A Multifocal Pediatric Papillary Thyroid Carcinoma (PTC) Harboring the AGK-BRAF and RET/PTC3 Fusion in a Mutually Exclusive Pattern Reveals Distinct Levels of Genomic Instability and Nuclear Organization

Simple Summary

Genetic alterations, such as RET/PTC and AGK-BRAF fusions, are frequent events in pediatric papillary thyroid carcinoma (PTC). However, their role as prognostic markers in pediatric PTC is still under investigation. In this study, we present a patient harboring three tumor foci with distinct genetic alterations (AGK-BRAF, RET/PTC3 and an absence of canonical alterations) that were investigated for DNA structure and telomere-related genomic instability. These preliminary results highlight that AGK-BRAF fusion likely affects nuclear architecture, which might explain a more aggressive disease outcome observed in pediatric PTC cases with AGK-BRAF fusion.

Abstract

The spectrum and incidence of gene fusions in papillary thyroid carcinoma (PTC) can differ significantly depending on the age of onset, histological subtype or radiation exposure history. In sporadic pediatric PTC, RET/PTC1-3 and AGK-BRAF fusions are common genetic alterations. The role of RET/PTC as a prognostic marker in pediatric PTC is still under investigation. We recently showed that AGK-BRAF fusion is prevalent in young patients (mean 10 years) and associated with specific and aggressive pathological features such as multifocality and lung metastasis. In this pilot study, we report a unique patient harboring three different foci: the first was positive for AGK-BRAF fusion, the second was positive for just RET/PTC3 fusion and the third was negative for both rearrangements. To investigate whether AGK-BRAF and RET/PTC3 are associated with genomic instability and chromatin modifications, we performed quantitative fluorescence in situ hybridization (Q-FISH) of telomere repeats followed by 3D imaging analysis and 3D super-resolution Structured Illumination Microscopy (3D-SIM) to analyze the DNA structure from the foci. We demonstrated in this preliminary study that AGK-BRAF is likely associated with higher levels of telomere-related genomic instability and chromatin remodeling in comparison with RET/PTC3 foci. Our results suggest a progressive disruption in chromatin structure in AGK-BRAF-positive cells, which might explain a more aggressive disease outcome in patients harboring this rearrangement.

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

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

Cholestatic syndrome as initial manifestation of pancreatic metastasis of papillary thyroid carcinoma: case report and review

Most papillary thyroid carcinomas (PTC) harbor excellent prognosis. Although rare, distant metastases normally occur in lungs and/or bones. Here we describe a rare case of pancreatic metastasis presenting with rapid onset cholestatic syndrome. A literature review was also performed. A 73-year-old man with a high risk PTC was submitted to total thyroidectomy (TT) followed by radioiodine therapy. After initial therapy, he persisted with progressive rising serum thyroglobulin levels but with no evidence of structural disease. Recently, the patient presented with a rapid onset and progressive cholestatic syndrome. A 4 cm lesion in pancreas was identified, with echoendoscopy fine-needle aspiration biopsy (FNAB) confirming a pancreatic metastasis from PTC. The patient was submitted to a successful pancreaticoduodenectomy. Pancreatic metastases of PTC are rare and few long-term follow-up data are available to guide management. Fourteen cases were former reported, mean age was 65.7 years-old with mean time between PTC and pancreatic metastasis diagnosis of 7.9 years. Nine of them had another distant metastasis, nine were diagnosed by FNAB and just two received sorafenib.

Breast Cancer After Treatment of Differentiated Thyroid Cancer With Radioiodine in Young Females: What We Know and How to Investigate Open Questions. Review of the Literature and Results of a Multi-Registry Survey

Published studies on the risk of radiation-induced second primary malignancy (SPM) after radioiodine treatment (RAI) of differentiated thyroid cancer (DTC) refer mainly to patients treated as middle-aged or older adults and are not easily generalizable to those treated at a younger age. Here we review available literature on the risk of breast cancer as an SPM after RAI of DTC with a focus on females undergoing such treatment in childhood, adolescence, or young adulthood. Additionally, we report the results of a preliminary international survey of patient registries from academic tertiary referral centers specializing in pediatric DTC. The survey sought to evaluate the availability of sufficient patient data for a potential international multicenter observational case-control study of females with DTC given RAI at an early age. Our literature review identified a bi-directional association of DTC and breast cancer. The general breast cancer risk in adult DTC survivors is low, ~2%, slightly higher in females than in males, but presumably lower, not higher, in those diagnosed as children or adolescents than in those diagnosed at older ages. RAI presumably does not substantially influence breast cancer risk after DTC. However, data from patients given RAI at young ages are sparse and insufficient to make definitive conclusions regarding age dependence of the risk of breast cancer as a SPM after RAI of DTC. The preliminary analysis of data from 10 thyroid cancer registries worldwide, including altogether 6,449 patients given RAI for DTC and 1,116 controls, i.e., patients not given RAI, did not show a significant increase of breast cancer incidence after RAI. However, the numbers of cases and controls were insufficient to draw statistically reliable conclusions, and the proportion of those receiving RAI at the earliest ages was too low.In conclusion, a potential international multicenter study of female patients undergoing RAI of DTC as children, adolescents, or young adults, with a sufficient sample size, is feasible. However, breast cancer screening of a larger cohort of DTC patients is not unproblematic for ethical reasons, due to the likely, at most slightly, increased risk of breast cancer post-RAI and the expected ~10% false-positivity rate which potentially produced substantial "misdiagnosis."

