Long-term course and predictive factors of elevated serum thyroglobulin and negative diagnostic radioiodine whole body scan in differentiated thyroid cancer

Active surveillance in differentiated thyroid cancer: a strategy applicable to all treatment categories response

Currently, the differentiated thyroid cancer (DTC) management is shifted toward a tailored approach based on the estimated risks of recurrence and disease-specific mortality. While the current recommendations on the management of metastatic and progressive DTC are clear and unambiguous, the management of slowly progressive or indeterminate disease varies according to different centers and different physicians. In this context, active surveillance (AS) becomes the main tool for clinicians, allowing them to plan a personalized therapeutic strategy, based on the risk of an unfavorable prognosis, and to avoid unnecessary treatment. This review analyzes the main possible scenarios in treated DTC patients who could take advantage of AS.

Applicability of Adults 2015 American Thyroid Association Differentiated Thyroid Cancer Guidelines for Postoperative Risk Stratification and Postradioiodine Treatment Dynamic Risk Stratification in Pediatric Population

Purpose  This retrospective study aimed to study the applicability of 2015 adult American Thyroid Association (ATA) differentiated thyroid cancer (DTC) postoperative risk stratification and guidelines in the pediatric population for evaluating the number of metastatic lymph nodes in the postoperative risk stratification and postradioactive iodine (RAI) treatment dynamic risk stratification (DRS) using response to treatment (RTT) reclassification. In addition, the effect of pubertal status and gender was assessed on disease presentation and prognosis.

Methods  Data of 63 DTC patients aged 20 years or less, stratified into prepubertal, pubertal, and postpubertal age groups, was divided into low, intermediate, and high-risk groups using pediatric ATA recurrence risk stratification. Forty-seven patients were classified as responders (excellent and indeterminate responses) and incomplete responders (biochemical and structurally incomplete responses) by assessing the RTT at 1.5 years follow-up similar to recommendation of 2015 adult DTC ATA guidelines.

Results  Female-to-male ratio showed a trend of gradual increase with increasing age. Significantly more responders were observed in low- and intermediate-risk groups than in high-risk group ( p  = 0.0013; p  = 0.017, respectively), while prepubertal group had more extensive (N1b) disease. Using DRS at follow-up of 1.5 year, pubertal and postpubertal groups showed significantly better response to RAI. More female than male patients showed response and took significantly less time to respond to RAI ( p  = 0.003).

Conclusion  RAI response in pediatric DTC depends on pubertal status, gender, and number of malignant nodes. DRS using RTT classification may be applicable early at 1.5 years after initial therapy in different pubertal age and risk groups.

Value of the Postablative Thyroglobulin Measurements for Assessment of Disease-Free Status in Patients with Differentiated Thyroid Cancer

Aim:

The aim of the study is to evaluate the value of thyroid-stimulating hormone (TSH)-stimulated thyroglobulin (sTg) measurements by the end of the 1^st-year postablation in differentiated thyroid cancer (DTC) patients with biochemical non complete response (indeterminate and incomplete response).

Patients and Methods:

One hundred patients with DTC underwent near-total thyroidectomy and radioactive remnant ablation by iodine-131 (I¹³¹) with regular follow-up every 6 months during the first 2 years and at 6–12-month intervals thereafter by I¹³¹ whole-body scan (WBS), neck ultrasound, and sTg measurement in the hypothyroid state (TSH >30 mU/L). Patients were divided according to the imaging findings and sTg level into three groups: excellent response (ER) – no evidence of disease by imaging and sTg <1 ng/mL, indeterminate or acceptable response (AR) – nonspecific findings on imaging studies and sTg < 10 ng/mL, and incomplete response (IR) – patients with incomplete structural and/or incomplete biochemical response (sTg > 10 ng/mL).

Results:

The follow-up at 6-month postablation showed ER in 3 (3%) patients, AR in 29 (29%) patients, and IR in 68 (68%) patients. The second follow-up at 9–12-month postablation showed dramatic biochemical response with ER, indeterminate, and IR in 50 (50%), 34 (34%), and 16 (16%) patients, respectively, and 14 (14%) patient had structural recurrence. This change is highly statistically significant (P = 0.00). In the last follow-up (ranges from 3 to 10 years), 53 (55.8%) patients achieved ER, 42 (44.2%) AR and no patient with non complete response. The change in patients with IR between the second and the last follow-up is also statistically significant (P = 0.001).

