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

Clinical and pathologic features of "sporadic" papillary thyroid carcinoma registered in the years 2005 to 2008 in children and adolescents of Belarus

BACKGROUND

A systematic analysis of the clinical and pathologic patterns of childhood "sporadic" thyroid carcinoma in Belarus, in the absence of the "Chernobyl radioactive iodine factor," has never been performed. The aim of this study was to establish the essential features of "sporadic" papillary thyroid carcinoma (PTC) in Belarusian children and adolescents, and the relationship of tumor pathology to extrathyroidal extension (ETE) and lymph node metastases.

METHODS

This was a retrospective population-based study with assessment of histological samples of 119 cases of thyroid cancer in Belarusian children and adolescents of 0-18 years old registered during 2005-2008 years. Sporadic PTC was noted in 94 children who were not exposed to the Chernobyl radiation release. None of the 119 cases of thyroid were follicular thyroid cancer.

RESULTS

The incidence rate of PTC was 1.13 per 100,000 persons. The median age at diagnosis was 15.1 years with fourfold predominance of diagnosis in female patients. Relapse was detected in 2% of cases with median follow-up of 4.2 years. Median tumor size was 12 mm. Three percent of the cases of PTC had multifocal growth. The classical variant of PTC was registered in 46% of the patients with thyroid cancer, the follicular variant of PTC was noted in 20% of the cases. The percent of rare types of PTC (tall cell and diffuse sclerosing) were equal to that for solid PTCs (13%, 12%, and 10%, respectively). Adolescents had a pure papillary carcinoma more often compared to children who represented tumors with mixed papillary/follicular patterns more frequently (p<0.05). Two-thirds of the patients with PTC had regional lymph node metastases. ETE was established in 39 of 74 patients in whom ETE could be assessed by morphology. Multivariate analysis showed that lymphatic invasion was the strongest independent factor associated with both ETE (p<0.0001) and lymph node metastases (p<0.0001).

CONCLUSION

In 2005-2008, sporadic thyroid cancer in children of Belarus was represented by high prevalence of PTC and absence of follicular thyroid cancer. Sporadic cases of PTC in Belarus were characterized by smaller tumor size, a small number of cases with multifocal growth, an equal number of rare types and solid PTCs, a relatively high prevalence of pure papillary variant of PTC in adolescents, and a low frequency of early relapses. A high frequency of ETE and lymph node metastases was detected. The strongest morphologic factor associated with both of them was lymphatic invasion.

Clinical features, treatment, and long-term outcome of papillary thyroid cancer in children and adolescents without radiation exposure

BACKGROUND

Cancer of the thyroid gland is rare in children and adolescents. A history of neck irradiation is a well-established risk factor for tumor development, and most previous reports focused on cases that were induced by radiation exposure. We present here a retrospective review of the clinical features, treatment, and long-term outcome of children and adolescents with papillary thyroid cancer (PTC) without a history of radiation exposure who were treated at our institution over a period of ~50 years.

METHODS

We retrospectively investigated 142 PTC patients without an irradiation history who were younger than 20 years of age when treated from 1961 to 2005 (17 males and 125 females; mean age = 16.3 ± 2.7 years; follow-up = 21.8 ± 12.0 years). The clinicopathological results were evaluated using the medical records. Disease-free survival (DFS) and cause-specific survival (CSS) were assessed with the Kaplan-Meier method and compared with the log-rank test. Parametric analyses were performed using Student's t test and nonparametric analyses were performed using the Mann-Whitney U test.

RESULTS

At diagnosis, three patients had distant lung metastasis and 33 had gross neck lymph node (LN) metastasis. All patients were treated with surgery (hemi/partial thyroidectomy in 45 patients, subtotal thyroidectomy in 85, total thyroidectomy in 12, no LN dissection in 50, central compartment dissection in 20, and modified radical neck dissection in 72), and postoperative external beam radiation therapy was administered to 59. Postoperative ablative therapy using I(131) was not performed in this series. Recurrence was found for regional LN (n = 25), lung (n = 9), remnant thyroid (n = 5), and others (n = 4). DFS and CSS at 40 years were 74.1 and 97.5%, respectively. DFS was significantly worse in patients aged <16 years with a family history of thyroid cancer, preoperative neck gross LN metastasis, maximum tumor diameter, and extrathyroidal invasion. Preoperative gross neck LN metastasis and distant metastasis at diagnosis were significant factors for CSS. No other factors contributed to DFS and CSS. When the clinical features of children and adolescents were compared, the incidence of preoperative gross neck LN metastasis and distant metastasis at diagnosis and tumors with a maximum diameter >10 mm were significantly higher in the children group than in the adolescent group. DFS was significantly shorter in the children group than in the adolescent group, but no significant difference was found in CSS between these two groups.

CONCLUSIONS

The prognosis of PTC in children and adolescents is excellent, regardless of the extent of thyroidectomy and LN dissection. We recommend that only children or adolescents with preoperative gross neck LN metastasis and distant metastasis at diagnosis should be subjected to postoperative ablative therapy.

Management of thyroid carcinoma in children and young adults

Thyroid cancers represent the largest group of pediatric carcinomas. Unlike other cancers of childhood, they have not been prospectively studied; instead adult data has been extrapolated to childhood and adolescent treatment. In this article we review the treatment of both well differentiated thyroid cancer (WDTC), as well as medullary thyroid cancer (MTC). The approach to both cancers relies on a low threshold of suspicion, and a willingness to biopsy suspicious lesions. Surgery remains the primary method of curing these patients, although radioactive iodine (RAI) may offer some benefit in WDTC for selected patients. For patients with MTC new medications, such as Vandetanib, may offer some adjuvant benefit following surgery. Lastly, suppression of thyroid stimulating hormone (TSH) may be one of the most beneficial treatments for WDTC.

Pediatric thyroid cancers: an Indian perspective

Pediatric thyroid cancer is a rare entity accounting for less than 5% of all thyroid cancers. This intriguing disease is characterized by advanced presentation, coupled with frequent lymph nodal metastases and often pulmonary metastases. It perhaps exhibits a distinct biology and behaviour, because in spite of its aggressiveness, survival is extremely good. This mandates meticulous treatment decisions that are well executed, because the complications of therapy in patients with good survival may spell prolonged morbidity. Being an unusual disease, it is unlikely that level I evidence guiding the management will come forth. There have been controversies regarding management, and the current consensus comes from large prospective studies. There have been only a few studies from India detailing pediatric thyroid cancers. In the current discussion, we review the existing evidence about pediatric thyroid cancers, and try to have an Indian perspective at the problem.

