Thyroid cancer recurrence in patients clinically free of disease with undetectable or very low serum thyroglobulin values

Comparison of Prognostic Value Between Stimulated and Nonstimulated Thyroglobulins in Differentiated Thyroid Cancer: A Retrospective Study

Purpose

The growing incidence of differentiated thyroid cancer (DTC) demands dependable prognostic factors to guide follow-up and treatment plans. This study investigated the prognostic value of response to therapy (RTT) assessment using TSH stimulated-thyroglobulin (sti-Tg) and nonstimulated-thyroglobulin (nonsti-Tg) and evaluates whether RTT using nonsti-Tg (nonstiRTT) can replace RTT using sti-Tg (stiRTT) in clinical practice to improve patients' quality of life during assessment.

Methods

We enrolled 419 DTC patients who underwent total thyroidectomy, radioactive iodine (RAI) therapy, and Tg assessment. Patients with structural incomplete responses were excluded. Initial RTT assessments based on the 2015 American Thyroid Association guidelines (excellent response; ER, indeterminate response, biochemical incomplete response) were performed 6-24 months after RAI therapy. The second RTT assessments were performed 6-24 months after the first assessment. Statistical analysis for recurrence-free survival (RFS) was done with the log-rank test for stiRTT and nonstiRTT.

Results

Although initial stiRTT and nonstiRTT were significant predictors for RFS (p < 0.0001), stiRTT provided better RFS prediction than nonstiRTT. The RFS analysis of the second RTT assessment demonstrated statistical significance only for stiRTT (p < 0.0001). In 116 patients classified as ER on initial stiRTT, there was no RFS difference between patients classified as ER on either second stiRTT or nonstiRTT.

Conclusion

The prognostic power of stiRTT surpasses that of nonstiRTT in both the initial and second RTT assessment. Nevertheless, among patients classified as ER on initial stiRTT, a second stiRTT may not be required for those classified as ER on the second nonstiRTT.

Supplementary Information

The online version contains supplementary material available at 10.1007/s13139-023-00811-8.

Thyroglobulin and thyroglobulin antibodies: assay-dependent management consequences in patients with differentiated thyroid carcinoma

OBJECTIVES

International guidelines recommend fixed cut-off values for thyroglobulin (Tg). These cut-offs do not take potential assay differences into account. This study aimed to evaluate if different assays for Tg and Tg antibodies (TgAb) affect management guidance for differentiated thyroid cancer (DTC) patients.

METHODS

In 793 samples derived from 413 patients with DTC, Tg and TgAb were simultaneously measured with two immunometric assays: Immulite 2000XPi and Kryptor compact plus. In addition, a qualitative measurement for TgAb interference (recovery test) was performed on the Kryptor compact plus platform. The extent to which different assays lead to different classifications of response to therapy was evaluated when applying the current cut-offs for Tg.

RESULTS

Mean Tg concentrations were 37.4% lower with Kryptor as compared with Immulite. Applying guideline based cut-off values for Tg, 33 (4.7%) samples had a Tg-on concentration ≥1.0 μg/L with Immulite and <1.0 μg/L with Kryptor. Of the samples tested as TgAb+ with at least one assay (n=125), 68 (54.4%) samples showed discrepancy in TgAb status. Differences between Immulite and Kryptor measurements resulted in a change in the response to therapy classification in 94 (12.0%) measurements derived from 67 (16.2%) individual patients.

CONCLUSIONS

A substantial portion of DTC patients were classified differently dependent on which Tg and TgAb assays are used, when applying the cut-off values as defined in clinical guidelines. Such differences can significantly affect clinical management. In the context of large between-method variation, the recommended Tg cut-offs in guidelines should be used with wisdom rather than as fixed cut-offs.

Can ultrasensitive thyroglobulin immunoassays avoid the need for ultrasound in thyroid cancer follow-up?

PURPOSE

Differentiated thyroid cancer (DTC) is the most common endocrine neoplasm, with a rising incidence and a long life expectancy. It has recently been suggested that patients with low- and intermediate-risk DTC with a good response to treatment at one year could be followed up using only highly sensitive immunoassays for thyroglobulin (Tg). The aim of this study was to examine the serum Tg levels in a series of DTC patients with histologically proven persistent or recurrent diseases.

METHODS

The study involved 50 consecutive patients being routinely followed up at our center, whose clinical, histological, and biochemical data were retrospectively collected.

RESULTS

The false-negative rate of ultrasensitive serum Tg assay was 14.3% (5/35) overall, and limited to anti-thyroglobulin autoantibodies (TgAb)-negative patients. Among them, only one patient had an excellent response to treatment at one-year follow-up and was diagnosed with a 4 mm recurrence, after more than seven years of periodic ultrasounds. The size of the neck lesion documented in the histological report was slightly larger in patients with detectable as opposed to negative Tg values (P < 0.05).

CONCLUSIONS

Serum highly sensitive Tg is undetectable in a proportion of patients with a proven persistent or recurrent DTC. The reasons behind this phenomenon are still unknown. However, in low/intermediate-risk patients cured at one-year follow-up, highly sensitive Tg without neck US seems an appropriate strategy for patients' management.

Undetectable thyroglobulin makes 123I whole-body scan and stimulated thyroglobulin obsolete in follow-up care of differentiated thyroid cancer: a retrospective study

Background

Differentiated thyroid cancer (DTC) is a common malignancy with increasing incidence. Follow-up care for DTC includes thyroglobulin (Tg) measurement and ultrasound (US) of the neck, combined with ¹³¹I remnant ablation when indicated. Diagnostic precision has evolved with the introduction of the new high-sensitive Tg-assays (sensitivity ≤0.1 ng/mL). The aim of the study was to determine the prognostic utility of high-sensitive Tg and the need for other diagnostic tests in DTC.

Methods

This was a retrospective, observational study. Patients with pathologically confirmed DTC, treated with total thyroidectomy and ¹³¹I remnant ablation, who had their complete follow-up care in our institution were selected (October 2013–December 2018). Subjects with possible thyroglobulin autoantibody interference were excluded. Statistical analysis was performed using the IBM SPSS® Statistics 24 software package.

Results

Forty patients were eligible for analysis. A total of 24 out of the 40 patients (60%) had an undetectable high-sensitive Tg 6 months after total thyroidectomy. None of these patients had a stimulated Tg above 1 ng/mL, or remnant on the ¹²³I Whole-Body Scan (WBS) after 1 year of follow-up. Ultrasound of the neck, performed between 6 and 12 months postoperative, was negative in 21 out of the 24 patients.

Conclusions

This study shows that an undetectable high-sensitive Tg can change the management of patients with DTC and decrease the use and need of stimulated Tg and ¹²³I WBS.

Prognostic Value of Serum Thyroglobulin Measured at 48 Hours Versus 72 Hours after Second Dose of Recombinant Human Thyrotropin in Surveillance of Well-Differentiated Thyroid Cancer

OBJECTIVE

The sensitivity of thyroglobulin (Tg) to detect differentiated thyroid cancer recurrence increases with the rise of the thyrotropin level. Since 1998, recombinant human thyrotropin (rhTSH) has been commercially available for this purpose. The traditional protocol for using rhTSH calls for 2 daily injections of rhTSH, followed by the measurement of Tg 72 hours after the second dose. In this study, we compared the performance of rhTSH-stimulated Tg (rhTSH-Tg) obtained at 48 versus 72 hours after the second rhTSH.