Conclusion:

sTg measurement by the end of the 1^st year is more reliable in the follow-up of patients with DTC and biochemical non complete response and considered significant predictor of disease-free status. Patients with biochemical IR still have the chance to achieve ER or AR by the passage of time without additional therapies.

BEHAVIOUR OF EARLY THYROGLOBULIN AFTER TOTAL THYROIDECTOMY FOR DIFFERENTIATED THYROID CANCER

Context

The objectives of treatment of thyroid carcinoma include hormonal suppression, radioiodine ablation and follow-up with serum thyroglobulin (Tg). Tg levels should not be measured before six weeks post-thyroidectomy.

Objective

To describe the behaviour of early postoperative Tg in patients who underwent total thyroidectomy and its ability to predict the serum Tg levels after suppression.

Design

This is a retrospective cohort study.

Subjects and methods

Adult patients who underwent total thyroidectomy with at least two postoperative measurements of serum Tg, negative TgAb and concomitant serum TSH values were included. Tg, TgAb and TSH level measurements were completed two weeks postoperatively and during the follow-up period.

Results

Twenty-nine patients fulfilled all criteria. The median serum Tg level at two weeks after surgery was 3.8 ug/L (0.3 -300) with a serum TSH level of 69.9 mU/L; 11-227. At the two-week measurement, 16 (55%) patients had serum Tg levels lower than 5 ug/L and 4 patients had levels between 5-10 µg/L.

Conclusions

Postoperative early serum Tg could be an alternative to values measured six months after surgery and could be used as a predictive tool to make earlier therapeutic decisions.

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.

Practice trends in patients with persistent detectable thyroglobulin and negative diagnostic radioiodine whole body scans: a survey of American Thyroid Association members

BACKGROUND

Management of patients with thyroglobulin (Tg)-positive/scan-negative thyroid cancer remains challenging. American Thyroid Association (ATA) guidelines recommend potential use of empiric (131)I therapy and various scanning modalities, but no standard for managing such cases exists.

METHODS

We surveyed ATA members to assess current practice in management of patients with Tg-positive/scan-negative disease. Members participated in a web-based survey of six case scenarios of Tg elevations but iodine scan negativity.

RESULTS

A total of 288 ATA members (80% male) participated. Patient age, sex, and basal and stimulated Tg varied between the cases. Respondents were asked their opinion regarding empiric (131)I therapy use, including (131)I dose, use and duration of low-iodine diet, thyroxine withdrawal or recombinant human thyrotropin (rhTSH), and utilization of additional imaging (neck ultrasound (US) or positron emission tomography/computed tomography (PET/CT)) and reconsideration of (131)I therapy. Between 16% and 51% recommended initial use of empiric (131)I for the various scenarios. The majority chose a (131)I dose between 75 and 150 mCi, and 73% employed a low-iodine diet for two or more weeks. Preference between thyroxine withdrawal versus rhTSH was evenly split. More than 98% obtained a neck US if empiric (131)I was not given; 52-89% would proceed to PET/CT if US was negative. Only 44% used rhTSH stimulation in PET scan preparation. (131)I use was more common with stimulated Tg significantly >10 ng/mL. (131)I therapy was slightly more likely with PET-positive (56%) than PET-negative status (45%). Respondents were split regarding empiric (131)I if basal and stimulated Tg increased ≥150% over two years. Providers in North America less commonly utilized (131)I treatment than those from other areas. In the face of possible heterophilic antibody interference in the Tg assay, the majority did not recommend (131)I therapy.

CONCLUSIONS

Empiric (131)I therapy is still utilized for patients with Tg-positive/scan-negative disease. Neck US is frequently used to further evaluate such cases as (18)FDG-PET/CT, albeit the latter is used somewhat less often. Use of (131)I therapy correlated with the degree of Tg elevation or development of Tg antibodies, and was recommended more commonly with PET-positive than PET-negative status in patients with lower Tg levels. (131)I was less commonly used by providers within North America.

