The relationship between chronic lymphocytic thyroiditis and central neck lymph node metastasis in North American patients with papillary thyroid carcinoma

Predicting central lymph node metastasis in papillary thyroid cancer: A nomogram based on clinical, ultrasound and contrast‑enhanced computed tomography characteristics

Central lymph node (CLN) status is considered to be an important risk factor in patients with papillary thyroid carcinoma (PTC). The aim of the present study was to identify risk factors associated with CLN metastasis (CLNM) for patients with PTC based on preoperative clinical, ultrasound (US) and contrast-enhanced computed tomography (CT) characteristics, and establish a prediction model for treatment plans. A total of 786 patients with a confirmed pathological diagnosis of PTC between January 2021 to December 2022 were included in the present retrospective study, with 550 patients included in the training group and 236 patients enrolled in the validation group (ratio of 7:3). Based on the preoperative clinical, US and contrast-enhanced CT features, univariate and multivariate logistic regression analyses were used to determine the independent predictive factors of CLNM, and a personalized nomogram was constructed. Calibration curve, receiver operating characteristic (ROC) curve and decision curve analyses were used to assess discrimination, calibration and clinical application of the prediction model. As a result, 38.9% (306/786) of patients with PTC and CLNM(-) status before surgery had confirmed CLNM using postoperative pathology. In multivariate analysis, a young age (≤45 years), the male sex, no presence of Hashimoto thyroiditis, isthmic location, microcalcification, inhomogeneous enhancement and capsule invasion were independent predictors of CLNM in patients with PTC. The nomogram integrating these 7 factors exhibited strong discrimination in both the training group [Area under the curve (AUC)=0.826] and the validation group (AUC=0.818). Furthermore, the area under the ROC curve for predicting CLNM based on clinical, US and contrast-enhanced CT features was higher than that without contrast-enhanced CT features (AUC=0.818 and AUC=0.712, respectively). In addition, the calibration curve was appropriately fitted and decision curve analysis confirmed the clinical utility of the nomogram. In conclusion, the present study developed a novel nomogram for preoperative prediction of CLNM, which could provide a basis for prophylactic central lymph node dissection in patients with PTC.

Malignancy risk of indeterminate lymph node at the central compartment in patients with thyroid cancer and concomitant sonographic thyroiditis

BACKGROUND

To evaluate the malignancy risk of sonographic (US) indeterminate lymph node (LN)s at the central compartment in thyroid cancer patients with US-thyroiditis (ST).

METHODS

Among the central compartments of suspicious, indeterminate, and probably benign LN US categories, the malignancy rates were compared between ST and non-US-thyroiditis (non-ST) groups. Those of indeterminate category were compared with suspicious and probably benign categories.

RESULTS

At 531 central compartments from 349 patients, the malignancy rate was lower in ST group (34.4% [44/128]) than non-ST group (43.4% [175/403]), although statistically not significant (p = 0.08). The malignancy rate of indeterminate category in ST group (35.7% [5/14]) was lower than non-ST group (71.9% [23/32]) (p = 0.047). Within ST group, the malignancy rate of indeterminate category (35.7% [5/14]) did not differ from probably benign category (29.1% [30/103]) (p = 0.756), but was lower than suspicious category (81.8% [9/11]) (p = 0.042).

CONCLUSIONS

The malignancy risk of US indeterminate LNs at the central compartment in thyroid cancer patients with US thyroiditis was lower than that in patients without US thyroiditis.

Clinical impact of coexistent chronic lymphocytic thyroiditis on central lymph node metastasis in low- to intermediate-risk papillary thyroid carcinoma: The MASTER study

BACKGROUND

The clinicopathological impact of chronic lymphocytic thyroiditis on patients with papillary thyroid carcinoma patients is still controversial. This study aimed to evaluate the clinicopathologic differences and risk factors for central lymph node metastasis based on the presence of coexistent chronic lymphocytic thyroiditis in patients with low- to intermediate-risk papillary thyroid carcinoma.

METHODS

The medical records of 1,022 patients with low- to intermediate-risk papillary thyroid carcinoma who underwent lobectomy and central neck dissection between June 2020 and March 2022 were reviewed. Differences in clinicopathological factors were analyzed in patients with papillary thyroid carcinoma with or without chronic lymphocytic thyroiditis. Furthermore, risk factors for central lymph node metastasis in patients with low- to intermediate-risk papillary thyroid carcinoma with or without chronic lymphocytic thyroiditis were evaluated.

RESULTS

Among the 1,022 patients with low to intermediate-risk papillary thyroid carcinoma, 102 (10.0%) had coexisting chronic lymphocytic thyroiditis. Female sex (odds ratio = 3.536, P = .001, 95% confidence interval 1.781-8.069), a multifocal tumor (odds ratio = 2.162, P = .001, 95% confidence interval 1.358-3.395), and angiolymphatic invasion (odds ratio = 0.365, P < .001, 95% confidence interval 0.203-0.625) were independent factors associated with patients who had coexisting chronic lymphocytic thyroiditis compared to those without chronic lymphocytic thyroiditis. There were 358 (35%) patients who had central lymph node metastasis. Multivariate analysis showed that younger age (odds ratio = 0.667, P = .013, 95% confidence interval 0.482-0.555), male sex (odds ratio = 0.549, P < .001, 95% confidence interval 0.402-0.751), tumor size >1 cm (odds ratio = 1.454, P = .022, 95% confidence interval 1.053-2.003), extrathyroidal extension (odds ratio = 1.874, P < .001, 95% confidence interval 1.414-2.486), and angiolymphatic invasion (odds ratio = 3.094, P < .001, 95% confidence interval 2.339-4.101) were risk factors for central lymph node metastasis. Angiolymphatic invasion (odds ratio = 11.184, P < .001, 95% confidence interval 3.277-46.199) was identified as the sole independent risk factor for central lymph node metastasis in patients with papillary thyroid carcinoma with coexisting chronic lymphocytic thyroiditis.

CONCLUSION

Our data suggest that patients with low to intermediate-risk papillary thyroid carcinoma with coexistent chronic lymphocytic thyroiditis exhibit different clinical features than patients with papillary thyroid carcinoma without chronic lymphocytic thyroiditis. Additionally, the presence of chronic lymphocytic thyroiditis may be considered a potential factor against central lymph node metastasis.

Ultrasound-guided fine needle aspiration thyroglobulin in the diagnosis of lymph node metastasis of differentiated papillary thyroid carcinoma and its influencing factors

Background

Ultrasound-guided fine needle aspiration thyroglobulin (FNA-Tg) is recommended for the diagnosis of lymph node metastasis (LNM) in differentiated thyroid cancer (DTC), but its optimal cutoff value remains controversial, and the effect of potential influencing factors on FNA-Tg levels is unclear.

Method

In this study, a retrospective analysis was conducted on 281 patients diagnosed with DTC, encompassing 333 lymph nodes. We analyze the optimal cutoff value and diagnostic efficacy of FNA-Tg, while also evaluating the potential influence of various factors on FNA-Tg.

Results

For FNA-Tg, the optimal cutoff value was 16.1 ng/mL (area under the curve (AUC)= 0.942). The optimal cutoff value for FNA-Tg/sTg was 1.42 (AUC = 0.933). The AUC for FNA combined with FNA-Tg yielded the highest value compared to other combined diagnostic methods (AUC = 0.955). It has been found that serum thyroglobulin (sTg) is positively correlated with FNA-Tg (Rs = 0.318), while serum thyroglobulin antibodies (sTgAb) is negatively correlated with FNA-Tg (Rs = -0.147). In cases where the TNM stage indicated N1b, the presence of large or high volume lymph node metastasis(HVLNM), lymph node lateralization/suspicion (L/S) ratio ≤ 2, ultrasound findings indicating lymph node liquefaction, calcification, and increased blood flow, patients with coexisting Hashimoto's thyroiditis (HT), a tumor size ≥10 mm, and postoperative pathology confirming invasion of the thyroid capsule, higher levels of FNA-Tg were observed. However, the subgroup classification of DTC and the presence or absence of thyroid tissue did not demonstrate any significant impact on the levels of FNA-Tg.

