Clinical aggressiveness and long-term outcome in patients with papillary thyroid cancer and circulating anti-thyroglobulin autoantibodies

Thyroglobulin Antibodies and Tumor Epitope-Specific Cellular Immunity in Papillary Thyroid Cancer

Papillary thyroid carcinoma (PTC) is characterized by T cell infiltration and frequently by the presence of anti-thyroglobulin antibodies (TgAbs). The role of cellular immunity and of TbAbs in this context is a matter of debate. The aim of our study was to correlate the presence of TgAbs, tumor epitope-specific T cells and the clinical outcome of PTC patients. We studied n=183 consecutive patients with a diagnosis of PTC which were treated with total thyroidectomy plus 131I ablation. During a follow-up of in mean 97 months, most of the PTC patients had no signs of tumor relapse (n=157 patients). In contrast, one patient had serum Tg levels above the detection limit and<1 ng/ml, two patients Tg serum levels≥1 ng/ml and<2 ng/ml and n=23 patients had Tg serum levels≥2 ng/ml. Morphological signs of tumor recurrence were seen in 14 patients; all of these patients had serum Tg levels≥2 ng/ml. Importantly, with the exception of one patient, all TgAb positive PTC patients (n=27) had no signs of tumor recurrence as the serum Tg levels were below the assays functional sensitivities. Tetramer analyses revealed a higher number of tumor epitope-specific CD8+T cells in TgAb positive patients compared to TgAb negative PTC patients. In summary, we show that the occurrence of TgAbs may have an impact on the clinical outcome in PTC patients. This might be due to a tumor epitope-specific cellular immunity in PTC patients.

The effect of positive thyroglobulin antibodies on the prognosis and treatment response in patients with papillary thyroid carcinoma

Almost 15-30% of patients with papillary thyroid carcinoma (PTC) experience some degree of recurrence after treatment. Long-term follow-up and examination after thyroidectomy are very important in dealing with this issue. Serum thyroglobulin (Tg) level and neck ultrasound are the main part of follow-up for this purpose. The presence of thyroglobulin antibodies (TgAbs) leads to unreliable thyroglobulin (Tg) levels. The present study aims to evaluate the relationship between the simultaneous measurement of Tg and TgAb with long-term survival and response to treatment in these patients. This study was conducted by surveying available data from the medical records of 204 out of 600 patients over a 20-year period. In this research, 104 patients with positive TgAb were considered as the case group, and 100 patients with negative TgAb were selected as the control group. The relationship of TgAb titer was investigated with the staging, response to treatment (including the surgery number, number of radiotherapies, and dose of radioactive iodine), and recurrence in these patients. Also, the trend of TgAb changes was examined in the presence of high or low thyroglobulin levels during the follow-up period. Patients with high TgAb levels had more lymph node involvement, higher cumulative dose, a higher number of times received iodine, more surgical number, higher recurrence rate, and less excellent response (ER) to treatment during follow-ups. This effect of TgAb worsened in the presence of high Tg titer and remained up to 36 months. Overall, the baseline level of TgAb and its changes can be a suitable factor for predicting subsequent response to treatment and recurrence in patients with PTC. Accordingly, in cases with high TgAb and Tg levels, close follow-up should be considered up to Tg and TgAb normalization.

Serum Anti-Thyroglobulin Autoantibodies Are Specific in Predicting the Presence of Papillary-like Nuclear Features and Lymphocytic Infiltrate in the Thyroid Gland

(1) Background: Previous studies have reported a correlation between serum anti-Thyroglobulin-antibodies (TgAb) and papillary thyroid carcinoma. The aim of our study was to evaluate whether serum TgAb and anti-thyroid-peroxidase antibody (TPO) positivity was also related to pre-neoplastic histological changes such as papillary-like nuclear features (PLNF) and with the presence of lymphocytic infiltrate (LI) in thyroid surgical specimens. (2) Methods: The study was retrospectively carried out on 70 consecutively recruited patients who underwent thyroidectomy for benign process and whose TgAb and TPOAb values were retrieved from clinical records. Histological sections of thyroid surgical samples were revised, looking for PLNF and lymphocytic infiltrate. HBME1 expression was assessed by immunohistochemistry. (3) Results: Our results showed a significant association between TgAb, PLNF, and lymphocytic infiltrate. The presence of TgAb was highly specific, but less sensitive, in predicting the presence of PLNF (sensitivity = 0.6, specificity = 0.9; positive predictive value (PPV) = 0.88; negative predictive value (NPV) = 0.63). TgAb positivity showed a good association with the presence of lymphocytic infiltrate (sensitivity = 0.62, specificity = 0.9; PPV = 0.88 and NPV = 0.68). HBME1 immunoreactivity was observed in the colloid of follicles showing PLNF and/or closely associated with LI. (4) Conclusions: The presence of PLNF and LI is associated with serum TgAb positivity. The presence of TgAb and of LI could be triggered by an altered thyroglobulin contained in the HBME1-positive colloid, and could be a first defense mechanism against PLNF that probably represent early dysplastic changes in thyrocytes.

Thyroglobulin antibodies: Trend over time and clinical impact in differentiated thyroid carcinoma with and without radioiodine ablation

INTRODUCTION

Thyroglobulin antibodies (TgAb) trend may be considered a surrogate marker for thyroglobulin in differentiated thyroid carcinoma. The aim of this study is to analyse, in cases with positive TgAb, trend over time and its relationship with response to treatment.

MATERIAL AND METHODS

Retrospective and descriptive study of 100 patients with differentiated thyroid carcinoma and positive TgAb (measured by electrochemoluminiscense) after thyroidectomy. Assessment of response to initial treatment was performed 6-24 months after surgery. Status at last follow-up was evaluated.

RESULTS

After the first year nearly half of the patients showed a reduction in TgAb levels ≥50%, in 91% of these patients, status at last follow up was excellent response (65%) or indeterminate response due to decreasing TgAb levels (26%). At first assessment, indeterminate responses were found in 49% of cases, without significant differences among initial risk of recurrence category or whether radioiodine ablation was performed. At last evaluation (median 53.5 months), 15% of ablated low-risk patients had an indeterminate response (due to declining TgAb), vs 62% in the non-ablated low-risk group (p 0.03). Median time to negativization for post-surgical TgAb levels<100UI/ml was 11 months [3-94] vs 31 months [8-119] for patients with TgAb≥100UI/ml (p 0.0003).

CONCLUSION

A reduction of ≥50% in TgAb levels during the first year correlated with favourable outcomes. Non-ablated patients and patients with higher levels of post-surgical TgAb may need a longer time to achieve negative conversion.

Circulating Biomarkers in Thyroid Cancer

Thyroid cancer is the most important endocrine cancer with increasing incidence. While thyroid cancers, especially papillary thyroid cancers, are known to exhibit generally a favorable outcome with excellent survival rates, some thyroid cancers are more aggressive with a poor prognosis. Several different biomarkers have been introduced for the diagnosis of disease, identification of tumor load, assessment of therapy response, and the detection of recurrence during follow-up of the thyroid cancer patients. This chapter gives a brief overview of the circulating biomarkers used in thyroid cancer patients.

Relationship Between Thyroid Autoantibodies and Recurrence of Papillary Thyroid Carcinoma in Children and Adolescents

Background

Numerous studies reported connection between papillary thyroid carcinoma (PTC) and thyroid autoantibody in adults, but few of them have investigated whether there is a similar link in children and adolescents. The purpose of this research was to explore the relationship between clinicopathological features, prognosis and preoperative thyroid peroxidase antibody (TPOAb) as well as thyroglobulin antibody (TgAb) status in children and adolescents with PTC.

Methods

This study retrospectively reviewed 179 patients of PTC who underwent a thyroidectomy from January 2000 to June 2021 at Tianjin Medical University Cancer Hospital. We compared preoperative TgAb and TPOAb status with the clinicopathological features and prognosis of children and adolescents with PTC in different age groups.

Results

Patients with positive preoperative TPOAb and TgAb had lower recurrence rate in the younger group (P = 0.006, 0.047, respectively). Patients with positive TPOAb preoperatively had normal level of preoperative Tg and less cervical LNM than patients with negative TPOAb in children and adolescents (P < 0.05). Positive TPOAb preoperatively of PTC patients had a longer median DFS (113.4 months) than negative TPOAb (64.9 months) (P = 0.009, log-rank). Univariate analyses showed age, maximal tumor size, T stage, multifocality, lateral LNM and N staging were predictors for cancer recurrence in children and adolescents (P<0.05). Cox regression analysis found younger age (HR 0.224, P < 0.001), lateral LNM (HR 0.137, P = 0.010), N stage (HR 30.356, P < 0.001) were independent risk factors for recurrence.

Conclusions

Our study found that presence of preoperative TPOAb and TgAb could serve as novel prognostic factors for predicting recurrence of PTC in children.