METHODS

A retrospective chart review of 1088 patients with thyroid cancer was conducted. Two hundred forty-nine rhTSH-Tg, without measurable Tg antibody, were identified, 134 of which were obtained at 48 hours (4-day test) and 115 at 72 hours after the second rhTSH (5-day test). The ability of rhTSH-Tg to identify recurrence or persistence of differentiated thyroid cancer and to predict response to therapy at the end of the study period was compared between the 2 groups.

RESULTS

The median duration of follow-up was 8 years. When recurrent/persistent cancer was present based on a combination of unstimulated Tg, imaging and procedures, the ratio of rhTSH-Tg ≥ 1 ng/mL was similar in both groups (P value: .153). The negative predictive value of rhTSH-Tg to predict response to therapy over the long term was 95% or higher in 4-day and 5-day tests.

CONCLUSION

Tg measured 48 and 72 hours after the second dose of rhTSH may provide a comparable prognostic value. These results encourage further studies to identify new protocols to obtain rhTSH-Tg.

Unstimulated Serum Thyroglobulin Levels after Thyroidectomy and Radioiodine Therapy for Intermediate-Risk Thyroid Cancer Are Not Always a Reliable Marker of Lymph Node Recurrence: Case Report and a Lesson for Clinicians

Over 50% of patients with papillary thyroid carcinoma (PTC) have cervical lymph-node metastasis on diagnosis, and up to 30% show nodal recurrence after surgery plus radioactive iodine (131I) (RAI) therapy. The combination of ultrasonography (US) and fine-needle aspiration cytology (FNAC) and the measurement of thyroglobulin (Tg) in washout fluid are cornerstones in the diagnosis of nodal metastasis. In the absence of anti-Tg antibodies, unstimulated serum thyroglobulin (Tg) levels are generally a reliable marker of recurrent disease, and 18F-FDG positron emission tomography (PET)/computed tomography (CT) plays an important role in the imaging work-up. We report the case of a 65-year-old man evaluated for a large multinodular goitre which caused compressive symptoms; the dominant nodule in the left lobe presented suspicious features on US. Thyroid function showed subclinical hypothyroidism, calcitonin was normal, serum thyroglobulin levels were low, and anti-thyroid antibodies were absent. The prevalent left nodule showed an intense uptake on 18F-FDG PET/CT but proved benign at FNAC. On the basis of the suspicious clinical and imaging features, total thyroidectomy was performed. Histology revealed a tall-cell variant of PTC with scattered expression of Tg and diffuse high expression of cytokeratin (CK) 19; RAI therapy was performed. Within 6 years of surgery, left laterocervical lymph-node recurrence was twice detected (first at levels II and III, then at levels IV and VI) by US and 18F-FDG-PET/CT and was confirmed by FNAC. Tg levels in the washout fluid proved clearly diagnostic of metastasis only in the second, larger, recurrence, whereas serum Tg levels (in the absence of anti-Tg antibodies) always remained undetectable on L-thyroxine therapy. Surgery was performed on both recurrences, and histology confirmed lymph-node metastasis of PTC. Immunohistochemical expression of Tg and CK 19 was similar to that of the primary tumour. No further relapses have occurred to date. Posttherapy (surgery and RAI) unstimulated serum Tg levels may not be a reliable marker of nodal recurrence in patients with differentiated thyroid cancer (DTC) that produces low amounts of Tg.

Utility of Stimulated Thyroglobulin in Reclassifying Low Risk Thyroid Cancer Patients' Following Thyroidectomy and Radioactive Iodine Ablation: A 7-Year Prospective Trial

CONTEXT

Following total thyroidectomy and radioactive iodine (RAI) ablation, serum thyroglobulin levels should be undetectable to assure that patients are excellent responders and at very low risk of recurrence.

OBJECTIVE

To assess the utility of stimulated (sTg) and non-stimulated (nsTg) thyroglobulin levels in prediction of patients outcomes with differentiated thyroid cancer (DTC) following total thyroidectomy and RAI ablation.

METHOD

A prospective observational study conducted at a University Hospital in Saudi Arabia. Patients diagnosed with differentiated thyroid cancer and were post total thyroidectomy and RAI ablation. Thyroglobulin levels (nsTg and sTg) were estimated 3-6 months post-RAI. Patients with nsTg <2 ng/ml were stratified based on their levels and were followed-up for 5 years and clinical responses were measured.

RESULTS

Of 196 patients, nsTg levels were <0.1 ng/ml in 122 (62%) patients and 0.1-2.0 ng/ml in 74 (38%). Of 122 patients with nsTg <0.1 ng/ml, 120 (98%) had sTg levels <1 ng/ml, with no structural or functional disease. sTg levels >1 occurred in 26 (35%) of patients with nsTg 0.1-2.0 ng/ml, 11 (15%) had structural incomplete response. None of the patients with sTg levels <1 ng/ml developed structural or functional disease over the follow-up period.

CONCLUSION

Suppressed thyroglobulin (nsTg < 0.1 ng/ml) indicates a very low risk of recurrence that does not require stimulation. Stimulated thyroglobulin is beneficial with nsTg 0.1-2 ng/ml for re-classifying patients and estimating their risk for incomplete responses over a 7 years follow-up period.

Re-treatment With Adjuvant Radioactive Iodine Does Not Improve Recurrence-Free Survival of Patients With Differentiated Thyroid Cancer

Introduction: Loco regional persistence or recurrence of differentiated thyroid cancer (DTC) is frequent despite initial thyroidectomy and radioactive iodine therapy (RAI). The aim of this study was to analyze the impact of a complementary adjuvant RAI (Ad-RAI) on disease recurrence following re-operation on patients with locally persistent or recurrent DTC. Patients and Methods: A retrospective study of 85 patients with DTC was conducted. All patients were initially treated with total thyroidectomy and RAI, and re-operated for a locally persistent or recurrent disease. Propensity score was calculated to predict the impact of Ad-RAI on survival after reoperation, and to reduce the bias of the limited sample size and the prognostic tests. Results: 49 (58%) patients were re-treated with Ad-RAI after re-operation while 36 (42%) were only followed up. Disease recurrence after re-treatment (re-operation ± Ad-RAI) was detected in 31 patients (36.5%). In multivariate analysis, age >55 years (HR: 3.9 [1.6; 9.5]; p < 0.00001) was the main poor prognostic factor for recurrence-free survival. Three parameters independently influenced the decision to administer ad-RAI: low number of previous RAI administrations, Nx before re-operation, and pTg > 30 μg/l. These parameters were incorporated in the Propensity score calculation. If ad-RAI tended to improve recurrence-free survival (median survival 17.4 vs. 10.9 months), adjustment using the Propensity score removed any difference between the groups (p = 0.54), confirming the limited value of ad-RAI. Conclusion: In patients with locally persistent or recurrent DTC, age is the main independent prognostic factor. Adjuvant RAI does not improve recurrence-free survival of DTC patients.

The Use of Post-ablation Stimulated Thyroglobulin in Predicting Clinical Outcomes in Differentiated Thyroid Carcinoma - What Cut-off Values Should We Use?

AIMS

Recently published international guidelines recommended using the stimulated thyroglobulin (sTg) post-radioactive iodine (RAI) ablation, in conjunction with tumour stage, as a risk stratification factor. The choice of cut-off values for sTg, namely 1 and 10 ng/ml, was, however, largely based on the functional sensitivities of the assays used, with relatively few published data addressing the prognostic impact of alternative cut-off values. Our study aims to provide data on the prognostic value of sTg at different levels of sensitivities and specificities.