Conclusion

The findings of this study indicate that the utilization of FNA in conjunction with FNA-Tg is a crucial approach for detecting LNM in DTC. TNM stage indicated N1b, the presence of HVLNM, the presence of HT, lymph node L/S ratio, liquefaction, calcification, tumor diameter, sTg and sTgAb are factors that can impact FNA-Tg levels.In the context of clinical application, it is imperative to individualize the use of FNA-Tg.

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.

Effect of Hashimoto's thyroiditis on the dual-energy CT quantitative parameters and performance in diagnosing metastatic cervical lymph nodes in patients with papillary thyroid cancer

BACKGROUND

To evaluate the effect of Hashimoto's thyroiditis (HT) on dual-energy computed tomography (DECT) quantitative parameters of cervical lymph nodes (LNs) in patients with papillary thyroid cancer (PTC), and its effect on the diagnostic performance and threshold of DECT in preoperatively identifying metastatic cervical LNs.

METHODS

A total of 479 LNs from 233 PTC patients were classified into four groups: HT+/LN+, HT+/LN-, HT-/LN + and HT-/LN - group. DECT quantitative parameters including iodine concentration (IC), normalized IC (NIC), effective atomic number (Zeff), and slope of the spectral Hounsfield unit curve (λHU) in the arterial phase (AP) and venous phase were compared. Receiver operating characteristic curve analyses were performed to evaluate DECT parameters' diagnostic performance in differentiating metastatic from nonmetastatic LNs in the HT - and HT + groups.

RESULTS

The HT+/LN + group exhibited lower values of DECT parameters than the HT-/LN + group (all p < 0.05). Conversely, the HT+/LN - group exhibited higher values of DECT parameters than the HT-/LN - group (all p < 0.05). In the HT + group, if an AP-IC of 1.850 mg/mL was used as the threshold value, then the optimal diagnostic performance (area under the curve, 0.757; sensitivity, 69.4%; specificity, 71.0%) could be obtained. The optimal threshold value of AP-IC in the HT - group was 2.050 mg/mL. In contrast, in the HT - group, AP-NIC demonstrated the highest area under the curve of 0.988, when an optimal threshold of 0.243 was used. The optimal threshold value of AP-NIC was 0.188 in the HT + group.

CONCLUSIONS

HT affected DECT quantitative parameters of LNs and subsequent the diagnostic thresholds. When using DECT to diagnose metastatic LNs in patients with PTC, whether HT is coexistent should be clarified considering the different diagnostic thresholds.

Thyroglobulin Antibody (TgAb) Positive is an Independent Risk Factor for Lymph Node Metastasis in Patients with Differentiated Thyroid Carcinoma

Objective

To investigate the relationship between lymph node metastasis and the clinicopathologic features of differentiated thyroid carcinoma (DTC) patients with thyroglobulin antibody (TgAb) positive and negative.

Methods

A total of 443 patients with DTC were included in this study. Clinicopathological data of the patients were collected, including tumor size, clinical stage, calcification, Hashimoto's thyroiditis, extra-membrane infiltration, BRAF V600E mutation status, and thyroid-related hormone and antibody levels. The relationship between of lymph node metastasis and clinicopathologic features was analyzed.

Results

There were 227(51.2%) TgAb negative and 216(48.8%) TgAb positive DTC patients. Compared with patients without lymph node metastasis, DTC patients with lymph node metastasis had a higher proportion of patients with <55 years of age, maximum tumor diameter >1cm, calcification, BRAF V600E mutation, and TgAb positive. Multivariate regression logistic analysis showed that <55 years old (odds ratio (OR): 2.744, 95% CI: 1.665-4.522, P<0.001), maximum tumor diameter >1cm (OR: 2.163, 95% CI: 1.431-3.271, P<0.001), BRAF V600E mutation (OR: 2.489, 95% CI: 1.397-4.434, P=0.002), and TgAb positive (OR: 1.540, 95% CI: 1.020-2.326, P=0.040) were risk factors for lymph node metastasis. Maximum tumor diameter >1cm and BRAF V600E increased the risk by more than one fold for lymph node metastasis in TgAb-negative and TgAb-positive DTC patients.

Conclusion

Younger age (<55 years old), maximum tumor diameter >1cm, BRAF V600E mutation, and TgAb positive were independent risk factors for lymph node metastasis in DTC. And maximum tumor diameter >1cm and BRAF V600E mutation were risk factors for lymph node metastasis both in TgAb positive and negative DTC patients.

Prevalence and Impact of BRAF mutation in patients with concomitant papillary thyroid carcinoma and Hashimoto's thyroiditis: a systematic review with meta-analysis

Background

Evidence suggests that patients with Hashimoto thyroiditis (HT) are at significantly higher risk of developing papillary thyroid cancer (PTC). However, the course of PTC in patients with both diseases concomitantly has been found to be more indolent than conventional PTC. Additionally, it has been well proven that BRAF mutation results in an aggressive course of PTC. The aims of this meta-analysis were to identify prevalence of BRAF mutation and its impact on clinicopathological features in patients with concomitant PTC-HT.

Methods

Medline, Cochrane Library, Scopus, and Web of Science were searched until 16.09.2022, resulting in 227 articles, of which nine studies were included. Summary estimates, comparing patients with (A) BRAF (+) PTC-HT versus BRAF (+) PTC, and (B) BRAF (+) PTC-HT versus BRAF (-) PTC-HT, were generated with Review Manager 5.0.

Results

In total, 6395 patients were included in this review. PTC-HT patients had significantly less BRAF mutation than PTC patients (Odds Ratio (OR) (95% Confidence Interval (CI))=0.45 (0.35-0.58), P<0.001). BRAF (+) PTC-HT patients were significantly more likely to have multifocal lesions (OR (95% CI)=1.22 (1.04-1.44), P=0.01) but less likely to have lymph node metastasis (OR (95% CI)=0.65 (0.46-0.91), P=0.01) and extrathyroidal extension (OR (95% CI)=0.55 (0.32-0.96), P=0.03) compared to BRAF (+) PTC patients. BRAF (+) PTC-HT patients were more likely to have multifocal lesions (OR (95% CI)=0.71 (0.53-0.95), P=0.02), lymph node metastasis (OR (95% CI)=0.59 (0.44-0.78), P<0.001) and extrathyroidal extension (OR (95% CI)=0.72 (0.56-0.92), P=0.01) compared to BRAF (-) PTC-HT patients.

Conclusion

This meta-analysis highlights that the lower prevalence of BRAF mutation in patients with PTC-HT than conventional PTC may explain the indolent clinicopathological course in this cohort.

Mapping the path towards novel treatment strategies: a bibliometric analysis of Hashimoto's thyroiditis research from 1990 to 2023

Background

Hashimoto's thyroiditis (HT), a common form of thyroid autoimmunity, is strongly associated with deteriorating clinical status and impaired quality of life. The escalating global prevalence, coupled with the complexity of disease mechanisms, necessitates a comprehensive, bibliometric analysis to elucidate the trajectory, hotspots, and future trends in HT research.

Objective

This study aims to illuminate the development, hotspots, and future directions in HT research through systematic analysis of publications, institutions, authors, journals, references, and keywords. Particular emphasis is placed on novel treatment strategies for HT and its complications, highlighting the potential role of genetic profiling and immunomodulatory therapies.

Methods

We retrieved 8,726 relevant documents from the Web of Science Core Collection database spanning from 1 January 1990 to 7 March 2023. Following the selection of document type, 7,624 articles were included for bibliometric analysis using CiteSpace, VOSviewer, and R software.

