Chronic thyroiditis as a favorable prognostic factor in papillary thyroid carcinoma

Characterization of Immune Infiltrate Along the Leading Edge of Differentiated Thyroid Cancer

Background: Although the impact of tumor-immune infiltrate has been reported on differentiated thyroid cancer (DTC) behavior, the expression of immune checkpoints [programmed cell death protein 1 (PD-1) and its ligand (PD-L1)] alone has not been able to predict response to immunotherapies. We aimed to identify tumor-infiltrating immune cells and checkpoints associated with DTC. Methods: We performed multiplex immunofluorescence on deparaffinized thyroid tissue collected at thyroidectomy from 17 adults with DTC to characterize the tumor immune microenvironment for leukocytes (CD45+), T cells (CD3+), T regulatory cells (Tregs) (CD3+FOXP3+), CD4+ T cells (CD3+CD4+), CD8+ T cells (CD3+CD8+), macrophages (CD68+), M2 macrophages (CD68+CD163+), M1 Macrophages (CD68+ inducible nitric oxide synthase [iNOS]+), and immune checkpoints PD-1 and PD-L1. We compared the mean percentage expression of immune markers between tumor and adjacent thyroid tissue from the same patient by paired t-test and performed spatial analysis along the tumor's leading edge. Results: Immune checkpoints PD-1 and PD-L1 showed a significant increase in expression intratumorally as compared to adjacent thyroid tissue (p < 0.05). A higher trend for M2 macrophages was observed intratumorally compared to adjacent tissue. Along the leading edge, PD-L1 expression correlated negatively with CD45 and positively with CD163 intratumorally. On exploratory analysis, there was a nonsignificant trend for higher FOXP3 but less CD8 and iNOS expression in tumor from DTC with (n = 3) versus without distant metastases (n = 14). There was a nonsignificant trend for higher CD58 and iNOS expression in DTC with (n = 7) than without thyroiditis (n = 10). Conclusions: Higher tumoral PD-1 and PD-L1 expression indicate their role in DTC occurrence. A trend for more Tregs and M2 macrophages but less M1 macrophages intratumorally in patients with distant metastatic DTC, suggests their potential role as prognostic biomarkers. Future studies with larger sample sizes are needed to compare various clinicopathologic severities to harness tumor microenvironment for cancer prognostication and therapy.

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.

Hashimoto Thyroiditis and Mortality in Patients with Differentiated Thyroid Cancer: The National Epidemiologic Survey of Thyroid Cancer in Korea and Meta-Analysis

BACKGRUOUND

Many studies have shown that Hashimoto's thyroiditis (HT) acts as a protective factor in differentiated thyroid cancer (DTC), but little is known about its effects on mortality. Therefore, this study was performed to reveal the prognosis of HT on mortality in patients with DTC.

METHODS

This study included two types of research.

RESULTS

retrospective cohort study using the National Epidemiologic Survey of Thyroid cancer (NEST) in Korea and meta-analysis study with the NEST data and eight selected studies.

RESULTS

Of the 4,398 patients with DTC in NEST, 341 patients (7.8%) died during the median follow-up period of 15 years (interquartile range, 12.3 to 15.6). Of these, 91 deaths (2.1%) were related to DTC. HT was associated with a smaller tumor size and less aggressive DTC. In Cox regression analysis after adjusting for age and sex, patients with HT showed a significantly lower risk of all-cause death (hazard ratio [HR], 0.71; 95% confidence interval [CI], 0.52 to 0.96) and DTC-related death (HR, 0.33; 95% CI, 0.14 to 0.77). The analysis with inverse probability of treatment weight data adjusted for age, sex, and year of thyroid cancer registration showed similar association. The meta-analysis showed that patients with HT showed a lower risk of all-cause mortality (risk ratio [RR], 0.24; 95% CI, 0.13 to 0.47) and thyroid cancer-related mortality (RR, 0.23; 95% CI, 0.13 to 0.40) in comparison with patients without HT.

CONCLUSION

This study showed that DTC co-presenting with HT is associated with a low risk of advanced DTC and presents a low risk for all-cause and DTC-related death.

Clinical and molecular impact of concurrent thyroid autoimmune disease and thyroid cancer: From the bench to bedside

The recent incorporation of immune checkpoint inhibitors targeting the PD-1 (programmed cell death receptor 1) and CTLA-4 (cytotoxic T lymphocyte antigen 4) pathways into the therapeutic armamentarium of cancer has increased the need to understand the correlation between the immune system, autoimmunity, and malignant neoplasms. Both autoimmune thyroid diseases and thyroid cancer are common clinical conditions. The molecular pathology of autoimmune thyroid diseases is characterized by the important impact of the PD-1/PD-L1 axis, an important inhibitory pathway involved in the regulation of T-cell responses. Insufficient inhibitory pathways may prone the thyroid tissue to a self-destructive immune response that leads to hypothyroidism. On the other hand, the PD-1/PD-L1 axis and other co-inhibitory pathways are the cornerstones of the immune escape mechanisms in thyroid cancer, which is a mechanism through which the immune response fails to recognize and eradicate thyroid tumor cells. This common mechanism raises the idea that thyroid autoimmunity and thyroid cancer may be opposite sides of the same coin, meaning that both conditions share similar molecular signatures. When associated with thyroid autoimmunity, thyroid cancer may have a less aggressive presentation, even though the molecular explanation of this clinical consequence is unclear. More studies are warranted to elucidate the molecular link between thyroid autoimmune disease and thyroid cancer. The prognostic impact that thyroid autoimmune disease, especially chronic lymphocytic thyroiditis, may exert on thyroid cancer raises important insights that can help physicians to better individualize the management of patients with thyroid cancer.

Circulating immunophenotypes are potentially prognostic in follicular cell-derived thyroid cancer

Background

Exploring the immune interface of follicular cell-derived thyroid cancer has prognostic and therapeutic potential. The available literature is lacking for comprehensive immunophenotyping in relation to clinical outcomes. In this study, we identify circulating immunophenotypes associated with thyroid cancer prognosis.

Methods

We conducted a pilot observational study of adults with follicular cell-derived thyroid cancer who underwent surgery at our tertiary care referral center and had consented for flow cytometry on peripheral blood collected at the time of thyroidectomy.

Results

Of the 32 included subjects, 20 (62%) had well differentiated, 5 (16%) had poorly differentiated, and 7 (22%) had anaplastic thyroid cancer. The most frequent AJCC stage was 4 (59%) and the ATA risk of recurrence category was high (56%). Patients with AJCC stage 3/4 demonstrated fewer circulating mononuclear cells (CD45+), more monocytes (CD14+), fewer total lymphocytes (CD14-), fewer T cells (CD3+), fewer CD4+ T cells, fewer gamma-delta T cells, fewer natural killer (NK) T-like cells, more myeloid-derived suppressor cells (MDSCs; Lin-CD33+HLADR-), and more effector memory T cells but similar CD8+ T cells compared to stage1/2. Immunophenotype comparisons by ATA risk stratification and course of thyroid cancer were comparable to those observed for stage, except for significant differences in memory T cell subtypes. The median follow-up was 58 months.

Conclusions

Aggressive follicular cell-derived thyroid cancer either at presentation or during follow-up is associated with down-regulation of the T cell populations specifically CD4+ T cells, gamma-delta T cells, and NK T-like cells but up-regulation of MDSCs and altered memory T cells. These immunophenotypes are potential prognostic biomarkers supporting future investigation for developing targeted immunotherapies against advanced thyroid cancer.

Predictive factors of lymph node metastasis in papillary thyroid cancer

This study aimed to evaluate factors that predict lymph node metastasis (LNM) in papillary thyroid cancer (PTC). This retrospective cross-sectional study compared the demographic, clinical, and ultrasonographic findings of patients with PTC with and without LNM. Subgroup analysis was conducted for micro-PTCs (<1 cm). Among total (n = 512; mean age, 47.3 ± 12.7 years) and micro-PTC patients (n = 312), 35.7% and 19.6% had LNM, respectively. Younger age, male sex, tumor size, bilaterality, and suspicious ultrasound features of the tumor were associated with LNM. In multiple logistic regression analysis, among all patients, age, tumor size, and extrathyroidal extension were independent risk factors for LNM (all p<0.05). In the micro-PTC subgroup, age, extrathyroidal extension, bilaterality of tumor, and presence of autoimmune thyroid disease were independent risk and protective factors for LNM (all p<0.05). In the receiver operating characteristic analysis, the accuracy of the multivariable logistic regression model for predicting LNM among all patients and micro-PTC was acceptable (area under the curve = 0.729 and 0.733, respectively). Age, sex, tumor size, and extrathyroidal extension can assist in predicting LNM in PTC patients. Additionally, the bilaterality of tumors and presence of autoimmune thyroid disease can assist in predicting LNM in micro-PTCs.