Thyroid cancer in children: a 20-year study at a Romanian oncology institute

Thyroid carcinoma (TC) has an increasing incidence in the last decade and continues to represent the most frequent form of endocrine tumor. The aim of the study was to analyze the pediatric files of TC from the registry of "Prof. Dr. Ion Chiricuta" Institute of Oncology Cluj-Napoca, Romania (IOCN) and to provide the data related to the impact of nuclear fallout of Chernobyl on this pathology. We studied 72 children with TC treated between 1991 and 2010. The mean age was 15.3 years; the ratio female/male was 6.2:1. Twenty-nine children (40.2%) revealed metastasis in regional lymph nodes or lungs at the initial diagnostic. There were 63 differentiated thyroid carcinoma (DTC), 6 cases with medullary cancer (MC), 1 case with anaplastic carcinoma (AC), and 2 mixed cases. All patients underwent total thyroidectomy and the radioiodine was administered in 64 cases (activities between 1.1 - 28.1 GBq I-131). Fifty-two children (80.5%) are free of disease, 8 are in partial remission and 4 children are in evolution of the disease at minimum 12 months of follow-up. The incidence of TC was significantly increased 10 years after the accident. In the years after, the increasing trendline was stopped and at 25 years, the number of cases is stationary. The diagnosis of pediatric TC is made frequently in metastatic disease and the therapies must be conducted for many years till complete remission. A more clear strategy adapted to children is needed in the future.

The treatment of differentiated thyroid cancer in children: emphasis on surgical approach and radioactive iodine therapy

Pediatric thyroid cancer is a rare disease with an excellent prognosis. Compared with adults, epithelial-derived differentiated thyroid cancer (DTC), which includes papillary and follicular thyroid cancer, presents at more advanced stages in children and is associated with higher rates of recurrence. Because of its uncommon occurrence, randomized trials have not been applied to test best-care options in children. Even in adults that have a 10-fold or higher incidence of thyroid cancer than children, few prospective trials have been executed to compare treatment approaches. We recognize that treatment recommendations have changed over the past few decades and will continue to do so. Respecting the aggressiveness of pediatric thyroid cancer, high recurrence rates, and the problems associated with decades of long-term follow-up, a premium should be placed on treatments that minimize risk of recurrence and the adverse effects of treatments and facilitate follow-up. We recommend that total thyroidectomy and central compartment lymph node dissection is the surgical procedure of choice for children with DTC if it can be performed by a high-volume thyroid surgeon. We recommend radioactive iodine therapy for remnant ablation or residual disease for most children with DTC. We recommend long-term follow-up because disease can recur decades after initial diagnosis and therapy. Considering the complexity of DTC management and the potential complications associated with therapy, it is essential that pediatric DTC be managed by physicians with expertise in this area.

Thyroid carcinoma in children and adolescents-systematic review of the literature

Thyroid cancer in children and adolescents is usually a major concern for physicians, patients, and parents. Controversies regarding the aggressiveness of the clinical presentation and the ideal therapeutic approach remain among the scientific community. The current recommendations and staging systems are based on data generated by studies in adults, and this might lead to overtreating in some cases as well as undertreating in others. Understanding the differences in the biology, clinical course, and outcomes in this population is crucial for therapeutic decisions. This paper evaluates the biology, clinical presentation, recurrences, and overall survival as well as the staging systems in children and adolescents with differentiated thyroid cancer.

Identification of a cut-off for the MACIS score to predict the prognosis of differentiated thyroid carcinoma in children and young adults

BACKGROUND

The metastases, age at diagnosis, completeness of resection, invasion, size of the tumor (MACIS) scoring system was developed to predict disease-specific survival in patients with differentiated thyroid carcinoma (DTC), mainly for adults, with a cut-off score of 6. The purpose of this study was to evaluate its ability to predict prognosis of DTC in children and young adults.

METHODS

The medical records of 66 children and young adult (<21 years old) patients with DTC were reviewed retrospectively. Receiver operating characteristic (ROC) analysis was performed to determine the cut-off for predicting poor prognosis.

RESULTS

Extrathyroidal invasion and regional lymph node metastasis were noted in 64% each, and distant metastases were found in 8%. The optimal cut-off for the MACIS score for poor prognosis was 4 (93% sensitivity, 67% specificity). The overall 10-year recurrence-free survival was better in patients with MACIS score <4 than score ≥4 (p < .05).

CONCLUSION

A MACIS score of more than 4 was associated with a poor prognosis in children and young adult patients with DTC.

Increased numbers of tumor-lysing monocytes in cancer patients

Lymphatic infiltration is a well known phenomenon in different tumors including endocrine malignancies. However, little is known about the role of antigen-presenting cells and T cell activation in this context. The aim of our study was to investigate the quantity and function of CD14+/CD56+ monocytes in tumor patients including endocrine malignancies. First, these cells were characterized in peripheral blood of endocrine and non-endocrine cancer patients as well as in tumor tissue samples. Cancer patients had in mean 3.7 times more CD14+/CD56+ monocytes in the peripheral blood compared to healthy controls (p≤0.0001), while the highest frequencies were seen in patients with heavy tumor load. Importantly, these cells additionally expressed several NK cell markers. A proof of CD14+/CD56+ infiltrations into papillary thyroid carcinoma was shown by immunohistochemical analyses. Functional analyses revealed an apoptosis inducing capacity in vitro after IFN-α re-stimulation. Our data indicate the importance of tumor-lysing monocytes in antitumor immunity.

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 a good response to initial therapy in children and adolescents with differentiated thyroid cancer

BACKGROUND

Therapeutic approaches in pediatric populations are based on adult data because there is a lack of appropriate data for children. Consequently, there are many controversies regarding the proper treatment of pediatric patients.

OBJECTIVE

The present study was designed to evaluate patients with differentiated thyroid carcinoma diagnosed before 20 years of age and to determine the factors associated with the response to the initial therapy.

METHODS

Sixty-five patients, treated in two tertiary-care referral centers in Rio de Janeiro between 1980 and 2005 were evaluated. Information about clinical presentation and the response to initial treatment was analyzed and patients had their risk stratified in Tumor-Node- Metastasis; Age-Metastasis-Extracapsular-Size; distant Metastasis-Age-Completeness of primary tumor resection-local Invasion-Size and American-Thyroid-Association classification

RESULTS

Patients ages ranged from 4 to 20 years (median 14). The mean follow-up was 12,6 years. Lymph node metastasis was found in 61.5% and indicated a poor response to initial therapy, with a significant impact on time for achieving disease free status (p = 0.014 for response to initial therapy and p<0,0001 for disease-free status in follow-up). Distant metastasis was a predictor of a poor response to initial therapy in these patients (p = 0.014). The risk stratification systems we analyzed were useful for high-risk patients because they had a high sensitivity and negative predictive value in determining the response to initial therapy.

CONCLUSIONS

Metastases, both lymph nodal and distant, are important predictors of the persistence of disease after initial therapy in children and adolescents with differentiated thyroid cancer.

Radioiodine treatment in pediatric Graves' disease and thyroid carcinoma

Graves' disease (GD) is the most common cause of hyperthyroidism in pediatric patients. Most pediatric thyroid cancer is differentiated thyroid cancer (DTC). The two diseases can be treated using different methods, such as antithyroid drug, radioactive iodine (RAI), and surgery for GD and surgery and RAI for DTC. RAI can be used to treat pediatric GD and DTC. In the article, we reviewed the RAI application in pediatric GD and DTC.