Results

The temporal evolution of HT research is categorized into three distinct phases: exploration (1990-1999), rapid development (1999-2000), and steady growth (2000-present). Notably, the United States, China, Italy, and Japan collectively contributed over half (54.77%) of global publications. Among the top 10 research institutions, four were from Italy (4/10), followed by China (2/10) and the United States (2/10). Recent hotspots, such as the roles of gut microbiota, genetic profiling, and nutritional factors in HT management, the diagnostic dilemmas between HT and Grave's disease, as well as the challenges in managing HT complicated by papillary thyroid carcinoma and type 1 diabetes mellitus, are discussed.

Conclusion

Although North America and Europe have a considerable academic impact, institutions from emerging countries like China are demonstrating promising potential in HT research. Future studies are anticipated to delve deeper into the differential diagnosis of HT and Grave's disease, the intricate relationship between gut microbiota and HT pathogenesis, clinical management of HT with papillary thyroid carcinoma or type 1 diabetes, and the beneficial effects of dietary modifications and micronutrients supplementation in HT. Furthermore, the advent of genetic profiling and advanced immunotherapies for managing HT offers promising avenues for future research.

Hashimoto's thyroiditis is negatively associated with lymph node metastasis in PTMC

PURPOSE

The association between Hashimoto's thyroiditis (HT) and lymph node metastasis (LNM) of papillary thyroid microcarcinoma (PTMC) remains poorly understood. We aimed to elucidate the impact of HT on PTMC and its association with LNM.

METHODS

A retrospective cohort study was conducted at a single cancer referral center. Patients diagnosed with PTMC and complete clinicopathological results between January 2013 and June 2018 were included. Propensity score matching (PSM) and logistic regression analysis were performed to evaluate the difference in LNM characteristics between patients with and without HT.

RESULTS

Among the 9929 PTMC patients, 2389 (24.1%) were pathologically diagnosed with HT. After PSM using variables including age, sex, primary tumor size, central neck dissection, extrathyroidal extension (ETE), gross ETE, multifocality and bilaterality, we identified 2324 pairs of patients for analysis. Patients with HT had a significantly lower incidence of LNM in the central neck (40.9% vs 56.2%, P < 0.001) and lateral neck (11.6% vs 14.2%, P = 0.016), a lower incidence of extranodal extension (ENE) (10.1% vs 17.0%, P < 0.001), fewer positive lymph nodes (median [IQR], 0 [0 to 2] vs 1 [0 to 3], P < 0.001), and a lower lymph node ratio (median [IQR], 0.00 [0.00 to 0.15] vs 0.12 [0.00 to 0.33], P < 0.001) than those without HT. Logistic regression analysis indicated that patients with HT had a significantly reduced risk of CLNM and LLNM compared to those without HT.

CONCLUSIONS

Our study indicated a negative association between HT and LNM in PTMC.

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.

Ultrasound-based Nomogram for Predicting the Pathological Nodal Negativity of Unilateral Clinical N1a Papillary Thyroid Carcinoma in Adolescents and Young Adults

RATIONALE AND OBJECTIVES

To develop and validate a nomogram incorporating clinical and ultrasound (US) characteristics for predicting the pathological nodal negativity of unilateral clinically N1a (cN1a) papillary thyroid carcinoma (PTC) among adolescents and young adults.

MATERIALS AND METHODS

From December 2016 to August 2021, 278 patients aged ≤ 30 years from two medical centers were enrolled and randomly assigned to the training and validation cohorts at a ratio of 2:1. After performing univariate and multivariate analyses, a nomogram combining all independent predictive factors was constructed and applied to the validation cohort. The performance of the nomogram was evaluated using receiver operating characteristic curves, calibration curves, and decision curve analysis .

RESULTS

Multivariate logistic regression analysis showed that unilateral cN1a PTC in young patients with Hashimoto's thyroiditis, T1 stage, no intra-tumoral microcalcification, and tumors located in the upper third of the thyroid gland was more likely to be free of central lymph node metastases. The nomogram revealed good calibration and discrimination in both cohorts, with areas under the receiver operating characteristic curve of 0.764 (95% confidence interval [CI]: 0.684-0.843) and 0.728 (95% CI: 0.602-0.853) in the training and validation cohorts, respectively. The clinical application of the nomogram was further confirmed using decision curve analysis.

CONCLUSION

This US-based nomogram may assist the assessment of central cervical lymph nodes in young patients with unilateral cN1a PTC, enabling improved risk stratification and optimal treatment management in clinical practice.

Predictive nomogram for central lymph node metastasis in papillary thyroid microcarcinoma based on pathological and ultrasound features

Background

Central lymph node metastases (CLNM) in papillary thyroid microcarcinoma (PTMC) are common, but management through prophylactic central lymph node dissection (pCLND) remains controversial. In this study, the independent predictors of CLNM in PTMC were retrospectively studied based on ultrasound and pathological data, and we aim to establish the prediction model to predict CLNM in PTMC.

Methods

This study included a total of 1,506 patients who underwent thyroid surgery for PTMC at the First Affiliated Hospital of Chongqing Medical University from 2015 to 2018. Ultrasound and clinicopathological features were summarized and analyzed. Univariate and multivariate analyses were performed to determine the risk factors associated with CLNM. The prediction model is established and verified according to the multivariate analysis results. The Kaplan-Meier curve was used to evaluate the effect of CLNM on survival.

Results

The CLNM rate was 44.5% (670/1,506). Multivariate analysis showed that men, younger age, smaller diameter, ETE, microcalcification, without Hashimoto's thyroiditis, and multifocal were independent risk predictors of CLNM. Nomogram has a good discriminative ability (C-index: 0.755 in the validation group), and the calibration effect is good. In the DCA curve, the CLNM prediction model performed better net benefit given any high-risk thresholds. The median follow-up time was 30 months (12-59 months), 116 cases were lost, and the follow-up rate was 92.8% (1,506/1,622). Of the 1,506 patients included, 12 (0.8%) experienced recurrence.

Conclusion

The likelihood of CLNM can be objectively quantified before surgery by using this reliable and accurate nomogram that combines preoperative ultrasound with clinicopathological features. Clinicians can use this nomogram to assess central lymph node status in patients with PTMC and consider prophylactic CND in patients with high scores.

Nomograms for Prediction of High-Volume Lymph Node Metastasis in Papillary Thyroid Carcinoma Patients

OBJECTIVE

The coexistence rate between chronic lymphocytic thyroiditis (CLT) and papillary thyroid carcinoma (PTC) is quite high. Whether CLT influences metastatic lymph nodes remains uncertain. High-volume lymph node metastasis is recommended as an unfavorable pathological feature. We aimed to investigate risk factors for high-volume central lymph node metastasis (CLNM) and lateral lymph node metastasis (LLNM) in PTC patients.

STUDY DESIGN

Retrospective cohort study.

SETTING

Changzhou First People's Hospital.

METHODS

Clinicopathological characteristics of 1094 PTC patients who underwent surgery in our center from January 2019 to November 2021 were analyzed.

RESULTS

The number of metastatic lymph nodes in the central compartment and lateral compartment were lower in the CLT group. We demonstrated that age, BRAF V600E, shape, and the number of foci were risk factors for high-volume CLNM in patients with CLT. For patients without CLT, sex, age, tumor size, number of foci, and margin were risk factors for high-volume CLNM. Tumor size, number of foci, location, and CLNM were all risk factors for high-volume LLNM in patients with or without CLT. Body mass index was only associated with high-volume LLNM in CLT patients. All the above factors were incorporated into nomograms, which showed perfect discriminative ability.

CONCLUSION

Separate predictive systems should be used for CLT and non-CLT patients for a more accurate clinical assessment of lymph node status. Our nomograms of predicting high-volume CLNM and LLNM could facilitate risk-stratified management of PTC recurrence and treatment decisions.

A retrospective study of papillary thyroid carcinoma: Hashimoto's thyroiditis as a protective biomarker for lymph node metastasis

PURPOSE

There is approximately 10%-50% of papillary thyroid carcinoma (PTC) patients with Hashimoto's thyroiditis (HT). In this research, we sought to better understand the role of HT in PTC progression as well as lymph node metastasis.

