobulin (Tg) and iodine-131 (131I) scanning. To enhance sensitivity and to circumvent antibodies that interfere with Tg immunoassays, we have developed RT-PCR assays that detect circulating thyroid messenger RNA (mRNA) transcripts. We now report results using a sensitive quantitative Tg mRNA assay (Taqman; ABI, Foster City, CA) in comparison with immunoassay in patients previously treated for thyroid cancer. We evaluated 107 patients: 84 during T4 therapy, 14 after T4 withdrawal, and 9 at both time points. All patients had near-total thyroidectomy, and 92% received postoperative 131I. Serum TSH, Tg protein, and Tg mRNA were measured. Patients were grouped based on most recent 131I scan or pathologically confirmed disease as having no detectable thyroid tissue (n = 33), thyroid bed uptake (n = 37), cervical/regional adenopathy (n = 21), or distant metastases (n = 16). During T4 therapy, median (range) Tg mRNA values (pg Tg Eq/microg thyroid RNA) for the groups were 1.5 (0-26.8), 9.4 (0.5-90.0), 15.4 (0.2-92), and 12.4 (1.9-16.6), respectively. Using a value of 3 pg Tg Eq/microg thyroid RNA as cut-point, Tg mRNA was positive in 38% of patients with no uptake, 75% with thyroid bed uptake, 84% with cervical/regional disease, and 94% with distant metastases. The median Tg mRNA value for patients with no uptake was lower than the median values for patients with thyroid bed uptake (P = 0.009) or with detectable thyroid tissue at any site (P = 0.010). Patients with negative 131I whole body scans were also less likely to have detectable Tg mRNA levels than were patients with thyroid bed uptake (P < 0.001) or any detectable thyroid tissue at any location (P < 0.001). Similar differences between these groups were seen after T4 withdrawal and for the 23 patients with circulating anti-Tg antibodies, when analyzed separately. Eight of the nine patients studied with low and high TSH concentrations displayed greater amounts of circulating Tg mRNA after T4 withdrawal. In three patients followed prospectively, the amount Tg mRNA correlated with the presence and absence of cervical metastases. In conclusion, we have demonstrated that a quantitative Tg mRNA assay can identify thyroid cancer patients with recurrent or residual thyroid tissue with greater sensitivity and similar specificity to Tg immunoassay during T4 therapy. The assay was unaffected by anti-Tg antibodies, responded to TSH-stimulation, and was reduced after surgical removal of metastases. These data suggest that this quantitative Tg mRNA assay may be a sensitive marker of tumor recurrence or response to therapy, particularly in patients with anti-Tg antibodies.

Quantitative reverse transcription-PCR measurement of thyroglobulin mRNA in peripheral blood of healthy subjects

BACKGROUND

Thyroglobulin mRNA can be detected qualitatively in the peripheral blood of patients with metastatic thyroid cancer, thyroid cancer patients with residual thyroid bed uptake, and individuals with no known thyroid disease with intact thyroid glands by use of a lengthy, highly sensitive extraction technique. To improve and broaden the clinical usefulness of this assay, we developed a quantitative reverse transcription (RT)-PCR assay for thyroglobulin mRNA, using RNA recovered from whole blood with a simplified extraction technique.

METHODS

Whole blood was drawn from 32 healthy subjects in standard EDTA blood collection tubes. Total RNA was extracted from whole blood, using the PUREscript RNA Isolation Kit. RT-PCR using intron-spanning primers was used to quantitatively amplify thyroglobulin mRNA, using the ABI PRISM 7700 Sequence Detection System with a fluorescent-labeled, thyroglobulin-specific oligonucleotide probe. Thyroid RNA calibration curves were created using total RNA recovered from a single nondiseased thyroid gland.