Hashimoto's Thyroiditis and Papillary Thyroid Carcinoma: A Follow-Up Study in Patients with Absence of Aggressive Risk Factors at the Surgery of the Primary Tumor

Hashimoto's thyroiditis (HT) is often associated with papillary thyroid carcinoma (PC); it is still a matter of controversy whether the behavior of carcinoma is more aggressive or not. During the follow-up, we retrospectively enrolled 97 patients with PC/HT after thyroidectomy without risk factors at the surgery of the primary tumor, such as multifocality/multicentricity, extrathyroid tumor extension, vascular invasion, neck and distant metastases, and aggressive histological variants. HT diagnosis was confirmed by histology and serum thyroid antibodies. Tumor size was ≤10 mm in 64 cases (microcarcinomas); 206 matched PC patients after thyroidectomy without HT and risk factors were enrolled as controls, totaling 122 microcarcinomas. During follow-up, metastases occurred in 15/97 (15.5%) PC/HT cases, eight microcarcinomas, and in 16/206 (7.8%) without HT, eight microcarcinomas (p = 0.04). Considering both PC/HT and PC patients without HT who developed metastases, univariate analysis showed an increased risk of metastases in patients with HT coexistence, OR: 2.17 (95% CI 1.03-4.60) p = 0.043. Disease-free survival (DFS) was significantly (p = 0.0253) shorter in PC/HT than in the controls. The present study seems to demonstrate that HT is not a cancer protective factor in PC patients given the less favorable outcomes and significantly shorter DFS. HT may also represent an independent recurrence predictor without other risk factors.

Tumor Microenvironment Features as Predictive Biomarkers in Metastatic Differentiated Thyroid Cancer and Their Relationship With 18F-Fluorodeoxyglucose Positron Emission Tomography/Computed Tomography (18F-FDG PET/CT) Metabolic Parameters

OBJECTIVE

The role of the tumor microenvironment in tumor progression and treatment response is being investigated for different types of cancer. This study aimed to determine the relationships between tumor microenvironment, histopathology, 18F-fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG PET/CT)-based metabolic parameters, treatment response, and overall survival (OS) in metastatic differentiated thyroid cancer (DTC).  Methods: Metastatic DTC patients who underwent 18F-FDG PET/CT between 2015-2019 were evaluated. Clinicopathological, histopathological features and PET/CT parameters of patients were recorded. Microenvironmental characteristics of the primary tumor, such as mitosis, intratumoral and peritumoral lymphocytosis, intratumoral and peritumoral fibrosis, were evaluated from the tissue samples. The relationships between these factors were statistically analyzed.

RESULTS

 Sixty-five patients (38 females, 27 males, age: 49±15 years) were included. Mitosis, intra/peritumoral lymphocytosis, and intra/peritumoral fibrosis were frequent; however, none of them had a statistically significant association with PET-positive metastases, treatment response, or OS. Univariate analysis showed that gender, size, thyroglobulin values, residual thyroid tissue, PET-positive metastases, and maximum standardized uptake value (SUVmax) were significant predictors of OS. At multivariate analysis, PET-positive metastases (HR=-2.65, 95%CI 0.007-0.707, p=0.024) and SUVmax (HR=-2.74, 95%CI 0.006-0.687, p=0.023) were the only independent predictors for OS.  Conclusion: Our study revealed that microenvironmental characteristics of the primary tumor did not show prognostic significance in metastatic DTC. PET-positive metastases and SUVmax levels were the only significant factors that predicted overall survival in DTC. Supporting the results of our study with further studies with a larger sample size may be necessary to determine the relationship between the tumor microenvironment and prognosis in DTC.

Lateral neck dissection for the treatment of synchronous and metachronous lateral neck metastasis of N1b papillary thyroid cancer

Introduction

Metachronous lateral neck recurrence after thyroidectomy for N1b papillary thyroid cancer is accompanied by high morbidity and increased difficulty of reoperation. From the perspective of recurrence, the objective of this study was to compare patients who underwent metachronous lateral neck dissection (mLND) despite initial thyroidectomy and patients who underwent synchronous lateral neck dissection (sLND) for papillary thyroid cancer and analyze the risk factors for recurrence after mLND.

Method

This retrospective study involved 1,760 patients who underwent lateral neck dissection for papillary thyroid cancer at the Gangnam Severance Hospital, a tertiary medical center in Korea, from June 2005 to December 2016. The primary outcome was structural recurrence, and secondary outcome measures were risk factors of recurrence in the mLND group.

Result

A total of 1,613 patients underwent thyroidectomy and sLND at diagnosis. In 147 patients, thyroidectomy alone was performed at the time of diagnosis, and mLND was performed when recurrence to the lateral neck lymph node was confirmed. During a median follow-up of 102.1 months, 110 (6.3%) patients experienced a recurrence. There was no significant difference in the recurrence between the sLND and mLND groups (6.1% vs 8.2%, P=.32). The period from lateral neck dissection to recurrence was longer in the mLND group than in the sLND group (113.6 ± 39.4 months vs 87.0 ± 33.8 months, respectively, P<.001). Age ≥50 years (adjusted HR=5.209, 95% CI=1.359-19.964; P=.02), tumor size >1.45 cm (adjusted HR=4.022, 95% CI=1.036-15.611; P=.04), and lymph node ratio in the lateral compartment (adjusted HR=4.043, 95% CI=1.079-15.148; P=.04) were independent variables predictive of recurrence after mLND.

Conclusion

mLND is suitable for treating lateral neck recurrence in patients with N1b papillary thyroid cancer who previously underwent thyroidectomy. Lateral neck recurrence after treatment in patients who underwent mLND was predicted by age, tumor size, and lymph node ratio in the lateral compartment.

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.

Hashimoto's Thyroiditis: A Protective Factor against Recurrence in BRAF-Wild Type Differentiated Thyroid Carcinoma

A recent work analyzing the concomitant factors BRAF mutation (risk factor) and Hashimoto's thyroiditis (HT) (protective factor) found that the presence of HT reduced lymph node metastasis in BRAF-mutated papillary thyroid carcinoma. Whether this notion is upheld with respect to disease recurrence and differentiated thyroid carcinoma (DTC), however, is unknown. We aimed to investigate the effect of underlying HT in DTC patients and its influence on recurrence with a specific emphasis in BRAF-mutated tumors. A total of 469 patients were included. Patients were stratified according to BRAF and HT status. Multivariate regression analysis was conducted to determine protective and risk factors of disease recurrence in patients with DTC. HT was associated with less-aggressive carcinomas including more frequent microcarcinomas (HT: 45.0% vs. no-HT: 34.0%, p = 0.02), less lymph node involvement (HT: 16.4% vs. no-HT: 26.1%, p = 0.02), and less disease recurrence (HT: 2.9% vs. no-HT: 11.9%, p = 0.002). BRAF mutation was also significantly associated with higher rates of lymph node involvement (BRAF-mutant: 41.9% vs. BRAF-wild type: 14.6%, p < 0.001) and almost two times the rate of recurrence (BRAF-mutant: 14.9% vs. BRAF-wild type: 6.5%, p = 0.004). Underlying HT was the only protective factor determined, reducing the odds of developing recurrence by 70% (HR: 0.30, 95%CI: 0.11-0.88). In the BRAF-wild type cohort, regression analysis continued to determine HT as a protective factor (p = 0.03). However, in the BRAF-mutant cohort, HT was no longer an independent protective factor (p = 0.20) against recurrence. Sub-group regression analysis, including PTC patients, similarly found HT as a protective factor only in BRAF-wild type patients (p = 0.039) and not BRAF-mutant (p = 0.627). The presence of underlying HT is associated with less aggressive tumors and is an independent protective factor against DTC recurrence, reducing the risk by 70%. HT remains a protective factor in BRAF-wild type carcinoma, but not in patients with BRAF-mutant carcinoma. HT may potentially be considered as a parameter which enhances American Thyroid Association patient risk stratification.

Clinical and Pathological Characteristics of Patients With Papillary Thyroid Carcinoma Coexisting With Hashimoto's Thyroiditis: A Retrospective Cohort Study

BACKGROUND

Papillary thyroid carcinoma (PTC) is the most common subtype of thyroid carcinoma, and Hashimoto's thyroiditis (HT) has been postulated to have a relationship with PTC. This study aims to assess clinical and pathological characteristics of patients with papillary thyroid carcinoma coexisting with Hashimoto's thyroiditis.