METHODS

It is a retrospective and cross-sectional study, and 4131 PTC patients who underwent thyroidectomy were finally enrolled. Chi-square test, univariate and multivariate logistic regression analyses were employed to evaluate both the risk factors and the critical roles of HT during PTC metastasis.

RESULT

In this cohort, 1555 patients (37.6%) were diagnosed with HT. According to multivariate analysis, male sex, high levels of TG and TPOAb, tumor extrathyroidal extension, maximum diameter >1 cm, and multifocality were independent risk factors for both central lymph node metastasis (CLNM) and lateral lymph node metastasis (LLNM). In addition, age <55 years and smoking were risk factors for CLNM, while CLNM was one of the risk factors for LLNM. Furthermore, HT was suggested a valuable protective factor for both CLNM and LLNM. In patients with HT, the total number of central lymph nodes was higher, while the positive rate was lower. Compared with those without HT, age and sex did not predict CLNM and LLNM in patients with HT.

CONCLUSION

HT is considered a protective factor for both CLNM and LLNM in PTC. For patients with HT, surgeons should pay more attention to the preservation of parathyroid gland and the protection of recurrent laryngeal nerve due to less lymph node metastasis. Otherwise, radical operation is highly recommended.

A clinical and molecular pathology prediction model for central lymph node metastasis in cN0 papillary thyroid microcarcinoma

BACKGROUND

The frequency of thyroid cancer has rapidly increased in recent years globally. Thus, more papillary thyroid microcarcinoma (PTMC) patients are being diagnosed, including clinical lymph node-negative (cN0) patients. Our study attempted to develop a prediction model for assessing the probability of central lymph node metastasis (CLNM) in cN0 PTMC patients.

METHODS

A total of 595 patients from the Affiliated Hospital of Qingdao University (training cohort: 456 patients) and the Affiliated Hospital of Jining Medical University (verification cohort: 139 patients) who underwent thyroid surgery between January 2020 and May 2022 were enrolled in this study. Their clinical and molecular pathology data were analyzed with multivariate logistic regression to identify independent factors, and then we established a prediction model to assess the risk of CLNM in cN0 PTMC patients.

RESULTS

Multivariate logistic regression analysis revealed that sex, Hashimoto's thyroiditis (HT), tumor size, extrathyroidal extension, TERT promoter mutations and NRAS mutation were independent factors of CLNM. The prediction model demonstrated good discrimination ability (C-index: 0.757 and 0.753 in the derivation and validation cohorts, respectively). The calibration curve of the model was near the optimum diagonal line, and decision curve analysis (DCA) showed a noticeably better benefit.

CONCLUSION

CLNM in cN0 PTMC patients is associated with male sex, tumor size, extrathyroidal extension, HT, TERT promoter mutations and NRAS mutation. The prediction model exhibits good discrimination, calibration and clinical usefulness. This model will help to assess CLNM risk and make clinical decisions in cN0 PTMC patients.

Preoperative prediction of central neck metastasis in patients with clinical T1-2N0 papillary thyroid carcinoma

BACKGROUND

Central neck metastasis (CNM) is common in patients with papillary thyroid carcinoma (PTC). However, the prediction of CNM risk remains poorly defined, especially for patients with clinically negative lymph nodes. We developed a preoperative clinical nomogram to predict CNM risk in patients with clinical T1-2N0 (cT1-2N0) PTC.

METHODS

Data from 436 patients with unifocal cT1-2N0 PTC were available. We analyzed the association between preoperative variables and CNM using univariate and multivariate logistic regression and developed a clinical nomogram based on the multivariate regression model. The nomogram was validated externally using an independent dataset.

RESULTS

The CNM rate was 25.5%. Three clinical variables were associated with CNM, including age, gender, and tumor size. We built a CNM nomogram integrating these three variables. It had a poor index of internal discrimination (C-index, 0.655; 95% CI 0.596-0.715) and a poor index of external discrimination (C-index, 0.690; 95% CI 0.611-0.769).

CONCLUSIONS

We developed a preoperative nomogram to quantify the risk of CNM in unifocal cT1-2N0 PTC patients. However, our data showed that preoperative clinical parameters were not able to accurately predict the likelihood of CNM. Other variables need to be investigated to improve the prediction capability of this nomogram.

Hashimoto’s Thyroiditis Minimizes Lymph Node Metastasis in BRAF Mutant Papillary Thyroid Carcinomas

Hashimoto’s thyroiditis (HT) (autoimmune thyroiditis) is a clinicopathological entity associated with chronic lymphocytic infiltration resulting in hypothyroidism. HT is a double-edged sword that increases the risk of papillary thyroid cancer (PTC), yet it serves as a protective factor for PTC progression. BRAF mutation in PTCs is associated with rapid cell growth, aggressive tumor characteristics, and higher mortality rates. Here, we aimed to analyze the influence of HT in patients with PTCs and its effect on lymph node metastasis (LNM) in BRAF mutant tumors. Adults diagnosed with PTC between 2008 and January 2021 were retrospectively included. A total of 427 patients, 128 of whom had underlying HT, were included. The HT group had significantly higher rates of microcarcinoma (49.2% vs. 37.5%, p = 0.025) and less lateral LNM (8.6% vs. 17.1%, p = 0.024). Interestingly, BRAF-mutated PTCs were found to have significantly less overall LNM (20.9% vs. 51%, p = 0.001), central LNM (25.6% vs. 45.1%, p = 0.040) and lateral LNM (9.3% vs. 29.4%, p = 0.010) in patients with HT when compared to those without underlying HT. HT was found to be an independent protective predictor of overall and lateral LNM. Altogether, HT was able to neutralize the effect of BRAF mutation and was determined to be an independent protective factor against LNM. Specifically, our work may influence treatment-aggressiveness decision making for endocrinologists, oncologists and surgeons alike.

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.

Ultrasound-based radiomics nomogram combined with clinical features for the prediction of central lymph node metastasis in papillary thyroid carcinoma patients with Hashimoto's thyroiditis

BACKGROUND

Hashimoto thyroiditis (HT) is the most common autoimmune thyroid disease and is considered an independent risk factor for papillary thyroid carcinoma (PTC), with a higher incidence of PTC in patients with HT.

OBJECTIVE

To build an integrated nomogram using clinical information and ultrasound-based radiomics features in patients with papillary thyroid carcinoma (PTC) with Hashimoto thyroiditis (HT) to predict central lymph node metastasis (CLNM).

METHODS

In total, 235 patients with PTC with HT were enrolled in this study, including 101 with CLNM and 134 without CLNM. They were divided randomly into training and validation datasets with a 7:3 ratio for developing and evaluating clinical features plus conventional ultrasound features (Clin-CUS) model and clinical features plus radiomics scores (Clin-RS) model, respectively. In the Clin-RS model, the Pyradiomics package (V1.3.0) was used to extract radiomics variables, and LASSO regression was used to select features and construct radiomics scores (RS). The Clin-CUS and Clin-RS nomogram models were built using logistic regression analysis.

RESULTS

Twenty-seven CLNM-associated radiomics features were selected using univariate analysis and LASSO regression from 1488 radiomics features and were calculated to construct the RS. The integrated model (Clin-RS) had better diagnostic performance than the Clin-CUS model for differentiating CLNM in the training dataset (AUC: 0.845 vs. 0.778) and the validation dataset (AUC: 0.808 vs. 0.751), respectively.

CONCLUSION

Our findings suggest that applying an ultrasound-based radiomics approach can effectively predict CLNM in patients with PTC with HT. By incorporating clinical information and RS, the Clin-RS model can achieve a high diagnostic performance in diagnosing CLNM in patients with PTC with HT.

Hashimoto's Thyroiditis: A "Double-Edged Sword" in Thyroid Carcinoma

BACKGROUND

The prevalence of thyroid carcinoma (TC) and Hashimoto's thyroiditis (HT) has been increasing dramatically over the past decades. We investigated the relationship between HT and TC.