An individualized approach to the child with thyroid cancer

Children with differentiated thyroid cancer (DTC) often present with extensive disease that inclined clinicians in prior decades toward aggressive treatment including total thyroidectomy, radical neck dissection and universal prescription of radioactive iodine (RAI). Recent series with 40 years of follow-up have shown that fewer than 2% of children ultimately die from DTC, but they may have increased all-cause mortality from second malignancies that might be related to previous radiation exposure. In this article, we review data to support the notion that an individualized, risk-stratified approach to therapy should be used for children with DTC. Ideally this will provide aggressive therapy for those in whom aggressive treatment is warranted, but withhold aggressive and risk-associated therapy from those who are not likely to benefit.

Long-term outcome in 215 children and adolescents with papillary thyroid cancer treated during 1940 through 2008

BACKGROUND

Controversy exists regarding the aggressiveness of initial therapy in childhood papillary thyroid cancer (PTC). Few studies with long-term outcome exist and second primary malignancies have rarely been analyzed.

METHODS

We studied 215 PTC patients younger than 21 years old managed during 1940 through 2008. The patients were aged 3-20 year old (median age = 16 years); the median follow-up was 29 years. Recurrence and mortality details were taken from a computerized database.

RESULTS

Median primary tumor size was 2.2 cm. Six percent had distant metastases at presentation, 5% had incomplete tumor resection, 86% had nodes removed at initial surgery, and 78% had nodal metastases. After complete surgical resection, PTC recurred in 32% by 40 years. At 20 years, the recurrence rates at local, regional, and distant sites were 7, 21, and 5%, respectively. During 1940-1969, local and regional recurrence rates after unilateral lobectomy (UL) were significantly (P < 0.001) higher than after bilateral lobar resection (BLR). During 1950-2008 radioiodine remnant ablation (RRA) was administered within 18 months to 32%; it did not diminish the 25-year regional recurrence rate of 16% seen after BLR alone (P = 0.86). Only two fatal events from PTC occurred at 28 and 30 years, for a cause-specific mortality at 40 years of only 2%. All-causes mortality rates did not exceed expectation through 20 years, but from 30 through 50 years, the number of deaths was significantly (P < 0.001) higher than predicted. Fifteen of 22 deaths (68%) resulted from nonthyroid malignancy.

CONCLUSION

Survival from childhood PTC should be expected, but later death from nonthyroid malignancy is disconcerting. Seventy-three percent of those who died from nonthyroid malignancy had received postoperative therapeutic irradiation.

Utilization of total thyroidectomy for differentiated thyroid cancer in children

PURPOSE

Recent recommendations suggest that total thyroidectomy (TT) is the surgical management of choice for differentiated thyroid cancer in children. The objective of this study is to assess trends in extent of surgical resection for differentiated thyroid cancer in children over the past two decades and to identify patient, tumor or hospital factors associated with use of TT.

PATIENTS AND METHODS

Of 8,013 patients (aged 0-21 years) with differentiated thyroid cancer from the National Cancer Data Base (1985-2007), 5,933 (74%) underwent TT. Trends in extent of surgery were examined. Logistic regression was used to identify factors that predict use of TT.

RESULTS

Use of TT increased from 50.6% in 1985 to 84% in 2007 (P < 0.001). Patients were more likely to undergo TT if they had higher household income or had private insurance (P = 0.002 and P = 0.037). Patients were more likely to undergo TT if they had larger tumors or if there were nodal metastases present at time of resection (both P < 0.001). After adjusting for patient and tumor factors, patients treated at high-volume or Children's Oncology Group hospitals were more likely to undergo TT than patients treated at low-volume or non-Children's Oncology Group hospitals (P < 0.001).

CONCLUSIONS

Overall utilization of TT in children with differentiated thyroid cancer has steadily increased over the past 23 years in the USA. Variations in use of TT are not only related to tumor factors including size and nodal involvement, but also are also related to socioeconomic and hospital factors, demonstrating disparities in care.

Childhood minimally invasive follicular carcinoma: clinical features and immunohistochemistry analysis

AIM

To report on two cases of childhood thyroid minimally invasive follicular carcinoma (MIFC) to highlight the clinical features, laboratory findings and diagnosis of this rare disease.

METHODS

The patients' age, gender, clinical features, laboratory findings, pathology and therapy were reviewed. Immunohistochemistry analysis was performed on the resected masses section.

RESULTS

From 2000 to 2008, a total of 15 cases of thyroid cancer were confirmed by pathological analysis, which account for about 2.16% of all malignant solid tumours. They included nine of thyroid papillary carcinoma, two of MIFC and one of undifferentiated thyroid carcinoma. For the two children with MIFC, one was an 8-year-boy and one was a 12-year-old girl. Thyroid mass was found as the primary sign. Imaging findings showed well-defined heterogeneous mass and radionuclide scintigraphy with 99mTc demonstrated small cold nodules in the right lobe of thyroid in two cases. Histopathology confirmed the diagnosis of MIFC. Immunohistochemical staining was positive for thyroglobulin, thyroid transcription factor-1, galectin-3, Hector Battifora mesothelial antigen-1, cytokeratin-AE1/AE3, cytokeratin-19, proliferating cell nuclear antigen and E-cadherin in two cases, and S-100 in one case, while CD56, vimentin and desmin were negative. One case was undertaken lobectomy and the other was undertaken subtotal thyreoidectomy with L-T4 replacement therapy.

CONCLUSION

MIFC is exceedingly rare in children and should be included in the differential diagnosis of thyroid mass. The diagnosis of MIFC depends mainly on the pathological findings.

Treatment strategy of papillary thyroid carcinoma in children and adolescents: clinical significance of the initial nodal manifestation

BACKGROUND

Risk factors and treatment strategy in younger patients with papillary thyroid carcinoma are still controversial.

METHODS

We reviewed 120 consecutive papillary thyroid carcinoma patients younger than 20 years who underwent initial surgery between 1977 and 2004 (14 male and 106 female subjects; mean age, 16.3 years; mean follow-up, 11.6 years). Outcomes were evaluated initially, and risk factors for disease-free survival (DFS) were analyzed statistically. Cox proportional multivariate analysis revealed that initial nodal manifestation (P < .001, hazard ratio 2.97) was the most statistically significant risk factor for DFS. The outcomes were then compared between four subgroups on the basis of the initial nodal manifestation and node dissection: 17 patients in group A (no lymphadenopathy, no or only prophylactic central dissection), 30 patients in group B (no lymphadenopathy, prophylactic modified neck dissection, MND), 46 patients in group C (nonpalpable lymphadenopathy detected by radiological or operative findings, therapeutic MND), and 27 patients in group D (palpable lymphadenopathy, therapeutic MND).

RESULTS

Subtotal/total thyroidectomy and radioactive iodine therapy were performed for 47.1 and 0% in group A, 33.3 and 0% in group B, 43.4 and 10.9% in group C, and 85.1 and 48.1% in group D, respectively. In groups A, B, C, and D, 0%, 3.3%, 28.3%, and 48.1% developed recurrence, respectively (P < .001). DFS Kaplan-Meier curves differed significantly among the four subgroups (P < .0005).