MATERIALS AND METHODS

We conducted a retrospective review of all adult cases of differentiated thyroid carcinoma receiving RAI ablation at our centre from 2008 to 2010. All patients had sTg measured at around 6 months post-ablation. The functional sensitivity of our assay was 0.5 ng/ml. The outcome was adverse clinical event, defined as cancer-related death, persistent macroscopic disease demonstrable on imaging (including radioisotope scan) and/or receiving further treatment for persistent or recurrent disease. A receiver operating characteristic (ROC) analysis was carried out.

RESULTS

We identified 140 patients treated in the review period, with 106 of them suitable for further analysis. The reasons for exclusion included the presence of anti-thyroglobulin antibodies and medullary or anaplastic histological subtypes. Most (54.7%) had intermediate-risk disease as per the American Thyroid Association classification (2009). The median follow-up duration was 6.4 years; the minimum, excluding deaths, was 5.0 years. ROC analysis showed that the optimal cut-off value of sTg for predicting adverse clinical events was >1.0 ng/ml, associated with a sensitivity of 90.9%, a specificity of 81.0%, a positive predictive value of 55.6% and a negative predictive value of 97.1%.

CONCLUSION

Based on ROC analysis of sensitivities and specificities, our data showed that a post-ablation sTg value of 1 ng/ml is the optimal cut-off in prognostication of adverse clinical events.

THYROGLOBULIN AS A TUMOR MARKER IN DIFFERENTIATED THYROID CANCER - CLINICAL CONSIDERATIONS

SUMMARY – Initial treatment of the majority of patients with differentiated thyroid cancer (DTC) includes total thyroidectomy. Postoperative ablation therapy with radioactive iodine (I-131) is indicated in all high-risk patients, however, there is disagreement regarding its use in low- and intermediate-risk patients. Over the last few decades, thyroglobulin (Tg) has been established as the primary biochemical tumor marker for patients with DTC. Thyroglobulin can be measured during thyroid hormone therapy or after thyroid-stimulating hormone (TSH) stimulation, through thyroid hormone withdrawal or the use of human recombinant TSH. In many studies, the cut-off value for adequate Tg stimulation is a TSH value ≥30 mIU/L. However, there is an emerging body of evidence suggesting that this long-established standard should be re-evaluated, bringing this threshold into question. Recently, a risk stratification system of response to initial therapy (with four categories) has been introduced and Tg measurement is one of the main components. The relationship between the Tg/TSH ratio and the outcome of radioiodine ablation has also been studied, as well as clinical significance of serum thyroglobulin doubling-time. The postoperative serum Tg value is an important prognostic factor that is used to guide clinical management, and it is the most valuable tool in long term follow-up of patients with DTC.

Circulating epithelial cells in patients with thyroid carcinoma

Goal: To investigate whether circulating epithelial cells (CEC) recognized via the epithelial cell adhesion molecule (EpCAM) can be identified in the blood of patients with thyroid carcinoma, given that CEC have already been detected in other types of carcinoma and are considered a potential marker of tumour dissemination. Patients, methods: Blood samples of patients with active differentiated thyroid carcinoma (DTC) (n = 50) were compared to samples of patients with: a) recent surgical excision of a thyroid carcinoma (postOP-DTC) (n = 16); b) athyreotic, tumour-free status after radioiodine ablation (AT-DTC) (n= 33); and c) benign thyroid diseases (BTD) (n = 51). Samples of volunteers with normal thyroid parameters (NT) (n = 12) were also investigated. Cells from EDTAblood were subjected to erythrocyte lysis, isolated by centrifugation, and incubated with a fluorescence-labeled antibody against EpCAM. The numbers of vital cells were counted via fluorescence microscopy. Results: CEC were identified in all groups, with the postOP-DTC group showing the highest mean CEC numbers of all groups. The DTC group had significantly higher CEC numbers than the NT group, and numerically higher numbers than the other groups, although not reaching statistical significance. Within the DTC group there was a correlation between levels of serum thyroglobulin and numbers of CEC (r = 0.409, p = 0.003). Conclusions: High CEC numbers were not specific to thyroid carcinoma. The methodology used here, based on a single measurement does not allow to identify severe forms of DTC, emphasizing the need of longitudinal measurements throughout therapy. Detection and characterization of tumour thyroid cells in circulation should be based on additiona l consideration of tissue-specific characteristics.

Improved follow-up of patients with differentiated thyroid carcinoma

Aim: Physicians typically are unaware of the radioiodine uptake (RIU) detection limit (LoD) on scintigrams of differentiated thyroid carcinoma (DTC) patients. We evaluated a novel method to determine LoD as a quantitative upper limit for RIU in negative scans and as a value to contextualize faint visible uptake. Patients, methods: To test whether LoD is related to physicians’ ratings, RIU and LoD were calculated from scintigraphic count statistics for 120 static planar neck scans and were compared with the ratings of five nuclear medicine specialists blinded to patient/ scan characteristics regarding visible cervical uptake. Scans were acquired on days 1 (d1) and 2 (d2) post-administration of 298 ± 30 MBq iodine-131 in 60 consecutive DTC patients after recombinant human thyrotropin (rhTSH) or thyroid hormone withdrawal (THW) (n = 30 each). Results: Indicating good inter-observer agreement, ≥ 4 readers concurred regarding 56 (93.3%) [54 (90.0%)] d1[d2] scans. Seventeen scans from 12 patients received ≥ 3 positive votes; in 15 (88.2%), RIU exceeded LoD. RIU assessed from regions-of-interest over former thyroid beds in scans with ≤ 2 positive votes was typically below the LoD (99/103 scans, 96.1%). In 48 patients with ≤ 2 positive votes in both scans, LoD was a median 0.0094% (0.0050%) in d1(d2) images and was significantly lower (p < 0.01) on early or late scans in 22 euthyroid rhTSH patients versus 26 hypo thyroid THW patients. Conclusion: LoD data obtained by the proposed method closely reflect nuclear medicine specialists’ scan ratings and provide comparators in serial scintigrams, improving diagnostic 131I imaging accuracy in differentiated thyroid carcinoma.

Higher preablative serum thyroid-stimulating hormone level predicts radioiodine ablation effectiveness in patients with differentiated thyroid carcinoma

INTRODUCTION

Radioiodine ablation of remnant thyroid tissue is an important adjuvant therapy of differentiated thyroid carcinoma (DTC) after thyroidectomy. Elevated serum thyroid-stimulating hormone (TSH) level is necessary for successful ablation. The optimum level of serum TSH level necessary for successful radioiodine ablation of well-DTC is, however, yet to be defined. We aimed to determine whether higher serum TSH level will result in a better rate of complete ablation of well-DTC using iodine-131 (I) following initial thyroidectomy.

PATIENTS AND METHODS

A total of 109 patients with differentiated thyroid cancer were divided into four treatment groups on the basis of serum TSH levels. They were followed up from 6 to 12 months after treatment with stimulated serum thyroglobulin level and a diagnostic whole-body scan with radioactive iodine I to determine early response.