METHODS

We followed the Meta-analysis of Observational Studies in Epidemiology (MOOSE) guidelines for carrying out and reporting this meta-analysis. The literature from January 1, 2010 to December 31, 2020, regardless of region and publication type, was searched comprehensively in PubMed, Embase, Web of Science, and Cochrane Library databases. After careful selection and data extraction, the pooled odds ratio of various clinical characteristics in 39 studies were calculated. Publication bias was analyzed using funnel plots.

RESULTS

Meta-analysis of 39 original research articles showed HT to be a risk factor of TC (pooled odds ratio = 1.71; 95% confidence interval, 1.57-1.80; p < 0.00001) and papillary thyroid carcinoma (1.67, 1.51-1.85, <0.00001). Patients with papillary thyroid carcinoma (PTC) combined with HT were more likely to have multifocal carcinomas. The prevalence of an extrathyroidal extension, metastasis, BRAF^V600E mutation, and recurrence was significantly lower in patients with PTC combined with HT.

CONCLUSIONS

HT is a "double-edged sword" in TC patients. HT increases the risk of TC and PTC but is a protective factor against PTC progression.

Prediction Model of Pathologic Central Lymph Node Negativity in cN0 Papillary Thyroid Carcinoma

Background

Most patients with papillary thyroid carcinoma (PTC) have an excellent prognosis. Although central lymph node invasion is frequent, management via central lymph node dissection (CLND) remains controversial. The present study retrospectively investigated independent predictors of pathologic central lymph node negativity (pCLN-) and established a prediction model for pCLN- in clinical lymph node negativity (cN0) PTC.

Methods

A total of 2,687 patients underwent thyroid surgery for cN0 PTC from 2013 to 2018 at the First Affiliated Hospital of Chongqing Medical University, and lobectomy plus ipsilateral CLND was the basic surgical extent. Clinicopathological characteristics were reviewed and analyzed. Univariate and multivariate analyses were performed to identify factors related to pCLN-. A prediction model was established based on the results of multivariate analyses.

Results

The pCLN- rate was 51.5% (1,383/2,687). Multivariate analysis revealed that sex, age, thyroid stimulating hormone (TSH), size, location, laterality, unifocality and extrathyroidal extension negativity (ETE-) were independent predictors of pCLN-. The nomogram showed good discriminative ability (C-index: 0.784 and 0.787 in derivation and validation groups, respectively) and was well calibrated. We quantified the clinical usefulness of the nomogram by decision curve analysis. The median length of follow-up was 30 (range 12– 83) months, and 190 cases were lost, with a follow-up rate of 92.9% (2,497/2,687). Of the 2,687 patients included, 21 (0.8%) experienced recurrence.

Conclusion

This nomogram, which integrates available preoperative clinicopathological features and intraoperative frozen biopsy outcomes, is a reliable tool with high accuracy to predict pCLN- in cN0 PTC.

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.

Influence Factors for Lymph Node Metastasis in Papillary Thyroid Carcinoma: Hashimoto's Thyroiditis Has a Weak Effect on Central or Lateral Lymph Node Metastasis

Purpose

To analyze the effect of Hashimoto’s thyroiditis (HT) concurrent with papillary thyroid cancer (PTC) on cervical lymph node metastasis (LNM).

Methods

Two thousand nine hundred twenty-six patients who underwent thyroidectomy and lymph node dissection between January 2015 and December 2018 were enrolled in this study. Patient demographics and clinicopathologic features were analyzed.

Results

Of the total enrolled patients, 598 (20.4%) had concurrent HT. There were 1482 PTC cases with N0, 1033 cases with N1a, and 411 cases with N1b. Patients with HT had lower frequency of extrathyroidal extension (ETE), lymphatic vascular (LV) invasion, high pathological T stage (III+IV) and central LNM rate. Stratifying central LNM by non-ETE or without intrathyroidal spreading, it was further found that central LNM rate in patients with HT was lower than that of patients without HT. However, there was no significant difference in the central LNM rate in patients with PTC stratified by ETE or intrathyroidal spreading. HT with PTC played a weak protective role in N1a, reducing the risk of N1a by 16.4%. Conversely, HT is a risk factor for N1b, increasing the risk by 1.336 times compared to patients without HT. TgAb is an independent risk factor for N1b, which appears related to the promotion of N1b by HT.

Conclusion

In PTC, HT has a protective effect on central LNM and a risk effect on lateral LNM, although the difference was not significant. This weak protective effect on N1a is more obvious in PTC with less aggressive clinicopathologic characteristics. The risk effect of HT on N1b may be associated with TgAb.

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.

Excellent diagnostic performance of FNA-Tg in detecting lymph nodes metastases from papillary thyroid cancer

Background: Thyroglobulin washout of fine needle aspiration (FNA-Tg) has proved to be useful in detecting lymph node metastases from papillary thyroid cancer; however, the influences of thyroid gland, Hashimoto thyroiditis, serum thyroglobulin (Tg) and anti-TG antibody on the diagnostic performance of FNA-Tg are controversial. Patients & methods: We retrospectively collected the FNA-Tg results of 176 preoperative or postoperative patients (356 lymph nodes) who finally were diagnosed with papillary thyroid cancer. The diagnostic abilities of FNA-Tg were evaluated and compared under different circumstances. Results: The diagnostic performance of FNA-Tg was uninfluenced irrespective of the status of thyroid gland or serum anti-TG antibody. However, high serum Tg was positively correlated with FNA-Tg (Exp(B) = 1.57; 95% CI: 1.209-2.309; p = 0.001). Conclusion: FNA-Tg was an excellent diagnostic tool, but it should be interpreted with caution only if serum Tg is higher than 10 ng/ml.

Predicting the factors associated with central lymph node metastasis in clinical node-negative (cN0) papillary thyroid microcarcinoma

PURPOSE

The aim of the present study was to investigate the risk factors associated with central lymph node metastasis (CLNM) in papillary thyroid microcarcinoma (PTMC).

METHODS

A total of 553 patients with PTMC confirmed by histological examination, who underwent thyroidectomy and central neck dissection (CND), were enrolled. The clinicopathological and ultrasonographic features from the patients were analyzed retrospectively.

RESULTS

PTMC patient age, Hashimoto thyroiditis (HT), tumor location, extrathyroidal extension (ETE), microcalcification and higher E values were correlated with the incidence of CLNM. Multivariate logistic regression analysis showed that age, HT, tumor location, ETE and E_max were related to the extent of CLNM. Chi-squared automatic interaction detection (CHAID) classification tree model showed that patients with tumor in upper/lower third combined ETE had a high risk of CLNM. Furthermore, cN0 PTMC patients with age ≤ 45 years and ETE had more extensive CLNM.

CONCLUSION

Our observations could be helpful for the assessment of prognostic factors of PTMC patients with CLNM.

Risk Factors for Cervical Lymph Node Metastasis of Papillary Thyroid Microcarcinoma: A Single-Center Retrospective Study

OBJECTIVE

To identify the clinicopathological features correlated to lymph node metastasis (LNM) in patients with papillary thyroid microcarcinoma (PTMC).

METHODS

Clinical data of 785 PTMC patients who underwent surgical treatment at the Lishui Municipal Central Hospital from September 2008 to December 2017 were retrospectively analyzed. Clinical and pathological risk factors for lymph node metastasis (LNM), central lymph node metastasis (CLNM), and lateral lymph node metastasis (LLNM) were analyzed.

RESULTS

LNM was found in 236 (30.2%) patients. Multivariate logistic regression analysis revealed that in PTMC, male gender, age < 55 years, tumor size > 5 mm, bilateral lesions, and extrathyroidal extension were independent risk factors for LNM in general and for CLNM. For LLNM, tumor size > 5 mm, multifocal lesions, and extrathyroidal extension were independent risk factors.

CONCLUSIONS

Identification of risk factors for cervical LNM could assist individualization of clinical management for PTMC.

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.