Total thyroidectomy versus lobectomy: surgical approach to T1-T2 papillary thyroid cancer

The incidence of papillary thyroid carcinoma, which accounts for 80-90% of all thyroid cancers, has recently been increasing. The current study aimed to compare the oncological and functional outcomes of total thyroidectomy (TT) and thyroid lobectomy (TL). To this end, a retrospective single-centre cohort study involving a tertiary care institution was conducted. Data regarding demographics, clinicopathology and postoperative complications from 586 patients with papillary thyroid cancer treated in a single institution were collected. Cox proportional-hazards models were utilised to determine differences in outcomes stratified according to propensity score. Our data suggested no significant difference in the risk for locoregional recurrence or distant metastasis between TL and TT among patients with pT1-2 pN0 papillary carcinoma. TT plays an important role in improving prognosis among patients with metastatic lymph nodes in the central neck compartment (pN1a) (p = 0.001). Moreover, TT had significantly higher rates of postoperative hypocalcaemia and recurrent laryngeal nerve paralysis compared to TL (p < 0.001 and p = 0.02, respectively).

Histology is more ιmportant than persistent anti-Tg antibodies for progression of differentiated thyroid cancer

CONTEXT

Anti-thyroglobulin antibodies (anti-Tg), present in 20%-25% of differentiated thyroid cancer (DTC) patients, interfere with thyroglobulin measurements posing a challenge in the follow-up.

OBJECTIVES

The aim of this study was to identify clinical-histological factors that may affect anti-Tg persistence and disease outcome in DTC with positive anti-Tg.

METHODS

We retrospectively studied 234 DTC patients, with positive anti-Tg at diagnosis (females: 82.1%, age at diagnosis: 46.0 ± 14.4 yrs, median follow-up: 5 yrs (1.5-32 yrs). 221/234 (94.4%) received radioiodine (RAI) ablation. Patients were divided into two subgroups: those whose anti-Tg became undetectable (anti-Tg-NEG) and those whose anti-Tg remained positive (anti-Tg-POS) at the end of the follow-up period.

RESULTS

Anti-Tg-POS patients (n = 80, 34.2%) compared to anti-Tg-NEG (n = 154, 65.8%) had more frequently lymph node infiltration (36.3% vs 20.1%, P = .01), extrathyroidal extension (ETE, 35.0% vs 22.1%, P = .04), poorly differentiated DTC and increased tumour size (P ≤ .004). They received higher total RAI dose (P < .001). In most cases, additional RAI administration and/or additional surgeries did not lead to anti-Tg elimination. These had more frequently structural disease persistence/progression compared to anti-Tg-NEG (remission: 78.8% vs 95.5%, persistence: 13.8% vs 3.9%, progression: 7.5% vs 0.6%, P < .001). In Kaplan-Meier analysis, the probability of disease progression was higher in anti-Tg-POS. In Cox proportional hazard analysis, the predictors of disease progression were size (P = .002) and ETE (P = .006).

CONCLUSIONS

Worse histological features are more frequent in patients with anti-Tg persistence during follow-up. Further additional RAI administration and/or surgeries do not affect anti-Tg elimination in most cases. Anti-Tg persistence correlates with structural persistence although tumour size and extrathyroidal extension are the main predictors of disease progression.

Clinical outcome of patients with differentiated thyroid cancer and raised antithyroglobulin antibody levels: a retrospective study

BACKGROUND

Thyroglobulin (Tg) is a specific tumor marker for differentiated thyroid cancer (DTC). However, in the presence of an antithyroglobulin antibody (TgAb), it becomes unreliable. The purpose of the study was to assess the long-term outcome of DTC patients with raised TgAb.

METHOD

In a retrospective study, we included patients with DTC who had raised TgAb following total thyroidectomy. We excluded patients with persistently raised Tg (≥ 1 ng/ml) or radioiodine avid disease. Serial TgAb levels, excellent response (ER), incomplete response (IR), and anatomical recurrence were evaluated.

RESULTS

A total of seventy-six patients were included in the study. Patients with IR had higher baseline TgAb (1071.27 ± 1216.17 vs. 99.61 ± 91.29 IU/ml, p < 0.001) and central compartment lymph node metastases (70.8% vs. 46.4%, p = 0.035) in comparison to those in the ER group. In the first follow-up, 64 (84.2%) patients had a stable or fall in the TgAb (0 to - 98.3%). Sixty-eight patients received high-dose radioiodine therapy (RIT). Out of these, 59 (86.5%) had transient, and 51 (75%) had a long-term fall in TgAb. After a follow-up period of 58.74 ± 26.26 months, 63.2% (48 out of 76) patients had IR. Nine (11.8%) patients had a rising TgAb level (3.7-170.9%) from baseline. Eleven patients underwent 18F-FDG PET/CT, and five of them demonstrated metabolically active recurrent disease. Three patients underwent cervical lymph nodes dissection. None of the patients died during the follow-up period.

CONCLUSION

High post-operative TgAb levels and central compartment lymph nodal metastases are risk factors for IR. RIT leads to a significant fall in the TgAb in these patients. The low level of raised TgAb is associated with an excellent outcome. Patients with recurrences had very high baseline TgAb > 1000 IU/ml. Raised TgAb was associated with good clinical outcomes and not associated with increased mortality.

Glycosylation of Anti-Thyroglobulin IgG1 and IgG4 Subclasses in Thyroid Diseases

OBJECTIVE

Thyroglobulin antibodies (TgAb), principally comprising immunoglobulin G (IgG), are frequently found in healthy individuals. Previously, we showed that the glycosylation levels of TgAb IgG differed across various thyroid diseases, suggesting an important role of glycosylation on antibodies in the pathogenesis of thyroid diseases. Since IgG1 and IgG4 are the primary TgAb IgG subclasses, this study aimed to investigate the glycosylation of TgAb IgG1 and IgG4 subclasses in thyroid diseases.

METHODS

TgAb IgG was purified by affinity chromatography from the serum of patients with Hashimoto's thyroiditis (HT) (n = 16), Graves' disease (GD) (n = 8), papillary thyroid carcinoma (PTC) (n = 6), and PTC with histological lymphocytic thyroiditis (PTC-T) (n = 9) as well as healthy donors (n = 10). TgAb IgG1 and IgG4 concentrations were determined by enzyme-linked immunosorbent assay, and a lectin microassay was used to assess TgAb IgG1 and IgG4 glycosylation.

RESULTS

Significantly elevated mannose, sialic acid, and galactose levels on TgAb IgG1 were found in HT and PTC patients compared to GD patients and healthy controls (all p < 0.05). The mannose, sialic acid, and core fucose levels on TgAb IgG1 in PTC-T patients were higher than in healthy controls (all p < 0.05). Additionally, TgAb IgG1 from PTC-T patients exhibited lower sialylation than that from patients with PTC and higher fucosylation than that from patients with HT (both p < 0.05). However, TgAb IgG4 glycosylation did not differ among the five groups (p < 0.05).

CONCLUSION

Our study describes different distributions of TgAb IgG1 glycosylation in various thyroid diseases. The aberrantly increased glycosylation levels of TgAb IgG1 observed in HT, PTC, and PTC-T might be indicative of immune disorders and participate in the pathogenesis of these diseases.

Thyroglobulin Antibodies as a Prognostic Factor in Papillary Thyroid Carcinoma Patients with Indeterminate Response After Initial Therapy

The clinical outcome of papillary thyroid carcinoma (PTC) patients with an indeterminate response after initial therapy is reported to be intermediate, between incomplete and excellent responses. This study evaluated the outcomes of PTC patients with indeterminate response after initial therapy. It was further determined whether the indeterminate findings predicted outcomes more precisely. Patients were further classified into 3 groups based on risk of structural persistence/recurrence: Tg group: detectable thyroglobulin, negative antithyroglobulin antibody, regardless nonspecific imaging findings; TgAb group: positive antithyroglobulin antibody, regardless thyroglobulin levels and nonspecific imaging findings, and Image group: nonspecific findings on neck ultrasonography or faint uptake in the thyroid bed on whole-body scan, undetectable thyroglobulin and negative antithyroglobulin antibody. Sixty-six patients aged 44.1±12.7 years were studied, of whom 58 (87.9%) were females. All patients underwent total thyroidectomy, and 52 patients (78.8%) received radioiodine. After 5.7 years (P25-75 2.6-9.75 years) of follow-up, most patients (89.4%) were reclassified as having an excellent response or remained in the indeterminate response to therapy. Structural recurrence/persistence disease was detected in 7 (10.6%) patients. The persistence/recurrence rate in groups were as follow: Tg, 2.63%; TgAb, 31.25%; Image, 8.3% (p=0.007). The 10-years disease-free survival rate in the TgAb group was significantly reduced (p=0.022). Our results suggest that patients with PTC and indeterminate response due to positive serum antithyroglobulin antibody have more risk of development of structural disease. These findings suggest a more individualized follow-up strategy for patients with an indeterminate response.

Positive Thyroid Peroxidase Antibody and Thyroglobulin Antibody are Associated With Better Clinicopathologic Features of Papillary Thyroid Cancer

OBJECTIVE

To compare the thyroid autoantibody status of patients with papillary thyroid cancer (PTC) and benign nodular goiter as well as possible associations between thyroid autoantibodies and clinicopathologic features of PTC.

METHODS

A total of 3934 participants who underwent thyroidectomy were enrolled in this retrospective study. Patients were divided into PTC and benign nodule groups according to pathological diagnosis. Based on the preoperative serum antibody results, PTC patients were divided into thyroid peroxidase antibody (TPOAb)-positive, thyroglobulin antibody (TgAb)-positive, dual TPOAb- and TgAb-positive, or antibody-negative groups.