RESULTS

Sixty-four patients had papillary thyroid carcinoma, whereas 45 patients had follicular carcinoma. An excellent response was observed in 66.7% of patients with TSH level more than 90 μIU/ml, 72.2% in the group with TSH level of 60-89 μIU/ml, 48.5% when TSH was 30-59 μIU/ml and 26.7% when TSH was less than 30 μIU/ml (P=0.002).

CONCLUSION

Higher preablative serum TSH predicts a better rate of ablation in patients with differentiated thyroid cancer treated with I after thyroidectomy.

Thyroglobulin levels and thyroglobulin/thyrotropin ratio could predict the success of the ablative/therapeutic 131I in the differentiated thyroid cancers

BACKGROUND

Stimulated thyroglobulin (STg) levels in patients with differentiated thyroid carcinomas (DTCs) after total thyroidectomy (TT) and before radioactive iodine (¹³¹I) ablation/therapy (RIT) are predictive of therapeutic success but can be influenced by the thyroid-stimulating hormone (TSH) level.

OBJECTIVES

This study compared the reliability of the STg/TSH ratio and STg measurement in predicting the success of RIT.

METHODS

Sixty-three DTC patients submitted to TT were assessed retrospectively to compare the ability of STg level and the STg/TSH ratio to predict successful RIT.

RESULTS

In this study 48 (76.2%) patients had successful RIT. The successful and unsuccessful groups received different ¹³¹I doses and had different STg levels and STg/TSH ratios. The STg and STg/TSH ratio cutoff values that predicted successful RIT were 4.41 ng/mL (sensitivity of 86.7% and specificity of 77%) and 0.093 (sensitivity of 80% and specificity of 79.2%), respectively. Age, STg level, STg/TSH ratio, and ¹³¹I dose were associated with successful RIT, but after multivariate analysis only STg remained associated (p < 0.05).

CONCLUSION

In conclusion, our data suggest that the STg/TSH ratio and measurement of STg are equally reliable in predicting successful RIT in DTC patients.

Papillary thyroid carcinomas with biochemical incomplete or indeterminate responses to initial treatment: repeat stimulated thyroglobulin assay to identify disease-free patients

Papillary thyroid cancer (PTC) patients treated with thyroidectomy and radioiodine remnant ablation (RRA) often have detectable TSH-stimulated thyroglobulin (Tg) levels without localizable disease after primary treatment. To assess the value of repeat stimulated Tg assays in these patients' follow-up, we retrospectively analyzed 86 cases followed in 5 Italian thyroid-cancer referral centers. We enrolled 86 patients with PTCs treated with total/near-total thyroidectomy plus RRA between January 1,1990 and January 31, 2006. In all cases, the initial postoperative visit revealed stimulated serum Tg ≥1 ng/mL, negative Tg antibodies, and no structural evidence of disease. None received empiric radioiodine therapy. Follow-up (median: 9.6 years) included neck ultrasound and basal Tg assays (yearly) and at least 1 repeat stimulated Tg assay. Of the 86 patients analyzed (initial risk: low 63 %, intermediate 35 %, high 2 %), one (1 %) had ultrasound-detected lymph node disease and persistently elevated stimulated Tg levels at 3 years. In 17 (20 %), imaging findings were consistently negative, but the final stimulated Tg levels was still >1 ng/mL (median 2.07 ng/mL, range 1.02-4.7). The other 68 (80 %) appeared disease-free (persistently negative imaging findings with stimulated Tg levels ≤1 ng/mL). Mean intervals between first and final stimulated Tg assays were similar (5.2 and 4.8 years) in subgroups with versus without Tg normalization. Reclassification as disease-free was significantly more common when initial stimulated Tg levels were indeterminate (<10 ng/mL). In unselected PTC cohorts with incomplete/indeterminate biochemical responses to thyroidectomy and RRA, periodic remeasurement of stimulated Tg allows most patients to be classified as disease-free.

Management of Differentiated Thyroid Cancer in Children: Focus on the American Thyroid Association Pediatric Guidelines

First introduced in 1946, radioactive iodine (I-131) produces short-range beta radiation with a half-life of 8 days. The physical properties of I-131 combined with the high degree of uptake in the differentiated thyroid cancers (DTCs) led to the use of I-131 as a therapeutic agent for DTC in adults. There are two indications for the potential use of I-131 therapy in pediatric thyroid disorders: nonsurgical treatment of hyperthyroidism owing to Graves' disease and the treatment of children with intermediate- and high-risk DTC. However, children are not just miniature adults. Not only are children and the pediatric thyroid gland more sensitive to radiation than adults but also the biologic behavior of DTC differs between children and adults as well. As opposed to adults, children with DTC typically present with advanced disease at diagnosis; yet, they respond rapidly to therapy and have an excellent prognosis that is significantly better than that in adult counterparts with advanced disease. Unfortunately, there are also higher rates of local and distant disease recurrence in children with DTC compared with adults, mandating lifelong surveillance. Further, children have a longer life expectancy during which the adverse effects of I-131 therapy may become manifest. Recognizing the differences between adults and children with DTC, the American Thyroid Association commissioned a task force of experts who developed and recently published a guideline to address the unique issues related to the management of thyroid nodules and DTC in children. This article reviews the epidemiology, diagnosis, staging, treatment, therapy-related effects, and suggestions for surveillance in children with DTC, focusing not only on the differences between adults and children with this disease but also on the latest recommendations from the inaugural pediatric management guidelines of the American Thyroid Association.

2015 American Thyroid Association Management Guidelines for Adult Patients with Thyroid Nodules and Differentiated Thyroid Cancer: The American Thyroid Association Guidelines Task Force on Thyroid Nodules and Differentiated Thyroid Cancer

BACKGROUND

Thyroid nodules are a common clinical problem, and differentiated thyroid cancer is becoming increasingly prevalent. Since the American Thyroid Association's (ATA's) guidelines for the management of these disorders were revised in 2009, significant scientific advances have occurred in the field. The aim of these guidelines is to inform clinicians, patients, researchers, and health policy makers on published evidence relating to the diagnosis and management of thyroid nodules and differentiated thyroid cancer.

METHODS

The specific clinical questions addressed in these guidelines were based on prior versions of the guidelines, stakeholder input, and input of task force members. Task force panel members were educated on knowledge synthesis methods, including electronic database searching, review and selection of relevant citations, and critical appraisal of selected studies. Published English language articles on adults were eligible for inclusion. The American College of Physicians Guideline Grading System was used for critical appraisal of evidence and grading strength of recommendations for therapeutic interventions. We developed a similarly formatted system to appraise the quality of such studies and resultant recommendations. The guideline panel had complete editorial independence from the ATA. Competing interests of guideline task force members were regularly updated, managed, and communicated to the ATA and task force members.

RESULTS

The revised guidelines for the management of thyroid nodules include recommendations regarding initial evaluation, clinical and ultrasound criteria for fine-needle aspiration biopsy, interpretation of fine-needle aspiration biopsy results, use of molecular markers, and management of benign thyroid nodules. Recommendations regarding the initial management of thyroid cancer include those relating to screening for thyroid cancer, staging and risk assessment, surgical management, radioiodine remnant ablation and therapy, and thyrotropin suppression therapy using levothyroxine. Recommendations related to long-term management of differentiated thyroid cancer include those related to surveillance for recurrent disease using imaging and serum thyroglobulin, thyroid hormone therapy, management of recurrent and metastatic disease, consideration for clinical trials and targeted therapy, as well as directions for future research.