Biochemical persistence in thyroid cancer: is there anything to worry about?

To evaluate the outcome of differentiated thyroid cancer (DTC) patients with biochemical persistence of disease (BP) after initial treatment (total thyroidectomy with or without lymph node dissection (LND) and thyroid remnant ablation). BP was defined as suppressed thyroglobulin (Tg) levels <1 ng/ml and rhTSH-stimulated thyroglobulin (St-Tg) >1ng/ml, with no evidence of structural disease. Structural persistence/recurrence (SPR): clinically identifiable disease. We reviewed 278 records of DTC patients. Tg-Ab positive patients (n = 73) were excluded and 32 were included in the analysis (median age 45 years, range 18-77 years); risk of recurrence ATA was: low in 38 %, Intermediate in 47 %, and high in 15 % of patients. All subjects had Tg levels <1 ng/ml under thyroid hormone therapy. Patients were divided into three groups: Group 1: St-Tg 1-2 ng/ml, n = 6; Group 2: St-Tg 2-10 ng/ml, n = 17; Group 3: St-Tg > 10 ng/ml, n = 9. In 5/32 (16 %) patients, SPR was observed after a median follow-up of 6 years (range 2-23 years). In Group 1: all patients were considered with no evidence of disease after a median follow-up of 2 years (range 1-2.5 years). In Group 2: 13/17 (76.5 %) patients continued with only a BP after a median follow-up of 4 years (range 2-10 years) and 4/17 (23.5 %) patients with intermediate risk of recurrence had a structural persistence (lymph nodes metastasis) diagnosed between 1 and 3.5 years after initial assessment. Following LND, all of them remained with BP after a median of 2 years (range 1.5-5 years). In Group 3: 8/9 (89 %) patients had BP after a median follow-up of 7 years (range 2-23 years) and 1/9 (11 %) had a SPR diagnosed 28 months after initial assessment, LND was indicated but he continued with BP, 5 years after the second surgery. Most patients with DTC and BP present an indolent course of the disease. In these patients the diagnosis of the structural recurrence did not change the outcome because all of them continued with BP.

Thyroglobulin as early prognostic marker to predict remission at 18-24 months in differentiated thyroid carcinoma

INTRODUCTION

Thyroglobulin (Tg), the most common marker to determine remission of differentiated thyroid carcinoma (DTC), can take 18 months or longer to be undetectable. We hypothesized that Tg stimulated after surgery and immediately before radioiodine treatment (baseline-stimulated Tg) could be a good predictor of remission at 18-24 months. The aim of this study was to evaluate the role of baseline-stimulated Tg as early prognostic marker of DTC.

PATIENTS AND METHODS

Retrospective study of 133 patients with DTC from 1998 to 2010 (age at diagnosis 47·4 ± 16·8, follow-up 5·09 ± 3·2 years). Initial subset analysis was performed after excluding patients with positive TgAb, who were later included in the second. Baseline-stimulated Tg was divided into tertiles. Multivariate logistic regression analysis included baseline Tg and other known prognostic markers and receiver operating characteristic (ROC) curve to identify the best cut-off level of baseline Tg were performed.

RESULTS

Baseline-stimulated Tg in the highest tertile was the only predictive variable of persistence of disease at 18-24 months in the initial analysis (OR 45·3, P < 0·01). In the second analysis, the predictive variables were baseline-stimulated Tg (OR 39·6, P < 0·001), presence of TgAb (OR 23·4, P < 0·005) and uptake outside of the thyroid bed post-treatment whole body scan (WBS; OR 5·3, P < 0·05) were predictive of persistence of disease. The ROC curve showed that baseline-stimulated Tg below 8·55 μg/l identified 95% of disease-free patients at 18-24 months after initial treatment.

CONCLUSIONS

Baseline-stimulated Tg is a good predictor of remission of disease at 18-24 months after initial treatment and could be a useful marker to stratify risk immediately after surgery.

Detectable thyroglobulin with negative imaging in differentiated thyroid cancer patients

In the absence of autoantibodies against thyroglobulin (Tg), Tg measurement nowadays is the cornerstone of clinical management of differentiated thyroid cancer patients. DTC patients presenting with a positive Tg measurement without an anatomical correlate on anatomic imaging provide a management challenge to the attending physician.