RESULTS

Of the 3934 enrolled patients, 2926 (74.4%) were diagnosed with PTC. Multivariate regression analyses suggested that high thyroid-stimulating hormone levels (adjusted odds ratio [OR] = 1.732, 95% CI [1.485-2.021], P < .001), positive TgAb (adjusted OR = 1.768, 95% CI [1.436-2.178], P < .001), and positive TPOAb (adjusted OR = 1.452, 95% CI [1.148-1.836], P = .002) were independent risk factors for predicting malignancy of thyroid nodules. Multinomial multiple logistic regression analyses indicated that positive TPOAb alone was an independent predictor of less central lymph node metastasis in PTC patients (adjusted OR = 0.643, 95% CI [0.448-0.923], P = .017), whereas positive TgAb alone was significantly associated with less extrathyroidal extension (adjusted OR = 0.778, 95% CI [0.622-0.974], P = .028). PTC patients with dual-positive TPOAb and TgAb displayed a decreased incidence of extrathyroidal extension (adjusted OR = 0.767, 95% CI [0.623-0.944], P = .012) and central lymph node metastasis (adjusted OR = 0.784, 95% CI [0.624-0.986], P = .037).

CONCLUSION

Although preoperative positive TPOAb and TgAb are independent predictive markers for PTC, they are also associated with better clinicopathologic features of PTC.

Investigating Antithyroglobulin Antibody As a Prognostic Marker for Differentiated Thyroid Cancer: A Meta-Analysis and Systematic Review

Background: Serum thyroglobulin (Tg) is used in the follow-up of patients with differentiated thyroid cancers (DTC), but the presence of antithyroglobulin antibodies (TgAbs) makes Tg measurements unreliable. TgAb decline after total thyroidectomy and persistent/increasing levels may indicate cancer persistence/recurrence. Hence, we aimed to determine whether TgAb might be a reliable prognostic marker for DTC. Methods: We conducted a meta-analysis and systematic review. A comprehensive literature search was performed to identify studies of patients with DTC with known TgAb status and prognostic outcomes in five databases (Medline, Embase, PubMed, Google Scholar, and Scopus). We used a random-effects model to calculate pooled odds ratios (ORs) and 95% confidence intervals (CIs) for TgAb status and its association with DTC prognosis. Results: After analysis of 34 studies, we found that TgAb+ patients have a higher risk of lymph node metastasis (OR = 1.18 [CI 1.47-2.25]) and cancer persistence/recurrence (OR = 2.78 [CI 1.55-4.98]) than TgAb- patients. However, no significant differences in mean/median tumor size, risk of extrathyroidal extension, tumor multifocality, and cancer mortality were found between the two groups. In a comparison of TgAb trends, patients with persistent/increasing TgAb levels were found to have a higher risk of cancer persistence/recurrence (OR = 9.90 [CI 4.36-22.50]) and cancer mortality (OR = 15.18 [CI 2.99-77]) than patients with decreasing TgAb levels. Conclusions: TgAb positivity and persistent/increasing trends were associated with compromised DTC prognosis. These results suggest that TgAb may be used as a prognostic marker in the follow-up of patients with DTC.

The De Novo Detection of Anti-Thyroglobulin Antibodies and Differentiated Thyroid Cancer Recurrence

Background: The prevalence and clinical significance of de novo detection of anti-thyroglobulin antibodies (TgAbs) during the follow-up of patients with differentiated thyroid cancer (DTC) is unknown. Methods: We utilized the National Thyroid Cancer Treatment Cooperative Study registry (1987-2012). Patients registered after 1996 (n = 3318) were analyzed. We identified 1545 subjects who had available TgAb status (TgAb cohort) between years 1996 and 2012, of whom 1325 were TgAb negative at first postoperative follow-up testing. From this initial TgAb-negative group, we excluded 513 patients: 423 patients who had less than 3 years of follow-up and/or fewer than three follow-up visits, 86 patients with persistent disease after initial treatment, and 4 patients with data entry errors. The remaining 812 patients were included for analysis, comprising the TgAb persistently negative group (defined as TgAb negative for at least 3 consecutive follow-up visits and at least 3 years of follow-up) (n = 772) and the de novo TgAb-positive group in whom TgAbs became detectable (n = 40). We then assessed whether de novo appearance of TgAb was associated with DTC structural recurrence by using the Kaplan-Meier method. Results: The de novo detection of TgAb occurred in 5% of DTC patients. Recurrence of DTC in the TgAb persistently negative group compared with the de novo TgAb-positive group did not differ significantly (9.6% vs. 15.0%, p = 0.23). Baseline characteristics, histology, history of radiation exposure, staging, and median duration of follow-up were similar between the two groups. Interestingly, in all six patients who suffered a recurrence in the de novo TgAb-positive group, the TgAbs were negative at the time of recurrence detection and became positive at a median of 2.1 (0.7-8.7) years after the structural recurrence. Conclusions: Utilizing a large North American DTC registry, we found the prevalence of de novo TgAb detection to be 5% among initially TgAb-negative patients. We did not find a statistically significant association between de novo TgAb development and DTC structural recurrence. Larger prospective studies are required to confirm these findings and further assess the significance of de novo TgAb detection in the follow-up of DTC.

Molecular Markers Guiding Thyroid Cancer Management

The incidence of thyroid cancer is rapidly increasing, mostly due to the overdiagnosis and overtreatment of differentiated thyroid cancer (TC). The increasing use of potent preclinical models, high throughput molecular technologies, and gene expression microarrays have provided a deeper understanding of molecular characteristics in cancer. Hence, molecular markers have become a potent tool also in TC management to distinguish benign from malignant lesions, predict aggressive biology, prognosis, recurrence, as well as for identification of novel therapeutic targets. In differentiated TC, molecular markers are mainly used as an adjunct to guide management of indeterminate nodules on fine needle aspiration biopsies. In contrast, in advanced thyroid cancer, molecular markers enable targeted treatments of affected signalling pathways. Identification of the driver mutation of targetable kinases in advanced TC can select treatment with mutation targeted tyrosine kinase inhibitors (TKI) to slow growth and reverse adverse effects of the mutations, when traditional treatments fail. This review will outline the molecular landscape and discuss the impact of molecular markers on diagnosis, surveillance and treatment of differentiated, poorly differentiated and anaplastic follicular TC.

Serum antithyroglobulin antibody levels are not a good predictive factor on detection of disease activity in patients with papillary thyroid carcinoma

Objective

Thyroglobulin antibodies (TgAb) are detected in thyroid cancer patients up to 25%. We investigated the prognostic value of TgAb positivity in patients with papillary thyroid carcinoma (PTC) after initial therapy.

Patients and Methods

A database of 109 consecutive patients who underwent total thyroidectomy and therapeutic lateral neck dissection followed by remnant ablation for PTC between January 1989 and December 2014 was reviewed We recorded the patients' all serum Tg and TgAb levels over time to establish changing trends. Patients were classified as either positive or negative according to serum TgAb levels. The recurrence or persistence rates in both groups were compared.

Results

Of the 109 patients enrolled 14 patients had TgAb positivity. Thirty-two (29.3%) showed disease recurrence or persistent disease during 101 months of follow-up. Twenty-seven of 95 patients (28.4%) with negative TgAb had persistent or recurrent disease, whereas 5 of 14 patients (35.7%) with positive TgAb had persistence or recurrence (P = 0.57). No significant difference in disease-free survival (115.3 ± 10.8 vs. 224.1 ± 16.6 months, P = 0.78) and overall survival (P = 0.59) was observed between TgAb positive and TgAb negative patients.

Conclusions

TgAb status is not useful as a prognostic and predictive factor for clinical outcomes in patients with PTC in our experience.

Calcitonin levels by ECLIA correlate well with RIA values in higher range but are affected by sex, TgAb, and renal function in lower range

Calcitonin (CT) is a marker for both initial diagnosis and monitoring of patients with residual or recurrent medullary thyroid carcinoma (MTC). In Japan, serum CT had been measured by radioimmunoassay (RIA) until recently. Electrochemiluminescence immunoassay (ECLIA) became commercially available in 2014, and this technique is now the only method used to examine CT concentration. The purposes of this study were to investigate the correlations between the CT concentration measured with ECLIA (ECLIA-CT) and RIA (RIA-CT) and to explore the clinical characteristics of patients with elevated ECLIA-CT. CT concentrations of 348 sera samples from 334 patients with various thyroid disorders including nine MTC were measured using both assays. The correlation analysis revealed an excellent correlation between ECLIA-CT and RIA-CT among the cases with CT level >150 pg/mL by both assays (r_s = 0.991, p < 0.001). However, 63% of all samples exhibited undetectable ECLIA-CT, while their RIA-CTs were measured between 15 and 152 pg/mL. The ECLIA-CTs in all patients who underwent total thyroidectomy for non-MTC showed low concentrations. High ECLIA-CT was observed in patients with MTC or pancreas neuroendocrine tumor. ECLIA-CT was also increased in 14 other male patients with non-MTC, including four with renal failure. Multivariate logistic regression analysis showed that male sex, negative TgAb, and lower estimated glomerular filtration rate were independent factors to predict detectable ECLIA-CT (≥0.500 pg/mL). These results indicate that ECLIA-CT correlates well with RIA-CT in higher range and is affected by sex, TgAb, and renal function.