Patients with Oncocytic Variant Papillary Thyroid Carcinoma Have a Similar Prognosis to Matched Classical Papillary Thyroid Carcinoma Controls

BACKGROUND

Previous studies have suggested that oncocytic variant papillary thyroid carcinoma (PTC) may be more aggressive, with higher rates of recurrent disease. The aim of this study was to evaluate characteristics and outcomes of patients with oncocytic variant PTC compared to classical PTC.

METHODS

Patients with oncocytic variant PTC were retrospectively identified from 519 patients who underwent thyroidectomy for PTC between January 2009 and August 2015. Data collected included patient demographics, laboratory and pathology findings, imaging studies, treatment, and follow-up. Patients were matched 1:1 by age, sex, and TNM stage with patients who underwent total thyroidectomy for classical PTC during the same time period.

RESULTS

The cohort included 21 patients, of whom 18 (86%) were female, with a median age of 53 years (range 23-68 years). All patients underwent total thyroidectomy, and 17 (81%) had a central compartment neck dissection (8 [38%] prophylactic). The median tumor size was 2.0 cm (range 0.9-6.5 cm), and four (19%) patients had extrathyroidal extension. There was no significant difference in histopathologic characteristics, including extrathyroidal extension and lymphovascular invasion, between the two groups except for an increased incidence of thyroiditis in oncocytic variant PTC (90.5% vs. 57%; p = 0.01). In oncocytic variant PTC patients who underwent central compartment neck dissection, malignant lymph nodes were found in 12 (57%) patients compared to 13 (62%) classical (p = 0.75). Lateral neck dissection was performed in 5 (24%) oncocytic variant and classical PTC patients, with metastatic lymphadenopathy found in four (a median of four malignant lymph nodes; range 1-6) and five (a median of 2.5 malignant lymph nodes; range 1-9), respectively. Radioactive iodine was administered to 18 (86%) oncocytic variant PTC and 18 (86%) classical PTC patients. At a median follow-up of 51 months (interquartile range 38-61), one oncocytic variant PTC patient had recurrent disease and underwent reoperation at 24 months. In classical PTC patients with a median follow-up time of 77 months (range 56-87 months), two (9.5%) patients had detectable thyroglobulin levels indicating early recurrence, but neither has undergone reoperation.

CONCLUSIONS

Oncocytic variant PTC was present in 5% of PTC patients. Most (95%) patients remain disease-free at four years, similar to classical PTC outcomes, suggesting that oncocytic variant may not represent a more aggressive variant.

Reconsideration of tumor size threshold for total thyroidectomy in differentiated thyroid cancer

BACKGROUND

The optimal extent of surgery for differentiated thyroid cancer may not be well recognized initially. Identification of intermediate-risk features on surgical pathology may prompt the need for completion thyroidectomy if a lobectomy is performed. In this study, we examined the factors in relation to the need for completion thyroidectomy.

METHODS

We studied consecutive patients who underwent thyroidectomy for differentiated thyroid cancer from 2008 to 2017. Total thyroidectomy was indicated when tumor size >4 cm, clinical extrathyroidal extension, clinical lymph node metastasis, or distant metastasis was present. The need for completion thyroidectomy was defined as the presence of aggressive histology, extrathyroidal extension, lymphovascular invasion, or non-low-risk nodal metastasis.

RESULTS

Among 771 patients, 155 (20%) were definitely indicated for total thyroidectomy. The need for completion thyroidectomy was identified in 273 (44%) of the 616 patients initially eligible for lobectomy. The proportions of patients requiring completion thyroidectomy were 18% and 57% for microcarcinomas and tumors of 1-4 cm, respectively. Receiver operating characteristic curve analysis indicated that tumor size ≥1.1 cm had the highest accuracy of prediction. Multivariate logistic regression revealed that tumor size and BRAF V600E mutation were independent factors predicting the risk of requiring completion thyroidectomy.

CONCLUSION

A substantial portion of patients with differentiated thyroid cancer who are preoperatively eligible for lobectomy would be found to have intermediate-risk pathologic features. This should be incorporated into the shared decision making before surgery.

Current trends of practical issues concerning micropapillary thyroid carcinoma: The Korean Society of Thyroid-Head and Neck Surgery

Although several thyroid associations have published various guidelines, controversies especially in cases of micropapillary thyroid cancer (MPTC) still exist. This survey was designed to collect information about diagnostic tests and treatments performed on patients with MPTC and help identify current trends in thyroid surgery.We developed questionnaires about the management methods for MPTC, which were used to identify factors related to indications of fine needle aspiration (FNA), type of surgery, and central lymph node dissection (CLND). Active 60 members of the Korean Society of Thyroid-Head and Neck Surgery participated in the study in September 2016.Ultrasound-guided FNA was usually initiated when the tumor was at least 5 mm (60%). All respondents preferred ultrasound-guided FNA and surgery for nodules with extrathyroidal extension (ETE). The preferred treatment option for intraglandular MPTC was lobectomy (92%) rather than active surveillance (8%). Posterolateral ETE increased the respondents' preference for total thyroidectomy (61.7%). Active surveillance was preferred for tumors <5 mm, which was decreased by the presence of ETE. The presence of ETE (73.3%) and its proximity to critical organs (46.7%) were the main determining factors for prophylactic CLND. For multiple metastatic lymph nodes at level III, selective neck dissection including levels IIb (23.3%) and V (78.3%) was preferred in addition to levels IIa, III, VI, and V.Korean head and neck surgeons favored total thyroidectomy and CLND in cases wherein ETE, central lymph node metastasis, or critical organ involvement was suspected.

BRAFV600E mutation is not associated with central lymph node metastasis in all patients with papillary thyroid cancer: Different histological subtypes and preoperative lymph node status should be taken into account

The association between central lymph node metastasis (LNM) and risk factors, including the presence of the BRAF mutation, BRAF^V600E, in patients with papillary thyroid cancer (PTC) requires further investigation. A potent risk factor that can indicate LNM in different histological subtypes of PTC and in different preoperative central lymph node statuses also requires further research. A total of 287 patients with PTC who accepted thyroidectomy were included in the present study. Clinicopathological data of these patients were reviewed to examine the risk factors for central LNM through univariate and multivariate analyses. Overall, BRAF^V600E in patients with cN0 (subclinical nodal disease) and cN1 (other than cN0) PTC was associated with central LNM. However, multivariate analyses demonstrated that BRAF^V600E was not an independent risk factor in patients with cN1 or cN0 PTC. For patients with classical variant PTC (CVPTC), BRAF^V600E was independently associated with central LNM. However, on further analysis, the association was only significant in patients with cN0 CVPTC. For patients with follicular variant PTC (FVPTC) or aggressive variant PTC (AVPTC), the BRAF^V600E mutation rate was not significantly different between patients with and without central LNM. In conclusion, BRAF^V600E was an independent risk factor for central LNM overall in patients with PTC and in patients with CVPTC, particularly in patients with cN0 CVPTC. However, BRAF^V600E was not an independent risk factor for patients with FVPTC and AVPTC. Therefore, BRAF^V600E provides varied clinical significance in different histological subtypes and preoperative central lymph node status.

Programmed Death-Ligand 1 Expression in Papillary Thyroid Cancer and Its Correlation with Clinicopathologic Factors and Recurrence

BACKGROUND

Programmed death-ligand 1 (PD-L1) expression has been reported in several malignancies, but the expression of PD-L1 in papillary thyroid cancer (PTC) has been characterized rarely. The aim of this study was to assess the significance of PD-L1 expression and its associations with clinicopathologic factors and disease outcome in PTC.

METHODS

Immunohistochemistry staining was conducted retrospectively to evaluate the expression of PD-L1 in a total of 260 PTC tumors and corresponding non-tumor tissues. The correlations between PD-L1 expressions with clinicopathologic features and recurrence-free survival (RFS) were analyzed.