Thyroid nodules ≤ 1 cm and papillary thyroid microcarcinomas: Brazilian experts opinion

The indolent evolution of low-risk papillary thyroid microcarcinoma (mPTC) in adult patients and the consequences of thyroidectomy require a revision of the management traditionally recommended. Aiming to spare patients unnecessary procedures and therapies and to optimize the health system in Brazil, we suggest some measures. Fine-needle aspiration of nodules ≤ 1 cm without extrathyroidal extension on ultrasonography should be performed only in nodules classified as "very suspicious" (i.e., high suspicion according to ATA, high risk according to AACE, TI-RADS 5) and in selected cases [age < 40 years, nodule adjacent to the trachea or recurrent laryngeal nerve (RLN), multiple suspicious nodules, presence of hypercalcitoninemia or suspicious lymph nodes]. Active surveillance (AS) rather than immediate surgery should be considered in adult patients with low-risk mPTC. Lobectomy is the best option in patients with unifocal low-risk mPTC who are not candidates for AS because of age, proximity of the tumor to the trachea or RLN, or because they opted for surgery. The same applies to patients who started AS but had a subsequent surgical indication not due to a suspicion of tumor extension beyond the gland or multicentricity. Molecular tests are not necessary to choose between AS and surgery or, in the latter case, between lobectomy and total thyroidectomy. The presence of RAS or other RAS-like mutations or BRAFV600E or other BRAF V600E-like mutations should not modify the management cited above; however, the rare cases of mPTC exhibiting high-risk mutations, like in the TERT promoter or p53, are not candidates for AS.

CA19-9 as a Predictor of Worse Clinical Outcome in Medullary Thyroid Carcinoma

OBJECTIVE

Medullary thyroid carcinoma (MTC) is a rare disease, and its classic tumor marker is calcitonin. However, recently, very aggressive cases have been reported to also secrete carbohydrate antigen 19-9 (CA19-9), and its role as a marker of worse prognosis has been questioned. The aim of this study was to analyze the relationship between CA19-9 serum levels and MTC outcomes.

METHODS

We retrospectively reviewed 122 MTC patients followed in a tertiary cancer center from 1985 to 2017. Clinical-pathologic characteristics, therapeutic approaches, and outcomes were recorded and CA19-9 was collected.

RESULTS

Of the 122 patients included in the study, 48 had distant metastases, and at the end of follow-up 18.1% had structural persistent disease and 32.7% had progressive disease. CA19-9 was significantly higher in those who had disease progression than in those who had not (21.4 [14.3-110.9] vs. 7.27 [0.6-44.75] U/mL, p = 0.01) and was also higher in patients who died from MTC (18.4 [14.3-110.9] vs. 7.59 [0.6-67.8] U/mL, p < 0.001). Furthermore, using a ROC curve analysis, the cutoff point for CA19-9 in MTC patients was lower than that observed in pancreatic tumors.

CONCLUSION

CA19-9 might have a role as a prognostic factor in addition to calcitonin and carcinoembryonic antigen in metastatic MTC.

AGK-BRAF is associated with distant metastasis and younger age in pediatric papillary thyroid carcinoma

BACKGROUND

The incidence of thyroid carcinoma has increased in most populations, including pediatric patients. The increase is almost exclusively due to an increase in the incidence of papillary thyroid carcinoma (PTC). Genetic alterations leading to mitogen-activated protein kinase (MAPK) pathway activation are highly prevalent in PTC, with BRAF V600E mutation being the most common event in adult PTC. Although a lower prevalence of BRAF V600E had been reported among pediatric patients, a higher prevalence of BRAF fusion has been identified in both radiation-exposed and sporadic pediatric PTC. However, little is known about the prognostic implications of BRAF fusions in pediatric PTC.