Prognostic Significance of Thyroglobulin Antibodies in Differentiated Thyroid Cancer

Objective

To investigate whether variations in thyroglobulin autoantibodies (TgAb) are related to the recurrence or persistence of differentiated thyroid carcinoma (DTC) and may therefore be useful as surrogate tumor markers. Design and Methods. We retrospectively studied 98 subjects (83 women, 47 ± 15 years old) from an initial cohort of 1017 patients treated for DTC in five hospitals, with positive TgAb at any time during the follow-up. Patients presented five different patterns of evolution of serum TgAb concentrations: (1) stable positive TgAb, (2) de novo appearance, (3) an increase of more than 50%, (4) TgAb levels from positive to negative, and (5) a decrease of more than 50%.

Results

In the group of 11 patients with stable TgAb, four cases presented persistence of the disease with structural incomplete response. In the group of 22 patients with sustained increasing trend rising more than 50% or de novo detectable TgAb levels, three patients were diagnosed with structural incomplete response. There was no evidence of recurrence or persistence of the disease in any of the 65 patients who showed a significant decrease in (n = 35) or disappearance of (n = 30) TgAb.

Conclusions

Our results suggest that not only the appearance of a significant increase in TgAb but also stable concentrations of TgAb should be regarded as a sufficient risk condition for an active search for recurrent or persistent disease. Conversely, a significant decrease in TgAb levels can represent a good prognostic sign.

Chronic lymphocytic thyroiditis protects against recurrence in patients with cN0 papillary thyroid cancer

BACKGROUND

Chronic lymphocytic thyroiditis (CLT) frequently coexists with papillary thyroid carcinoma (PTC) that exhibits normal thyroid function. However, few studies have investigated the relationship between CLT and clinically lymph node (LN)-negative PTC. The aim of this study was to evaluate the relationship between subclinical central LN metastasis and CLT, and to assess the impact of CLT on the recurrence of clinically LN-negative PTC.

METHODS

We investigated the medical records of 850 patients with PTC who underwent prophylactic bilateral central neck dissection as well as total thyroidectomy between 2004 and 2010; the median follow-up time was 95.5 months (range, 12-158 months).

RESULTS

CLT was observed in 480 patients (56.5%). Female sex, a preoperative thyroid-stimulating hormone level >2.5 mU/L, a primary tumor ≤1 cm, no gross extrathyroidal extension, high number of harvested LNs, low number of metastatic LNs, and positive anti-thyroglobulin (Tg) antibody at 1 year post-initial treatment were significantly associated with the presence of CLT. Multivariate analysis revealed that patients with N1a stage (vs. N0 stage; hazard ratio [HR], 3.255; 95% confidence interval [CI], 1.290-8.213; p = 0.012) and positive anti-Tg antibody at 1 year post-initial treatment (vs. negative anti-Tg antibody; HR, 5.118; 95% CI, 2.130-12.296; p < 0.001) had poorer recurrence-free survival (RFS), while those with CLT (vs. no CLT; HR, 0.357; 95% CI, 0.157-0.812; p = 0.014) had favorable RFS outcomes.

CONCLUSIONS

CLT is associated with less aggressive tumor characteristics and LN metastasis. Clinically LN-negative PTC patients with CLT experience longer RFS intervals than those without CLT.

Male sex is associated with aggressive behaviour and poor prognosis in Chinese papillary thyroid carcinoma

The differences in prognosis of papillary thyroid carcinoma (PTC) by sex have been investigated in several previous studies, but the results have not been consistent. In addition, the impact of sex on the clinical and pathological characteristics, especially on central lymph node metastasis (CLNM), still remains unknown. To the best of our knowledge, the impact of sex on PTC has not been investigated in the Chinese PTC population. Therefore, our study retrospectively analysed the data of 1339 patients who were diagnosed with PTC and had received radical surgery at Ningbo Medical Center, Lihuili Hospital. In addition to cancer-specific death, structural recurrence and risk stratification, prognosis was also estimated by using three conventional prognostic systems: AMES (age, distant metastasis, extent, size), MACIS (distant metastasis, age, completeness of resection, local invasion, size) and the 8^th version TNM (tumor, lymph node, metastasis) staging system. The clinical and pathological characteristics and above prognostic indexes were compared between male and female PTC patients. The results showed that there were higher rates of non-microcarcinoma PTC (nM-PTC), CLNM, lateral lymph node metastasis (LLNM), advanced disease and bilateral disease, but there was a lower rate of concurrent Hashimoto’s thyroiditis (HT) in male PTC patients than in female PTC patients. Additionally, the rate of intermediate-risk, high-risk or advanced disease was higher in male PTC patients. The above findings indicate that PTC in men is a more aggressive disease and may have a worse prognosis; thus, it should be treated with more caution.

Contemporary Debates in Adult Papillary Thyroid Cancer Management

An ever-increasing population of patients with papillary thyroid cancer is engaging with health care systems around the world. Numerous questions about optimal management have arisen that challenge conventional paradigms. This is particularly the case for patients with low-risk disease, who comprise most new patients. At the same time, new therapies for patients with advanced disease are also being introduced, which may have the potential to prolong life. This review discusses selected controversial issues in adult papillary thyroid cancer management at both ends of the disease spectrum. These topics include: (i) the role of active surveillance for small papillary cancers; (ii) the extent of surgery in low-risk disease (lobectomy vs total thyroidectomy); (iii) the role of postoperative remnant ablation with radioiodine; (iv) optimal follow-up strategies in patients, especially those who have only undergone lobectomy; and (v) new therapies for advanced disease. Although our current management is hampered by the lack of large randomized controlled trials, we are fortunate that data from ongoing trials will be available within the next few years. This information should provide additional evidence that will decrease morbidity in low-risk patients and improve outcomes in those with distant metastatic disease.

UNFAVORABLE RESPONSES TO RADIOIODINE THERAPY IN N1B PAPILLARY THYROID CANCER: A PROPENSITY SCORE MATCHING STUDY

Objective: Regional nodal metastases carry prognostic significance in papillary thyroid cancer (PTC). However, whether different locational nodal metastases correlate with different therapeutic responses remains controversial. We innovatively applied the response to therapy restratification system to evaluate the dynamic disease status after surgery and radioactive iodine (RAI) therapy in PTC patients with different locational nodal metastases. Methods: A total of 585 nondistant-metastatic PTC patients who underwent total thyroidectomy and RAI therapy were retrospectively enrolled. Patients with nodal metastases were categorized into N1a and N1b groups. Propensity score matching was used to balance the bias between the 2 groups. Therapeutic responses were dynamically evaluated, and responses to RAI therapy were classified into excellent (ER), indeterminate (IDR), biochemical incomplete (BIR) and structural incomplete response (SIR). Results: N1b group patients showed a significantly higher pre-ablation stimulated thyroglobulin (Ps-Tg) level than N1a group patients (7.4 ng/mL versus 3.2ng/mL, P<.001). After RAI therapy, N1b group patients took a longer time to achieve ER (9.86 months versus 3.29 months, P<.001) and exhibited a higher proportion of non-ER (IDR, BIR, and SIR) (39.15% versus 17.46%, P<.001) compared to N1a group patients. In logistic regression, N1b and Ps-Tg ≥10 ng/mL were confirmed to be independent factors predicting non-ER (odds ratio: 2.591, and 9.196, respectively). In Cox regression, patients with N1b disease and Ps-Tg ≥10 ng/mL showed significantly lower hazards for achieving ER (hazard ratio: 0.564, and 0.223, respectively). Conclusion: N1b PTC patients showed inferior responses to surgery and RAI therapy compared to N1a patients. N1b was confirmed to be an independent factor predicting unfavorable responses to RAI therapy. Abbreviations: AJCC = American Joint Committee on Cancer; ATA = American Thyroid Association; BIR = biochemical incomplete response; BRAF^V600E = proto-oncogene B-Raf V600E mutation; CI = confidence interval; CT = computed tomography; DNA = deoxyribonucleic acid; DTC = differentiated thyroid cancer; ER = excellent response; ETE = extrathyroidal extension; HR = hazard ratio; IDR = indeterminate response; LNM = lymph node metastasis; N1a = central cervical LNM; N1b = lateral cervical LNM; OR = odds ratio; PSM = propensity score matching; Ps-Tg = pre-ablation stimulated thyroglobulin; PTC = papillary thyroid cancer; RAI = radioactive iodine; SIR = structural incomplete response; Tg = thyroglobulin; TgAb = thyroglobulin antibody; TSH = thyroid-stimulating hormone.

In properly selected patients with differentiated thyroid cancer, antithyroglobulin antibodies decline after thyroidectomy and their sole presence should not be an indication for radioiodine ablation

OBJECTIVE

Our objective was to evaluate the trend of antithyroglobulin antibodies (TgAb) during follow-up of patients with differentiated thyroid cancer (DTC) treated without RAI, as well as their role in the risk of recurrence.