METHODS

A retrospective study was conducted in a cohort of patients with thyroid carcinoma at the Department of Surgery, Shanghai General Hospital from January 2017 to December 2018. Medical records of patients who had PTC with or without HT were reviewed and clinical and histopathological characteristics of these patients were analyzed.

RESULTS

A total of 632 patients with thyroid carcinoma were identified. Among them, 614 (97.15%) had PTC and 120/614 (19.0%) harbored PTC together with HT. PTC was significantly associated with HT, as compared with other histological subtypes (P < .001). Patients with coexisting PTC and HT (PTC + HT group) were significantly younger than patients with PTC alone (PTC group) (P = .008). There were more women in the PTC + HT group than in the PTC group (88.3% vs. 73.1%, P < .001). TSH, TGAb, and TPOAb levels were significantly higher in the PTC + HT group than in the PTC group (P ≤ .001). In addition, tumor diameter was smaller in the PTC + HT group than in the PTC group (P = .034). The PTC + HT group showed a significant better recurrence-free survival than the PTC group. Furthermore, immunohistochemical analysis revealed that patients in the PTC + HT group had a higher positive rate and higher expression intensity of Ki67 than patients in the PTC group.

CONCLUSIONS

Our study revealed that patients with coexisting PTC and HT were younger, had smaller tumor diameters, a better prognosis, and higher positive rates and expression intensity of Ki67, than did patients with PTC alone.

Molecular Landscape of Pediatric Thyroid Cancer: A Review

Thyroid carcinomas (TC) are rare in the pediatric population; however, they constitute the most common endocrine malignancy. Despite some similarities with adult carcinomas, they have distinct clinical behavior and responses to therapy due to their unique pathology and molecular characteristics. The age cut-off used for defining the pediatric age group has been variable across different studies, and the universally accepted recommendations influence accurate interpretation of the available data. Moreover, factors such as radiation exposure and germline mutations have greater impact in children than in adults. Papillary TC is the most common and the most evaluated pediatric TC. Others, including follicular, poorly differentiated and medullary carcinomas, are rarer and have limited available literature. Most studies are from the West. Asian studies are primarily from Japan, with few from China, India, Saudi Arabia and Republic of Korea. This review provides a comprehensive account of the well-established and novel biomarkers in the field, including point mutations, fusions, miRNA, and thyroid differentiation genes. Familial and syndromic associations are also discussed. Current management guidelines for pediatric patients are largely derived from those for adults. An awareness of the molecular landscape is essential to acknowledge the uniqueness of these tumors and establish specific diagnostic and therapeutic guidelines.

Papillary thyroid cancer with Hashimoto’s thyroiditis attenuates the tumour aggressiveness through the up-regulation of E-cadherin and TGF-β expression

Human papillary thyroid cancer (PTC) is often associated with Hashimoto’s thyroiditis (HT), and their coexistence improves the prognosis of PTC. Aim of the study. The objective of our study is to investigate the expression of cadherins and TGF-β which are regulators in the tumour aggressiveness with metastatic spread in PTC patients and its relationship with HT. The expression of E-cadherin and N-cadherin was measured in thyroid tissues of healthy volunteers and PTC patients with HT (PTC/HT) or without. The E-cadherin expression was also determined in thyroid cancer cells (TPC1, SNU373, SNU790, 8505C, CAL62, and FTC133). Cell migration was measured by wound healing assay. The expression of N-cadherin, ICAM1, and TGF-β was measured in thyroid tissues and plasma. The E-cadherin expression was significantly increased in PTC/HT patients compared with PTC alone. Meanwhile, the N-cadherin expression was significantly decreased in PTC/HT patients. The E-cadherin expression was only observed in FTC cells, and the overexpression of E-cadherin inhibited cancer cell migration. The TGF-β expression was significantly increased in PTC/HT patients, and the plasma levels were higher in PTC/HT patients than in PTC alone. The expression of N-cadherin and ICAM-1 was significantly decreased in PTC/HT patients. Our results indicate that the expression of E-cadherin and TGF-β was higher in PTC/HT patients than in PTC alone. This suggests that the presence of PTC with HT may attenuate the tumour aggressiveness and metastasis through the up-regulation of E-cadherin and TGF-β expression.

Is total thyroidectomy with bilateral central neck dissection the only surgery for papillary thyroid carcinoma patients with clinically involved central nodes?

Background

In clinical practice, we often observed that patients who underwent total thyroidectomy due to clinically involved nodal disease (cN1a) actually had less extensive CLNM on final pathology. This study investigates whether total thyroidectomy and therapeutic bilateral CND are necessary for all PTC patients with cN1a.

Methods

This study retrospectively reviewed 899 PTC patients who underwent total thyroidectomy with bilateral CND from January 2012 to June 2017. The patients were divided into two groups according to pre-operative central lymph node (CLN) status: cN0, no suspicious CLNM; cN1a, suspicious CLNM. We compared the clinicopathological features of these two groups.

Results

There was no significant difference in recurrence between cN0 and cN1a groups after a mean follow-up time of 59.1 months. Unilateral cN1a was related to the largest central LN size ≥ 2 mm (OR = 3.67, p < 0.001) and number of CLNM > 5(OR = 2.24, p = 0.006). On the other hand, unilateral cN1a was not associated with an increased risk of contralateral lobe involvement (OR = 1.35, p = 0.364) and contralateral CLNM (OR = 1.31, p = 0.359). Among 106 unilateral cN1a patients, 33 (31.1%) were found to be pN0 or had ≤ 5 metastatic CLNs with the largest node smaller than 2 mm.

Conclusions

Most cN1a patients were in an intermediate risk group for recurrence and required total thyroidectomy. However, lobectomy with CND should have performed in approximately 30% of the cN1a patients. Pre-operative clinical examination, meticulous radiologic evaluation, and intra-operative frozen sections to check the nodal status are prerequisites for this approach.

Association between Hashimoto thyroiditis and clinical outcomes of papillary thyroid carcinoma: A meta-analysis

Objective

To assess association between Hashimoto thyroiditis (HT) and clinical outcomes of papillary thyroid carcinoma (PTC).

Methods

Databases including Pubmed, Embase, Cochrane Library, and Web of Science were searched. Weighed mean differences (WMDs) and odds ratios (ORs) were used to evaluate association between HT and clinical outcomes of PTC, and the effect size was represented by 95% confidence intervals (CIs). Heterogeneity test was performed for each indicator. If the heterogeneity statistic I²≥50%, random-effects model analysis was carried out, otherwise, fixed-effect model analysis was performed. Sensitivity analysis was performed for all outcomes, and publication bias was tested by Begg’s test.

Results

Totally 47,237 patients in 65 articles were enrolled in this study, of which 12909 patients with HT and 34328 patients without HT. Our result indicated that PTC patients with HT tended to have lower risks of lymph node metastasis (OR: 0.787, 95%CI: 0.686–0.903, P = 0.001), distant metastasis (OR: 0.435, 95%CI: 0.279–0.676, P<0.001), extrathyroidal extension (OR: 0.745, 95%CI: 0.657–0.845, P<0.001), recurrence (OR: 0.627, 95%CI: 0.483–0.813, P<0.001), vascular invasion (OR: 0.718, 95%CI: 0.572–0.901, P = 0.004), and a better 20-year survival rate (OR: 1.396, 95%CI: 1.109–1.758, P = 0.005) while had higher risks of multifocality (OR: 1.245, 95%CI: 1.132–1.368, P<0.001), perineural infiltration (OR: 1.922, 95%CI: 1.195–3.093, P = 0.007), and bilaterality (OR: 1.394, 95%CI: 1.118–1.739, P = 0.003).

Conclusions

PTC patients with HT may have favorable clinicopathologic characteristics, compared to PTCs without HT. More prospective studies are needed to further elucidate this relationship.

Preoperative Thyroid Peroxidase Antibody Predicts Recurrence in Papillary Thyroid Carcinoma: A Consecutive Study With 5,770 Cases

Background

Thyroid autoimmunity is common in papillary thyroid carcinoma (PTC) and was believed to confer a better prognosis; however, controversy still remains. This study aimed to investigate the prognostic value of chronic lymphocytic thyroiditis (CLT) and preoperative thyroid peroxidase antibody (TPOAb) in PTC patients.

Methods

A retrospective analysis was performed on 5,770 PTC patients who underwent surgical treatment with pathologically confirmed PTC in our institution between 2012 to 2016. The patients were divided into groups with respect to the coexistence of CLT or preoperative TPOAb levels. The clinicopathological characteristics and disease-free survival (DFS) rates were compared between the groups.