PROCEDURE

In this study, we investigated the prevalence of BRAF alterations (AGK-BRAF fusion and BRAF V600E mutation) in a large set of predominantly sporadic pediatric PTC cases and correlate with clinicopathological features. Somatic AGK-BRAF fusion was investigated by RT-PCR and confirmed by FISH break-apart. The BRAF V600E mutation was screened using Sanger sequencing.

RESULTS

AGK-BRAF fusion, found in 19% of pediatric PTC patients, was associated with distant metastasis and younger age. Conversely, the BRAF V600E, found in 15% of pediatric PTC patients, was correlated with older age and larger tumor size.

CONCLUSION

Collectively, our results advance knowledge concerning genetic bases of pediatric thyroid carcinoma, with potential implications for diagnosis, prognosis, and therapeutic approaches.

Serum calcitonin nadirs to undetectable levels within 1 month of curative surgery in medullary thyroid cancer

OBJECTIVE

Because serum calcitonin (CT) is a reliable marker of the presence, volume, and extent of disease in medullary thyroid cancer (MTC), both the ATA and NCCN guidelines use the 2-3 month post-operative CT value as the primary response to therapy variable that determines the type and intensity of follow up evaluations. We hypothesized that the calcitonin would nadir to undetectable levels within 1 month of a curative surgical procedure.

SUBJECTS AND METHODS

This retrospective review identified 105 patients with hereditary and sporadic MTC who had at least two serial basal CT measurements done in the first three months after primary surgery.

RESULTS

When evaluated one year after initial surgery, 42 patients (42/105, 40%) achieved an undetectable basal calcitonin level without additional therapies and 56 patients (56/84, 67%) demonstrated a CEA within the normal reference range. In patients destined to have an undetectable CT as the best response to initial therapy, the calcitonin was undetectable by 1 month after surgery in 97% (41/42 patients). Similarly, in patients destined to have a normalize their CEA, the CEA was within the reference range by 1 month post-operatively in 63% and by 6 months in 98%. By 6 months after curative initial surgery, 100% of patients had achieved a nadir undetectable calcitonin, 98% had reached the CEA nadir, and 97% had achieved normalization of both the calcitonin and CEA.

CONCLUSION

The 1 month CT value is a reliable marker of response to therapy that allows earlier risk stratification than the currently recommended 2-3 month CT measurement.

Clinical Assessment and Risk Stratification in Differentiated Thyroid Cancer

Thyroid cancer management is rapidly evolving to a personalized management approach. Risk stratification systems are designed to assist in personalized management. Differentiating patients who may benefit from aggressive therapy and intense follow-up as opposed to those who can be successfully treated with minimalized initial management options and follow-up is crucial to the development of the right treatment plan for the right patient in order to optimize initial therapy and follow-up testing. This article aims to describe and discuss the risk stratification systems currently recommended for differentiated thyroid cancer.

Genotype and phenotype landscape of MEN2 in 554 medullary thyroid cancer patients: the BrasMEN study

Multiple endocrine neoplasia type 2 (MEN2) is an autosomal dominant genetic disease caused by RET gene germline mutations that is characterized by medullary thyroid carcinoma (MTC) associated with other endocrine tumors. Several reports have demonstrated that the RET mutation profile may vary according to the geographical area. In this study, we collected clinical and molecular data from 554 patients with surgically confirmed MTC from 176 families with MEN2 in 18 different Brazilian centers to compare the type and prevalence of RET mutations with those from other countries. The most frequent mutations, classified by the number of families affected, occur in codon 634, exon 11 (76 families), followed by codon 918, exon 16 (34 families: 26 with M918T and 8 with M918V) and codon 804, exon 14 (22 families: 15 with V804M and 7 with V804L). When compared with other major published series from Europe, there are several similarities and some differences. While the mutations in codons C618, C620, C630, E768 and S891 present a similar prevalence, some mutations have a lower prevalence in Brazil, and others are found mainly in Brazil (G533C and M918V). These results reflect the singular proportion of European, Amerindian and African ancestries in the Brazilian mosaic genome.

The Impact of Zoledronic Acid and Radioactive Iodine Therapy on Morbi-Mortality of Patients with Bone Metastases of Thyroid Cancer Derived from Follicular Cells

OBJECTIVE

Bone metastases bring greater morbi-mortality to patients with differentiated thyroid carcinoma (DTC). Treatment was limited to radioactive iodine (RAI) and local approaches. Currently, bisphosphonates are included in the therapeutic arsenal. The aim of this study is to evaluate the impact of bone metastases and their treatment with zoledronic acid (ZA) and RAI therapy.