SUBJECTS AND METHODS

This was a prospective, descriptive study. A total of 152 consecutive patients with DTC treated in a single institution undergoing total thyroidectomy without RAI and followed for a median of 2.3 years (0.5-10.3) were divided in two groups: TgAb(-) (n = 111) and TgAb(+) (n = 41). Patients were classified according to AJCC 7th and 8th editions, as well as to their risk of recurrence and response to treatment categories.

RESULTS

Both groups, TgAb(-) and TgAb(+), were similar regarding patient and tumor characteristics. At the end of follow-up, 90 (59.2%), 57 (37.5%), 3 (2%) and 2 (1.3%) patients achieved excellent, indeterminate, biochemically incomplete and structurally incomplete response, respectively. The risk of structural recurrence was similar in both groups (TgAb[-] 0.9% vs. TgAb[+] 2.4%, p = 0.46). In the TgAb(+) group, TgAb became negative in 10 (24.4%), decreased ≥ 50% without negativization in 25 (60.9%), decreased < 50% in 4 (9.8%) and remained stable or increased in 2 (4.9%) cases. The only incomplete structural response had increasing TgAb during follow-up.

CONCLUSIONS

In properly selected patients with DTC, TgAb concentration immediately after total thyroidectomy should not mandate RAI ablation, and their trend during follow-up may impact the risk of recurrence.

Clinical Applicability of Low Levels of Thyroglobulin Autoantibodies as Cutoff Point for Thyroglobulin Autoantibody Positivity

BACKGROUND

Thyroglobulin (Tg) is an established tumor marker in differentiated thyroid carcinoma (DTC). However, Tg assays can be subject to interference by autoantibodies against Tg (TgAbs). No clinical consensus exists on the cutoff value of TgAb positivity and its relationship to Tg assay interference. The aims of this study were to investigate the most applicable cutoff value for TgAb positivity in clinical practice and to evaluate whether tumor characteristics differ between TgAb+ and TgAb- patients during ablation therapy using the manufacturer's cutoff (MCO) and institutional cutoff (ICO).

METHODS

This single-center cohort study included 230 DTC patients diagnosed between January 2006 and December 2014. Serum Tg and TgAbs were measured with the Tg-IRMA (Thermo Fisher Scientific) and ARCHITECT Anti-Tg (Abbott Laboratories) assays. Patients were divided into TgAb- and TgAb+ based on the limit of detection (LoD; ≥0.07 IU/mL), functional sensitivity (FS; ≥0.31 IU/mL), MCO (≥4.11 IU/mL), and ICO (≥10 IU/mL).

RESULTS

All patients were TgAb+ based on the LoD; one patient was negative on FS. Fifty-five (23.9%) and 34 (14.8%) patients had TgAbs above the MCO and ICO, respectively. Histology, presence of multifocality, tumor-node-metastasis, and American Thyroid Assocation risk stratification did not differ between TgAb- and TgAb+ patients using MCO and ICO during ablation.

CONCLUSIONS

This study supports the use of a higher cutoff value than that of the FS for TgAb positivity in clinical settings. The LoD and FS are too sensitive to discriminate TgAb positivity and negativity in DTC patients during ablation therapy. The presence of TgAbs during ablation is not related to tumor characteristics and risk profile. This implies that TgAb positivity should not be considered a separate risk factor.

Clinical implications of anti-thyroglobulin antibody measurement before surgery in thyroid cancer

Thyroglobulin antibody (TgAb) is a class G immunoglobulin and a conventional marker for thyroid autoimmunity. From a clinical perspective, TgAb is less useful than thyroid peroxidase antibodies for predicting thyroid dysfunction. However, TgAb is found more frequently in differentiated thyroid cancer (DTC) and can interfere with thyroglobulin (Tg) measurements, which are used to monitor the recurrence or persistence of DTC. Recent studies suggested a small but consistent role for preoperative TgAb in predicting DTC in thyroid nodules, and in reflecting adverse tumor characteristics or prognosis, including lymph node metastasis, but this is still controversial. Postoperative TgAb can serve as a biomarker for remnant thyroid tissue, so follow-up measures of TgAb are useful for predicting cancer recurrence in DTC patients. Since high serum TgAb levels may also affect the fine needle aspiration washout Tg levels from suspicious lymph nodes of DTC patients, it is important to use caution when interpreting the washout Tg levels in patients who are positive for TgAb.

Follow-up of differentiated thyroid cancer - what should (and what should not) be done

The treatment paradigm for thyroid cancer has shifted from a one-size-fits-all approach to more personalized protocols that range from active surveillance to total thyroidectomy followed by radioiodine remnant ablation. Accurate surveillance tools are available, but follow-up protocols vary widely between centres and clinicians, owing to the lack of clear, straightforward recommendations on the instruments and assessment schedule that health-care professionals should adopt. For most patients (that is, those who have had an excellent response to the initial treatment and have a low or intermediate risk of tumour recurrence), an infrequent assessment schedule is sufficient (such as a yearly determination of serum levels of TSH and thyroglobulin). Select patients will benefit from second-line imaging and more frequent assessments. This Review discusses the strengths and weaknesses of the surveillance tools and follow-up strategies that clinicians use as a function of the initial treatment and each patient's risk of recurrence.

Diagnostic performance of PET in thyroid cancer with elevated anti-Tg Ab

We aimed to explore the role of the diagnostic accuracy of F-18 fluorodeoxyglucose positron emission tomography/computed tomography (PET/CT) for the detection of recurrent and/or metastatic diseases in differentiated thyroid cancer (DTC) patients with progressively and/or persistently elevated TgAb levels and negative radioactive iodine whole-body scan (RI-WBS) through a systematic review and meta-analysis. The MEDLINE, EMBASE and Cochrane Library database, from the earliest available date of indexing through June 30, 2017, were searched for studies evaluating the diagnostic performance of F-18 FDG PET/CT for the detection of recurrent and/or metastatic diseases in DTC patients with progressively and/or persistently elevated TgAb levels and negative RI-WBS. We determined the sensitivities and specificities across studies, calculated positive and negative likelihood ratios (LR+ and LR-). Across 9 studies (515 patients), the pooled sensitivity for F-18 FDG PET/CT was 0.84 (95% CI; 0.77-0.89) a pooled specificity of 0.78 (95% CI; 0.67-0.86). Likelihood ratio (LR) syntheses gave an overall positive likelihood ratio (LR+) of 3.8 (95% CI; 2.5-5.7) and negative likelihood ratio (LR-) of 0.21 (95% CI; 0.14-0.30). The pooled diagnostic odds ratio (DOR) was 18 (95% CI; 10-34). The area (AUC) under the hierarchical summary receiver-operating characteristic (HCROC) curve was 0.88 (95% CI: 0.85-0.90). F-18 FDG PET or PET/CT demonstrated moderate sensitivity and specificity for the detection of recurrent and/or metastatic diseases in DTC patients with progressively and/or persistently elevated TgAb levels and negative RI-WBS.

Clinical Impact of Detectable Antithyroglobulin Antibodies Below the Reference Limit (Borderline) in Patients with Papillary Thyroid Carcinoma with Undetectable Serum Thyroglobulin and Normal Neck Ultrasonography After Ablation: A Prospective Study

BACKGROUND

Interference of antithyroglobulin antibodies (TgAb) with serum thyroglobulin (Tg) can occur even at detectable TgAb concentrations below the reference limit (borderline TgAb). Thus, borderline TgAb is considered as TgAb positivity in patients with thyroid cancer. This prospective study evaluated patients with papillary thyroid carcinoma with undetectable Tg and normal neck ultrasonography (US) after total thyroidectomy and ablation with ¹³¹I, and compared tumor persistence/recurrence and long-term Tg and TgAb behavior in those with borderline versus undetectable TgAb.

METHODS

A total of 576 patients were evaluated, divided into two groups: group A with undetectable TgAb (n = 420), and group B with borderline TgAb (n = 156).

RESULTS

Groups A and B were similar in terms of patient and tumor characteristics. The time of follow-up ranged from 24 to 120 months. During follow-up, 11 (2.6%) patients in group A and 5 (3.2%) in group B developed a recurrence (p = 0.77). In group A, recurrences occurred in 9/390 patients who continued to have undetectable TgAb and in 1/9 patients who progressed to borderline TgAb. In group B, recurrences were detected in 1/84 patients who progressed to have undetectable TgAb, in 1/45 who still had borderline TgAb, and in 3/12 who developed elevated TgAb. In the presence of Tg levels <0.2 ng/mL, recurrences were detected in 2/486 patients with undetectable TgAb, in 0/67 with borderline TgAb, and in 3/12 with elevated TgAb. The results of post-therapy whole-body scanning (RxWBS) of 216 patients with Tg ≤0.2 ng/mL and normal US at the time of ablation were also analyzed. In low-risk patients, none of the 40 patients with borderline TgAb and none of the 94 with undetectable TgAb exhibited ectopic uptake on RxWBS. In intermediate-risk patients, lymph node metastases were detected by RxWBS in 1/25 (4%) with borderline TgAb and in 2/57 (3.5%) with undetectable TgAb.

CONCLUSIONS

The results suggest that among low- or intermediate-risk patients with undetectable Tg and normal US after thyroidectomy, those with borderline TgAb are at no greater risk of tumor persistence or recurrence than those with undetectable TgAb. When undetectable Tg levels persist, recurrence should be suspected in the case of a TgAb elevation above the reference limit.