Based on the literature we will provide an overview of the most important steps to undertake in such patients and their potential clinical consequences.

Outcomes of patients with differentiated thyroid cancer risk-stratified according to the American thyroid association and Latin American thyroid society risk of recurrence classification systems

OBJECTIVES

The aims of this study were to validate the proposed Latin American Thyroid Society (LATS) risk of recurrence stratification system and to compare the findings with those of the American Thyroid Association (ATA) risk of recurrence stratification system.

SUBJECTS AND METHODS

This study is a retrospective review of papillary thyroid cancer patients treated with total thyroidectomy and radioactive iodine at a single experienced thyroid cancer center and followed according to the LATS management guidelines. Each patient was risk-stratified using both the LATS and ATA staging systems. The primary endpoints were (i) the best response to initial therapy defined as either remission (stimulated thyroglobulin [Tg] <1 ng/mL, negative ultrasonography) or persistent disease (biochemical and/or structural), and (ii) clinical status at final follow-up defined as no evidence of disease (suppressed Tg <1 ng/mL, negative ultrasonography), biochemical persistent disease (suppressed Tg >1 ng/mL in the absence of structural disease), structural persistent disease (locoregional or distant metastases), or recurrence (biochemical or structural disease identified after a period of no evidence of disease).

RESULTS

One hundred seventy-one papillary thyroid cancer patients were included (mean age 45 ± 16 years, followed for a median of 4 years after initial treatment). Both the ATA and LATS risk stratification systems provided clinically meaningful graded estimates with regard to (i) the likelihood of achieving remission in response to initial therapy, (ii) the likelihood of having persistent structural disease in response to initial therapy and at final follow-up, (iii) the likely locations of the persistent structural disease (locoregional vs. distant metastases), (iv) the likelihood of recurrence, and (v) the likelihood of being no evidence of disease at final follow-up. The likelihood of having persistent biochemical evidence of disease was not significantly different across the staging categories.

CONCLUSIONS

Both the ATA and LATS risk of recurrence systems effectively risk-stratify patients with regard to multiple important clinical outcomes. When used in conjunction with a staging system that predicts disease-specific mortality, either of these systems can be used to guide risk-adapted individualized initial management recommendations.

Clinical outcomes following empiric radioiodine therapy in patients with structurally identifiable metastatic follicular cell-derived thyroid carcinoma with negative diagnostic but positive post-therapy 131I whole-body scans

BACKGROUND

While radioiodine (RAI) therapy remains the most effective treatment modality for RAI-avid distant metastatic follicular cell-derived thyroid cancer, the therapeutic utility of empiric RAI therapy in patients with structurally identifiable distant metastases that demonstrate RAI avidity only on the post-therapy scan (negative diagnostic whole-body scan [DxWBS]) remains uncertain.

METHODS

We report a retrospective assessment of the structural response to RAI therapy in 27 patients (median age 54 years, 59% male) with metastatic thyroid cancer (45% classical papillary thyroid cancer, 21% poorly differentiated, 15% tall-cell variant, 15% follicular variant, and 4% Hurthle cell carcinoma) with structurally identifiable distant metastases (86% pulmonary metastases) in whom a properly conducted DxWBS was negative, and the post-therapy scan showed RAI-avid metastatic lesions at the time of RAI remnant ablation.

RESULTS

In response to the initial RAI ablation, none of the selected patients demonstrated structural disease regression, and no patient was rendered free of disease. However, 12 patients (44%) demonstrated stable lesions on serial structural imaging after an RAI ablation. Structural disease progression was seen in the remaining 56% (15/27), a median of 6 months after ablation. Unfortunately, additional RAI therapies given to 12/15 patients with progressive disease and 5/12 patients with stable lesions failed to cause structural disease regression, cure, or conversion from progressive to stable disease in any patient. All of the disease-specific deaths (7/27) were in patients who had structural disease progression (n=15) in response to RAI ablation. None of the patients with persistent but stable lesions on structural imaging (n=12) have died of thyroid cancer over a median follow-up period of 3.7 years.

