Is Hashimoto's thyroiditis a risk factor for medullary thyroid carcinoma? Our experience and a literature review

The risk of thyroid cancer and sex differences in Hashimoto's thyroiditis, a meta-analysis

BACKGROUND AND OBJECTIVE

The prevalence of thyroid cancer (TC) has exhibited an upward trajectory in recent years. An accelerating amount of evidence shows a significant association between Hashimoto's thyroiditis (HT) and TC. The present study encompasses a meticulously designed systematic review and meta-analysis with the aim of scrutinizing the risk of TC and clarifying sex disparities in HT.

METHODS

A comprehensive search was conducted across reputable online databases, including PubMed, Cochrane Library, EMBASE, and Web of Science. English-language publications on the correlation between HT and TC were examined without temporal restrictions. Two authors independently screened the articles and extracted pertinent data. The collected data underwent statistical analysis using the STATA software, enabling the calculation of the pooled Odds Ratio (OR) and 95% confidence intervals (CI). Additionally, a supplementary analysis was conducted on studies incorporating sex-specific data to determine the OR (female vs. male) and the sex-based prevalence of TC in HT.

RESULTS

A total of 2,845 records were obtained, and 26 retrospective studies were included in this meta-analysis. The results indicated a significant role for HT in TC (OR: 2.22, 95% CI: 1.85-2.67). Supplementary analysis indicated that the prevalence of TC in HT patients was lower in women (0.31, 95% CI: 0.17-0.45) than in men (0.37, 95% CI: 0.21-0.53). However, the result was not statistically significant.

CONCLUSION

This systematic review and meta-analysis provide evidence that HT is associated with increasing odds of TC. Regular review of HT patients holds positive clinical significance.

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.

Geographic variation in the association between Hashimoto's thyroiditis and Papillary thyroid carcinoma, a meta-analysis

PURPOSE

The association between papillary thyroid cancer (PTC) and Hashimoto's thyroiditis (HT) remains a matter of debate. Several genetic and environmental factors have been found to influence this association. Because of the variation in these factors among different populations, we conducted a country- and region-based meta-analysis to examine whether the geographic area influences this association.

METHODS

We searched PubMed and Web of Science databases for original articles that investigated the association between HT and PTC from February 1955 to February 28, 2023. The included studies were stratified according to their country and region of origin. Various subgroup analyses were conducted. The primary outcome was the pooled relative risk (RR) and its 95% confidence interval (CI) for each region and country.

RESULTS

Forty-six studies including a total of 93,970 participants met our inclusion criteria. They originated from 16 countries distributed in five regions. Significant variation was found among countries but not among regions. Upon analysis of all 46 included studies, countries were classified based on their RR and its 95% CI. Excluding countries with pooled sample sizes <500, Sri Lanka (RR 4.23, 95% CI 2.91-6.14), Poland (RR 3.16, 95% CI 2.79-3.57) and Japan (2.68, 2.14-3.36) showed the strongest association between HT and PTC while Greece (RR 1.06, 95% CI 1.00-1.13), Spain (RR 0.70, 95% CI 0.23-2.11), and Jordan (0.62, 0.32-1.32) showed no significant association.

CONCLUSION

Our findings revealed a variation in the association between HT and PTC among countries but not among regions. The country-to-country variation could be due to certain genetic and/or environmental factors subject to geographic variation that influence this association. These findings may help guide health policies aiming to mitigate the risk of PTC in the HT population by helping identify high-risk and low-risk countries.

Association between chronic lymphocityc thyroiditis and papillary thyroid carcinoma: Systematic review and meta-analysis of studies on surgical specimens