Results

The coexistence of CLT was likely to have bilateral, multifocal tumors. Particularly, PTC patients with TPOAb++ (&gt;1,000 IU/L) had a larger tumor size (p = 0.007) and higher rates of bilaterality and multifocality than those with TPOAb− (TPOAb&lt; 100 IU/L), while for lymph node metastasis and extrathyroidal extension, there is no statistical difference. Tumor recurrence was found in 15 of 425 (3.5%), 9 of 436 (2.1%), and 56 of 3,519 (1.6%) patients with TPOAb++, TPOAb+, and TPOAb−, respectively (p = 0.017). On univariate analysis, TPOAb++ was correlated with tumor recurrence, with a hazard ratio of 2.20 [95% confidence interval (CI), 1.25–3.89], which remained as an independent risk factor at 1.98 (95% CI, 1.10–3.55) on multivariate analysis. PTC patients with TPOAb++ had the lowest DFS rates (96.5 vs. 97.9 vs. 98.4%, p = 0.020).

Conclusion

CLT is not a protective factor in PTC patients. We provide initial evidence that the preoperative TPOAb instead predicts recurrence in papillary thyroid carcinoma.

Coexisting CLT in PTC is an independent predictor of tumor aggressiveness for patients aged under 55: a retrospective analysis of 635 patients

BACKGROUND

The study was aimed at investigating the potential role of chronic lymphocytic thyroiditis (CLT) in papillary thyroid cancer (PTC) aggressiveness for patients aged below 55, as well as to figure out factors influencing potential recurrence risk in different age groups.

METHODS

A total of 635 adult patients were retrospectively analyzed. 188 patients were diagnosed with coexistent CLT and the remaining 447 were classified as non-CLT. Then the characteristics of CLT-coexisted patients and non-CLT ones were compared respectively when patients were aged ≥ 55 years or below. The association among postoperative clinicopathological features were also analyzed using multivariate regression. In addition, the prognostic value of several variables relating to high-risk recurrence were estimated within different age groups.

RESULTS

When divided in two age groups (55 years as the borderline), non-CLT group (aged below 55 years) had a remarkable frequency of small size lesion (Dmax ≤ 1 cm) compared with CLT-coexisted patients (54.6% to 43.0%, p = 0.02). In addition, non-CLT patients tended to have intrathyroidal extension as opposed to those with coexistent CLT (20.2% to 28.2%, p = 0.05). In multivariate analysis, CLT still significantly acted as an independent risk factor of greater lesion size (Dmin > 1 cm) (OR = 1.7, p = 0.02) and mildly promoted gross extrathyroidal extension (ETE) (OR = 1.4, p = 0.06). However, associations didn't emerge in the characteristics mentioned above with CLT when patients were ≥ 55 years old. The prognostic value of CLT in high-risk recurrence was evident only in patients aged 35-44 years. (OR = 2.4, 95%CI:1.2-5.4, p = 0.02). Greater lesion size independently promoted gross ETE, no matter patients were aged above 55 years or not. Its prognostic value of high-risk recurrence was significant throughout all age groups.

CONCLUSION

These findings revealed that CLT coexistence might be the unfavorable factor of PTC aggressiveness in patients aged below 55 years. Its role as well as greater tumor size may potentially predict higher recurrence risk according to results figured out in the prediction model.

Is Hashimoto thyroiditis associated with increasing risk of thyroid malignancies? A systematic review and meta-analysis

Background and purpose

Hashimoto thyroiditis (HT) is the most common inflammatory autoimmune thyroid disease and also the most common cause of hypothyroidism in developed countries. There is evidence of the role of HT in developing thyroid cancers (TCs). This study investigated the association between HT and different types of TCs.

Methods

Results of a comprehensive search in three major databases, as well as hand searching, were screened in title/abstract and full-text stages and the relevant data were extracted from the studies that met the inclusion criteria. Risk of bias (RoB) was assessed using the Joanna Briggs Institute (JBI) critical appraisal tools and the meta-analysis was conducted with Comprehensive Meta-Analysis software.

Results

Out of 4785 records, 50 studies were included in the systematic review, and 27 of them met the criteria for quantitative synthesis. The results indicated a significant role for HT in developing papillary TC (OR: 1.65; 95% CI: 1.04 to 2.61), medullary TC (OR: 2.70; 95% CI: 1.20 to 6.07) and lymphoma (OR:12.92; 95% CI: 2.15 to 77.63); but not anaplastic TC (OR: 1.92; 95% CI: 0.29 to 1.90) and follicular TC (OR: 0.73; 95% CI: 0.41 to 1.27). Also, this study found a significant association between HT and thyroid malignancies (OR: 1.36; 95% CI: 1.05 to 1.77).

Conclusion

Although we found a significant association between HT and some types of TCs, High RoB studies, high level of heterogeneity, and the limited number of well-designed prospective studies, suggested the need for more studies to reach more reliable evidence.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13044-021-00117-x.

The Effects of Chronic Lymphocytic Thyroiditis on Clinicopathological Factors In Papillary Thyroid Cancer

INTRODUCTION

This study evaluated the impact of chronic lymphocytic thyroiditis (CLT) on clinicopathological parameters, prognostic outcome and initial treatment responses in patients with papillary thyroid cancer (PTC).

METHODS

A retrospective review was made of 1409 patients with PTC, comprising 443 pathology proven PTC patients with CLT and 447 PTC patients without CLT.

RESULTS

The median follow-up time was 58 (8-380) months and the median age at the time of diagnosis was 43 years. The diagnosis age was significantly lower in patients with CLT (42 vs. 45 years, p:0.001). The preoperative TSH level was found to be significantly higher in CLT patients (1.71 mIU/L vs. 1.28 mIU/L, p<0.001). Multifocality, capsular, lymphovascular and perineural invasion were detected at a higher rate in the group with CLT than in the group without CLT (p:0.015, p:0.024, p:0.004, p:0.039, respectively). No difference was found between the two groups in terms of tumor size, bilaterality, extrathyroidal invasion, lymph node metastasis, disease stage and response to treatment (p>0.05).

CONCLUSION

The results of the present study demonstrated that coexistence of PTC and CLT is very frequent. It was found that patients with PTC and CLT coexistence were diagnosed at an earlier age and the TSH level was higher. Contrary to previous studies, no positive effect of CLT and PTC combination was detected on any clinicopathological factor. In addition, lymphovascular and perineural invasion, which had negative effects on prognosis, was more common in the CLT group.

Prevalence of Hashimoto Thyroiditis in Adults With Papillary Thyroid Cancer and Its Association With Cancer Recurrence and Outcomes

IMPORTANCE

Hashimoto thyroiditis (HT) has been suggested to be associated with papillary thyroid cancer (PTC) development. However, its association with PTC progression remains unclear.

OBJECTIVE

To examine the association between HT and PTC presentation and outcomes.

DESIGN, SETTING, AND PARTICIPANTS

This retrospective cohort study included a review of patients aged 18 to 75 years who had pathologically confirmed PTC treated at a single center in China from January 1, 2001, to December 31, 2014. Data analysis was performed from November 1 to December 31, 2020.

EXPOSURES

Coexistent HT was defined according to evaluation of postoperative paraffin sections.

MAIN OUTCOMES AND MEASURES

The primary outcome was the association of HT with PTC-related mortality, assessed using Cox proportional hazards regression models. The secondary outcome was the association of HT with aggressive characteristics and structural recurrence of PTC, assessed using logistic regression and Cox proportional hazards regression with and without adjustment for related factors.

RESULTS

Of 9210 patients with PTC (mean [SD] age, 43.6 [12.0] years; 6872 [75%] women) included in the analysis, 1751 (19%) had HT. In the logistic regression model, HT was negatively associated with frequencies of primary tumor size of 4 cm or greater (adjusted odds ratio [aOR], 0.20; 95% CI, 0.12-0.33; P < .001), gross extrathyroidal extension (aOR, 0.44; 95% CI, 0.36-0.54; P < .001), extranodal extension (aOR, 0.66; 95% CI, 0.55-0.80; P < .001), and distant metastasis (aOR, 0.17; 95% CI, 0.04-0.71; P = .02). After a median follow-up of 85 months (range, 12-144 months), 131 PTC-related deaths were identified in the cohort; 2 patients who died had HT. Patients with HT had significantly superior outcomes compared with patients without HT in terms of unadjusted 10-year disease-specific survival (99.9% vs 96.6%; log-rank P < .001) and recurrence-free survival (92.0% vs 87.6%; log-rank P = .001). After adjusting for sex, age, primary tumor size, extrathyroidal extension, lymph node metastasis, distant metastasis, extent of surgery, and radioactive iodine ablation, HT was associated with decreased PTC-related mortality (hazard ratio [HR], 0.19; 95% CI, 0.05-0.76; P = .02). Stratified analysis showed that HT was associated with less frequent structural recurrence in patients with extrathyroidal extension (HR, 0.52; 95% CI, 0.38-0.71; P < .001; P = .002 for interaction) or after total thyroidectomy (HR, 0.50; 95% CI, 0.35-0.69; P < .001; P = .009 for interaction).