CONCLUSIONS

We have developed evidence-based recommendations to inform clinical decision-making in the management of thyroid nodules and differentiated thyroid cancer. They represent, in our opinion, contemporary optimal care for patients with these disorders.

Management Guidelines for Children with Thyroid Nodules and Differentiated Thyroid Cancer

BACKGROUND

Previous guidelines for the management of thyroid nodules and cancers were geared toward adults. Compared with thyroid neoplasms in adults, however, those in the pediatric population exhibit differences in pathophysiology, clinical presentation, and long-term outcomes. Furthermore, therapy that may be recommended for an adult may not be appropriate for a child who is at low risk for death but at higher risk for long-term harm from overly aggressive treatment. For these reasons, unique guidelines for children and adolescents with thyroid tumors are needed.

METHODS

A task force commissioned by the American Thyroid Association (ATA) developed a series of clinically relevant questions pertaining to the management of children with thyroid nodules and differentiated thyroid cancer (DTC). Using an extensive literature search, primarily focused on studies that included subjects ≤18 years of age, the task force identified and reviewed relevant articles through April 2014. Recommendations were made based upon scientific evidence and expert opinion and were graded using a modified schema from the United States Preventive Services Task Force.

RESULTS

These inaugural guidelines provide recommendations for the evaluation and management of thyroid nodules in children and adolescents, including the role and interpretation of ultrasound, fine-needle aspiration cytology, and the management of benign nodules. Recommendations for the evaluation, treatment, and follow-up of children and adolescents with DTC are outlined and include preoperative staging, surgical management, postoperative staging, the role of radioactive iodine therapy, and goals for thyrotropin suppression. Management algorithms are proposed and separate recommendations for papillary and follicular thyroid cancers are provided.

CONCLUSIONS

In response to our charge as an independent task force appointed by the ATA, we developed recommendations based on scientific evidence and expert opinion for the management of thyroid nodules and DTC in children and adolescents. In our opinion, these represent the current optimal care for children and adolescents with these conditions.

Ability of the rhTSH stimulation test to predict relapse in patients with differentiated thyroid carcinoma, after long-term follow-up

The analysis of serum thyroglobulin (Tg) following thyroid-stimulating hormone (TSH) stimulation (sTg) has been recommended in the follow-up of differentiated thyroid carcinoma (DTC) patients, however, its routine use remains controversial. The aim of the current study was to evaluate the accuracy of sTg testing following recombinant human (rh) TSH stimulation in DTC patients, with a follow-up of 12.4 years. Retrospective studies were conducted of 125 DTC patients, who underwent rhTSH stimulation testing between 1999 and 2002. The exclusion criteria were: Patients with anti-Tg antibodies, Tg levels >1 ng/ml under TSH suppression and the absence of radioactive iodine (RAI) ablation therapy following surgery. In total, 49 patients were included in the study and all had been previously treated with total or near total thyroidectomy (with or without central neck dissection) and RAI, postoperatively. The Tg functional sensitivity was 1.0 ng/ml. The follow-up for patients was performed annually. During the median follow-up of 12.4 years after the rhTSH stimulation test, nine patients exhibited recurrence (18.4%). Of the nine patients, six exhibited sTg levels >2 ng/ml (positive result) and three exhibited levels <2 ng/ml (negative result). Relapse occurred at a mean of 5.9 years following the rhTSH stimulation test. The positive predictive value and negative predictive value (NPV) of positive sTg were 50 and 91.9%, respectively, with a sensitivity of 66.6% and a specificity of 85.0%. The rhTSH-stimulated Tg levels have a high NPV, allowing the identification of the patients who are free of the tumour. These results are consistent with the previously published data; however, to the best of our knowledge, this is the study with the longest follow-up duration after rhTSH stimulation.

Management of recurrent/persistent nodal disease in patients with differentiated thyroid cancer: a critical review of the risks and benefits of surgical intervention versus active surveillance

BACKGROUND

The primary goals of this interdisciplinary consensus statement are to define the eligibility criteria for management of recurrent and persistent cervical nodal disease in patients with differentiated thyroid cancer (DTC) and to review the risks and benefits of surgical intervention versus active surveillance.

METHODS

A writing group was convened by the Surgical Affairs Committee of the American Thyroid Association and was tasked with identifying the important clinical elements to consider when managing recurrent/persistent nodal disease in patients with DTC based on the available evidence in the literature and the group's collective experience.

SUMMARY

The decision on how best to manage individual patients with suspected recurrent/persistent nodal disease is challenging and requires the consideration of a significant number of variables outlined by the members of the interdisciplinary team. Here we report on the consensus opinions that were reached by the writing group regarding the technical and clinical issues encountered in this patient population.

CONCLUSIONS

Identification of recurrent/persistent disease requires a team decision-making process that includes the patient and physicians as to what, if any, intervention should be performed to best control the disease while minimizing morbidity. Several management principles and variables involved in the decision making for surgery versus active surveillance were developed that should be taken into account when deciding how best to manage a patient with DTC and suspected recurrent or persistent cervical nodal disease.

Update on differentiated thyroid cancer staging

In this review, we demonstrate how initial estimates of the risk of disease-specific mortality and recurrent/persistent disease should be used to guide initial treatment recommendations and early management decisions and to set appropriate patient expectations with regard to likely outcomes after initial therapy of thyroid cancer. The use of ongoing risk stratification to modify these initial risk estimates is also discussed. Novel response to therapy definitions are proposed that can be used for ongoing risk stratification in thyroid cancer patients treated with lobectomy or total thyroidectomy without radioactive iodine remnant ablation.

Low but measurable stimulated serum thyroglobulin levels <2 µg/L frequently predict incomplete response in differentiated thyroid cancer patients

INTRODUCTION

The study was aimed to determine the response and predictive risk factors of differentiated thyroid cancer (DTC) with measurable (0.4-2.0 µg/L) stimulated serum thyroglobulin (sTg) during the 10-24 months after radioiodine remnant ablation (RRA) and their long-term outcomes.

METHODS

Out of 839 retrospectively reviewed patients, 95 eligible DTC patients were included. Patients were classified as having incomplete response or no evidence of disease (NED). The sTg cut-off values with highest predicted accuracy for incomplete response at 10-24 months were calculated with receiver operator characteristics curve analysis.

RESULTS AND CONCLUSION

At 10-24 months after RRA, incomplete response was identified in 54 patients (57%) and 38/54 (70.4%) patients were found with structural evidence of disease. The remaining 16 patients (29.6%) had biochemical evidence of disease without structural evidence of disease. Forty-one patients (43%) were classified as having NED at 10-24 months after RRA and 27 patients (66%) did not receive further radioactive iodine (RAI) therapy and remained disease free at median follow-up of 6.5 years. Fourteen patients received second RAI treatment after 6 months and before the 10-24 months assessment time point. Of these, 2 had persistent tumor 6 years later. The sTg >0.6 µg/L at 6-10 months after RRA had optimal sensitivity (83.3%), specificity (56%) and negative predictive value (72%) of detecting incomplete response at 10-24 months after RRA. A total of 23/43 patients in the American Thyroid Association low-risk category had incomplete response after first RRA and 5/23 (21.7%) had recurrent/persistent disease at long-term follow-up.

Remnant uptake as a postoperative oncologic quality indicator

BACKGROUND

The purpose of this study was to examine the utility of remnant uptake on postoperative radioiodine scans as an oncologic indicator after thyroidectomy for differentiated thyroid cancer (DTC).