CONCLUSIONS

Initial nodal manifestation is useful to predict DFS in younger papillary thyroid carcinoma patients. Our findings will be beneficial to determine the treatment strategy. Conservative therapy is considered acceptable for patients without risk factors.

Pediatric differentiated thyroid carcinoma in stage I: risk factor analysis for disease free survival

BACKGROUND

To examine the outcomes and risk factors in pediatric differentiated thyroid carcinoma (DTC) patients who were defined as TNM stage I because some patients develop disease recurrence but treatment strategy for such stage I pediatric patients is still controversial.

METHODS

We reviewed 57 consecutive TNM stage I patients (15 years or less) with DTC (46 papillary and 11 follicular) who underwent initial treatment at Ito Hospital between 1962 and 2004 (7 males and 50 females; mean age: 13.1 years; mean follow-up: 17.4 years). Clinicopathological results were evaluated in all patients. Multivariate analysis was performed to reveal the risk factors for disease-free survival (DFS) in these 57 patients.

RESULTS

Extrathyroid extension and clinical lymphadenopathy at diagnosis were found in 7 and 12 patients, respectively. Subtotal/total thyroidectomy was performed in 23 patients, modified neck dissection in 38, and radioactive iodine therapy in 10. Pathological node metastasis was confirmed in 37 patients (64.9%). Fifteen patients (26.3%) exhibited local recurrence and 3 of them also developed metachronous lung metastasis. Ten of these 15 achieved disease-free after further treatments and no patients died of disease. In multivariate analysis, male gender (p = 0.017), advanced tumor (T3, 4a) stage (p = 0.029), and clinical lymphadenopathy (p = 0.006) were risk factors for DFS in stage I pediatric patients.

CONCLUSION

Male gender, tumor stage, and lymphadenopathy are risk factors for DFS in stage I pediatric DTC patients. Aggressive treatment (total thyroidectomy, node dissection, and RI therapy) is considered appropriate for patients with risk factors, whereas conservative or stepwise approach may be acceptable for other patients.

UICC-2002 TNM classification is not suitable for differentiated thyroid cancer in children and adolescents

BACKGROUND

Recently the UICC-TNM classification for differentiated thyroid cancer (DTC) was changed neglecting the special circumstances for children affected by the disease. While the 1997 TNM classification grouped tumours </=1 cm as T1, the 2002 system changed this to a margin of </=2 cm. The consequences of this change were evaluated by analysing patients enrolled in the multicentre interdisciplinary therapy study of the German Society of Paediatric Oncology and Haematology (GPOH) on malignant endocrine tumours in children and adolescents, GPOH-MET 97.

PROCEDURE

Between 1998 and 2005, 82 patients with histologically proven DTC entered the study. Patients classified according to UICC-TNM classification 1997 were reclassified according to the new classification (2002/2003) and vice versa by cross checking with original pathologist's reports.

RESULTS

Twenty males and 62 females at a mean age of 12.5 years were evaluated. We observed a definite shift from patients formerly classified as T2 (1-4 cm) to category T1 (</=2 cm) according to the 2002 TNM classification. Among these patients a threefold increase of lymph node involvement and/or distant metastases could be demonstrated.

CONCLUSIONS

The 2002 UICC-classification may have a disadvantage for children with tumours measuring between 1 and 2 cm, as those are now classified as T1. A high rate of lymph node involvement in this group reflects the risk of under-diagnosis and -treatment of this group. The current TNM classification for DTC in children should be changed taking the physiological and anatomical differences between children and adults into consideration.

Differentiated thyroid cancer in children: diagnosis and management

PURPOSE OF REVIEW

Differentiated thyroid cancer is the most common endocrine malignancy in children. In 2006, the American Thyroid Association Guidelines Taskforce released detailed management recommendations for differentiated thyroid cancer, which primarily addressed the approach for treating adult patients. Children with differentiated thyroid cancer present with more advanced disease and yet have a more favorable outcome than adults. Thus optimal treatment for younger patients with differentiated thyroid cancer may differ from that for adults.

RECENT FINDINGS

All available data regarding differentiated thyroid cancer treatment in children are retrospective. In the past year, several large case series have been published that strengthen the argument for total thyroidectomy at the time of diagnosis, followed by administration of radioactive iodine for remnant ablation. There have also been recent advances in understanding the genetic abnormalities associated with pediatric thyroid cancer.

SUMMARY

The optimal treatment of differentiated thyroid cancer in pediatric patients continues to be debated. Recent publications from institutions around the world provide useful data regarding current approaches to this unusual disease. Further collaborative studies are needed to further refine the surgical approach, particularly the extent of lymph-node dissection, radioactive iodine dosing, and the role of genetic analysis in diagnosis and clinical approach.

Thyroid cancer in children

In 1996, the authors were asked to review the subject of thyroid cancer in children. Over the subsequent decade, much has been learned about the treatment and outcome of these uncommon tumors. We now recognize quantitative and perhaps qualitative differences in genetic mutations and growth factor expression patterns in childhood thyroid cancers compared with those of adults. We also know that thyroid cancers induce a robust immune response in children that might contribute to their longevity. Patients under 10 years of age probably represent a unique subset of children at particularly high risk for persistent or recurrent disease; the management of these patients is under evaluation. We remain limited in our knowledge of how to stratify children into low- and high-risk categories for appropriate long-term follow-up and in our knowledge of how to treat children who have detectable serum thyroglobulin but negative imaging studies. In this article, the authors update our understanding of thyroid cancers in children with special emphasis on how these data relate to the current guidelines for management of thyroid cancer developed by the American Thyroid Association Taskforce. The limited data regarding management of children who have detectable serum thyroglobulin but negative whole-body scans are also reviewed.

Childhood thyroid cancer in Belarus, Russia, and Ukraine after Chernobyl and at present

Thyroid cancer in children is usually rare, but in the individuals exposed to radiation risk of disease increases considerably. After the Chernobyl accident in 1986, an over 10-fold maximal elevation in the incidence of thyroid cancer was registered about a decade later, cumulatively resulting in more than a thousand of newly diagnosed cases in children who lived in the territories of Belarus, Russia, and Ukraine affected by radioactive fallouts. Experience from the epidemic substantially promoted knowledge in clinical pediatric oncology, pathology and basic sciences. This article overviews epidemiology, clinical features, results of treatment and follow-up of childhood patients with radiation-induced Chernobyl thyroid cancer in comparison to sporadic cases diagnosed at present. In addition, we discuss general issues of pathology and molecular findings in childhood thyroid carcinomas.

Comprehensive clinical assessment of 740 cases of surgically treated thyroid cancer in children of Belarus

OBJECTIVE

A retrospective study was designed to evaluate the results of surgical treatment and follow-up data in thyroid cancer patients less than 15 years old at the time of surgery.

SUMMARY BACKGROUND DATA

Pediatric thyroid carcinomas have a high rate of lymph nodal and distant metastases. Risk factors for recurrences and postoperative morbidity have not been assessed yet in a representative series.