CONCLUSIONS

While 44% of patients with the DxWBS-negative/post-therapy scan-positive macroscopic distant metastasis will have stable cross-sectional imaging after RAI remnant ablation, the other 56% will demonstrate structural disease progression that cannot be effectively treated with repeated empiric RAI activities. Furthermore, the high disease-specific mortality rate seen within the first few years of remnant ablation in this small subset of patients with persistent progressive disease despite a positive post-therapy RAI scan argues that treatments other than repeated empiric RAI dosing be strongly considered.

Even without additional therapy, serum thyroglobulin concentrations often decline for years after total thyroidectomy and radioactive remnant ablation in patients with differentiated thyroid cancer

BACKGROUND

Current management guidelines suggest that 6-12 months after total thyroidectomy and radioactive iodine remnant ablation (RAI-RA), patients with differentiated thyroid cancer should be re-evaluated with serum thyroglobulin (Tg) and neck ultrasonography to assess the efficacy of initial treatment and to guide subsequent management. However, if serum Tg levels can continue to decline for many years after RAI-RA, then an early assessment of response to therapy could lead to excessive evaluations and treatments in patients with low-level Tg values that are likely to resolve over time without additional therapies.

METHODS

Serum Tg concentrations in patients with differentiated thyroid cancer, who had been thyroidectomized (Tx), received RAI-RA, and who were receiving levothyroxine to suppress serum thyrotropin (suppressed serum Tg), were retrospectively analyzed. The study included 299 patients, 69% of whom were women with an overall median age of 46 years and who had a median follow-up of 7 years. The study was limited to patients who received no additional treatments beyond total Tx, RAI-RA, and levothyroxine therapy to suppress thyrotropin. The primary endpoints were the time required to achieve the lowest Tg (nadir Tg) and the time required to achieve a suppressed serum Tg<1 ng/mL.

RESULTS

The nadir -suppressed serum Tg was achieved by 6 months in 58% of the patients and by 12 months in 75% of the patients. The remaining 25% of patients required 18 months or longer to reach the nadir Tg. However, in the subgroup of patients that eventually reached a nadir suppressed serum Tg<1 ng/mL (n=223 patients), this goal was achieved by 6 months in 81%, by no more than 12 months in 91%, and by no more than 18 months in 94%. In patients with a 6-month suppressed serum Tg of 1-5 ng/mL, 54% eventually developed a suppressed serum Tg of <1 ng/mL without additional therapy.

CONCLUSIONS

In patients selected for continued observation, serum Tg levels often continue to decline for several years after total Tx and RAI-RA. While a 6-12-month assessment of the response to initial therapy is useful in patient management, strong consideration should be given to continued observation without additional therapy in patients with well-differentiated thyroid cancer who have 6-month suppressed serum Tg values of 1-5 ng/mL without a structurally identifiable disease.

Spontaneous remission in thyroid cancer patients after biochemical incomplete response to initial therapy

OBJECTIVE

To validate the American Thyroid Association (ATA) initial risk of recurrence scheme and the Memorial Sloan Kettering Cancer Center (MSKCC) response to therapy re-stratification approach in a large cohort of patients with differentiated thyroid cancer (DTC) treated outside of the United States.

DESIGN

Retrospective chart review.

PATIENTS

Five hundred and six patients with DTC followed for a median of 10 years after total thyroidectomy and RAI remnant ablation at a major cancer centre in Brazil.

MEASUREMENTS

Final clinical outcomes were assessed based on American Joint Cancer Committee (AJCC)/Union Internationale Contre le Cancer (UICC) staging, ATA risk stratification and response to therapy assessment (excellent, acceptable, biochemical incomplete and structural incomplete).

RESULTS

The AJCC/UICC staging system did not adequately stratify patients with regard to the risk of recurrence/persistent disease. However, the ATA system demonstrated a 13% risk of recurrent/persistent disease in low-risk patients, 36% in intermediate risk patients, and 68% in high-risk patients. Furthermore, an excellent response to therapy decreased the risk of recurrent/persistent disease to 1·4%. At the time of final follow-up, 34% of the biochemical incomplete response patients had been re-classified as having no evidence of disease (NED) without having received any additional therapy beyond continue levothyroxine suppression. Conversely, even after additional therapies, only 9% of the patients with an incomplete structural response were eventually re-classified as NED.