RESULTS

Qualitative RT-PCR demonstrated the presence of thyroglobulin mRNA in the whole blood sample of each healthy subject. The mean concentration of thyroglobulin mRNA detected in these subjects was 433 +/- 69 ng of total thyroid RNA per liter of whole blood (range, 26-1502 ng/L). Overall assay imprecision (CV) was 24% for five samples analyzed 10 times each in separate analytical runs on different days.

CONCLUSIONS

Thyroglobulin mRNA can be accurately detected and quantified in peripheral blood from healthy subjects. This new quantitative technique may improve the clinical utility of circulating thyroglobulin mRNA detection in patients with thyroid disease.

Preservation of nucleic acids for polymerase chain reaction after prolonged storage at room temperature

A guanidinium isothiocyanate (GITC) lysis solution was evaluated for its efficacy in preserving nucleic acids for subsequent analysis after prolonged storage at room temperature. Aliquots of thyroid crude cell lysates were stored at 22 degrees C for 8 weeks in the GITC solution. Crude cell lysates stored for 2 weeks in the GITC solution consistently provided adequate RNA and DNA for reverse transcriptase-polymerase chain reaction (RT-PCR) and PCR, respectively, of beta 2-microglobulin, thyroid stimulating hormone receptor (TSHR), and thyroglobulin. Interestingly, the thyroglobulin and TSHR messages from thyroid fine needle aspirate samples were detected by RT-PCR only when stored at room temperature for less than 1 week, whereas the RT-PCR product for beta 2-microglobulin was detectable in 95% of the samples at 3 months. In addition, thyroglobulin DNA was amplified by PCR in nearly all samples stored at 22 degrees C for 2 months. These data suggest that GITC solutions can be used to preserve nucleic acids in most circumstance until transported to laboratories equipped and staffed with appropriate resources.

Clinical features associated with metastasis and recurrence of differentiated thyroid cancer in children, adolescents and young adults

OBJECTIVE

Differentiated thyroid cancer (DTC), including papillary (PTC) and follicular (FTC) variants, is unusual in children and accounts for only 10% of all cases. For that reason, knowledge of the clinical features which predict recurrence is limited. We reviewed 170 cases of childhood DTC to determine if specific clinical or pathological findings were associated with increased risk of recurrence.

DESIGN

This was a retrospective study of children and adolescents with DTC registered in the Department of Defense Automated Centralized Tumor Registry.

PATIENTS

We reviewed 137 cases of PTC and 33 cases of FTC diagnosed between 1953 and 1996 at < or = 21 years of age.

RESULTS

In the PTC group (median follow-up 6.6 years, range 2 month-39.5 years), only one patient died, but 21 developed local and 6 developed distant recurrence. By univariate analysis, recurrence was more common in patients with multifocal (odds ratio 7.5) or large tumours (odds ratio 4.1), and in those with palpable cervical lymphadenopathy (odds ratio 3.0) or metastasis at diagnosis (odds ratio 2.8). By multivariate analysis focality was the best predictor of recurrence (P = 0.0019). In the FTC group (median follow-up 5 years, range 6 month-38.1 years), no patient died of disease, but 5 developed recurrence. As with PTC, recurrence was more likely in patients with multifocal tumours (odds ratio 22.0).

CONCLUSIONS

Differentiated thyroid cancer in children and adolescents has low mortality, but a high risk of recurrence. Young patients with large, multifocal tumours that are already metastatic at diagnosis have the greatest risk of recurrence.

The impact of initial surgical management on outcome in young patients with differentiated thyroid cancer

BACKGROUND/PURPOSE

It is generally believed that differentiated thyroid cancer (DTC) in young patients has an excellent prognosis. This calls into question the need for more extensive surgical ablation of the thyroid gland with attendant risks of surgical complications. The purpose of this report was to investigate both the incidence of surgical morbidity and the impact of surgery on locoregional recurrence of disease.

METHODS

The authors reviewed the clinical course of patients under 22 years of age treated for DTC within Department of Defense hospitals since 1950. Data were available for determination of surgical morbidity in 126 and for outcome in 105.