METHODS

We conducted a retrospective review of patients undergoing total thyroidectomy for DTC and subsequent radioactive iodine (RAI) treatment. Of the eight surgeons included, three were considered high volume, performing at least 20 thyroidectomies per year. Patients with distant metastases at diagnosis or poorly differentiated variants were excluded. To control for the effect of varying RAI doses, the remnant uptake was analyzed as a ratio of the percentage uptake to the dose received (uptake to dose ratio [UDR]). Multivariate logistic regression was used to determine the influence of UDR on recurrence.

RESULTS

Of the 223 patients who met inclusion criteria, 21 patients (9.42%) experienced a recurrence. Those with a recurrence had a 10-fold higher UDR compared with those who did not (0.030 vs. 0.003, p=0.001). Similarly, patients with increasing postoperative thyroglobulin measurements (0.339 vs. 0.003, p<0.001) also had significantly greater UDRs compared with those with stable thyroglobulin. The UDRs of high-volume surgeons were significantly smaller than low-volume surgeons (0.003 vs. 0.025, p=0.002). When combined with other known predictors for recurrence, UDR (OR 3.71 [95%CI 1.05-13.10], p=0.041) was significantly associated with recurrence. High-volume surgeons maintained a low level of permanent complications across all UDRs, whereas low-volume surgeons had greater permanent complications associated with higher uptake.

CONCLUSIONS

Remnant uptake is a useful postoperative oncologic quality indicator that can predict a patient's risk of disease recurrence and indicate the completeness of resection.

German Association of Endocrine Surgeons practice guideline for the surgical management of malignant thyroid tumors

INTRODUCTION

Over the past years, the incidence of thyroid cancer has surged not only in Germany but also in other countries of the Western hemisphere. This surge was first and foremost due to an increase of prognostically favorable ("low risk") papillary thyroid microcarcinomas, for which limited surgical procedures are often sufficient without loss of oncological benefit. These developments called for an update of the previous practice guideline to detail the surgical treatment options that are available for the various disease entities and tumor stages.

METHODS

The present German Association of Endocrine Surgeons practice guideline was developed on the basis of clinical evidence considering current national and international treatment recommendations through a formal expert consensus process in collaboration with the German Societies of General and Visceral Surgery, Endocrinology, Nuclear Medicine, Pathology, Radiooncology, Oncological Hematology, and a German thyroid cancer patient support organization.

RESULTS

The practice guideline for the surgical management of malignant thyroid tumors includes recommendations regarding preoperative workup; classification of locoregional nodes and terminology of surgical procedures; frequency, clinical, and histopathological features of occult and clinically apparent papillary, follicular, poorly differentiated, undifferentiated, and sporadic and hereditary medullary thyroid cancers, thyroid lymphoma and thyroid metastases from primaries outside the thyroid gland; extent of thyroidectomy; extent of lymph node dissection; aerodigestive tract resection; postoperative follow-up and surgery for recurrence and distant metastases.

CONCLUSION

These evidence-based recommendations for surgical therapy reflect various "treatment corridors" that are best discussed within multidisciplinary teams and the patient considering tumor type, stage, progression, and inherent surgical risk.

In thyroidectomized patients with thyroid cancer, a serum thyrotropin of 30 μU/mL after thyroxine withdrawal is not always adequate for detecting an elevated stimulated serum thyroglobulin

BACKGROUND

The thyrotropin (TSH) level or duration of thyroid hormone withdrawal (THW) required to detect stimulated thyroglobulin (Tg) in differentiated thyroid cancer (DTC) monitoring is unknown. The objective of this study was to evaluate the TSH cutoff of >30 μU/mL as a means to detect stimulated Tg ≥2 ng/mL after THW (THW-Tg≥2), and sensitivity of the Functional Assessment of Chronic Illness Therapy-Fatigue (FACIT-F) questionnaire for detecting hypothyroid symptoms.

METHODS

This was a prospective longitudinal cohort study done at a tertiary academic medical center. Forty-seven patients with DTC undergoing their first Tg stimulation or after previously abnormal Tg stimulation had weekly measurements of TSH and Tg during the 4 weeks THW, and repeated questionnaire assessments.

RESULTS

TSH did not reach a plateau in any patient, and in those whose Tg did not remain undetectable, Tg continued to rise. Seventy-five percent of patients had an undetectable Tg <0.2 ng/mL at baseline (95% were <0.5 mg/mL) with 16% remaining undetectable throughout THW. The majority of patients (72.7% and 97.8%) achieved TSH >30 μU/mL by 3 and 4 weeks THW, respectively. Of the 15 patients with maximum stimulated THW-Tg≥2, 38% were detected before the minimal TSH >30 μU/mL cutoff. At 2 weeks THW, 3 had a TSH>30 μU/mL, and none of them had Tg ≥2 ng/mL. At 3 weeks THW, 11 had a TSH >30 μU/mL, and 64% of them had Tg ≥2 ng/mL. Only 60% were detected at 3-week THW regardless of their TSH level. Eighty-six percent were detected by TSH 60-<80 μU/mL. Conversely, all patients whose serum Tg was <0.2 ng/mL when their serum TSH was >20 μU/mL did not achieve a THW-Tg≥2.

CONCLUSION

The minimal TSH cutoff of >30 μU/mL was inadequate to detect many patients with final stimulated THW-Tg≥2 during complete THW. TSH >80-100 μU/mL was a better cutoff, achieved in only 53% after 4-week THW. Conversely, we propose a preliminary THW-stopping rule for ending THW early in selected patients. In patients with a Tg <0.2 ng/mL when TSH >20 μU/mL, all had a final stimulated Tg ≤2 ng/mL, potentially saving qualifying patients 40% of THW duration compared to 4-week THW. FACIT-F correlated with TSH, but was not sensitive to detect mild hypothyroidism.

Lymph node ratio predicts recurrence in papillary thyroid cancer

BACKGROUND

Lymph node metastasis occurs in 20%-50% of patients presenting for initial treatment of papillary thyroid cancer (PTC). The significance of lymph node metastases remains controversial, and the aim of this study is to determine how the lymph node ratio (LNR) may predict the likelihood of disease recurrence.

METHODS

We conducted a retrospective review of patients undergoing total thyroidectomy for PTC at our institution from 2005 to 2010. A total LNR (positive nodes to total nodes) and central lymph node ratio (cLNR) was calculated. Regression was used to determine a threshold LNR that best predicted recurrence. Multivariate logistic regression then determined the influence of LNR on recurrence while accounting for other known predictors of recurrence. Kaplan-Meier analysis and the log-rank test were used to compare differences in disease-free survival.

RESULTS

Of the 217 patients undergoing total thyroidectomy for PTC, 69 patients had concomitant neck dissections. Sixteen (23.2%) patients developed disease recurrence. When disease-free survival functions were compared, we found that patients with a total LNR ≥0.7 (p < .01) or a cLNR ≥0.86 (p = .04) had significantly worse disease-free survival rates than patients with ratios below these threshold values. Considering other known predictors of recurrence, we found that LNR was significantly associated with recurrence (odds ratio: 19.5, 95% confidence interval: 4.1-22.9; p < .01).

CONCLUSIONS

Elevated total LNR and cLNR are strongly associated with recurrence of PTC after initial operation. LNR in PTC is a tool that can be used to determine the likelihood of the patient developing recurrent disease and inform postoperative follow-up.