METHODS

We retrospectively review 50 DTC patients with structurally evident bone metastases followed in a tertiary cancer center from 1994 to 2018. Clinical-pathologic characteristics, skeletal related events (SRE), and therapeutic approaches were recorded.

RESULTS

Among the 50 patients analyzed, 22 underwent ZA adjuvant therapy and 28 did not. Mortality rate was 44%. Those patients presented SREs more frequently (90.9 vs. 67.9% the survival group, p = 0.05) and also had a greater number of bone lesions (40.9 vs. 10.7% had more than 6 metastatic sites, p = 0.03). The same group of patients was analyzed before and after therapy with ZA and the incidence of SRE decreased from 1.81 (0-8) before therapy to 0.29 (0-7) after therapy (p = 0.006). Comparing similar groups of 22 patients treated with ZA with 28 patients not treated, there was a trend of better overall survival (OS) in the group that received this drug (147 vs. 119 months, p = 0.06) and significantly improvement when bone metastases were RAI avid 155 (125-185) versus 120 (85-157) months, p < 0.01. Conclusion : ZA can successfully diminish the chance of having new SRE and possibly affect OS in DTC patients with bone metastases. The positive impact of RAI adjuvant treatment on OS is directly associated with RAI uptake.

TERTp mutation is associated with a shorter progression free survival in patients with aggressive histology subtypes of follicular-cell derived thyroid carcinoma

PURPOSE

Evaluate the impact of TERTp mutation on the outcomes after initial treatment of 45 patients with thyroid carcinomas derived from follicular cells (TCDFC) with aggressive histology, in which the role of this mutation is not yet well defined.

METHODS

Analysis of the presence of TERTp (-124C > T and -146C > T), BRAF (V600E), and NRAS (Q 61R) mutations by Sanger sequencing and analysis of their correlation with the patient's outcomes.

RESULTS

Forty-five patients with aggressive histopathologic variants were included in the study. Of these, 68.9% had aggressive variants of papillary thyroid cancer (PTC), 22.2% had poorly differentiated thyroid carcinoma (PDTC)/insular carcinoma, and 8.9% had invasive follicular thyroid cancer (FTC) with Hurthle cell features (Hurthle cell carcinoma). Lymph node metastases were present in 46.7% and distant metastases in 54.6%. The response to the initial therapy was excellent in 45.5% and structurally incomplete in 50%. During the follow-up period (median of 56 months; 5-360 months), 47.7% presented with disease progression and 17.8% experienced disease-related death. In 53.3% of the cases at least one molecular alteration (TERTp in 33.4%, BRAF in 24.5%, RAS in 8.9%) was detected. In the multivariate analysis, TERTp mutation was the factor associated with the highest risk (6 times) of having structural disease after initial therapy (p = 0.01), followed by vascular invasion (p = 0.02), gross extrathyroidal extension (ETE) (p = 0.02) and distant metastasis (p = 0.04). Regarding mutational status, only TERTp mutation was associated with disease progression, and diminished disease progression-free survival (PFS). The presence of distant metastasis, vascular invasion and gross ETE were significantly associated with the risk of disease progression.

CONCLUSIONS

TERTp mutation appears be an indicator of both persistence and progression of structural disease after initial therapy in aggressive variants of TCDFC, and associates with a shorter progression free survival regardless of the therapy employed.

Clinical outcomes of low and intermediate risk differentiated thyroid cancer patients treated with 30mCi for ablation or without radioactive iodine therapy

OBJECTIVE

To retrospectively evaluate the outcomes of patients with low and intermediate risk thyroid carcinoma treated with total thyroidectomy (TT) and who did not undergo radioiodine remnant ablation (RRA) and to compare them to patients receiving low dose of iodine (30 mCi).

SUBJECTS AND METHODS

A total of 189 differentiated thyroid cancer (DTC) patients treated with TT followed by 30mCi for RRA or not, followed in two referral centers in Brazil were analyzed.

RESULTS

From the 189 patients, 68.8% was ATA low-risk, 30.6% intermediate and 0.6% high risk. Eighty-seven patients underwent RRA and 102 did not. The RRA groups tended to be younger and had a higher frequency of extra-thyroidal extension (ETE). RRA did not have and impact on response to initial therapy neither in low (p = 0.24) nor in intermediate risk patients (p = 0.66). It also had no impact on final outcome and most patients had no evidence of disease (NED) at final follow-up. Recurrence/persistence of disease was found in 1.2% of RRA group and 2% in patients treated only with TT (p = 0.59).