METHODS

The group included 740 pediatric patients with thyroid cancer. Total thyroidectomy was performed in 426 (57.6%), lobectomy in 248 (33.5%), subtotal thyroidectomy in 58 (7.8%) cases, and 8 patients (1.1%) underwent partial lobectomy.

RESULTS

The mean follow-up period was 115.8 months (range, 1.5-236.4 months). Recurrence was diagnosed in 204 cases (27.6%), including 73 local relapses (9.9%), 90 distant metastases (12.2%), and a combination of local and distant recurrences in 41 (5.5%) patients. Multivariate statistical assessment revealed the following independent parameters significantly associated with the risk of recurrent nodal disease: a young age at diagnosis, multifocal carcinomas, N1 status, and lack of neck lymph node dissection. For lung metastases, the significant risk factors were female gender, young age at diagnosis, and presence of symptoms. The observed 5- and 10-year survival for the entire group was 99.5% and 98.8%, respectively. Postoperative hypoparathyroidism was significantly associated with multifocal tumors, central compartment removal, and ipsilateral dissection.

CONCLUSIONS

Total thyroidectomy followed by radioiodine therapy is an optimal treatment strategy that makes it possible to achieve a cure in a vast majority of pediatric patients with differentiated thyroid carcinomas. Risk of recurrence is strongly associated with tumor stage, extent of surgery, the young patient's age, and presence of symptoms at diagnosis.

Thyroid cancer and the immune system: a model for effective immune surveillance

Differentiated thyroid cancers, including papillary and follicular variants, are a useful model with which to examine interactions between cancer and the immune system. Differentiated thyroid cancers are detected in only 20,000 individuals annually in the USA, but thyroid microcarcinomas (< 1 cm in diameter) are far more common. This suggests that the immune system might restrain the growth of these microcarcinomas. On the clinical level, patients with lymphocytes that infiltrate into papillary thyroid cancer have improved survival, supporting the notion that immune system activation might improve this. Together, these observations suggest that the growth and distant spread of thyroid carcinoma are suppressed by mechanisms of immune surveillance, possibly involving lymphocytes, macrophages and their secreted products. In this review, we examine the general hypothesis of immune surveillance and the data pertaining to the roles of lymphocytes, dendritic cells and cytokines in the immune response against thyroid cancers.

The role of a more extensive surgical approach in the initial multimodality management of papillary thyroid cancer in children

PURPOSE

Papillary thyroid cancer (PTC) in children is rare. The optimal initial surgical treatment remains controversial, given the generally favorable overall prognosis but high rate of cervical metastasis and local recurrence. Our objective was to examine the surgical outcomes of a policy of total thyroidectomy and routine selective lymph node dissection (SLND) as the initial surgical approach to children with PTC.

METHODS

This is a retrospective cohort study comprising 14 children (age, < or =17 years) with PTC referred for thyroid surgery during the past 15 years. Clinical presentation, the surgical procedure, final pathology, lymph node involvement, complications, and recurrence rates are reported.

RESULTS

There were 9 females and 5 males, with an average age of 12.5 years. Seven patients (50%) had clinically apparent cervical lymphadenopathy at the time of surgical referral. All subjects underwent total thyroidectomy, and 12 (86%) had SLND. Of the 12 who underwent SLND, 10 (83%) had nodal metastases. Temporary hypocalcemia was noted in 3 of the patients (21%), and 1 patient has required ongoing intermittent calcium supplementation. All patients are alive and well at follow-up with no clinical, biochemical, or radiological evidence of local recurrence.

CONCLUSIONS

Total thyroidectomy with initial SLND is an appropriate surgical approach in children with PTC. It can be done without a significantly increased risk for permanent complications and may reduce the requirement for subsequent surgical intervention for local recurrence in this young population.

BRAF mutations are uncommon in papillary thyroid cancer of young patients

Mortality is low for young patients (younger than 21 years) with papillary thyroid cancer (PTC), and different mutations might contribute to this. Previous studies detected ret/PTC rearrangements more frequently in PTC from children than adults, and recent reports describe a high incidence of BRAF T1796A transversion in adult PTC. However, BRAF mutations have not been adequately studied in PTC from young patients. We amplified and sequenced segments of the BRAF gene spanning the T1796A transversion site in 14 PTC from patients 10-21 years of age (mean, 17.5 +/- 3.5 years). The PTC (7 = class 1; 5 = class 2; 1 = class 3) ranged from 0.7-2.9 cm in diameter (mean, 1.4 +/- 0.75 cm). None of them (0/14) contained BRAF T1796A and none recurred (mean follow-up, 66 +/- 40 months). This incidence of BRAF T1796A is significantly less than that reported for adult PTC (270/699, 38.6%, p = 0.0015) in several series. None of our PTC (0/10) contained ras mutations, but 7/12 (58%) contained ret/PTC rearrangements. We conclude that BRAF mutations are less common in PTC from young patients, and ret/PTC rearrangements were the most common mutation found in these childhood PTC.

Thyroid cancers express CD-40 and CD-40 ligand: cancers that express CD-40 ligand may have a greater risk of recurrence in young patients

The immune response might suppress thyroid cancer recurrence. Although the factors that control this are unknown, CD-40 and CD-40 ligand might be important. To test this, we stained 36 papillary (PTC) and four follicular (FTC) thyroid carcinomas for CD-40 (n = 37) and CD-40 ligand (n = 36) and graded staining from absent (grade 0) to intense (grade 3). Follicular cells of the majority of thyroid tumors expressed CD-40 (30/37, 81%) and CD-40 ligand (15/24, 69%). Cancers from young patients (< or =21 years of age) that expressed CD-40 contained more numerous lymphocytes/high-power field (36 +/- 11) than cancers that failed to express CD-40 (4 +/- 3, p = 0.01), but there was no correlation with clinical outcome. Among young patients, CD-40 ligand expression was more intense in multifocal (1.1 +/- 0.2 vs. 0.45 +/- 0.2, p = 0.037), aggressive (1.14 +/- 0.14 vs. 0.65 +/- 0.2, p = 0.05) and recurrent tumors (1.2 +/- 0.2 vs. 0.65 +/- 0.2, p = 0.05) and associated with reduced disease-free survival (p = 0.03). We conclude that the majority of thyroid cancers express CD-40 and CD-40 ligand. In patients < or =21 years of age, tumors with intense expression of CD-40 ligand are more often multifocal, aggressive, and recurrent.