RESULTS

PD-L1 expression was positive in 52.3% (136/260) of PTC tumor tissues, which was significantly higher than in corresponding non-tumor thyroid tissues. In clinicopathologic analyses, this positive staining of PD-L1 was positively linked to multifocality (p = 0.001) and extrathyroidal extension (p = 0.001). In multivariate Cox regression analysis, positive PD-L1 expression in tumor tissue was significantly associated with worse RFS (hazard ratio 2.825 [confidence interval 1.149-6.943], p = 0.024). In subgroup analyses based on clinicopathologic factors, positive PD-L1 staining of tumor tissue was associated with worse RFS in males (p = 0.001), older patients (≥45 years; p = 0.001), and patients with a primary tumor size >4 cm (p = 0.002), multifocal tumors (p = 0.031), extrathyroidal extension (p = 0.012), and lymph node metastasis (p = 0.004). In contrast, positive PD-L1 staining predicted worse RFS in the subgroup of patients without Hashimoto's thyroiditis (p = 0.001) and treated with total thyroidectomy (p = 0.019).

CONCLUSIONS

PD-L1 is important in determining aggressiveness of PTC and could predict the prognosis of patients. Therefore, inhibition of PD-L1 is suggested as a potential strategy for the treatment of advanced PTC with high expression of PD-L1.

Predictors of Regional Lymph Node Recurrence after Initial Thyroidectomy in Patients with Thyroid Cancer

Background. Regional lymph node recurrence (RLNR) is common in patients with thyroid cancer but clinicopathological predictors are unclear. We aimed to clarify these predictors and identify patients who would benefit from prophylactic lymph node dissection the most. Method. 343 patients with different types of thyroid cancer were analyzed retrospectively. All patients underwent total thyroidectomy between 2007 and 2013. Results. The median ± interquartile range of patients' age was 40 ± 25 years. 245 (71.4%) patients were female. Regarding the risk of regional lymph node recurrence, we found that male gender, age ≥45 years, non-PTC (i.e., medullary, follicular, and anaplastic types) histopathology, T3 (i.e., tumor size >4 cm in the greatest dimension limited to the thyroid or any tumor with minimal extrathyroid extension), stage IVa, and isolated cervical lymphadenopathy as initial manifestation (ICL) are significant risk factors. T3 (p < 0.001; odds ratio = 156.41, 95% CI [55.72–439.1]) and ICL (p < 0.001; odds ratio = 77.79, 95% CI [31.55–191.81]) were the strongest predictors of regional lymph node recurrence. Conclusion. We found easily achievable risk factors for RLNR in thyroid cancers patients. We suggested that patients with specific clinicopathological features like male gender, age ≥45 years, larger tumor size, and extrathyroidal extension be considered as prophylactic lymphadenectomy candidates.

Pathologic features of metastatic lymph nodes identified from prophylactic central neck dissection in patients with papillary thyroid carcinoma

The importance of pathologic features of metastatic lymph nodes (LNs), such as size, number, and extranodal extension, has been recently emphasized in patients with papillary thyroid carcinoma (PTC). We evaluated the characteristics of metastatic LNs identified after prophylactic central neck dissection (CND) in patients with PTC. We performed a retrospective review of 1,046 patients who underwent unilateral or bilateral thyroidectomy with ipsilateral prophylactic CND. We reviewed the characteristics of the metastatic LNs and analyzed their correlation to the clinicopathologic characteristics of the primary tumor. Cervical LN metastasis after prophylactic CND was identified in 280 out of 1046 patients (26.8 %). The size of metastatic foci (≥2 mm) was independently correlated with primary tumor size (≥1 cm) (p = 0.016, OR = 1.88). Primary tumor size (≥1 cm) was also correlated to the number of metastatic LNs (≥5) (p = 0.004, OR = 3.14) and extranodal extension (p = 0.021, OR = 2.41) in univariate analysis. The size of the primary tumor affects pathologic features of subclinical LN metastasis in patients with PTC. Patients with primary tumors ≥1 cm have an increased risk of larger LN metastases (≥2 mm), an increased number of LN metastases (≥5), and a higher incidence of ENE, which should be considered in decision for prophylactic CND.

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.

The Clinical Relevance of Psammoma Body and Hashimoto Thyroiditis in Papillary Thyroid Carcinoma: A Large Case-control Study

This study aims to investigate the impact of psammoma body (PB) on papillary thyroid carcinoma (PTC), and evaluate the association among PB, Hashimoto thyroiditis (HT), and other clinicopathologic characteristics in PTC patients.We conducted a retrospective case-control study involving 1052 PTC patients who underwent total thyroidectomy or lobectomy with lymph node dissection.Psammoma body was observed in 324 out of 1052 PTC (30.8%) patients. Ultrasonographic (US) calcification (P < 0.001), multifocality of the tumor (P = 0.047), lymph node metastasis (LNM) (P < 0.001), HT (P < 0.001), and Primary tumor (T), Regional lymph nodes (N), Distant metastasis (M) staging (P = 0.001) were significantly related to the presence of PB. The presence of PB was significantly associated with US microcalcification (P < 0.001). In the subgroup with HT, compared with the patients without PB, the patients with PB exhibited a higher frequency of central LNM (54.7% vs 32.1%; P < 0.001) and US microcalcification (94.7% vs 38.8%; P < 0.001), as well as smaller tumors (0.9 ± 0.6 vs 1.3 ± 0.9 cm; P < 0.001). In the subgroup without HT, the patients with PB displayed a higher incidence of lateral LNM (25.8% vs 14.6%; P < 0.001), US microcalcification (87.3% vs 52.5%; P < 0.001), and extrathyroidal extension (47.2% vs 34.8%; P = 0.001), as well as larger tumors (1.3 ± 0.9 vs 1.0 ± 0.8 cm; P < 0.001) than without PB. Moreover, in the subgroup with PB, the PTC patients with HT showed a higher LNM (77.9% vs 57.2%; P < 0.001) and a lower frequency of extrathyroidal extension (20.0% vs 47.2%; P < 0.001) than without HT.Psammoma body is a useful predictor of aggressive tumor behavior in PTC patients. HT with PB shows more aggressive behaviors than non-HT with PB in PTC patients.

Histopathological Evidence of Lymph Node Metastasis in Papillary Thyroid Carcinoma

Prophylactic lymph node dissection is still controversial due to the potentially surgery-related morbidity in management of papillary thyroid carcinomas. So, some histopathological predictors for lymph node metastasis in thyroidectomy specimens may reveal importance. The objective of this study was to define histomorphological indicators of lymph node metastasis in the patients who had been performed thyroidectomy without lymph node dissection. Clinicopathological features of patients archived in Department of Pathology at Trakya University Medical Faculty were reviewed. A total of 211 patients who had been diagnosed as papillary carcinoma and had been performed total thyroidectomy/lobectomy with central/cervical lymph node dissection were included in the study. Clinical features (age, gender, preoperative/postoperative clinical, and laboratory findings) and histopathological features (histological variant, tumor size, focality, extrathyroidal extension, tumor border, lateral tubular growth, intraglandular dissemination, stromal and lymphocytic tumor response, lymphocytic thyroiditis, lymphovascular invasion, lymph node metastasis, number of metastatic lymph nodes, extranodal extension, size of the metastatic foci) were evaluated. Male gender, conventional variant, tumor size greater than 10 mm, multifocality, extrathyroidal extension, lateral tubular growth, intraglandular dissemination, lymphocytic and stromal tumor response, and absence of lymphocytic thyroiditis were predictive, and older age (≥45 years) and follicular variant PTC were protective for lymph node metastasis. In order to optimize the management of papillary thyroid carcinomas, pathologists should search for the clues of lymph node metastasis particularly intraglandular dissemination, lateral tubular growth, tumor border and lymphocytic/stromal tumor response, multifocality, concomitant lymphocytic thyroiditis besides the actual prognostic criteria especially in younger aged male patients.

Predictive factors for longer operative times for thyroidectomy

BACKGROUND/OBJECTIVE

Conventional open thyroidectomy is considered as a safe surgery nowadays. However, surgeons sometimes encounter unexpected difficulty when performing thyroidectomies. The aim of this paper was to identify the predictors of a difficult thyroidectomy for the management of patients with papillary thyroid carcinoma.