Long-term consequence of elevated thyroglobulin in differentiated thyroid cancer

BACKGROUND

Serum thyroglobulin (Tg) is the most sensitive biomarker for recurrence of differentiated thyroid cancer (DTC). We have assessed the changing pattern of stimulated Tg (sTg) and the clinical course of patients with no structural evidence of disease (NSED), based on imaging studies such as neck ultrasonography (US), fluorodeoxyglucose positron emission tomography, and/or chest computed tomogram (CT). We sought to determine if, in patients with DTC who had been treated with bilateral thyroidectomy and remnant ablation with radioactive iodine, sTg 1 year (sTg1) after initial treatment and repeated sTg measurements, 1-2 years after sTg1, helped predict the long-term outcome with respect to structural recurrence and biochemical remission (BR), which is defined as sTg <1 ng/mL.

METHODS

We retrospectively assessed the records of patients with DTC who had been treated with bilateral thyroidectomy and remnant ablation with radioactive iodine between 1995 and 2004. The study included 186 patients who had NSED with sTg1 ≥2 ng/mL and subsequent sTg measurements (sTg2) without additional treatment. Patients were classified into three groups based on their sTg1 measurements: Group A, 2-4.9 ng/mL; Group B, 5-19.9 ng/mL; and Group C, ≥20 ng/mL. Patients were also classified into two groups based on whether sTg2, 1-2 years after sTg1, had decreased by ≥50% (Group 1) or had either decreased by <50% or increased (Group 2). sTg was measured every 1-2 years until structural recurrence or BR.

RESULTS

Patients remaining in NSED showed a decrease in serial sTg. Of patients in Groups A, B, and C, 41%, 17%, and 1%, respectively, achieved BR, and there was a significant difference in the BR rate between Groups 1 and 2 (p<0.001). In patients with structural recurrence, serial sTg generally did not decrease from sTg1. There was a significant difference in the recurrence rate among Groups A, B, and C (p=0.005) and between Groups 1 and 2 (p<0.001).

CONCLUSIONS

We found that 41% of patients with sTg1 in the range 2-5 ng/mL achieved BR, and that sTg1 and percent change of subsequent sTg were predictive of BR. Repeated sTg measurements are useful for predicting patient prognosis in patients with DTC.

Update in utility of secondary node dissection for papillary thyroid cancer

BACKGROUND

Detection of recurrent/persistent thyroid cancer has improved significantly in the past decade. Disease is detected earlier in recently treated patients and localized in patients long out from initial treatment. This update reviews recent literature regarding the utility of secondary node dissection for papillary thyroid carcinoma. Outcomes include disease-free status measured biochemically and clinically.

RESULTS

The utility of secondary node dissection as measured by clinically detectable disease exceeds 70% for all series and 90% for most. The utility as measured biochemically is more modest, with rates of biochemical cure ranging from 27-81% depending upon strictness of definition and patient selection. In predominately radioiodine scan-negative patients, using the strictest definition of biochemical cure, undetectable stimulated thyroglobulin (Tg) of less than 0.5 ng/ml, a rate of 27% is reported. Biochemical cure rates are reportedly 30-51% for stimulated Tg of less than 2 ng/ml and 56-71% for basal Tg of less than 2 ng/ml, with higher preoperative Tg levels less likely to achieve biochemical cure. Radioiodine-avid disease appears more amenable to cure, with 81% of patients achieving negative stimulated Tg after repeat I131 treatment and radio-assisted surgery. Complication rates of secondary nodal surgery appear similar to initial surgery in experienced hands; however, bilateral reoperative central neck dissection is associated with significantly higher complication rates than unilateral.

SUMMARY

Surgical resolution of clinically detectable disease is likely. Biochemical cure rates are more modest, with the greatest likelihood of biochemical cure occurring in patients with radioiodine-avid disease. In radioiodine-negative patients, there may be a higher likelihood of biochemical cure for those with lower preoperative detectable Tg levels.

Long-term clinical outcome of differentiated thyroid cancer patients with undetectable stimulated thyroglobulin level one year after initial treatment

BACKGROUND

Measurement of the serum thyroglobulin (Tg) level with TSH stimulation (sTg) is the cornerstone of monitoring for the recurrence or persistence of differentiated thyroid cancer (DTC) in patients who have undergone surgery and remnant ablation. However, there have been several reports that an undetectable sTg could not predict the absence of future recurrence. The aim of this study was to evaluate the long-term outcome of DTC patients who achieved biochemical remission (BR, defined as sTg<1 ng/mL) after initial treatment, and to determine the role of repeated sTg measurement in detecting a clinical recurrence.

METHODS

This is a retrospective observational cohort study in a tertiary referral hospital. There were 1010 DTC patients who achieved BR at 12 months after the initial treatment (surgery and ablation), and they were eligible for analysis. Among them, 787 patients had values of repeated sTg.

RESULTS

Thirteen out of 1010 (1.3%) patients had clinical recurrences during a median 84 months of follow-up. All of the clinical recurrences were limited to the cervical lymph nodes without clinical evidence of distant metastasis. Among 787 patients with available repeated sTg, 10 had clinical recurrences (5 out of 750 patients with repeated sTg<1 ng/mL and 5 out of 37 patients with repeated sTg ≥ 1 ng/mL). Patients with repeated sTg ≥ 1 ng/mL had a much greater chance of disease recurrence (log-rank statistics=43.7, df=1, p<0.001).

CONCLUSIONS

About 1% of DTC patients who had sTg<1 ng/mL 12 months after initial treatment had a clinical recurrence. All of clinical recurrences were loco-regional recurrences. Although repeated sTg measurement can be helpful to predict recurrence, we could not recommend it for surveillance in patients with BR due to its very low yield.

Undetectable sensitive serum thyroglobulin (<0.1 ng/ml) in 163 patients with follicular cell-derived thyroid cancer: results of rhTSH stimulation and neck ultrasonography and long-term biochemical and clinical follow-up

CONTEXT

Surveillance of patients with differentiated thyroid cancer (DTC) is achieved using serum thyroglobulin (Tg), neck ultrasonography (US), and recombinant human TSH (rhTSH)-stimulated Tg (Tg-stim).

OBJECTIVE

Our primary aim was to assess the utility of rhTSH Tg-stim in patients with suppressed Tg (Tg-supp) below 0.1 ng/ml using a sensitive assay. Our secondary aims were to assess the utility of US and to summarize the profile of subsequent Tg-supp measures.

DESIGN

This is a retrospective study conducted at two sites of an academic institution.

PATIENTS

A total of 163 patients status after thyroidectomy and radioactive iodine treatment who had Tg-supp below 0.1 ng/ml and rhTSH Tg-stim within 60 d of each other were included.

RESULTS

After rhTSH stimulation, Tg remained below 0.1 ng/ml in 94 (58%) and increased to 0.1-0.5 in 56 (34%), more than 0.5-2.0 in nine (6%), and above 2.0 ng/ml in four (2%) patients. Serial Tg-supp levels were obtained in 138 patients followed over a median of 3.6 yr. Neck US were performed on 153 patients; suspicious exams had fine-needle aspiration (FNA). All positive FNA were identified around the time of the initial rhTSH test. Six of seven recurrences were detected by US (Tg-stim >2.0 ng/ml in one, 0.8 in one and ≤ 0.5 in four). One stage IV patient had undetectable Tg-stim.