CONCLUSIONS AND RELEVANCE

In this cohort study, patients with coexistent HT had less aggressive characteristics at presentation and better outcomes of PTC than did patients without HT. The findings suggest that autoimmune thyroiditis has a protective role in association with thyroid cancer.

The Association of Histologically Proven Chronic Lymphocytic Thyroiditis with Clinicopathological Features, Lymph Node Metastasis, and Recurrence Rates of Differentiated Thyroid Cancer

The influence of chronic lymphocytic thyroiditis (CLT) on clinicopathological features and behavior of differentiated thyroid carcinoma (DTC) is still debated. In the present study, we aimed to evaluate the prognosis of DTC on the presence of CLT. A total of 649 total thyroidectomized patients (379 female, 270 male) with DTC, who had follow-up data for at least 36 months were included. Clinical, histopathological data, preoperative thyroid peroxidase antibody (TPO-ab), thyroglobulin antibody (Tg-ab), thyroid-stimulating hormone (TSH) levels, and presence of recurrent/persistent disease (R/PD) were evaluated retrospectively. Presence of CLT was defined by histopathology. Frequency of CLT was 32% (n = 208) among DTC patients. Mean tumor size (maximal diameter) was smaller in CLT group when compared to non-CLTs (p = 0.006). Capsular invasion, vascular invasion, tumor stage, risk groups, and R/PD were negatively associated with CLT (p < 0.01, p = 0.04, p = 0.03, p = 0.02, p < 0.01, respectively). Extrathyroidal extension was more frequent in non-CLT group when compared CLT (p = 0.052). Preoperative TSH level was positively associated with lymph node metastasis (LNM) and higher in patients with lateral LNM when compared to central LNM (p < 0.01). Central LNM, lateral LNM, stage 4 tumor, and intermediate- and high-risk tumor groups increased the risk of R/PH, 2.5-, 2.9-, 12.7-, 2.3-, and 4.2-fold, respectively. Presence of CLT was independently related with favorable outcomes, as the risk of R/PD was decreased by 0.49-fold. In conclusion, coexistence of CLT was negatively associated with tumor size, capsular invasion, vascular invasion, and tumor stage in DTC. Risk of R/PD was decreased by approximately half in patients with CLT.

A nomogram model based on the preoperative clinical characteristics of papillary thyroid carcinoma with Hashimoto's thyroiditis to predict central lymph node metastasis

OBJECTIVE

Preoperative prediction of central lymph node (LN) metastasis in papillary thyroid carcinoma (PTC) with Hashimoto's thyroiditis (HT) provides an important basis for surgical decision-making, especially regarding the extent of tumour resection. We aimed to develop and validate a nomogram model for the preoperative assessment of central LN metastasis.

METHODS

We retrospectively collected the data of 994 PTC patients with HT who underwent surgery at the West China Hospital from January 2008 to December 2017. Among them, 606 patients who underwent surgeries relatively earlier comprised the training cohort for nomogram development, while the other 388 who underwent surgeries relatively later formed the validation cohort to validate the model's performance. Univariate and multivariate logistic regression analyses were conducted using the data of the two respective cohorts, as well as the data of the combined cohort. The relevant preoperative potential risk factors include demographic characteristics, medical history information, thyroid function test, ultrasound characteristics and BRAF V600E gene detection. A nomogram model was subsequently developed. The performance, discrimination and calibration of the nomogram model were assessed in the training and validation cohorts and in the combined cohort.

RESULTS

The central LN metastasis rate of PTC with HT was 49.7% (301/606) and 48.7% (193/388) in the training and validation cohorts, respectively. The univariate and multivariate logistic regression analyses indicated that younger age, normal body mass index, BRAF V600E mutation, larger maximum diameter, left lobe tumour, aspect ratio >1, capsular invasion and calcification were significant risk factors for central LN metastasis in PTC patients with HT. The preoperative nomogram showed good calibration and discrimination for the training and validation cohorts, as well as for the combined data set.

CONCLUSION

The nomogram we developed and validated with a comprehensive set of preoperative factors is effective in predicting central LN metastasis in PTC patients with HT.

The Impact of Coexistent Hashimoto's Thyroiditis on Central Compartment Lymph Node Metastasis in Papillary Thyroid Carcinoma

BACKGROUND

Hashimoto's thyroiditis (HT) is the most prevalent inflammatory disorder of the thyroid gland. Current studies have reported the coexistence rate between HT and papillary thyroid carcinoma (PTC) is quite high. The objective of this study was to evaluate the impact of HT on the predictive factors of central compartment lymph node metastasis (CLNM) in PTC.

METHODS

A retrospective investigation was performed on PTC patients. They were subclassified into HT and non-HT groups. The results of preoperative neck ultrasound (US) examinations were reviewed. The clinical characteristics and the predictive value for CLNM were explored and compared between the two groups.

RESULTS

A total of 756 patients were included in this study. There were more female patients (86.1%) in the PTC coexistent with the HT group than non-HT group. The patients with HT group had higher preoperative serum level of TSH. There was statistically significant difference between the HT patients and non-HT patients in nodular vascularization. Univariate and multivariate analyses showed that male, age ≤45 years old, tumor diameter >1 cm, and presence of suspicious central compartment lymph node on US, irregular nodular shape, multifocal carcinoma were independent predictive factors of CLNM in PTC patients. It was showed that male, age ≤45 years old, tumor diameter >1 cm, multifocality, and presence of suspicious central lymph node on US were risk factors for CLNM in non-HT patients. Only tumor diameter >1 cm and presence of suspicious central lymph node on US were independently correlated with CLNM in HT patients. The sensitivity of the multivariate model was 63.5%, and specificity was 88.9% for prediction CLNM in HT patients. For non-HT patients, the AUC was 80.6%, the sensitivity of the multivariate model was 64.5%, and specificity was 85.2.

CONCLUSION

PTC combined with HT is more common in women, and TSH level in HT group is higher than that in patients with PTC alone. Regardless of that HT is not a related risk factor of CLNM in PTC, our result suggested that different predictive systems should be used for HT and non-HT patients respectively to have a more accurate evaluation of CLNM in clinic.

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 8th 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.

PD-L1 expression in papillary thyroid cancer with and without lymphocytic thyroiditis: a cross sectional study

The impact of concurrent autoimmune thyroid disease on the tumour microenvironment and disease progression in papillary thyroid cancer (PTC) is not well understood. Studies evaluating the programmed cell death ligand 1 (PD-L1) tumour expression in PTC have shown variable results, and the effect of lymphocytic thyroiditis (LT) on tumour PD-L1 expression has not been adequately assessed. The main aim of this study was to determine expression of PD-L1 in PTC with and without LT. We examined 81 PTC cases; 28.5% of all reviewed PTC had presence of LT. In PTC specimens without LT, tumour PD-L1 expression was significantly lower compared to PD-L1 expression in PTC with LT, 6.9% vs 39.1%, respectively. Expression of PD-L1 did not differ with PTC stage, even when sub-categorised according to the presence and absence of LT. Utility of PD- L1 expression as a prognostic marker in thyroid cancer needs to be interpreted with caution.

Dynamics of serum antithyroglobulin antibodies in patients with differentiated thyroid cancer

PURPOSE

Serum antithyroglobulin antibodies (sTgAb) affect the reliability of Tg measurement in patients with thyroid cancer. We compared the outcome of patients with detectable and undetectable sTgAb, stratified according to the initial risk of recurrence (RR); also the response to treatment in patients with detectable sTgAb treated with total thyroidectomy (TT) with and without radioiodine remnant ablation (RA) and the sTgAb trend in the long-term follow-up according to the initial response.

METHODS

We included 432 patients submitted to TT, with or without RA; 106 patients had detectable sTgAb levels. Median follow-up was 53 months.