METHODS

A database of patients who underwent open conventional thyroidectomy with cervical lymph node dissection after diagnosed papillary thyroid carcinoma between July 2008 and June 2013 was examined. In addition, the patients were subgrouped by difficult thyroidectomy (DT) and nondifficult thyroidectomy to determine the predictors of DT according to operation time. Clinicopathologic characteristics, surgical outcomes, and postoperative morbidities were investigated.

RESULTS

No between-group differences in clinicopathologic factors and postoperative complications, except for male sex (p < 0.001) and tumor size (p = 0.039), were noted. Male sex [odds ratio (OR) 4.158, 95% confidence interval (CI) 2.020-8.559, p = 0.043] and age < 45 years (OR 2.239, 95% CI 1.304-3.843, p = 0.003) were independent factors associated with DT in a multivariate logistic regression model. Elevated antithyroglobulin antibody (OR 1.004, 95% CI 1.000-1.008, p = 0.030) was a variable which is statistically significant, but not clinically significant.

DISCUSSION

Young age and male sex might be regarded as predictors of DT. Expecting DT before surgery might help surgeons, especially beginners, prevent troublesome situations.

Predictive factors for difficult robotic thyroidectomy using the bilateral axillo-breast approach

BACKGROUND

The purpose of this study was to identify predictors of difficult robotic thyroidectomy using the bilateral axillo-breast approach (BABA) for the management of patients with papillary thyroid carcinoma (PTC).

METHODS

We examined a database containing details of patients with PTC who had undergone robotic thyroidectomy with cervical lymph node dissection between July 2008 and June 2013. Patients were subgrouped into difficult thyroidectomy and non-difficult thyroidectomy to identify predictors associated with difficult thyroidectomy corresponding to the time of operation. Clinicopathologic characteristics, surgical outcomes, and postoperative morbidities were investigated.

RESULTS

Male sex was the only significantly different clinicopathologic factor between the 2 groups (p = .013). Other factors, such as age (p = .809) and body mass index (BMI; p = .202), were comparable between the 2 groups. The rates of postoperative complications, such as hypoparathyroidism, vocal cord palsy, and seroma, in the difficult thyroidectomy group were not significantly different from those in the non-difficult thyroidectomy group. There was no hematoma or wound infection. Male sex was the only independent factor associated with difficult thyroidectomy (odds ratio [OR] = 5.379; 95% confidence interval [CI] = 1.052-27.502; p = .043), according to the multivariate logistic regression model.

CONCLUSION

Male sex was the only predictive factor for difficult robotic thyroidectomy using BABA. Further evaluations should be performed to ascertain additional factors associated with difficult robotic thyroidectomy. © 2015 Wiley Periodicals, Inc. Head Neck 38: E954-E960, 2016.

Clinical risk factors for central lymph node metastasis in papillary thyroid carcinoma: a systematic review and meta-analysis

BACKGROUND

Prophylactic central lymph node dissection (CLND) in clinically node-negative patients remains controversial, and predictive factors for central lymph node metastasis (CLNM) in patients with papillary thyroid carcinoma (PTC) are not well defined. Herein, we conducted a systematic review to quantify the clinicopathologic factors predictive for CLNM in patients with PTC.

METHODS

A systematic search of electronic databases (PubMed, Embase, Cochrane CENTRAL, Scopus and Wanfang Database) for studies published until July 2014 was performed. Cohort, case-control studies and randomized controlled trials that examined clinical risk factors of CLNM were included.

RESULTS

Twenty-five studies (4 prospective and 21 retrospective studies) involving 7,719 patients met final inclusion criteria. From the pooled analyses, male gender (OR 1.93, 95% CI 1.40 to 2.64), tumour multifocality (OR 1.93, 95% CI 1.62 to 2.30), tumour size >0.5 cm (OR 3.48, 95% CI 2.24 to 5.41), capsular invasion (OR 1.91, 95% CI 1.36 to 2.67), extrathyroidal extension (OR 2.42, 95% CI 1.58 to 3.71), lymphovascular invasion (OR 13.29, 95% CI 5.61 to 31.48) and lateral lymph node metastasis (OR 14.33, 95% CI 5.34 to 38.50) were significantly associated with increased risk of CLNM, while age >45 years (OR 0.65, 95% CI 0.51 to 0.83) and lymphocytic thyroiditis (OR 0.70, 95% CI 0.53 to 0.92) resulted in decreased risk of CLNM. Bilaterality and tumour location were not significantly associated with CLNM development (all P > 0.05).

CONCLUSIONS

Our analysis identified several clinicopathologic factors associated with CLNM. These findings may guide the necessity and extent of prophylactic CLND and ultimately improve the outcomes of patients with PTC.

Sonographic features of primary tumor as independent predictive factors for lymph node metastasis in papillary thyroid carcinoma

PURPOSE

The aim of this research was to find the sonographic features of primary tumor as independent predictive factors for lymph node metastasis in papillary thyroid carcinoma.

METHODS/PATIENTS

To facilitate the research, 514 patients with papillary thyroid carcinoma were divided into solitary and multifocal groups. In solitary group, thyroid lesions were divided into several subgroups by size, border, margin, echogenicity, echohomogeneity, calcification, vascularization, location, stiffness and Hashimoto's thyroiditis (HT) conditions. Then, univariable and multivariable analyses were performed to find the sonographic features of primary tumor as independent predictive factors for lymph node metastasis in papillary thyroid carcinoma.

RESULTS

A significant difference of lymph node metastasis rate was found between multifocal and solitary groups (P < 0.05). In univariable analysis, size, vascularization and coexistence of HT were found to be statistically significant factors (P = 0.004, 0.118, 0.016). Multivariable analysis revealed that lymph node metastasis rate was mainly associated with size [odds ratio (OR) = 1.690, 95 % confidence interval (CI) 1.157-2.469] and coexistence of HT (OR = 0.441, 95 % CI 0.219-0.888).

CONCLUSION

Preoperative sonographic features of primary tumor including the number, size and coexistence of HT were independent predictive factors for the state of cervical lymph node metastasis in patients with papillary thyroid carcinoma.

The Effect of Thyroiditis on the Yield of Central Compartment Lymph Nodes in Patients with Papillary Thyroid Cancer

BACKGROUND

In patients who have undergone thyroidectomy and central compartment neck dissection (CCND) for papillary thyroid cancer (PTC), visualization of enlarged lymph nodes may lead to more extensive CCND. This study sought to determine the effect of patient age and the presence of thyroiditis on the number of malignant and total lymph nodes resected in patients who underwent CCND for PTC.

METHODS

This retrospective review examined a prospective database of patients who underwent total thyroidectomy and CCND for PTC between April 2009 and June 2013 and had thyroiditis on the final pathology. The patients were categorized into age groups by decade (18-29, 30-39, 40-49, 50-59, and ≥60 years) and compared with a control group of patients matched by age, gender, and tumor size.

RESULTS

Of 74 patients with thyroiditis, 64 (87 %) were women. The median age of the patients was 47.5 years (range 18.2-72.0 years). The patients with thyroiditis had more lymph nodes resected than those without thyroiditis (median 11 vs 7; p < 0.01). However, these patients had fewer malignant lymph nodes (median 0 vs 1.5; p = 0.06), resulting in a lower lymph node ratio (0 vs 0.18; p = 0.02) for the entire cohort, but particularly for the youngest (18-29 years) and oldest (≥60 years) age groups.

CONCLUSIONS

Patients with thyroiditis and PTC who underwent CCND had more lymph nodes resected but a had lower proportion of metastatic lymph nodes than those without thyroiditis. Given the relatively low yield of malignant cervical lymphadenopathy, a more judicious approach to CCND might be considered, particularly for the youngest and oldest patients with PTC and thyroiditis.

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

BACKGROUND

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

METHODS

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

SUMMARY

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

CONCLUSIONS

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