CONCLUSION

In patients with DTC whose T(4)-suppressed serum Tg is below 0.1 ng/ml, long-term monitoring with annual Tg-supp and periodic neck US are adequate to detect recurrences. In our experience, rhTSH testing does not change management and is not needed in this group of patients.

Value of repeat stimulated thyroglobulin testing in patients with differentiated thyroid carcinoma considered to be free of disease in the first year after ablation

BACKGROUND

In patients with differentiated thyroid carcinoma considered to be free of the disease after initial therapy, the appropriate timing or necessity of subsequent stimulated thyroglobulin (Tg) testing is uncertain. The objective of this study was to determine the value of a repeat stimulated Tg in patients considered to be free of disease 6-12 months after thyroid ablation, and also who continued to have serum Tg <1 ng/mL while on thyrotropin suppressive doses of thyroxine (T4) (Tg/T4), negative anti-Tg antibodies (TgAb), and a normal clinical examination 5 years after their initial therapy.

METHODS

The study participants were 203 patients who had total thyroidectomy followed by ablation with (131)I, who were considered to be free of disease 6-12 months after ablation (stimulated Tg <2 ng/mL in the absence of TgAb and negative diagnostic whole-body scanning), who had no recurrence, and who continued to have serum Tg/T4 of <1 ng/mL, negative TgAb and a normal clinical examination 5 years after initial therapy. These patients were evaluated with repeat stimulated Tg testing after 4 weeks of T4 withdrawal.

RESULTS

Repeat stimulated Tg values after 5 years were <2 ng/mL in 192 (94.6%) patients of whom 188 were <1 ng/mL. Subsequent follow-up after a mean of 102 months did not detect new cases of tumor recurrence in this subgroup. Eleven patients (5.4%) had stimulated Tg levels of >2 ng/mL. Neck ultrasonography (US) revealed metastases in three and other imaging methods detected metastases in five patients with negative US. In the other three patients, no metastases were detected initially or during follow-up. Gender, age, and tumor stage were not predictors of recurrence or elevated Tg upon repeat testing after 5 years.

CONCLUSIONS

The present results favor repeating stimulated Tg 5 years after ablation in patients who were initially considered to be free of disease and who continued to have Tg/T4 values of <1 ng/mL and negative TgAb tests. A negative predictive value of 100% was obtained for patients who continued to have low stimulated Tg values.

Approach to and treatment of differentiated thyroid carcinoma

Thyroid cancer is the most common endocrine malignancy, although representing fewer than 1% of all human tumors. Differentiated thyroid carcinoma (DTC) includes the papillary and follicular histotypes and their variants, accounting for more than 90% of all thyroid cancers. Given the changing presentation of DTC in the last years, the aim of DTC management is to ensure the most effective but least invasive treatment, and adequate follow-up for a disease that nowadays is mostly cured just with surgery and is rarely fatal. This review addresses the multiple steps of current management, based on previous assumptions.

Papillary thyroid carcinoma patients assessed to be at low or intermediary risk after primary treatment are at greater risk of long term recurrence if they are thyroglobulin antibody positive or do not have distinctly low thyroglobulin at initial assessment

BACKGROUND

In papillary thyroid carcinoma (PTC), recurrences during long-term follow-up (R-LTFU) occur even in those who appear to have an excellent prognosis after initial thyroid surgery and usually, radioactive iodine (i.e., "primary treatment"). Initial studies that predict R-LTFU are not well defined. Values for serum thyroglobulin (Tg) measurements when serum thyrotropin (TSH) is >30 μU/mL, as a result of either recombinant TSH or L-thyroxine withdrawal, referred to here as stimulated Tg (STg), have been previously evaluated. The aim of the current study was to determine the parameters associated with R-LTFU in patients with PTC categorized as having low-risk disease 9 to 12 months after their primary treatment.

METHODS

This was a retrospective study of 469 patients with PTC with a mean follow-up 5.8±3.9 years. Study patients had to have no uptake in the first postablative diagnostic (131)iodine whole body scan (WBS) performed 9-12 months after primary treatment, a normal cervical ultrasonography (C-US), and STg of <2 ng/mL if their test for antithyroglobulin antibody (anti-Tg) was negative. The first two criteria were required for patients with a positive anti-Tg test, and their nominal serum Tg concentrations were not analyzed.

RESULTS

Twelve patients developed recurrences (2.6%) in cervical region. Greater tumor size, higher STg, and positive anti-Tg tests at initial evaluation were associated with greater R-LTFU. The recurrence rates were 1.5% (7/450) and 26% (5/19), respectively, in patients with negative and positive anti-Tg tests at initial evaluation. Recurrence-free survival was lower in the patients with initial lymph node metastases, positive anti-Tg tests, and STg of ≥0.3 ng/mL at the first postablative WBS (p=0.022, 0.001, 0.035, respectively, by log-rank test). Regression analysis in patients who were anti-Tg negative revealed that STg ≥0.3 ng/mL at this first WBS was the only parameter related to recurrence (p=0.031, odds ratio: 10.30, confidence interval: 1.23-83.3).

CONCLUSION

Patients with PTC traditionally categorized as low risk during their first 9 to 12 months after primary treatment have a greater risk of R-LTFU if their postablative STg is ≥0.3 ng/mL, or they have positive anti-Tg, even at this early stage. Periodic C-US is important in these patients and should probably be more frequent in patients with PTC who have positive anti-Tg tests or STg ≥0.3 ng/mL in the first year after diagnosis.

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.

Factors determining the persistence or recurrence of well-differentiated thyroid cancer treated by thyroidectomy and/or radioiodine in the Boston, Massachusetts area: A retrospective chart review

OBJECTIVE

To assess predictors of well-differentiated thyroid cancer (WDTC) persistence/recurrence.

DESIGN

This was a retrospective chart review of thyroid carcinoma patients seen 1979-2007 in a Boston, Massachusetts-area multispecialty group. Of 1,025 patients, 431 met eligibility criteria. Cox proportional hazards models were used to assess predictors (gender, age, ethnicity, tumor size, surgical histology) of WDTC persistence/recurrence (elevated thyroglobulin levels with negative thyroglobulin-antibodies; or positive imaging). Local extension of disease and lymph node involvement could not be assessed.

RESULTS

Mean age at initial surgery (n = 431, 74% women, 79% Caucasian) was 45.8 ± 13.5(SD) years. Mean tumor (papillary, 91%; follicular, 5%; Hurthle cell, 2%; ≥1 type, 2%) size was 2.5 ± 1.6(SD) cm. Most tumors were unifocal (57%) and ≥1 cm (89%). Over 2,600 person-years of follow-up, persistence/recurrence occurred in 52 patients (12%) 4.3 years (median; range 0.2-23.2 years) after surgery. Gender, ethnicity, tumor size, multifocality, and histology were not predictive of persistence/recurrence, while older age was predictive in some models.

CONCLUSIONS

In WDTC patients treated by total and near total thyroidectomy and radioiodine and analyzed without consideration of local, locoregional, and distant extent of disease, neither size of tumor nor male gender contribute to disease persistence/recurrence. Age at diagnosis seems to have some positive prognostic value even if only patients older than 21 years at diagnosis are considered. Due to the rare occurrence of follicular (also oxyphilic) histotype, this conclusion refers mainly to patients with papillary thyroid cancer.