RESULTS

There were no statistically significant differences considering presentation between negative or positive sTgAb subjects. The frequency of structural incomplete response (SIR) in low, intermediate, and high RR was similar. Undetectable sTgAb in patients was achieved in a median of 16 months in ablated patients compared with 11 months in those without RA (p = 0.0232). Patients without RA had a higher rate of undetectable sTgAb during the first 12 months. A SIR was observed in 3% of patients with declining sTgAb, in 19% of those with stable levels, and in 43% with increasing sTgAb (p = 0.004). The status of no evidence of disease was achieved more frequently in patients with initial sTgAb levels < 200 mUI/l, independently of the initial RR.

CONCLUSIONS

There was no impact of sTgAb on the initial clinical presentation and the response to therapy in low-risk patients treated with or without RA. sTgAb trend is more useful than an absolute value to predict a SIR.

Degree of technical difficulty of thyroidectomy for autoimmune thyroid disease

BACKGROUND

Our goal was to elucidate the differences in degree of technical difficulty of thyroidectomy in patients with autoimmune thyroid diseases.

METHODS

Charts of adult patients who had undergone thyroidectomy were reviewed. Patients with Hashimoto's Thyroiditis (HT) or Graves' Disease (GD) were individually compared to a control group of patients with early stage malignancy or goiter.

RESULTS

The HT (n = 65) group was significantly more likely to have friable (P = .001) and fibrotic (P < .001) thyroids, longer operative times (P = .02), and a 22-modifier (P = .005). The GD (n = 169) group was significantly more likely to have friable (P < .001), vascular (P < .001), fibrotic (P = .038), and heavy (P = .002) thyroids, longer operative times (P = .03), increased length of stay (P = .01) and a 22-modifier (P = .01).

CONCLUSION

Our experience at an institution with a high-volume thyroid practice demonstrates that patients with autoimmune thyroid disease have consistent qualitative changes of the thyroid and significantly increased operative times and surgical difficulty.

Hobnail cells in encapsulated papillary thyroid carcinoma: Report of 2 cases with immunohistochemical and molecular findings and literature analysis

Papillary thyroid carcinoma (PTC) is the most common malignant tumor of the thyroid gland with most tumors behaving in an indolent fashion. However, morphologic variants have been described, such as tall cell, diffuse sclerosing, columnar cell etc. which are biologically more aggressive. One of these variants includes the more recently described hobnail variant (HVPTC) which shows micropapillae and presence of large cells with apically placed hyperchromatic nuclei, reverse polarity, and eosinophilic cytoplasm, akin to hobnail cells. The presence of >30% hobnail cells in a PTC deserves categorization as a hobnail variant. This variant is usually associated with extra thyroidal extension, lymphovascular invasion and lymph node metastasis. We describe the pathologic and molecular features of two cases of encapsulated PTC with hobnail cells in a 68 year old male and a 22 year old female (30% and 10% hobnail cells respectively). Both cases presented as low stage (pT2) tumors and showed no aggressive features like lymph node metastasis, or extrathyroidal extension (ETE) at the time of presentation. Tumors in both cases showed presence of BRAFV600E mutation, absence of RAS and/or TP53 mutations, and were negative for RET and PAX88/PPARG gene rearrangements.

Decreased staging of differentiated thyroid cancer in patients with chronic lymphocytic thyroiditis

PURPOSE

The biological association between chronic lymphocytic thyroiditis (CLT) and differentiated thyroid cancer (DTC) has not been elucidated yet. The aim of the study was to assess whether the presence of CLT exerts any influence on clinical or histological presentation of DTC.

METHODS

Nine hundred and seven consecutive patients with DTC treated in the years 1998-2016 were divided into two groups according to the presence or absence of concomitant CLT. The statistical differences were analysed.

RESULTS

Out of 907 patients included in the study, 331 were diagnosed with DTC and CLT (studied group), while 576 patients with DTC but without CLT constituted a control group. The distribution of papillary and follicular thyroid cancer did not differ. In CLT group, the prevalence of pT1 was greater than for pT2-pT4 DTC (P = 0.0003; OR = 1.69, 95% CI 1.27-2.24) compared to controls (68.3 vs. 56.1%, respectively). The presence of multifocal lesions was similar. The thyroid capsule infiltration without extrathyroidal invasion (P < 0.0001; OR = 0.21, 95% CI 0.14-0.31) was more frequent in the studied group, unlike extracapsular invasion, which was significantly more often present in patients with DTC but without CLT (P = 0.004; OR = 1.66; 95% CI 1.17-2.34) as well as nodal involvement (P = 0.048; OR = 0.65, 95% CI 0.42-0.99).

CONCLUSIONS

The collected data indicate a protective role of CLT in preventing the spread of the DTC. The presence of CLT might limit tumour growth to the primary site.

The value of preoperative antithyroidperoxidase antibody as a novel predictor of recurrence in papillary thyroid carcinoma

The link between chronic lymphocytic thyroiditis (CLT) and papillary thyroid carcinoma (PTC) is widely recognized. Considering the strong association between raised antithyroidperoxidase antibody (TPOAb) and CLT, we postulated that the preoperative TPOAb can predict the prognosis of PTC, particularly for recurrence. A total of 2,070 patients who underwent total thyroidectomy for classical type PTC with tumor size ≥1 cm and with available data on preoperative TPOAb and TgAb were enrolled to compare disease-free survival (DFS) according to the presence of preoperative TPOAb, TgAb, and coexistent CLT. Patients with positive preoperative TPOAb had a significantly better DFS compared to patients without positive preoperative TPOAb (hazard ratio (HR) 0.53; 95% confidence interval (CI) 0.30-0.94, p = 0.028) while no difference in DFS was found according to preoperative TgAb status. Positive preoperative TPOAb was an independent prognostic factor for structural persistent/recurrent disease after adjustment for major preoperative risk factors such as age, sex, and tumor size (HR 0.52, 95% CI 0.28-0.99, p = 0.048). Although the coexistence of CLT lowered the risk for structural persistence/recurrence in univariate analysis (HR 0.52, 95% CI 0.31-0.86, p = 0.012), it was not an independent favorable prognostic factor by multivariate analysis (HR 0.65, 95% CI 0.38-1.10, p = 0.106). However, when coexistent CLT was combined with positive preoperative TPOAb, it indicated an independent protective role in structural persistent/recurrent disease (HR 0.39, 95% CI 0.16-0.98, p = 0.045). Our study clearly showed that presence of preoperative TPOAb can be a novel prognostic factor in predicting structural persistence/recurrence of PTC.

Associations between Hashimoto Thyroiditis and Clinical Outcomes of Papillary Thyroid Cancer: A Meta-Analysis of Observational Studies

BACKGROUND

Epidemiological studies have suggested an association between Hashimoto thyroiditis (HT) and papillary thyroid cancer (PTC) development. Other studies, however, have reported a protective role of HT against PTC progression. Through this updated meta-analysis, we aimed to clarify the effects of HT on the progression of PTC.

METHODS

We searched citation databases, including PubMed and Embase, for relevant studies from inception to September 2017. From these studies, we calculated the pooled odds ratios (ORs) of clinicopathologic features and the relative risk (RR) of PTC recurrence with 95% confidence intervals (CIs) using the Mantel-Haenszel method. Additionally, the Higgins I² statistic was used to test for heterogeneity.

RESULTS

The meta-analysis included 71 published studies with 44,034 participants, among whom 11,132 had HT. We observed negative associations between PTC with comorbid HT and extrathyroidal extension (OR, 0.74; 95% CI, 0.68 to 0.81), lymph node metastasis (OR, 0.82; 95% CI, 0.72 to 0.94), distant metastasis (OR, 0.49; 95% CI, 0.32 to 0.76), and recurrence (RR, 0.50; 95% CI, 0.41 to 0.61).

CONCLUSION

In this meta-analysis, PTC patients with HT appeared to exhibit more favorable clinicopathologic characteristics and a better prognosis than those without HT.

Hashimoto's thyroiditis – an independent risk factor for papillary carcinoma

Introduction

The link between Hashimoto's thyroiditis and thyroid carcinoma has long been a topic of controversy.

Objective

The aim of our study was to determine the prevalence of thyroid carcinoma and Hashimoto's thyroiditis coexistence in histopathologic material of thyroidectomized patients.

Methods

In a retrospective study, the clinicohistopathologic data of 2117 patients (1738 females/379 males), who underwent total or partial thyroidectomy for thyroid gland disorder at a single institution from the 1st of January 2005 to the 31st of December 2014 were analyzed.