CONCLUSIONS

Our study shows that in low and intermediate-risk patients, RRA with 30 mCi seems to have no major advantage over patients who did not undergo RRA regarding response to initial therapy in each risk group and also in long term outcomes.

Somatostatin receptor subtype 1 might be a predictor of better response to therapy in medullary thyroid carcinoma

PURPOSE

Medullary thyroid carcinoma (MTC) is a malignant neoplasm of parafollicular cells. Because it is a neuroendocrine tumor, it has known somatostatin receptors (SSTRs). The actual frequencies of the SSTR subtypes and their potential influences (by binding with endogenous somatostatin) on MTC cell proliferation have not been fully elucidated to date. The present study evaluated the occurrence of SSTR subtypes 1, 2, 3 and 5 as well as the possible role that each subtype plays in the clinical evolution of patients with MTC.

METHODS

This retrospective, longitudinal study analyzed thyroid surgical material from 42 patients with MTC. Immunohistochemical staining was performed with monoclonal antibodies against subtypes 1, 2, 3 and 5 of SSTR. The histological material was classified as negative, focal positive or diffuse positive, in relation to each of the SSTR subtypes. The initial response to treatment, clinical course and patient mortality rate were assessed and related to the presence of SSTR subtypes.

RESULTS

The most prevalent SSTR subtype was SSTR 3, which was found in 81% of the patients, when considering any pattern of positivity. However, subtype 2 had the lowest number of positive patients, with 28.6% demonstrating any positive pattern. Subtypes 1 and 5 had an intermediate prevalence of positivity, with subtype 1 present in 45.2% of the patients and subtype 5 positive in 54.8% of the patients, when considering any pattern of positivity. The presence of STR 1, in the form of diffuse positivity, independently predicted a better response to the initial therapy, with a hazard ratio (HR) of 4.80 (p = 0.03).

CONCLUSION

This is the first study to show the correlation of the presence of SSTR1, detected by monoclonal immunohistochemical techniques, and better response to initial treatment and possibly better long-term clinical response in patients with MTC. In addition, these patients had low positivity rates for SSTR2, which might explain the low sensitivity of diagnostic and limited therapeutic response to octrotide based radioisotopes.

Metastatic lymph node characteristics as predictors of recurrence/persistence in the neck and distant metastases in differentiated thyroid cancer

OBJECTIVE

The aim of this study was to evaluate the association between this characteristic and outcomes in patients with lymph node metastasis in a Brazilian cohort.

SUBJECTS AND METHODS

This study examined a retrospective cohort of adult patients diagnosed with differentiated thyroid cancer and lymph node metastases from 1998 to 2015 in two referral centers. Number, location, size and extranodal extension (ENE) of metastatic lymph nodes were assessed and correlated with response to initial therapy.

RESULTS

A greater number of metastatic nodes, larger size, presence of lateral neck disease and ENE were all associated with a lower probability of achieving an excellent response to initial therapy (p ≤ 0.05 for all these parameters). Local recurrent disease had a significant association with lymph node number (6 in the recurrence/persistence group versus 4 in the non-recurrent group; p = 0.02) and ENE (19.2 versus 75%, p = 0.03). Lateral neck disease was the only characteristic associated with distant metastasis and was present in 52.1% of the group without metastasis and 70.4% of the group with metastasis (p = 0.001).

CONCLUSION

The lymph node characteristics were associated with response to initial therapy and neck recurrence/persistence, confirming the importance of the analysis of these factors in risk stratification in a Brazilian population and its possible use to tailor initial staging and long term follow-up.

Molecular Markers Involved in Tumorigenesis of Thyroid Carcinoma: Focus on Aggressive Histotypes