CONCLUSIONS

These data validate the ATA risk classification as an excellent initial predictor of recurrent/persistent disease and confirm the clinical utility of the MSKCC dynamic risk assessment system in a cohort of patients evaluated and treated outside the United States.

Is there a role for unstimulated thyroglobulin velocity in predicting recurrence in papillary thyroid carcinoma patients with detectable thyroglobulin after radioiodine ablation?

Background

In the follow-up of papillary thyroid cancer (PTC) patients treated with curative thyroidectomy and radioiodine ablation, raised thyroglobulin (Tg) predicts recurrence with reasonable sensitivity and specificity. However, a proportion of patients present with raised Tg level but no other clinical evidence of disease. Only limited data on Tg kinetics have been reported to date. Here we aim to evaluate the prognostic and predictive significance of nonstimulated serum Tg velocity (TgV).

Methods

Consecutive PTC patients treated with curative thyroidectomy and radioiodine ablation between 2003 and 2010 were analyzed. Patients with at least one detectable Tg measurement (>0.2 ng/mL) were included. TgV was defined as the annualized rate of Tg change. Logistic regression analyses were performed to evaluate the role of TgV in the prediction of disease recurrence. The optimal TgV cutoff was assigned by receiver–operating characteristic curve analysis. Overall survival of patients above versus below the TgV cutoff were determined by the Kaplan–Meier method and compared.

Results

Of a total of 501 patients, 87 had at least one Tg value >0.2 ng/mL; in these latter patients, 29 (33.3 %) developed recurrence. TgV was an independent predictor of the recurrence. TgV ≥0.3 ng/mL per year predicted recurrence with a sensitivity of 83.3 % and specificity of 94.4 %. Patients with TgV below the cutoff had a significantly better overall survival (p = 0.038).

Conclusions

TgV predicts recurrence with high sensitivity and specificity, and is a prognosticator of survival in postthyroidectomy and postablation PTC patients with raised Tg.

Electronic supplementary material

The online version of this article (doi:10.1245/s10434-012-2391-6) contains supplementary material, which is available to authorized users.

Thyroid lobe ablation with radioactive iodine as an alternative to completion thyroidectomy after hemithyroidectomy in patients with follicular thyroid carcinoma: long-term follow-up

BACKGROUND

Radioactive iodine lobe ablation (RAI-L-ABL) is a possible alternative to completion thyroidectomy (C-Tx) for follicular thyroid carcinoma (FTC), but no long-term outcome data are available after lobe ablation. We analyzed the long-term outcome of lobe ablation in a series of patients with FTC.

METHODS

This was a retrospective study of patients who were treated with lobe ablation between 1983 and 2008. Of 134 patients with FTC, 37 (27.6%) had lobe ablation with (131)I (30-32 mCi) (RAI-L-ABL), 68 (50.7%) had C-Tx, and 29 (21.6%) had initial total thyroidectomy (T-Tx). The main outcomes analyzed were (131)I uptake after lobe ablation, C-Tx or T-Tx, serum thyroglobulin (Tg), serum thyroid-stimulating hormone (TSH), long-term disease-specific mortality, and disease-free survival.

RESULTS

After lobe ablation, radioiodine uptake was significantly lower for the RAI-L-ABL group (0.6%) than for the C-Tx group (2.0%, p<0.005) or T-Tx group (1.3%, p=0.054). Subsequent remnant ablation was performed in 12 of 37 (32%) patients in the RAI-L-ABL group, in 58 of 68 (85.3%) patients in the C-Tx group, and in 25 of 29 (86.2%) patients in the T-Tx group (p<0.01). With median follow-up of 95 months for the RAI-L-ABL group, 47 months for the C-Tx group, and 53 months for the T-Tx group, there was one death in the RAI-L-ABL group and one death in the T-Tx group. No other RAI-L-ABL patients had detectable disease, whereas patients in the C-Tx group and two patients in the T-Tx group had detectable disease (p=0.18). Long-term stimulated or suppressed Tg of <1 ng/mL were found in 87.5% of the RAI-L-ABL group (n=28), 86.3% of the C-Tx group (n=57), and 77.8% of the T-Tx group (n=21). Tg was detectable in 40.6% of the RAI-L-ABL group compared to 13.8% of C-Tx and 28.6% of T-Tx groups (p<0.05, between groups).