Results

Thyroid carcinoma was detected in 318 cases (15%) and microcarcinoma (thyroid cancer ≤10 mm in diameter) was found in permanent sections in 169 cases (8%). Hashimoto's thyroiditis was detected in 318 (15%) patients. Hashimoto's thyroiditis was significantly more often associated with thyroid carcinoma and microcarcinoma compare to benign condition (p = 0.048, p = 0.00014, respectively). Coexistence of Hashimoto's thyroiditis and thyroid carcinoma/thyroid microcarcinoma did not affect tumor size (p = 0.251, p = 0.098, respectively), or tumor multifocality (p = 0.831, p = 0.957, respectively). Bilateral thyroid microcarcinoma was significantly more often detected when Hashimoto's thyroiditis was also diagnosed (p = 0.041), but presence of Hashimoto's thyroiditis did not affect bilateral occurrence of thyroid carcinoma (p = 0.731).

Conclusion

Hashimoto's thyroiditis is associated with significantly increased risk of developing thyroid carcinoma, especially thyroid microcarcinoma.

Identifying risk factors for recurrence of papillary thyroid cancer in patients who underwent modified radical neck dissection

Background

Papillary thyroid cancer (PTC) patients with ipsilateral neck metastatic lymph node (LN) and those with contralateral neck metastatic LN belong to N1b. Only a few studies have reported on comparisons with regard to laterality of metastatic lateral LN. The aim of this study was to evaluate predictive factors for contralateral neck LN metastasis and to determine prognostic factors for recurrence in PTC patients with N1b.

Methods

This retrospective study reviewed the medical records of 390 PTC patients who underwent total thyroidectomy and central LN dissection plus ipsilateral or bilateral modified radical neck dissection (MRND) between January 2004 and December 2012.

Results

During a median follow-up of 81 (range, 6–156) months, 84 patients had a recurrence in any lesion. Male gender, a main tumor of more than 2 cm, number of metastatic central LN, number of harvested and metastatic lateral LN, total LN ratio, multifocality, bilaterality, and gross ETE had significance in the patients who underwent bilateral MRND. In multivariate analysis according to recurrence, patients with LN ratio > 0.44 in the central compartment (hazard ratio [HR], 1.890; 95% confidence interval [CI], 1.124–3.178; p = 0.015), LN ratio > 0.29 in the lateral compartment (HR, 2.351; 95% CI, 1.477–3.743; p < 0.001), and multifocality (HR, 1.583; 95% CI, 1.030–2.431; p = 0.036) were associated with worse RFS. However, the type of MRND was statistically significant only in univariate analysis.

Conclusions

Recurrence in N1b PTC patients is predicted by central neck LN ratio > 0.44, lateral neck LN ratio > 0.29, and multifocality of tumors. We suggest that patients with these factors should receive short-term follow-up using image modalities like ultrasonography and computed tomography.

Clinical analysis of Hashimoto thyroiditis coexistent with papillary thyroid cancer in 1392 patients

Papillary thyroid carcinoma (PTC) is the most common malignant tumour of the thyroid. The effect of the concurrent presence of Hashimoto's thyroiditis (HT) and PTC is still under debate. The aim of this study is to investigate the influence of coexistent HT on prognostic outcomes and the association of coexistent HT with clinicopathological features. The demographic and clinicopathological data of 1,392 patients who underwent surgery in our hospital from 2007 to 2016 was collected and analysed. Among 1,392 PTC patients, the rate of HT was 25.6%. There were significant differences in the mean levels of thyroid stimulating hormone (3.27 vs. 2.41 μIU/L, p < 0.01), thyroperoxidase antibodies (110.31 vs. 131.2 U/ml, p < 0.01) and thyroglobulin antibodies (131.90 vs. 113.53 ng/ml, p < 0.01) between the two groups. PTC patients with HT had the following characteristics compared to patients without HT: smaller tumour size (p < 0.01), female predominance (p < 0.01) and higher rate of multifocality (p = 0.024). In addition, patients with HT had a significantly lower rate of lymph node metastasis (LNM) and advanced TNM stage than patients without HT (all p < 0.01). Multivariate analysis found that both age and multifocality were significantly associated with central LNM in HT patients (p < 0.01, p = 0.019, respectively). Extrathyroidal invasion and TSH level were also significant independent factors for lateral LNM in HT patients (p < 0.008, p = 0.04, respectively). HT is associated with a significantly higher risk of PTC. The coexistence of HT in PTC patients is associated with favourable clinical outcomes compared to PTC without HT. Total thyroidectomy and prophylactic central compartment lymphadenectomy should be a choice for PTC patients with HT.

Effects of Chronic Lymphocytic Thyroiditis on the Clinicopathological Features of Papillary Thyroid Cancer

BACKGROUND

The effects of chronic lymphocytic thyroiditis (CLT) on the presentation and outcome of papillary thyroid carcinoma (PTC) have long been a topic of controversy.

OBJECTIVE

To evaluate the effect of coexistent CLT on the clinicopathological features of PTC.

DESIGN

Retrospective study.

PATIENTS

All patients with PTC who had been followed by the 2 co-investigators (Juan Rivera and Richard J. Payne) between 2006 and 2011 were included.

RESULTS

CLT was present in 35% (166) of the included patients and was associated with a higher proportion of patients with TNM stage I (p = 0.027) and fewer patients with persistent disease (p = 0.014) in comparison with the PTC-only group. Analysis of the data based on age (<45 or >45 years) revealed that in the older group, the presence of CLT was associated with fewer patients with persistent disease (p = 0.03) and capsular invasion (p = 0.05). However, in patients <45 years of age, the presence of CLT was associated with more capsular invasion (p = 0.003) and extrathyroidal extension (p = 0.004) compared with the PTC-only group.

CONCLUSIONS

CLT in patients with PTC was associated with lower-stage disease and less disease persistence in patients >45 years of age. In patients <45 years, the presence of CLT appeared to be associated with unfavorable pathological features.

Influence of coexistent Hashimoto's thyroiditis on the extent of cervical lymph node dissection and prognosis in papillary thyroid carcinoma

OBJECTIVE

Previous studies did not focus on the differences in the extent of cervical lymph node (LN) dissection according to coexistent Hashimoto's thyroiditis (HT) in patients with papillary thyroid carcinoma (PTC) and its clinical impact. We aimed to determine whether extensive cervical LN dissection is responsible for favourable clinical outcomes in PTC patients with HT and whether the coexistence of HT itself has an independent protective effect regardless of LN status.

DESIGN

Retrospective cohort study.

PATIENTS

1369 patients with PTC who underwent total thyroidectomy with central compartment neck dissection.

MEASUREMENTS

Metastatic LN ratio, defined as number of metastatic LNs divided by number of removed LNs, was used to evaluate the extent of LN dissection as well as the status of LN metastasis. Disease-free survival and dynamic risk stratification were compared for clinical outcomes.

RESULTS

Presence of HT did not lower the risk of cervical LN metastasis (61.6% in patients with HT vs 65.1% in patients without HT, P = .292). Patients with HT had significantly larger numbers of removed LNs than patients without HT (11 vs 8, respectively, P < .001). Accordingly, metastatic LN ratio was smaller in patients with HT (P = .002), which was independently associated with structural persistent/recurrent disease (hazard ratio [HR] 2.33, 95% confidence interval [CI] 1.30-4.16, P = .004). HT itself was negatively associated with structural persistent/recurrent disease after adjustment for other clinicopathological factors (HR 0.39, 95% CI 0.18-0.87, P = .020).

CONCLUSIONS

Coexistence of HT itself is an independent factor associated with favourable outcome in PTC patients, regardless of the extent of LN dissection.

Hashimoto's thyroiditis predicts outcome in intrathyroidal papillary thyroid cancer

Hashimoto's thyroiditis (HT) seems to have favourable prognostic impact on papillary thyroid cancer (PTC), but data were obtained analysing all disease stages. Given that HT-related microenvironment involves solely the thyroid, we aimed to assess the relationship between HT, as detected through pathological assessment, and outcome in intrathyroidal PTC. This was a multicentre, retrospective, observational study including 301 PTC with no evidence of extrathyroidal disease. Primary study endpoint was the rate of clinical remission. Auxiliary endpoint was recurrence-free survival (RFS). HT was detected in 42.5% of the cohort and was associated to female gender, smaller tumour size, lower rate of aggressive PTC variants and less frequent post-surgery radio-iodine administration. HT showed relationship with significantly higher rate of clinical remission (P < 0.001, OR 4, 95% CI 1.78-8.94). PTCs with concomitant HT had significantly longer RFS, as compared with non-HT tumours (P = 0.004). After adjustment for other parameters affecting disease outcome at univariate analysis (age at diagnosis, histology, tumour size and multifocality), prognostic effect of HT remained significant (P = 0.006, OR 3.28, 95% CI 1.39-7.72). To verify whether HT could optimise the identification of PTCs with unfavourable outcome, we assessed the accuracy of 'non-HT status' as negative prognostic marker, demonstrating poor capability of identifying patients not maintaining clinical remission until final follow-up (probability of no clinical remission in PTCs without HT: 21.05%, 95% CI 15.20-27.93). In conclusion, our data show that HT represents an independent prognostic parameter in intrathyroidal PTC, but cannot improve prognostic specificity.