Thyroid cancer derived from follicular cells (TCDFC) comprises well-differentiated (papillary and follicular) carcinoma, poorly differentiated carcinoma, and anaplastic carcinoma. Papillary thyroid carcinoma is the most common endocrine cancer, and its incidence is steadily increasing. Lethality and aggressiveness of TCDFC is inversely correlated with differentiation degree. In this review, an emphasis has been put on molecular markers involved in tumorigenesis of thyroid carcinoma with a focus on aggressive histotypes and the role of such biomarkers in predicting thyroid cancer outcome. Genetic rearrangements in TCDFC (RET/PTC, PAX8/PPARG) and mutations in RAS, BRAF, TERT promoter (TERTp), TP53, PIK3CA, and AKT1 are discussed. The majority of the studies to date indicate that TERTp mutations can serve as a marker of more aggressive disease in all the subtypes of thyroid carcinoma, being the best current marker of poor prognosis, due to its independent association with distant metastases and increased disease-specific mortality. Some studies suggested that a more accurate prediction of thyroid cancer outcome may be possible through a more extensive genetic analysis. The same is true concerning the identification of other mutations that are only relatively frequent in advanced tumors (e.g., TP53, PIK3CA, or AKT1). A better understanding of the prognostic role of TERTp mutation (together with additional ones like BRAF, RAS, PIK3CA, AKT1, or TP53) and the clarification of their putative role in fine-needle aspiration biopsies are likely to allow, in the future, an early refinement of the stratification risk in patients with well-differentiated carcinomas. It is worth noting that, as with any categorical staging system, the risk evaluation within each category (low, intermediate, and high) varies depending on the specific clinicopathologic features of individual patients and the specific biological behavior of the tumor. Finally, besides the diagnostic and/or prognostic significance of the above-mentioned mutations, it is crucial to understand that the molecular pathways and epigenetic alterations will likely turn into interesting targets for new therapies.

Prognostic Factors for Early and Long-Term Remission in Pediatric Differentiated Thyroid Carcinoma: The Role of Sex, Age, Clinical Presentation, and the Newly Proposed American Thyroid Association Risk Stratification System

BACKGROUND

The incidence of pediatric differentiated thyroid carcinoma (DTC) has been rising in recent years, and the main risk factors for recurrence are lymph node and distant metastasis at diagnosis. Other clinical features remain unclear, such as the impact of age, sex, and puberty. Furthermore, until now, this population has been treated using the same strategies used to treat adults. In 2015, the American Thyroid Association (ATA) published the first guidelines targeted at this age group. The aims of this study were to investigate the prognostic factors for early and long-term remission and also to validate the ATA risk stratification proposal in a population outside the United States.

METHODS

Clinical records from 118 patients <18 years old followed in two referral centers were reviewed. The median age was 12 years (range 4-18 years), and 20.3% (24 patients) were <10 years old at diagnosis. The median follow-up was 9.1 years. The majority were female (72%) and received total thyroidectomy and radioiodine therapy (RAI), and 61.8% were treated with more than one dose of RAI. The majority were classified as high risk (48.3%) by the new ATA pediatric guidelines due to distant metastasis (30 patients) or extensive lymph node involvement (27 patients). The remained were classified as low risk (31.3%) and intermediate risk (20.4%).

RESULTS

Females with no lymph node or distant metastasis and low ATA pediatric risk were more likely to have no evidence of disease (p < 0.05) within the first year and also in the long term. In this study, age did not significantly predict outcomes. Furthermore, patients also benefitted from multiple doses of RAI, but when the cumulative activity was >400 mCi, this benefit was diminished.

CONCLUSIONS

This study shows that the ATA risk stratification proposal for pediatric patients is useful in predicting early and long-term outcomes in pediatric patients with DTC. In addition, it shows that sex and metastatic disease are important prognostic factors in pediatric populations.

Dynamic Risk Stratification in Patients with Differentiated Thyroid Cancer Treated Without Radioactive Iodine

CONTEXT

Although response to therapy assessment is a validated tool for dynamic risk stratification in patients with differentiated thyroid cancer (DTC) treated with total thyroidectomy (TT) and radioactive iodine therapy (RAI), it has not been well studied in patients treated with lobectomy or TT without RAI. Because these responses to therapy definitions are heavily dependent on serum thyroglobulin (Tg) levels, modifications of the original definitions were needed to appropriately classify patients treated without RAI.

OBJECTIVE

This study aimed to validate the response to therapy assessment in patients with DTC treated with lobectomy or TT without RAI.

DESIGN AND SETTING

This was a retrospective study, which took place at a referral center.

PATIENTS

A total of 507 adults with DTC were treated with lobectomy (n = 187) or TT (n = 320) without RAI. They had a median age of 43.7 y, 88% were female, 85.4% had low risk, and 14.6% intermediate risk.

MAIN OUTCOME MEASURE

Main outcome measured was recurrent/persistent structural evidence of disease (SED) during a median followup period of 100.5 months (24-510).

RESULTS

Recurrent/persistent SED was observed in 0% of the patients with excellent response to therapy (nonstimulated Tg for TT < 0.2 ng/mL and for lobectomy < 30 ng/mL, undetectable Tg antibodies [TgAb] and negative imaging; n = 326); 1.3% with indeterminate response (nonstimulated Tg for TT 0.2-5 ng/mL, stable or declining TgAb and/or nonspecific imaging findings; n = 2/152); 31.6% of the patients with biochemical incomplete response (nonstimulated Tg for TT > 5 ng/mL and for lobectomy > 30 ng/mL and/or increasing Tg with similar TSH levels and/or increasing TgAb and negative imaging; n = 6/19) and all (100%) patients with structural incomplete response (n = 10/10) (P < .0001). Initial American Thyroid Association risk estimates were significantly modified based on response to therapy assessment.