Cytoplasmic localization of the paired box gene, Pax-8, is found in pediatric thyroid cancer and may be associated with a greater risk of recurrence

The paired box-8 protein (Pax-8) has been observed in the nucleus of normal adult thyroids, follicular adenomas, follicular thyroid cancers, and papillary thyroid cancers (PTC) but not undifferentiated thyroid cancers. To our knowledge, Pax-8 has not been studied in pediatric thyroid cancer. Because of the more favorable prognosis for PTC in children compared to young patients, we hypothesized that Pax-8 expression might be different in pediatric thyroid cancers. To test this, we stained 47 thyroid lesions from children and young patients for Pax-8. Pax-8 was located in the cytoplasm (cPAX) or nucleus (nPAX) in the majority of samples. There was no significant difference in nPAX between benign and malignant lesions. However, cPAX was more commonly seen in PTC than autoimmune diseases (p = 0.01) and the intensity of cPAX staining correlated with tumor size (p = 0.041), metastasis, age, completeness of resection, local invasion, and tumor size (MACIS) scores (p = 0.045), and the presence of invasion, metastasis, recurrence, or persistence (p = 0.012). Disease-free survival was significantly reduced for cancers with intense cPAX staining (p = 0.0003). These data show that cPAX is common in PTC, and although limited by small sample size, suggest an association with higher MACIS scores, an aggressive clinical course, and an increased risk of clinically evident recurrence for children and young patients.

Câncer de tireóide na infância e adolescência: relato de 15 casos

Tumores tireoideanos são raros na infância e adolescência. Foram revisados os prontuários de quinze pacientes (8 do sexo feminino) com idades entre 5,8 e 15,2 anos, atendidos na Unidade de Endocrinologia Pediátrica (UEP) do HC-UFPR entre fevereiro de 1988 e março de 2003. Nódulo cervical anterior foi a queixa inicial mais freqüente. Dez pacientes eram portadores de carcinoma papilífero (CP), quatro apresentavam carcinoma medular (CMT; dos quais, três com NEM-2B) e um, carcinoma folicular. Dois pacientes com NEM-2B apresentam mutação de novo (Met918Thr) do proto-oncogene RET. PAAF, efetuada em dez pacientes, foi positiva para neoplasia em cinco deles. Todos os pacientes foram submetidos a tireoidectomia total. Terapia adjuvante com 131I foi realizada em dez pacientes. Dois pacientes faleceram por doença não relacionada ao tumor. Nove pacientes não apresentam evidência clínica ou laboratorial do tumor; um (CP) apresentou recidiva 5 anos após o tratamento inicial e três (1 CP, 2 CMT) ainda têm evidência da doença. Nossos dados estão de acordo com a literatura em relação ao prognóstico e manifestações clínicas. Entretanto, a prevalência de CMT (27%), a distribuição por sexo e os resultados da PAAF diferem da maioria das casuísticas publicadas, o que pode ser atribuído ao número de casos aqui relatado.

Current Strategies for Surgical Management and Adjuvant Treatment of Childhood Papillary Thyroid Carcinoma

Childhood papillary thyroid carcinoma is associated with more locally aggressive and more frequent distant disease than its adult counterpart. Recurrence rates tend to be higher in children, but cause-specific mortality remains low. Optimal initial treatment of childhood papillary thyroid carcinoma should include total or near-total thyroidectomy and central compartment node clearance. Modified neck dissections should be performed for biopsy-proven lateral neck disease. Every effort should be made to maintain parathyroid and laryngeal nerve function. Radical neck dissections are to be avoided. Radioiodine remnant ablation (RRA), appropriate thyroid hormone suppressive therapy (THST), and judicious use of therapeutic doses of (131)I are applied to achieve a disease-free status, which is most often confirmed by negative neck ultrasonography, negative whole-body scan (either withdrawal or recombinant human thyroid-stimulating hormone-stimulated), and extremely low levels of serum thyroglobulin. Appropriate utilization of (131)I, THST, repeat surgery, external beam radiotherapy, and rarely chemotherapy may provide long-term palliation and some cures in patients with recurrent/persistent disease. Follow-up should be lifelong, and the care of children after age 17 should subsequently be transferred to adult-care endocrinologists with expertise in managing thyroid neoplasia. Optimal surgical management can be achieved if adequate operations are routinely carried out by "high-volume" thyroid surgeons with expertise in the care of children. Nowhere is a multidisciplinary approach (endocrinologists, surgeons, nuclear medicine physicians, pediatricians, pathologists, oncologists) more critical than in the long-term management of papillary thyroid carcinoma that presents during childhood.

Predictive Factors for Recurrence from a Series of 74 Children and Adolescents with Differentiated Thyroid Cancer

The influence of clinical and treatment factors on the risk of recurrence was analyzed from a retrospective series of 74 children and adolescents with thyroid cancer (55 girls, 19 boys; age 2-20 years). Two groups, comparable in terms of age, sex, and previous radiotherapy, were compared according to the presence (group 1) or absence (group 2) of cervical lymph nodes identified by palpation or ultrasonography. Total thyroidectomy (TT) with lymph node dissection (LND) was performed in the 19 group 1 patients, whereas in group 2 patients (n = 55) lobectomy was performed in 29, TT in 26, and LND in 7. Pathology studies showed papillary thyroid carcinoma in 95% of cases. In group 1, tumors were more frequently multifocal (89% vs. 16% in group 2), invasive with extension beyond the thyroid capsule (68% vs. 5% in group 2), and of the diffuse sclerosing variety (63% vs. 4% in group 2) (p < 0.001). With a median follow-up of 61 months, lymph node recurrence was seen in 53% of group 1 patients and in no patients in group 2. Three group 2 patients (10%) were reoperated for a local recurrence after lobectomy. Risk factors for reintervention were young age (< 15 years) (p < 0.01) and cervical lymph nodes (p < 0.001). Survivals without reintervention at 5 and 10 years were, respectively, 58% and 38% for group 1 and 94% and 90% for group 2 (p < 0.001). At the time of analysis, 68% of group 1 patients and 98% of group 2 patients were in remission. In conclusion, the presence of palpable cervical lymph nodes at diagnosis is associated with more invasive forms of malignancy and is a predictive factor of recurrence regardless of the extent of the initial surgery.

Differentiated thyroid carcinomas from children and adolescents express IGF-I and the IGF-I receptor (IGF-I-R). Cancers with the most intense IGF-I-R expression may be more aggressive

Adult thyroid cancers express IGF and IGF-I receptor (IGF-I-R), but the clinical impact is not clear. No previous study examined any childhood thyroid cancers that are well-differentiated and have a favorable prognosis. We used immunohistochemistry to determine IGF-I and IGF-I-R in 23 papillary thyroid cancers (PTC) and 6 follicular thyroid cancers (FTC) from children and adolescents. IGF-I was detected in 45% and IGF-I-R in 43% of cancers. IGF-I and IGF-I-R were found more often in PTC (IGF-I = 9/23, IGF-I-R = 8/19) than normal surrounding thyroid (IGF-I = 0/10, p = 0.032 and IGF-I-R = 0/10, p = 0.030). There were too few FTC to support independent statistical analysis, but IGF-I was found in 4 of 6 FTC (0/10 normal), and IGF-I-R was found in 2 of 4 FTC (0/10 normal). IGF-I-R staining was more intense in aggressive (invasive, metastatic, recurrent, or persistent) than indolent tumors (confined to the gland, p = 0.029). Over time, six tumors recurred, five of which expressed IGF-I-R. Overall recurrence risk was significantly greater for tumors that expressed IGF-I-R (p = 0.05) but only approached statistical significance (p = 0.08) when disease-free survival was determined. We conclude that differentiated thyroid cancers of children and adolescents express IGF-I and IGF-I-R. Tumors that express IGF-I-R are more likely to show aggressive clinical features (invasion beyond the capsule, metastasis, or recurrence) and persistence despite treatment.