RESULTS

The incidence of postoperative hypocalcemia was 17% and of recurrent laryngeal nerve injury 3%. Factors predictive of morbidity were (1) more extensive thyroid surgery (P = .023), and (2) the presence of gross tumor invasion (P = .022). The incidence of neck recurrence was analyzed among a cohort of 90 patients. A total of 19 (21%) patients had a local recurrence. The median time to recurrence was 24 months. The factor predictive of recurrence was the presence of gross invasion (P = .0001). A strong trend toward locoregional recurrence was found among patients with metastatic disease to more than five cervical nodes (P < .08). The primary operations on the thyroid and regional nodes were not significant predictors of neck recurrence. Among these 19 patients there have been no deaths, but 25% had persistent disease at a mean follow-up of 12.6 years.

CONCLUSIONS

The incidence of surgical morbidity does increase with more extensive surgery. Outcome is predicted primarily by the initial extent of disease.

Clinical features associated with an increased risk of thyroid malignancy in patients with follicular neoplasia by fine-needle aspiration

The application of fine-needle aspiration (FNA) to the evaluation of the thyroid nodule has greatly enhanced the ability of the clinician to appropriately select patients for thyroidectomy. However, despite extensive experience with thyroid FNA, the cytological distinction of benign from malignant follicular neoplasia remains problematic. As a result, most patients with FNA findings of a follicular neoplasm are referred for thyroidectomy. The goal of the present study was to develop clinical criteria capable of predicting malignancy in patients with an FNA diagnosis of follicular neoplasm. Among 1121 patients undergoing thyroid FNA at two large teaching centers during the period 1990 to 1995, 149 patients had cytological findings consistent with a follicular neoplasm. Among 103 patients referred for thyroidectomy, 22 (21%) were found to have a malignancy in the biopsied nodule. Among patients subjected to thyroidectomy, the risk of malignancy was significantly higher when follicular neoplasia was present in a male (43% vs. 16% for females, p = 0.007), when the nodule was greater than 4 cm to palpation (40% vs. 13% for nodules less than 4 cm, p = 0.03), or when the nodule was judged to be solitary by palpation (25% vs. 6% for a dominant nodule in a multinodular goiter, p = 0.02). Bayesian analysis of the data reveals that after an FNA showing a follicular neoplasm, the risk of malignancy in males with large nodules was nearly 80%, compared with a rate of only 3% in females with small nodules. These results suggest that clinical features including gender, nodule size, and character of the gland by palpation can be systematically integrated into the decision analysis, thereby improving the selection of patients for surgical referral.

Telomerase activity in the differential diagnosis of papillary carcinoma of the thyroid

BACKGROUND

Although fine-needle aspiration (FNA) is 90% sensitive in the detection of papillary carcinoma (PC) of the thyroid, its specificity has been reported as low as 52%. Consequently, patients who have an FNA suspicious for PC may undergo operation for a benign process. The ribonucleoprotein telomerase has been noted to be activated in a wide variety of carcinomas. We examined 30 PCs for telomerase activity to determine whether this would be a useful adjunct to FNA in the diagnosis of lesions suspicious for PC.

METHODS

Standard telomere repeat amplification protocol assays were performed on fresh frozen tissue samples from 30 PCs, 3 benign nodules, and 10 normal thyroids.

RESULTS

Telomerase activity was documented in 20 of 30 (67%) of the PCs, 0 of 3 benign nodules, and 0 of 10 normal thyroids. In all, 11 of the 20 PCs had FNA cytology that was nondiagnostic of PC, and 2 of the benign nodules had FNA that was suspicious for PC.

CONCLUSIONS

The telomerase assay appears useful in the distinction of benign from malignant thyroid lesions that have FNA suspicious for but not diagnostic of PC. On the basis of these findings, a prospective trial examining telomerase activity in FNAs suspicious for thyroid cancer has been initiated.