CONCLUSIONS

Our data validate the newly proposed response to therapy assessment in patients with DTC treated with lobectomy or TT without RAI as an effective tool to modify initial risk estimates of recurrent/persistent SED and better tailor followup and future therapeutic approaches. This study provides further evidence to support a selective use of RAI in DTC.

An International Multi-Institutional Validation of Age 55 Years as a Cutoff for Risk Stratification in the AJCC/UICC Staging System for Well-Differentiated Thyroid Cancer

BACKGROUND

Age is a critical factor in outcome for patients with well-differentiated thyroid cancer. Currently, age 45 years is used as a cutoff in staging, although there is increasing evidence to suggest this may be too low. The aim of this study was to assess the potential for changing the cut point for the American Joint Committee on Cancer/Union for International Cancer Control (AJCC/UICC) staging system from 45 years to 55 years based on a combined international patient cohort supplied by individual institutions.

METHODS

A total of 9484 patients were included from 10 institutions. Tumor (T), nodes (N), and metastasis (M) data and age were provided for each patient. The group was stratified by AJCC/UICC stage using age 45 years and age 55 years as cutoffs. The Kaplan-Meier method was used to calculate outcomes for disease-specific survival (DSS). Concordance probability estimates (CPE) were calculated to compare the degree of concordance for each model.

RESULTS

Using age 45 years as a cutoff, 10-year DSS rates for stage I-IV were 99.7%, 97.3%, 96.6%, and 76.3%, respectively. Using age 55 years as a cutoff, 10-year DSS rates for stage I-IV were 99.5%, 94.7%, 94.1%, and 67.6%, respectively. The change resulted in 12% of patients being downstaged, and the downstaged group had a 10-year DSS of 97.6%. The change resulted in an increase in CPE from 0.90 to 0.92.

CONCLUSIONS

A change in the cutoff age in the current AJCC/UICC staging system from 45 years to 55 years would lead to a downstaging of 12% of patients, and would improve the statistical validity of the model. Such a change would be clinically relevant for thousands of patients worldwide by preventing overstaging of patients with low-risk disease while providing a more realistic estimate of prognosis for those who remain high risk.

Is radioactive iodine- 131 treatment related to the occurrence of non-synchronous second primary malignancy in patients with differentiated thyroid cancer?

OBJECTIVE

Much controversy relates to the risk of non-synchronous second primary malignancies (NSSPM) after radioactive iodine treatment (RAI-131) in differentiated thyroid cancer (DTC) patients. This study evaluated the relationship between RAI-131 and NSSPM in DTC survivors with long-term follow-up.

MATERIALS AND METHODS

Retrospective analysis of 413 DTC cases was performed; 252 received RAI-131 and 161 were treated with thyroidectomy alone. Exclusion criteria were: prior or synchronous non-thyroidal malignancies (within the first year), familial syndromes associated to multiple neoplasms, ionizing radiation exposure or second tumors with unknown histopathology.

RESULTS

During a mean follow-up of 11.0 ± 7.5 years, 17 (4.1%) patients developed solid NSSPM. Patients with NSSPM were older than those without (p = 0.02). RAI-131 and I-131 cumulative activity were similar in patients with and without NSSPM (p = 0.18 and p = 0.78, respectively). Incidence of NSSPM was 5.2% in patients with RAI-131 treatment and 2.5% in those without RAI-131 (p = 0.18). Using multivariate analysis, RAI-131 was not significantly associated with NSSPM occurrence (p = 0.35); age was the only independent predictor (p = 0.04). Under log rank statistical analysis, after 10 years of follow-up, it was observed a tendency of lower NSSPM-free survival among patients that received RAI-131 treatment (0.96 vs . 0.87; p = 0.06), what was not affected by age at DTC diagnosis.

CONCLUSION

In our cohort of DTC survivors, with a long-term follow-up period, RAI-131 treatment and I-131 cumulative dose were not significantly associated with NSSPM occurrence. A tendency of premature NSSPM occurrence among patients treated with RAI-131 was observed, suggesting an anticipating oncogenic effect by interaction with other risk factors.