Thyroid Autoimmunity and Thyroid Cancer: Review Focused on Cytological Studies

The association between Hashimoto thyroiditis (HT) and papillary thyroid carcinoma (PTC) has been originally suggested by retrospective pathological studies and has recently been re-evaluated and proposed on the basis of several fine-needle aspiration cytology (FNAC) studies. In FNAC studies, the association between HT and PTC is based on the comparison of anti-thyroid autoantibodies (ATA) (anti-thyroperoxidase [TPOAb] and anti-thyroglobulin [TgAb]), thyroid function (TSH), and cytology with histology of thyroid nodules and lymphocytic thyroid infiltration (LTI) of operated thyroid glands. Most of the pathological studies found a high prevalence rate of PTC in HT. In most FNAC studies, the risk ratio of PTC in HT patients was evaluated using multivariate statistical analysis: increased TSH levels represented the main and common independent risk factor of malignancy, although it resulted not consistently related to HT. On the other hand, several studies provided a positive relationship between ATA and PTC, particularly with TgAb. Two recent FNAC studies from the same referral center clearly demonstrated an independent risk for thyroid malignancy conferred by both TPOAb and TgAb, confirming the role of increased TSH levels, and found a significant association between PTC and ATA and diffuse LTI at histology. These studies are consistent with the hypothesis that autoimmune thyroid inflammation and increased serum TSH concentration may be involved in thyroid tumor growth. The complex relationship between HT and PTC, which involves immunological/hormonal pathogenic links, needs to be further investigated with prospective studies.

Leveraging the immune system to treat advanced thyroid cancers

Inflammation has long been associated with the thyroid and with thyroid cancers, raising seminal questions about the role of the immune system in the pathogenesis of advanced thyroid cancers. With a growing understanding of dynamic tumour-immune cell interactions and the mechanisms by which tumour cells evade antitumour immunity, the field of cancer immunotherapy has been revolutionised. In this Review, we provide evidence to support the presence of an antitumour immune response in advanced thyroid cancers linked to cytotoxic T cells and NK cells. This antitumour response, however, is likely blunted by the presence of immunosuppressive pathways within the microenvironment, facilitated by tumour-associated macrophages or increased expression of negative regulators of cytotoxic T-cell function. Current and future efforts to incorporate immune-based therapies into existing tumour cell or endothelial-derived therapies-eg, with kinase inhibitors targeting tumour-associated macrophages or antibodies blocking negative regulators on T cells-could provide improved and durable responses for patients with disease that is otherwise refractory to treatment.

Association between Hashimoto's Thyroiditis and Thyroid Cancer in 64,628 Patients

Background

The incidence of thyroid cancer (TC) is increasing although explanatory causes are lacking. A link between cancer and inflammation is well documented but unclear for autoimmune thyroid diseases and TC. We aimed to systematically review the association between Hashimoto’s thyroiditis (HT) and papillary, follicular, medullary, anaplastic thyroid carcinoma, and thyroid lymphoma (TL).

Methods

PubMed, OVID Medline, Google Scholar, and the Cochrane Library were searched from 1955 to 2016. The inclusion criteria were age >18 years, ≥20 cases of HT or TC. We collectively examined the incidence of HT in TC and of TC in HT.

Results

We identified 36 studies (64,628 subjects) published between 1955 and 2016 from 13 countries. We found a relative risk (RR) of HT among papillary thyroid cancer (PTC) of 2.36 [95% confidence intervals (CIs) 1.55–3.29, p < 0.001], an RR of PTC among HT of 1.40 (95% CI 1.07–1.85, p = 0.016), and an RR of TL among HT of 9.74 (95% CI 3.93–24.13, p < 0.001).

Conclusion

We report an association between HT and PTC and between HT and TL. No association was found between HT and follicular, medullary, or anaplastic thyroid cancer.

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.

Impact of co-existent thyroiditis on clinical outcome in papillary thyroid carcinoma with high preoperative serum antithyroglobulin antibody: a retrospective cohort study

OBJECTIVES

The aim of this study was to investigate the impact of co-existent chronic lymphocytic thyroiditis (CLT) on changes in serum antithyroglobulin antibody (TgAb) and clinical outcome in papillary thyroid carcinoma (PTC) patients with high preoperative serum TgAb.

DESIGN

A retrospective cohort study.

SETTING

University teaching hospital.

PARTICIPANTS

Thirty-seven PTC patients with high preoperative serum TgAb level (≥100 U/mL) were evaluated. All patients underwent total thyroidectomy followed by high-dose I-131 ablation.

MAIN OUTCOME MEASURES

Per cent changes of TgAb between pre-treatment and post-treatment, and disease-free survival were calculated.

RESULTS

Twenty-two patients (59.5%) had co-existent CLT, and seven had residual/recurrent tumours. There was a higher proportion of females among the patients with CLT compared to those without CLT (95.5% versus 66.7%; P = 0.0306). There were trends towards more aggressive pathologies, such as tumour size, extrathyroidal extension, surgical margin and lymph node stage, in PTC without CLT than in that with co-existent CLT. Pre-treatment and post-treatment TgAb were all higher in PTC with co-existent CLT. But, per cent changes of TgAb between pre-treatment and post-treatment were no significant difference between PTC with and without CLT (P < 0.05). Patients with co-existent CLT showed a significantly lower residual/recurrent tumour rate than those without CLT (4.5% versus 40%; P = 0.0113).

CONCLUSION

Residual/recurrent tumour rate was lower in PTC patients with co-existent CLT than in those without CLT.

Less aggressive disease in patients with primary squamous cell carcinomas of the thyroid gland and coexisting lymphocytic thyroiditis

Aim of the study

Primary squamous cell carcinoma (SCC) of the thyroid gland is extremely rare. Infrequently, primary SCC of the thyroid gland is accompanied by other thyroid diseases such as Hashimoto's thyroiditis (HT). Recently, studies have demonstrated that differentiated thyroid cancer with coexisting HT has a better prognosis. However, the prognosis of patients with primary SCC of the thyroid gland and coexistent HT has not been clearly identified. We compared the clinical characteristics and disease stages of patients with primary SCC with and without lymphocytic thyroiditis (LT).

Material and methods

We reviewed reports of primary SCC of the thyroid gland published in the English literature.

Results and conclusions

We identified 46 papers that included 17 cases of primary SCC of the thyroid gland with LT and 77 cases of primary SCC of the thyroid gland without LT. Lymph node metastasis and local invasion rates did not differ between these two groups. Distant metastases were absent in patients with LT, and were observed in 13 (16.9%) patients without LT. A greater proportion of patients without LT had advanced stage disease (stage IV A-B-C) than patients with LT (p < 0.05). Patients with primary SCC of the thyroid gland and coexisting LT had lower tumour-node-metastasis stage and frequency of distant metastasis than those without LT. Lymphocytic infiltration in patients with SCC appears to limit tumour growth and distant metastases.

The impact of coexistent Hashimoto's thyroiditis on lymph node metastasis and prognosis in papillary thyroid microcarcinoma

The impact of coexistent Hashimoto's thyroiditis (HT) on lymph node metastasis (LNM) and prognosis in papillary thyroid microcarcinoma (PTMC) remains controversial. We evaluated the association of coexistent HT with clinicopathologic parameters, LNM, and prognosis by retrospectively reviewing a series of consecutive patients treated for PTMC at Fudan University Cancer Center from January 2005 to December 2010. Of all 1,250 patients with complete data for analysis, 364 (29.1 %) had coexistent HT (HT group) and 886 patients (70.9 %) had no evidence of HT (control group). The HT group had higher proportion of female (87.9 vs 70.1 %) patients, higher mean level of thyroid-stimulating hormone (TSH) (2.39 vs 2.00 mIU/L), and lower incidence of extrathyroidal extension (7.4 vs 11.7 %) than those in the control group. However, the incidence of LNM and recurrence was similar between the two groups, and HT was not associated with LNM and recurrence. A series of clinicopathologic factors identified for predicting LNM and recurrence in the control group did not show any prediction in the HT group. In summary, this study suggested that coexistent HT had insignificant protective effect on LNM and prognosis in PTMC, which was inconsistent with prior studies. Further studies aiming to determine novel predictors are recommended in PTMC patients with coexistent HT.