The MACIS score predicts the clinical course of papillary thyroid carcinoma in children and adolescents

MACIS (distant Metastasis, patient Age, Completeness of resection, local Invasion, and tumor Size) scores are employed to predict mortality for papillary thyroid carcinoma (PTC) in adults. However, this system has not been validated in children and adolescents. We hypothesized that MACIS scores would correlate with recurrent and persistent disease in children. Patients with PTC (n = 48) were divided into those with aggressive (invasive, metastasic, recurrent or persistent disease) or indolent (lacking these features) disease. Those with aggressive PTC (n = 11) had average MACIS score = 5.2 +/- 1.3, compared to 3.7 +/- 0.4 in patients with indolent disease (n = 37, p < 0.0005). A cutoff score of 4.0 provides a PPV of 29% and NPV of 94% in predicting recurrence, and a PPV of 43% and NPV of 91% in predicting persistent disease. MACIS scores may be useful in predicting outcome in the pediatric population.

Differentiated thyroid carcinoma in childhood and adolescence-clinical course and role of radioiodine

BACKGROUND

Differentiated thyroid carcinoma (DTC) in childhood has a good prognosis despite a high incidence of relapse. The use of radioactive iodine (RAI) has not been well established.

PROCEDURE

This is a review of 60 patients less than 21 years of age; mean follow-up was 14 years.

RESULTS

Patients had a higher relapse rate with papillary thyroid carcinoma (PTC) than with follicular thyroid carcinoma (FTC): 24.5 vs. 9.1%. Compared with 997 patients with age > or = 21, patients <21 years of age had a higher female to male ratio (7.6 vs. 3.9), higher incidence of nodal metastasis (45 vs. 28%), and lung metastasis (15 vs. 7.8%), and improved 10-year cause-specific survival (CSS) (98.3 vs. 89.5%). The 10-year rates of CSS, local-regional failure-free survival (LRFFS), and distant metastasis failure-free survival (DMFFS) for the young patients were 98.3, 79.3, and 90.7%, respectively. In patients with no distant metastasis at presentation, RAI improved 10-year LRFFS (71.9 vs. 86.5%; P = 0.04). At last follow-up, 10 of 12 patients (80%) with local-regional (LR) relapse and five of nine patients (55.6%) with distant metastasis were rendered disease-free. No patient has experienced a second malignancy.

CONCLUSIONS

Prognosis of DTC in young patients was good. Patients with LR relapse and distant metastasis had a high rate of remission after treatment. RAI treatment can reduce the rate of LR relapse in patients with no distant metastasis and result in complete remission in half of those with distant metastasis. No patient experienced a second malignancy.

[Follow-up of children and young adults with differentiated thyroid cancer treated with radioiodine]

This is a retrospective study carried out in a group of 30 patients with differentiated thyroid cancer (age at diagnosis equal to or less than twenty years old). The aim of the study is to evaluate outcome after 131I therapy. Patients were classified into three groups on the basis of initial surgery, pathology and scintigraphic results: group I (thyroid extent), group II (locoregional extent), and group III (distant metastatic disease). Clinical parameters, 131I scans, serum thyroglobulin determinations and 131I therapeutic administered doses were evaluated in the follow-up. Some other complementary techniques such as chest X-ray and pulmonary function tests are also described. Scintigraphic absence of thyroid tissue has been observed in 83% of the cases; high thyroglobulin level is still detectable in 34% of the patients as a single evidence of disease, and 21% remain without any abnormal clinical, scintigraphic or analytical findings. Total doses administered have increased in groups I, II and III respectively, and have also been inversely proportional to the extension of lymph node surgery. At present, all the patients are alive and in good general condition. According to the results obtained, we conclude that children and young adults with DTC should undergo periodical 131I therapeutic doses in case of positive scans (once total thyroidectomy has been realized, with or without lymph node resection depending on the extension of disease). In our experience, the use of radioiodine is effective and safe in the follow-up of children and youngs with DTC.

Well-differentiated carcinoma of the thyroid

Thyroid cancer will be diagnosed in more than 20,000 individuals in the United States in 2002. Approximately 16,000 of these patients will be women. During the same year, an estimated 1300 deaths from thyroid cancer are expected. The various types of thyroid cancer include papillary carcinoma, follicular carcinoma, Hurthle cell carcinoma, medullary carcinoma, anaplastic carcinoma, and thyroid lymphoma. Papillary, follicular, and Hurthle cell carcinoma are considered well-differentiated thyroid cancers and constitute the focus of this article.

Surgical experience in children with differentiated thyroid carcinoma

BACKGROUND

The optimal surgical treatment in children with well-differentiated thyroid carcinoma remains an important point of discussion. In this study, we evaluated our surgical experience and reviewed the literature accordingly to identify the most adequate treatment.

METHODS

We retrospectively analyzed 21 children, all under the age of 18 years at the time of diagnosis, with differentiated thyroid carcinoma (17 papillary, 3 follicular, and 1 Hürthle cell carcinoma). Total thyroidectomy was performed, followed by radioiodine therapy, as a part of the initial treatment in all patients. The results were compared with data from the literature.

RESULTS

Eleven children (52%) who presented with cervical lymph node metastases were treated by a modified radical neck dissection. Pulmonary metastases were seen at diagnosis in three patients. Six patients developed temporary complications. During follow-up, with a median of 11 years (range, 2-26 years), two patients (10%) developed recurrences, and no patient died during this observation period. A literature search confirmed our experience of excellent results without an increase of complications in the more aggressively treated patients.

CONCLUSIONS

In children with differentiated thyroid cancer, treatment should consist of total thyroidectomy, followed by a modified radical neck dissection (when indicated) and iodine-131 ablation treatment. This aggressive approach seems to be justified because of the high incidence of nodal involvement and the low complication and recurrence rate after surgery.

Differentiated thyroid carcinoma that express sodium-iodide symporter have a lower risk of recurrence for children and adolescents

The sodium-iodide symporter (NIS) is expressed by papillary (PTC) and follicular (FTC) thyroid carcinoma, and is essential for iodine uptake. We hypothesized that PTC and FTC with detectable NIS immunostaining would be more amenable to radioactive iodine ((131)I) treatment and follow a more benevolent course. To test this, we determined NIS expression by immunohistochemistry in 23 PTC, 9 FTC, and 12 benign thyroid lesions from children and adolescents. NIS expression was determined by two blinded examiners and graded as absent = 0, minimal = 1, moderate = 2, intense = 3, and very intense = 4. NIS was detected in 35% (eight of 23) of PTC, 44% (four of 9) of FTC, 25% (two of eight) of benign tumors, and 100% (four of four) of autoimmune lesions. The intensity of NIS expression was similar in PTC (0.61 +/- 0.24), FTC (0.56 +/- 0.24), and benign tumors (0.50 +/- 0.33) but was more intense in autoimmune lesions (3.0 +/- 0.7, p < 0.005). Distant metastases were found only among PTC with undetectable NIS (two of 15, 13%), and recurrence developed exclusively from PTC and FTC with undetectable NIS (four of 20, 20% versus zero of 12, p = 0.043). The dose of iodine 131 required to achieve remission in the five patients with PTC who had undetectable NIS (213.3 +/- 53 mCi) was greater than that required by patients with similar age and extent of disease for whom NIS expression is unknown (109 +/- 22 mCi, p = 0.06). We conclude that NIS expression is associated with a lower risk of recurrence for PTC and FTC of children and adolescents.