A new appraisal of iodine refractory thyroid cancer

Thyroid cancer incidence is increasing all over the world - mostly due to an increase in the detection of small tumors that were previously undetected. A small percentage of these tumors lose the ability to uptake and/or to respond to radioiodine (RAI) therapy, especially in metastatic patients. There are several new therapeutic options that have emerged in the last 5 years to treat RAI refractory thyroid cancer patients, however, it is very important to properly identify RAI refractory patients and to clarify those appropriate for these treatments. In this review, we discuss the RAI refractory definitions and the criteria that have been suggested based on RAI uptake in the post therapy scan, as well as the response after RAI therapy and the possible molecular mechanisms involved in this process. We offer a review of the therapeutic options available at the moment and the therapeutic considerations based on a patient's individualized personal characteristics, primary tumor histology, tumor burden and location and velocity of lesion growth.

Survival from Differentiated Thyroid Cancer: What Has Age Got to Do with It?

BACKGROUND

In most staging systems, 45 years of age is used to differentiate low risk thyroid cancer from high risk thyroid cancer. However, recent studies have questioned both the precise 45 year age point and the concept of using a binary cut off as accurate predictors of disease specific mortality.

METHODS

A cohort of 3664 thyroid cancer patients that received surgery and adjuvant treatment at Memorial Sloan Kettering Cancer Center (MSKCC) from the years 1985 to 2010 were analyzed to determine the significance of age at diagnosis as a categorical variable at a variety of age cutoffs (5 year intervals between 30 and 70 years of age). The unadjusted and adjusted hazard ratio for the association between disease-specific survival and age was determined using a Cox proportional hazards model adjusted for other predictive variables sex, histology, and pathological T, N, and M status. Furthermore, predictive nomograms of disease-specific mortality were created and validated on an external dataset of 4551 patients to evaluate the impact of age at diagnosis as both a categorical and continuous variable.

RESULTS

In the MSKCC cohort, with a median follow-up time of 54 months (range 1-332), there were 59 deaths from thyroid cancer with a 10 year disease-specific survival of 96%. Adjusted hazard ratios for all age cutoffs from age 30 to age 70 years were significant. There was no specific cutoff age which risk stratifies patients with differentiated thyroid cancer (DTC). Categorizing age into five strata (<40, 40-49, 50-59, 60-69 and >70 years) showed a 37-fold increase in hazard ratio from age <40 years to age >70 years. A predictive nomogram using age as a continuous variable with other predictive variables had a high concordance index of 96%. Validation on the external cohort had a concordance index of 73%.

CONCLUSIONS

Mortality from DTC increases progressively with advancing age. There is no specific cutoff age which risk stratifies patients with DTC. A predictive nomogram using age as a continuous variable may be a more appropriate tool for stratifying patients with DTC and for predicting outcome.

Surgical approach and radioactive iodine therapy for small well-differentiated thyroid cancer

BACKGROUND

Management of small well-differentiated thyroid cancer (DTC) has generated much debate regarding the surgical approach and radioactive iodine treatment (RAI).

AIM

The aim of the study was to evaluate the impact of surgical extension and RAI on the outcome of DTC ≤2 cm.

METHODS

A retrospective analysis of 176 cases of DTC ≤2 cm was performed.

RESULTS

At diagnosis, tumor size was 1.38 ± 0.55 cm, age 40.2 ± 13.6 years. After a mean follow-up period of 14.1 ± 4.5 years, 15.9 % patients had recurrent/persistent structural disease, with cervical neck disease (thyroid gland area and/or cervical lymph nodes) in 11.9 % cases and distant metastasis in 5.1 %. Disease specific mortality was of 1.1 %. No difference in outcome was observed between patients submitted to total or subtotal thyroidectomy. After total and subtotal thyroidectomy, the rate of recurrent/persistent structural disease was 19.1 and 10.6 % (p = 1.00), respectively. Using the multivariate cox proportion hazards analysis, no difference in the clinical outcome was observed after total or subtotal thyroidectomy (p = 0.703) neither after RAI (p = 0.807). Similar results were observed after stratification by tumor size. Multifocal disease (p = 0.007), extra-thyroid extension (p = 0.007) and presence of lymph node metastasis (p = 0.000) were associated with unfavorable outcome.

CONCLUSIONS

Total thyroidectomy and RAI did not improve clinical outcomes of DTC ≤2.0 cm when compared with less extensive surgery and no RAI in selected patients. Therefore, in carefully selected patients with DTC ≤2.0 cm and no unfavorable risk factors (multifocal disease, extra-thyroid extension, lymph node and/or distant metastasis), less extensive surgery and no RAI may be acceptable treatment options.