CONCLUSIONS

RAI-L-ABL, C-Tx, and T-Tx are equally effective in achieving serum TSH concentrations of >25 mIU/L and preparing patients for conventional (131)I treatment and whole body scanning with similar long-term outcomes. However, persistent measurable Tg (range 0.2-2.2 ng/mL) is more common after RAI-L-ABL.

Serum thyroglobulin level measured after thyroxine withdrawal is useful to predict further recurrence in whole body scan-negative papillary thyroid cancer patients after reoperation

The best treatment option for recurrent papillary thyroid carcinoma (PTC) is reoperation when the recurrent lesion is locoregional. The prognostic significance of serum thyroglobulin (Tg) levels before reoperation and the association between the outcome of reoperation and Tg level remain unclear. Our study aimed to determine the outcomes of patients who underwent reoperation and their association with serum Tg levels. We retrospectively studied 79 patients with PTC with locoregional recurrence whose whole-body scan results were negative for any recurrence but whose serum Tg levels were detectable after first-line treatment. All the patients underwent reoperation and follow-up examinations, which involved serial serum Tg measurements after thyroxine withdrawal (T4-off Tg), neck ultrasonography, chest computed tomography, and/or fluorodeoxyglucose-positron emission tomography, to detect further recurrence. During the median follow-up duration of 89 months (range, 38-332 months), 30 patients (38.0%) experienced a second recurrence even after the reoperation. Among all patients, only 12 whose Tg levels decreased postoperatively to undetectable levels showed no recurrence. Most recurrences were detected in the patients with high T4-off Tg levels after the reoperation (T4-off Tg level (ng/mL), number of patients with recurrence, %: <1, 0/12, 0%; 1-10, 9/31, 33.3%; >10, 16/22, 72.7%; P < 0.001). In conclusion, recurrence occurred in 38.0% of the patients even after the reoperation. The postoperative T4-off Tg level was a good indicator of recurrence after the reoperation. Therefore, patients who experience recurrence should undergo follow-up examinations that involve routine measurements of T4-off Tg levels, especially when postreoperative values exceed 10 ng/mL.

Increased serum thyroglobulin levels and negative imaging in thyroid cancer patients: are there sources of benign secretion? A speculative short review

After thyroidectomy and 131I ablation for differentiated thyroid cancer (DTC), serum thyroglobulin (Tg) became a sensitive marker of residual disease. It is not uncommon to find patients at follow-up with persistent serum Tg levels and no other clinical or imaging evidence for the disease. The vast majority of these patients, most probably, have occult foci of disease, often in minute cervical lymph nodes. A review of the literature including papers published on PubMed/Medline until June 2010 was made. In this study we speculated that a minority of patients who had undergone surgery for differentiated thyroid cancer might have benign sources of Tg secretion at follow-up. These sources may be foci of radio-resistant ectopic thyroid tissue or a thyroid stimulating hormone-stimulated thymus.

Empiric high-dose 131-iodine therapy lacks efficacy for treated papillary thyroid cancer patients with detectable serum thyroglobulin, but negative cervical sonography and 18F-fluorodeoxyglucose positron emission tomography scan

CONTEXT

Some patients with elevated serum thyroglobulin (Tg) but a negative diagnostic whole body scan (WBS) after initial therapy for differentiated thyroid carcinoma may benefit from empirical radioactive iodine (RAI) therapy. However, previous studies enrolled patients with negative diagnostic WBS, regardless of neck ultrasonography (USG) and/or (18)F-fluorodeoxyglucose positron emission tomography (FDG-PET), which have become the preferred diagnostic procedures in such patients.

OBJECTIVE

The aim of this study was to evaluate the usefulness of empirical RAI therapy in patients with elevated stimulated Tg level and negative USG/FDG-PET findings after initial therapy for papillary thyroid carcinoma (PTC).

DESIGN

This comparative study enrolled 39 patients with elevated stimulated Tg, negative diagnostic WBS, and negative USG/FDG-PET 1 yr after initial treatment. Empirical RAI therapy was performed in 14 patients (treatment group), whereas 25 patients were followed up without therapy (control group).