Recent advances in managing differentiated thyroid cancer

The main clinical challenge in the management of thyroid cancer is to avoid over-treatment and over-diagnosis in patients with lower-risk disease while promptly identifying those patients with more advanced or high-risk disease requiring aggressive treatment. In recent years, novel clinical and molecular data have emerged, allowing the development of new staging systems, predictive and prognostic tools, and treatment approaches. There has been a notable shift toward more conservative management of low- and intermediate-risk patients, characterized by less extensive surgery, more selective use of radioisotopes (for both diagnostic and therapeutic purposes), and less intensive follow-up. Furthermore, the histologic classification; tumor, node, and metastasis (TNM) staging; and American Thyroid Association risk stratification systems have been refined, and this has increased the number of patients in the low- and intermediate-risk categories. There is now a need for new, prospective data to clarify how these changing practices will impact long-term outcomes of patients with thyroid cancer, and new follow-up strategies and biomarkers are still under investigation. On the other hand, patients with more advanced or high-risk disease have a broader portfolio of options in terms of treatments and therapeutic agents, including multitarget tyrosine kinase inhibitors, more selective BRAF or MEK inhibitors, combination therapies, and immunotherapy.

Unfavorable efficacy to 131I ablation in BRAFV600E mutant papillary thyroid carcinoma with positive TgAb

The BRAFV600E mutation has shown a close relationship of aggressiveness in papillary thyroid carcinoma (PTC), while it remains unclear about its influence on the therapeutic response. As a common clinicopathologic risk factor, thyroglobulin antibody (TgAb) may have a correlation of prognosis in PTC. The objective was to investigate the relationship between BRAFV600E mutation and TgAb, and their combined effect on efficacy to radioiodine remnant ablation (RRA). This was a retrospective study including 298 PTC patients and they were divided into four groups according to the combined status. The BRAFV600E mutation rates declined along with increasing TgAb levels in the entire cohort. The ablative efficacy in terms of success or failure rate was statistically different among four groups (89.7%, 74.1%, 67.5%, 57.8%, respectively, P=0.009), group with both positive BRAF and TgAb presented the lowest efficacy. The combined status was associated with the poor efficacy to RRA independently (P=0.029). Among patients with positive TgAb, the effect of RRA in reducing TgAb level might be weakened in BRAF mutant status. The combined status of BRAFV600E mutation and positive TgAb predicts low efficacy to RRA and might be served as an independent unfavorable prognostic factor for PTC. BRAF mutant might weaken the effect of RRA in reducing TgAb levels in PTCs.

Prognostic value of change in anti-thyroglobulin antibodies after thyroidectomy in patients with papillary thyroid carcinoma

PURPOSE

Anti-thyroglobulin antibodies (TgAb) can be used as a surrogate tumor marker in the follow-up of papillary thyroid carcinoma (PTC). We try to determine if the change in TgAb levels in the first post-operative year is a good predictor of persistence/recurrence risk in TgAb-positive PTC patients.

METHODS/PATIENTS

105 patients with PTC who underwent thyroidectomy between 1988 and 2014 were enrolled. We calculated the percentage of change in TgAb levels with the first measurement at 1-2 months after surgery and the second one at 12-14 months.

RESULTS

TgAb negativization was observed in 29 patients (27.6%), a decrease of more than 50% was observed in 57 patients (54.3%), less than 50% in 12 patients (11.4%) and in 7 patients (6.7%) the TgAb level had increased. The percentage of persistence/recurrence was 0, 8.8, 16.7 and 71.4% in each group, respectively (p < 0.001). In the multivariate analysis, only the percentage of change in TgAb showed a significant association with the risk of persistence/recurrence, regardless of other factors such as age, size and TNM stages.

CONCLUSIONS

Changes in TgAb levels in the first year after surgery can predict the risk of persistence/recurrence of TgAb-positive PTC patients. Patients who achieved negativization of TgAb presented an excellent prognosis.

Thyroid autoimmune antibodies in patients with papillary thyroid carcinoma: a double-edged sword?

PURPOSE

The relationship between thyroid autoimmunity and thyroid cancer remains controversial. The objective of this study is to comprehensively analyze the association between thyroid autoimmune antibodies and disease statuses of papillary thyroid carcinoma (PTC).

METHODS

Patients were divided into different groups according to their final diagnoses after radioiodine therapy as well as their serum anti-thyroglobulin antibody (TgAb) and anti-thyroidperoxidase antibody (TPOAb) titers. Clinicopathologic characteristics were then compared between groups.

RESULTS

In all, 1126 PTC patients met the inclusion criteria. When compared with thyroid autoimmune antibody negative group, patients in positive group were young female predominant. After age and gender adjusted, patients in thyroid autoimmune antibody positive group had much more cervical metastatic node count and this effect was limited to the central compartment but not to the lateral compartment. Antibody positivity rate was much lower in patients with distant metastasis and multivariable logistic regression analysis showed positive status of antibody was a protective factor of distant metastasis of PTC with an OR value of 0.403 (95% CI 0.216-0.622, p < 0.001). Additionally, subgroup analysis demonstrated single TgAb positivity and combined positivity of TgAb and TPOAb were shown to be related to less distant metastatic disease.

CONCLUSIONS

Positive thyroid auto-antibody status could be a risk factor of more metastatic cervical lymph nodes while a protective factor of distant metastatic disease in PTC patients. The association between thyroid autoimmunity and thyroid cancer can be patient and antibody specific. A systemic immunosupression status may exist in PTC patients with distant metastasis.

Prevalence and Significance of Thyroglobulin Antibodies in Pediatric Thyroid Cancer

CONTEXT

Circulating thyroglobulin antibodies (TgAb) can confound measurement of serum thyroglobulin and impair thyroid cancer surveillance. Few data exist on the significance of TgAb in pediatric thyroid cancer.

OBJECTIVE

To describe the prevalence, natural history, and clinical significance of TgAb in children with thyroid cancer.

DESIGN

Retrospective cohort study.

SETTING

Single academic pediatric center.

PATIENTS

Seventy-three consecutive children (≤18 years) with nonmedullary thyroid cancer who had serum TgAb measured within 6 months after diagnosis.

MAIN OUTCOME MEASURES

Prevalence and natural history of TgAb; association of TgAb status and resolution with patient and disease characteristics.

RESULTS

TgAb were detected in 41% of subjects (30 of 73) and were associated with lymph node metastasis (83% vs 53%, P = 0.01) but not distant metastasis. In patients with TgAb, resolution occurred in 44% (11 of 25) over a median follow-up of 3.8 years. Median time to clear TgAb was 10.7 months, and 10 of 11 patients who cleared (91%) did so within 2 years. Resolution of TgAb was associated with lower initial TgAb level (median 4.5 vs 76 normalized units, P = 0.003). TgAb positivity at diagnosis was not independently associated with persistent or recurrent disease (odds ratio 3.20, 95% confidence interval 0.95 to 10.80, P = 0.06).

CONCLUSIONS

TgAb are common at diagnosis in children with thyroid cancer but resolve in nearly half of patients within 1 to 2 years. TgAb are associated with the presence of lymph node metastasis at diagnosis, but the long-term prognostic significance remains to be determined.

Prognostic value of preoperative anti-thyroglobulin antibody in differentiated thyroid cancer

CONTEXT

The coexistence of differentiated thyroid cancer (DTC) and thyroid autoimmune disease could represent a better or worse prognosis. This study investigated the prognostic importance of preoperative anti-thyroglobulin antibody (TgAb) in DTC patients.

DESIGN AND PATIENTS

This retrospective hospital-cohort study enrolled 1171 consecutive DTC patients with preoperative TgAb data, who underwent total thyroidectomy between January 2006 and December 2011. Clinical parameters studied included demographics, primary tumour characteristics, radioiodine therapy, thyroid function tests, preoperative thyroglobulin (Tg) and TgAb levels, and cancer persistence/recurrence.

RESULTS

A total of 254 (21.7%) patients were preoperatively TgAb positive. The percentage positive for thyroid peroxidase (TPO) antibody and lymphocytic thyroiditis was significantly higher in the TgAb-positive group. The TgAb-positive group had a significantly higher rate of lymphatic invasion and lymph node metastasis both overall and in patients without TPOAb and lymphocytic thyroiditis (non-HT group). The mean number of total and central lymph nodes dissected and rate of lateral lymph node dissection were significantly higher in the TgAb-positive group, both overall and in non-HT patients. In regression analysis, preoperative TgAb was an independent risk factor for lateral lymph node metastasis. Over 50.2±14.5 months of follow-up, disease persistence/recurrence was not significantly different between patients with and without TgAb, both overall and in non-HT patients. Preoperative TgAb showed no significant correlation with final disease status.

CONCLUSION

Positive preoperative serum TgAb is associated with worse primary tumour characteristics but rarely showed poor prognosis, probably due to more aggressive treatment of these subjects.