Intense expression of the b7-2 antigen presentation coactivator is an unfavorable prognostic indicator for differentiated thyroid carcinoma of children and adolescents

Previous observations suggest that an immune response against thyroid carcinoma could be important for long-term survival. We recently found that infiltration of thyroid carcinoma by proliferating lymphocytes is associated with improved disease-free survival, but the factors that control lymphocytic infiltration and proliferation are largely unknown. We hypothesized that the antigen presentation coactivators (B7-1 and B7-2), which are important in other immune-mediated thyroid diseases, might be important in lymphocytic infiltration of thyroid carcinoma. To test this, we determined B7-1 and B7-2 expression by immunohistochemistry [absent (grade 0) to intense (grade 3)] in 27 papillary (PTC) and 8 follicular (FTC) thyroid carcinomas and 9 benign thyroid lesions. B7-1 and B7-2 were expressed by the majority of PTC and FTC (78% of PTC and 100% of FTC expressed B7-1; 88% of PTC and 88% of FTC expressed B7-2). B7-1 expression was more intense in PTC (1.4 +/- 0.2; P = 0.01) and FTC (2.6 +/- 0.2; P < 0.001) than in benign tumors (0.57 +/- 0.30) or presumably normal adjacent thyroid (0.07 +/- 0.07) and was more intense in carcinoma that contained lymphocytes (1.95 +/- 0.21) than in carcinoma that did not (1.08 +/- 0.26; P = 0.016). B7-2 expression was of similar intensity in benign and malignant tumors (PTC, 1.6 +/- 0.2; FTC, 2.1 +/- 0.4; benign, 1.86 +/- 0.4), but was more intense than in presumably normal adjacent thyroid (0.64 +/- 0.25; P </= 0.013). B7-2 expression also correlated with the number of tumor-associated lymphocytes per high power field (r = 0.38; P = 0.02). Recurrence developed exclusively from tumors that expressed B7-2, and intense B7-2 expression was associated with a reduced probability of remission (P = 0.04). In conclusion, these data support the hypothesis that the antigen presentation coactivators B7-1 and B7-2 may be important for lymphocytic infiltration and the immune response against thyroid carcinoma.

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.

Current controversies in the management of pediatric patients with well-differentiated nonmedullary thyroid cancer: a review

Current treatment strategies for pediatric patients with nonmedullary, well-differentiated thyroid carcinoma (WDTC) are derived from single-institution clinical cohorts, reports of extensive personal experience, and extrapolation of several common therapeutic practices for this tumor in adults. Because pediatric WDTC is an uncommon malignancy, the issues of its optimal initial and subsequent long-term treatment and follow-up remain controversial. Pediatric patients with WDTC can be divided into two groups: children younger than 10 years of age and teenagers/adolescents between 10 and 18 years of age because these groups have different recurrence and mortality rates. We hereby present our views and interpret them in the light of the pertinent literature. Our recommendations on treatment strategies are more relevant for younger children. After midpuberty, optimal treatment is adequately addressed in the relevant literature on adults. For the majority of patients, total/near-total thyroidectomy is currently recommended as the standard initial therapy for WDTC. This is commonly followed by administration of radioiodine (RAI; (131)I) therapy to destroy residual normal thyroid tissue (remnant). Routine (131)I remnant ablation has been shown to: (1). decrease the risk of local recurrences, (2) increase the sensitivity of subsequent diagnostic RAI whole-body scanning (WBS), and (3) render serum thyroglobulin (Tg) a highly sensitive marker for recurrent/residual disease during long-term follow-up. We recognize that the above practices are not universally adhered to in children and adolescents, because the risk stratification and intensity of applied therapeutic measures are influenced by institutional traditions and personal experience. In our view, aggressive initial management, followed by evaluations at regular intervals after thyroidectomy and (131)I remnant ablation, in conjunction with long-term thyroid hormone suppressive therapy (THST), result in decreased recurrence rates in pediatric patients with WDTC. Follow-up examinations should include a diagnostic RAI ((131)I or (123)I) WBS and measurement of serum Tg, both performed under conditions of TSH stimulation, as well as neck ultrasonography (US). Our strategy is corroborated by data from retrospective clinical cohort studies. In this malignancy, no evidence of disease (NED) status can be defined as the combination of a negative diagnostic WBS and the presence of undetectable or low serum Tg levels, both tested under TSH stimulation. These findings should be accompanied by the absence of anatomically definable disease by standard imaging modalities, e.g., neck US or chest computed tomography (CT). Although the long-term survival rates are good overall in this disease, selected patients may require further surgery or (131)I therapy for the eradication or clinical control of metastases. Finally, and importantly, because the duration of follow-up is lifelong, the care of children with prior diagnosis of WDTC should be transferred to an adult endocrinologist after they reach adulthood, even if they have achieved NED status by that time.

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.

Differentiated thyroid cancer in children and adolescents

In this retrospective study we analyzed cancer characteristics and outcome in a consecutive series of 48 young patients (< or =20 yr of age) with a differentiated thyroid cancer (DTC), observed during the period 1977-1998. In none of them was thyroid cancer related to ionizing radiation. The median age was 18.1 yr, range 7-20, and the female/male ratio was 2.5/1. Papillary thyroid cancer (PTC) occurred in 83% and follicular thyroid cancer (FTC) in 17% of cases. All patients underwent total or near total thyroidectomy plus pre- and/or paratracheal lymphnode dissection. Surgery complication rate was low (4% permanent hypoparathyroidism; no permanent lesion of recurrent laryngeal nerve). Extrathyroid disease was present in 52% of patients with PTC and in 50% of patients with FTC, while nodal metastases were present in 62.5% of patients with PTC and in 12.5% of patients with FTC. Lung metastases occurred in 10 patients with PTC (25%) and in none with FTC. Twenty-one patients required radioiodine treatment for metastatic disease: 11 patients for relapsing lymph-node metastases, 4 patients for lung metastases, 6 patients for both lymph-node and lung metastases. After a mean follow-up of 85+/-12 months all patients followed regularly (no.=47) were alive; 37 patients (79%) were free of disease and 10 (21%) had residual disease. Our results indicate that non-radiation-related DTC occurring in young patients often presents at an advanced stage. For this reason, although the prognosis is usually good in these patients, we believe that total or near total thyroidectomy with lymphadenectomy is always the required initial surgical treatment.

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.

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.