RESULTS

There was no significant between-group difference in basal clinicopathological parameters. None of the 14 patients in the treatment group showed iodine uptake on posttreatment WBS. Five of 14 patients (36%) in the treatment group and eight of 25 (32%) in the control group had recurrence during the median 37 months of follow-up (P = 0.99). Changes in serum stimulated Tg concentrations did not differ between the two groups.

CONCLUSION

Empirical RAI therapy and posttreatment WBS were not useful diagnostically or therapeutically in patients with positive serum stimulated Tg if such patients had negative USG and negative FDG-PET findings after initial treatment of PTC.

Therapeutic outcomes of papillary thyroid carcinomas with tumors more advanced than T1N0M0

PURPOSE

This retrospective study analyzed the role of total or near-total thyroidectomy and adjuvant radioactive iodide ((131)I) therapy in papillary thyroid carcinoma patients with disease more advanced than T1N0M0.

METHODS

The study analyzed 1055 consecutive papillary thyroid cancer patients, 825 women and 230 men, who underwent near-total or total thyroidectomy, thyroid remnant ablation with (131)I, and follow-up at Chang Gung Medical Center in Linkou, Taiwan. Patients with T1N0M0 stage tumors were excluded. Patients were categorized into four groups according to treatment outcome. Group A was disease-free patients with negative results of (131)I whole body scan, undetected serum thyroglobulin (Tg) and Tg antibody, and no recurrence. Group B patients had no clinical evidence of persistent or recurrent thyroid cancer but were not in disease-free status. Group C were patients with cancer tissue persisting after surgery. Group D were patients suffering cancer recurrence after surgery and (131)I ablation.

RESULTS

After a mean follow-up period of 10.1+/-5.4 years (median: 9.5 years), 46 (4.36%) patients died of thyroid cancer. Nine Group A cases with persistent or recurrent cancer were treated until achieving disease-free status. Group C patients received the highest (131)I dose but had a 25.7% mortality rate. In Group D, the mean duration from first thyroidectomy to recurrence was 5.1+/-0.4 years and ranged from 0.8 to 18.7 years. Four of 56 (7.1%) patients with recurrent local neck cancer died of thyroid cancer and 12 (21.4%) died of thyroid cancer with distant metastases.

CONCLUSIONS

Radioactive iodide therapy effectively controlled papillary thyroid carcinoma after neck surgery in 23.9% of patients. After surgery and (131)I treatments, most patients with persistent or recurrent local-regional neck cancer were free of relapse; the cancer mortality rate was 19.0%.

Approach to the patient with a positive serum thyroglobulin and a negative radioiodine scan after initial therapy for differentiated thyroid cancer

The 10-yr survival of differentiated thyroid cancer is about 76-93%, and at least 10% of patients manifest tumor persistence or recurrence, depending on their disease stage, after initial therapy, which typically includes total thyroidectomy and (131)I ablation. Previously the realization of their residual/recurrent cancer often presented simultaneously with the additional surprise that they lacked pathological uptake on their diagnostic whole-body radioiodine image despite their elevated stimulated serum thyroglobulin (Tg) level, a scenario referred to as the scan-negative, Tg-positive patient. Now that serum Tg and neck ultrasonography have supplanted the diagnostic whole-body scan because of its inferior sensitivity, patients are often recognized to harbor residual disease without radioiodine imaging, and a new challenging scenario has emerged: the ultrasonography-negative, Tg-positive patient. Similarities and differences of these two patient populations aside, these Tg-positive patients are frequently encountered, and some are considered for additional (131)I therapy, although now typically after negative anatomic +/- (18)F-fluorodeoxyglucose positron emission tomography imaging or in the setting of known or suspected distant metastases already localized by anatomic imaging. Thus, the scan-negative, Tg-positive patient of today differs from those of the past, but the term still has relevance to current practice. The optimal evaluation and treatment of these patients remain controversial, partly because many of these patients will not die from thyroid cancer, and there are no randomized trials to demonstrate that intervention could have prevented the deaths that do occur. Here a case is presented that adds the complexity of advanced age, and one approach to these challenging patients is offered.