Anti-thyroglobulin antibodies do not significantly increase the risk of finding iodine avid metastases on post-radioactive iodine ablation scan in low-risk thyroid cancer patients

OBJECTIVE

Post-operative thyroglobulin (Tg) levels can predict the likelihood of residual cancer, including distant metastases, thereby influencing postsurgical treatment strategies even in patients with low-risk disease. Circulating anti-thyroglobulin antibodies (anti-Tg Abs) interfere with Tg measurement preventing this clinical use. It is not known if the presence of anti-Tg Abs predicts metastatic disease on post-therapy scan in patients with low-risk disease or if they should influence the use or dose of I-131 therapy. In the present study, we compare post-therapy scans in low-risk patients with and without anti-Tg Abs.

METHODS

This is a single-institution retrospective study. The study population (Group A) included all patients with low-risk differentiated thyroid cancer (DTC) who underwent total thyroidectomy and RAI between 1/1/2006 to 9/11/2015 with intrathyroidal T1-T2, Nx, N0 or N1a (≤5 nodes all measuring, when reported, <2 mm) that had anti-thyroglobulin antibodies. Patients were excluded if they had known distant metastases and/or extensive vascular invasion. A second group of patients (Group B) treated during the same period but without anti-Tg antibodies was selected to match group A by propensity core matching with a logistic regression model.

RESULTS

Each group included 37 patients. In group A: Median age was 40 years, 86% female and 76% PTC. Median tumor size was 2 cm (0.2-3.8), 32% had multifocal disease, 16% were N1a and 4% had vascular invasion. Parameters in group B were not statistically different from Group A, as expected based on the selection criteria, except being less likely to have Hashimoto's thyroiditis on pathology (p < 0.001). Post-therapy scan results were compared by Chi-square test with 86% negative post therapy scan frequency in group A and 92% in group B without evidence of a difference (p = 0.45).

CONCLUSION

In patients with low-risk DTC, anti-Tg Abs did not significantly predict metastatic disease on post-therapy scan. If confirmed, these data suggest that the presence of anti-Tg Abs alone should not influence initial therapy in patients with low-risk DTC.

Influence of chronic lymphocytic thyroiditis on the risk of persistent and recurrent disease in patients with papillary thyroid carcinoma and elevated antithyroglobulin antibodies after initial therapy

INTRODUCTION

In patients with papillary thyroid carcinoma who have negative serum thyroglobulin after initial therapy, the risk of structural disease is higher among those with elevated antithyroglobulin antibodies compared to patients without antithyroglobulin antibodies. Other studies suggest that the presence of chronic lymphocytic thyroiditis is associated with a lower risk of persistence/recurrence of papillary thyroid carcinoma.

OBJECTIVE

This prospective study evaluated the influence of chronic lymphocytic thyroiditis on the risk of persistence and recurrence of papillary thyroid carcinoma in patients with negative thyroglobulin but elevated antithyroglobulin antibodies after initial therapy.

METHODS

This was a prospective study. Patients with clinical examination showing no anomalies, basal Tg<1ng/mL, and elevated antithyroglobulin antibodies 8-12 months after ablation were selected. The patients were divided into two groups: Group A, with chronic lymphocytic thyroiditis on histology; Group B, without histological chronic lymphocytic thyroiditis.

RESULTS

The time of follow-up ranged from 60 to 140 months. Persistent disease was detected in 3 patients of Group A (6.6%) and in 6 of Group B (8.8%) (p=1.0). During follow-up, recurrences were diagnosed in 2 patients of Group A (4.7%) and in 5 of Group B (8%) (p=0.7). Considering both persistent and recurrent disease, structural disease was detected in 5 patients of Group A (11.1%) and in 11 of Group B (16.1%) (p=0.58). There was no case of death related to the disease.

CONCLUSION

Our results do not support the hypothesis that chronic lymphocytic thyroiditis is associated with a lower risk of persistent or recurrent disease, at least in patients with persistently elevated antithyroglobulin antibodies after initial therapy for papillary thyroid carcinoma.

Relationship between circulating anti-thyroglobulin antibodies (TgAb) and tumor metabolism in patients with differentiated thyroid cancer (DTC): prognostic implications

PURPOSE

TgAb have been proposed as tumor markers in DTC. Recent evidence links TgAb levels with DTC aggressiveness. We aimed to evaluate the relationship between TgAb and tumor glucose metabolism in DTC patients.

METHODS

Seventy-one DTC patients who underwent ¹⁸F-FDG PET/CT were included. According to TgAb value and trends, patients were divided into TgAb positive (TgAb+) or negative (TgAb-) as well as in patients with increasing (Inc-TgAb) or decreasing (Dec-TgAb) trend. On the basis of the results of FDG-PET, post-therapy 131I and Tg levels, patients were divided into two groups according to the evidence (ED) or absence (NED) of disease. ED patients were further divided into three subgroups: 1. radioiodine avid with positive ¹⁸F-FDG PET/CT (PET+/131I+), 2. radioiodine refractory with positive ¹⁸F-FDG PET/CT (PET+/131I-) and 3. radioiodine avid with negative ¹⁸F-FDG PET/CT (PET-/131I+). MeanSUV of FDG-avid lesions was assessed and averaged for each patient (SUVmean-pt). T test was performed to assess the difference between SUVmean in TgAb-, TgAb+ and in Inc-TgAb and Dec-TgAb subgroups. Difference in TgAb between ED and NED patients as well as between ED patients and PET+/131I+, PET+/131I- and PET-/131I+ subgroups was compared.

RESULTS

SUVmean was significantly higher in Inc-TgAb with respect to Dec-TgAb subgroup (5.2 ± 1.5 vs. 2.9 ± 1.1, p < 0.05). TgAb were higher only in the ED PET+/131I+ subgroup with respect to NED patients (p < 0.01).

CONCLUSIONS

The relationship between higher tumor metabolism and trend of TgAb supports a prognostic relevance of TgAb in DTC patients. Significantly higher TgAb in radioiodine avid tumors with positive ¹⁸F-FDG PET/CT further testify the role of TgAb as surrogate tumor marker in DTC.

Clinicopathological relevance of antithyroglobulin antibodies in low-risk papillary thyroid cancer

OBJECTIVE

The extent of initial surgical management in papillary thyroid cancer (PTC) is controversial. We examined whether the presence of perioperative antithyroglobulin antibodies (TGA) could predict long-term recurrence and occurrence of adverse features among a homogenous group of patients with PTC.

METHODS

The clinical features of patients with PTC treated at a single institution (Jewish General Hospital, McGill University, Montreal, Canada) were obtained from the medical records, and all clinicopathologic information was reviewed. Only low-risk PTC without clinical evidence of nodal disease before surgery and treated with 30 mCi of radioactive iodine was included in the study.

RESULTS

The chart review retrieved 361 patients with a median follow-up of 85.0 months (Q25-Q75 73-98). Forty-two (11.6%) patients had presence of perioperative TGA. Perioperative TGAs were associated with present extrathyroidal extension (P=.005), unsuspected nodal disease (P=.001) and autoimmune thyroiditis (P<.0001). Overall, 17 (4.7%) patients experienced locoregional recurrence. Perioperative TGAs were a significant predictor of recurrence in univariable (P=.021) but not in multivariable analysis (P=.13).

CONCLUSION

Presence of perioperative TGAs is associated with aggressive histological features and the presence of thyroiditis. Detection of TGA perioperatively may encourage surgeons to consider more extensive initial surgery.

Chronic lymphocytic thyroiditis does not influence the risk of recurrence in patients with papillary thyroid carcinoma and excellent response to initial therapy

BACKGROUND

This study evaluated the recurrence in patients with papillary thyroid cancer and an excellent response to initial therapy, comparing those with and without chronic lymphocytic thyroiditis.

METHODS

This was a prospective study. Patients who met the following criteria were selected: diagnosis of papillary thyroid cancer; submitted to total thyroidectomy followed or not by ablation with ¹³¹I; and neck ultrasonography without abnormalities, nonstimulated thyroglobulina (Tg) ≤0.2 ng/ml, and undetectable antithyroglobulin antibodies (TgAb) 12-18 months after initial therapy. The patients were divided into two groups: group A, with chronic lymphocytic thyroiditis on histology; group B, without chronic lymphocytic thyroiditis on histology.

RESULTS

Groups A and B were similar in terms of sex and age of the patients, characteristics of the tumor, tumor-node-metastase stage and risk category. The time of follow-up ranged from 24 to 120 months (median 66 months). During follow-up, 5 patients of group A (2.6 %) and 9 patients of group B (2 %) developed recurrence (p = 0.77). Patients with chronic lymphocytic thyroiditis were more likely to progress to persistently borderline TgAb. No patient had positive TgAb (above the reference value) during follow-up. Recurrences occurred in 12/588 patients (2 %) with undetectable TgAb in all measurements, in 1/32 (3.1 %) with detectable TgAb on some occasion but that returned to undetectable spontaneously, and in 1/13 (7.7 %) with persistently borderline TgAb. These rates did not differ significantly (p = 0.25).

CONCLUSION

The results of the present study showed the absence of an association between chronic lymphocytic thyroiditis and recurrence risk at least in patients with an excellent response to initial therapy.

Thyroglobulin autoantibodies before radioiodine ablation predict differentiated thyroid cancer outcome

Background:

Serum thyroglobulin (Tg) is essential to manage differentiated thyroid carcinoma (DTC). However, Tg determination is affected by circulating Tg antibodies (TgAb), and a role of TgAb as surrogate biomarker has been proposed. Here we evaluated the role of TgAb measured before and after radioiodine ablation (RRA) as potential predictors of prognosis.

Methods:

Patients treated since 2006 were screened. Cancers with structural relapse were defined as recurrent. Both Tg and TgAb were measured by immunoassays on the fully automated Kryptor

Results:

A series of 215 DTC patients was enrolled, of whom 28.8% had positive preablation TgAb. Overall, 2.8% patients died by DTC and 11% recurred. High-risk class (p=0.004) and cancer relapse (p=0.007) occurred more frequently in positive TgAb, whereas better disease-free survival was observed in negative group (hazard ratio 2.59, p=0.01). Having positive preablation TgAb was significantly associated with risk to develop recurrence (odds ratio 3.57, p=0.004). Among positive TgAb subgroup, higher levels were recorded in recurrent cases (p=0.0001), and the most accurate preablation TgAb threshold was 107.5 IU/mL. When TgAb were measured at first follow-up, recurrence rate was significantly (p<0.0001) higher in persistently TgAb-positive patients (75%) than normalized ones (2.4%). At that time, the highest negative predictive value could be obtained when considering TgAb normalization (<33 IU/mL) or reduction by ≥36.4%.

Conclusions:

Positive TgAb before RRA indicates higher risk of poor prognosis, but their significant drop 6–12 months later could be considered a favorable factor.

Identification of Thyroid-Associated Serum microRNA Profiles and Their Potential Use in Thyroid Cancer Follow-Up

Context:

Trends toward more conservative management of papillary thyroid cancer (PTC) diminish the primacy of serum thyroglobulin (Tg) assays as a posttreatment surveillance tool.

Objective:

To identify thyroid tumor-associated microRNAs (miRNAs) in the serum with potential for development as unique biomarkers of PTC recurrence.

Methods:

We measured expression of 754 miRNAs in serum samples collected from 11 patients with PTC before and 30 days after thyroidectomy. Major candidates were then re-evaluated by absolute quantitative polymerase chain reaction analysis in an independent cohort of patients with PTC (n = 44) or benign nodules and 20 healthy controls (HCs). The 2 miRNAs most significantly associated with thyroid tumors were then assessed in matched serum samples (before and 30 days and 1 to 2 years after surgery) from the 20 PTC patients with complete follow-up datasets and results correlated with American Thyroid Association (ATA) responses to therapy.

Results:

Eight miRNAs (miR-221-3p, miR-222-3p, miR-146a-5p, miR-24-3p, miR-146b-5p, miR-191-5p, miR-103a-3p, and miR-28-3p) displayed levels in prethyroidectomy serum samples from patients with PTC that significantly exceeded those measured after thyroidectomy and those found in samples from HCs. The 2 most promising candidates—miR-146a-5p and miR-221-3p —were further analyzed in the 20 PTC patients mentioned earlier. Serum levels of both miRNAs after 1 to 2 years of follow-up were consistent with ATA responses to therapy in all patients, including 2 with structural evidence of disease whose Tg assays remained negative (<1 ng/mL).

Conclusion:

miR-146a-5p and miR-221-3p hold remarkable promise as serum biomarkers for post-treatment monitoring of PTC patients, especially when Tg assay results are uninformative.

Survival Analysis of Papillary Thyroid Carcinoma in Relation to Stage and Recurrence Risk: A 20-Year Experience in Pakistan

OBJECTIVE

The aim of this study was to evaluate the overall and progression-free survival of papillary thyroid carcinoma (PTC), comparing the American Thyroid Association (ATA) guideline for risk of recurrence with the TNM staging system with dynamic assessment at 2 years.

PATIENTS AND METHODS

This study is a retrospective analysis of 689 PTC patients over a 20-year period at a single center. Disease-free survival based on the TNM staging and ATA recurrence risk was calculated using Kaplan-Meier curves. Dynamic response assessment during the first 2 years was compared for both systems. Survival was calculated based on age, baseline resectability, and postthyroidectomy serum tumor marker levels.

RESULTS

Six hundred eighty-nine (72.2%) of the total thyroid cancer patients had PTC. Four hundred sixty-nine patients were females, and 220 patients were males. The age range was 6 to 87 years. Five hundred thirty-five patients were resectable, and 56 patients were unresectable. One hundred fifty-one patients were excluded due to insufficient information on recurrence risk. By ATA categorization, 39% had low risk, no disease-related mortality; 44% had intermediate risk, 3 died; and 17% had high risk, 32 died. The 5-year disease-free survival was 54%, 26%, and 5% in low-, intermediate-, and high-risk groups, respectively. The log-rank test showed a significant difference in the percent survival (P < 0.01). TNM stage wise, in terms of survival, 1.3% in stage I, 2.2% in stage II, 0% in stage III, and 37.5% in stage IV died. The 20-year disease-free survival showed the following: stage I, 43%; stage II, 28%; stage III, 18%; and stage IV, 2%. There is significant difference in survival rate (P < 0.01). Both ATA risk classification and TNM staging were significant predictors of disease-free survival. On bivariate analysis, ATA classification (hazards ratio, 2.1; 95% confidence interval, 1.64-2.67; P = 0.001) was better predictive of overall survival versus TNM classification (hazards ratio, 1.3; 95% confidence interval, 1.11-1.43; P = 0.063).

CONCLUSIONS

The ATA risk stratification and continuous reassessment during the first 2 years predicts disease-free survival better than the TNM staging. Age older than 45 years, unresectable disease, and elevated postthyroidectomy thyroglobulin levels dictate a poorer prognosis.

Thyroglobulin Liquid Chromatography-Tandem Mass Spectrometry Has a Low Sensitivity for Detecting Structural Disease in Patients with Antithyroglobulin Antibodies

BACKGROUND

Thyroglobulin (Tg) measurement in patients with positive antithyroglobulin antibodies (anti-TgAbs) is not reliable. Tg measurement using liquid chromatography-tandem mass spectrometry (LC/MS) may be useful in this setting.

METHODS

This is a retrospective study with the objective of determining the accuracy of Tg-LC/MS in patients with thyroid cancer with anti-TgAbs. All patients with follicular cell-derived thyroid cancer (TC) who had thyroglobulin measured using LC/MS assay from November 1, 2013, to November 7, 2014, were evaluated. The frequency of detectable Tg-LC/MS was evaluated, with a functional sensitivity (FS) of 0.5 ng/mL in patients with structural disease. Then performance of Tg-LC/MS versus Tg immunometric assay (IMA) was compared using either Immulite assay (Tg-1) with a FS of 0.9 ng/mL or Beckman assay (Tg-B) with a FS of 0.1 ng/mL in detecting structural disease in patients with positive anti-TgAbs.

RESULTS

A total of 154 consecutive patients were included in this evaluation. Of these, 116 (75%) patients were positive for anti-TgAbs. In patients with structural disease and positive anti-TgAbs, Tg-LC/MS was undetectable in 43.7% of patients. Then the diagnostic accuracy for structural disease of Tg-LC/MS was compared with each Tg-IMA assay separately. In the 26 patients with positive anti-TgAbs where a Tg-I assay was used, the sensitivity and specificity for detecting structural disease were 33.3% and 88.2%, respectively, for the Tg-I assay, and 44.4% and 94.1%, respectively, for the Tg-LC/MS assay. In the 74 patients with positive anti-TgAbs where Tg-B was used, the sensitivity and specificity for detection of structural disease were 72.7% and 71.4%, respectively, for the Tg-B assay, and 62.6% and 93.7%, respectively, for the Tg-LC/MS assay.

CONCLUSION

In patients with thyroid cancer with positive anti-TgAbs, Tg-LC/MS was frequently undetectable and was less sensitive for detecting disease than a Tg assay was with a functional sensitivity of 0.1 ng/mL. For patients with detectable Tg-LC/MS and anti-TgAbs, use of the assay for monitoring requires further prospective studies.

Insights into the posttranslational structural heterogeneity of thyroglobulin and its role in the development, diagnosis, and management of benign and malignant thyroid diseases

Thyroglobulin (Tg) is the major glycoprotein produced by the thyroid gland, where it serves as a template for thyroid hormone synthesis and as an intraglandular store of iodine. Measurement of Tg levels in serum is of great practical importance in the follow-up of differentiated thyroid carcinoma (DTC), a setting in which elevated levels after total thyroidectomy are indicative of residual or recurrent disease. The most recent methods for serum Tg measurement are monoclonal antibody-based and are highly sensitive. However, major challenges remain regarding the interpretation of the results obtained with these immunometric methods, particularly in patients with endogenous antithyroglobulin antibodies or in the presence of heterophile antibodies, which may produce falsely low or high Tg values, respectively. The increased prevalence of antithyroglobulin antibodies in patients with DTC, as compared with the general population, raises the very pertinent possibility that tumor Tg may be more immunogenic. This inference makes sense, as the tumor microenvironment (tumor cells plus normal host cells) is characterized by several changes that could induce posttranslational modification of many proteins, including Tg. Attempts to understand the structure of Tg have been made for several decades, but findings have generally been incomplete due to technical hindrances to analysis of such a large protein (660 kDa). This review article will explore the complex structure of Tg and the potential role of its marked heterogeneity in our understanding of normal thyroid biology and neoplastic processes.