Introduction. Inconsistent results exist in the literature regarding the hypothesis statement suggesting an increased likelihood of documenting papillary thyroid carcinoma (PTC) in surgical specimens with changes compatible with chronic lymphocytic thyroiditis. Existing meta-analyses have included studies that are not methodologically comparable and do not propose clear sources of bias, thus, this is justification for the present meta-analysis. Methods. A literature search in PubMed and Embase was performed from January 1, 1950 to December 31, 2020. Retrospective studies comparing the prevalence of papillary thyroid carcinoma in specimens with and without chronic lymphocytic thyroiditis changes were obtained. The collected evidence was statistically analyzed. Results. A total of 22 articles were included. The study population consisted of 63,548 surgical specimens. The pooled OR, based on the studies, was 1.81 (95% CI: 1.51-2.21). There was heterogeneity between the distribution of prevalence ratios and opportunity ratios across studies (I²= 91%; p>0.00001). The funnel plot shape of the studies included in the analysis appears to be symmetrical, indicating the absence of bias attributable to small studies. Conclusions. The current literature suggests that there is an increased risk of documenting papillary thyroid carcinoma in surgical specimens in which chronic lymphocytic thyroiditis-compatible changes are observed; however, there are sources of bias that will not be possible to control for in retrospective studies, so we recommend studying the hypothesis suggesting an increased likelihood of diagnosing PTC in specimens with chronic lymphocytic thyroiditis-compatible changes using prospective methodologies.

Occurrence of sporadic medullary thyroid carcinoma in Graves' disease in association with a RET proto-oncogene mutation

BACKGROUND

Graves' disease may be associated with thyroid cancer, particularly differentiated thyroid cancer. Medullary thyroid cancer (MTC) is less common. The occurrence of sporadic MTC in Graves' disease in the presence of a RET proto-oncogene has never been reported.

CLINICAL PRESENTATION

A 63-year-old woman was referred for Graves' disease. A thyroid ultrasound disclosed five nodules, one of which was classified as Eu-Tirads 5 with a size of 6.7 × 6.5× 11 mm. Fine needle aspiration was reported as Bethesda class IV follicular neoplasm of a Hürthle cell subtype. Calcitonin level was found to be elevated. A total thyroidectomy confirmed the diagnosis of MTC and a bilateral cervical lymphadenectomy was performed, with four lymph nodes being infiltrated by MTC. Genetic testing revealed a M918T mutation in the RET proto-oncogene.

CONCLUSION

MTC may occur in Graves' disease, especially if a nodule is present. In this case, genetic testing should always be performed even if MTC is sporadic. Increased incidence of thyroid cancer in autoimmune thyroid diseases, as well as the link existing between autoimmunity, inflammation and carcinogenesis, leads us to hypothesize that the association here reported is not coincidental.

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.

Association between various thyroid gland diseases, TSH values and thyroid cancer: a case-control study

BACKGROUND

The goal of this retrospective cohort study was to analyze the association between benign thyroid alteration and thyroid cancer in patients followed in general practices in Germany.

METHODS

Patients aged 18-80 who had received an initial diagnosis of thyroid cancer in one of 1261 general practices in Germany between January 2009 and December 2018 were included in this study (index date). These patients were matched (1:1) to non-cancer patients by age, sex, physician and index year. The main outcome of the study was the association between various benign thyroid alterations and thyroid cancer.

RESULTS

The study included 2787 patients with thyroid cancer and 2787 individuals without cancer (mean age: 52.8 years, 73.5% women). The main finding was that all benign changes in the thyroid with the exception of thyroiditis were associated with thyroid cancer. The strongest association was observed by the nontoxic goiter. Half of the patients with thyroid cancer had nontoxic goiter compared to just one-sixth of the control group. Thyrotoxicosis was found in 12.9% of the cancer group and in 3.9% of the controls. By analyzing TSH in groups, we found an association between suppressed TSH and elevated TSH levels and thyroid cancer.

CONCLUSION

In accordance with the literature, we confirmed that any kind of benign thyroid alteration was associated with an elevated risk of thyroid cancer. The odds ratio was greatest for nontoxic goiter, followed by benign neoplasms of the thyroid, other disorders of the thyroid such as Hashimoto and thyrotoxicosis. We also found an elevated risk of cancer in patients with either a suppressed or elevated TSH.

Medullary thyroid carcinoma co-existent with Hashimoto's thyroiditis diagnosed by a comprehensive cytological approach

Fine-needle aspiration cytology (FNAC) is a preliminary test for the diagnosis of thyroid lesions. We hereby report a rare case of medullary thyroid carcinoma (MTC) co-existing with Hashimoto's thyroiditis (HT). This case was substantiated with ancillary tests on cytology material to give a novel insight. A 60-year-old female presented clinically with diffuse enlargement of the thyroid, and right-side nodule on ultrasonography. FNAC of the isthmic area showed features of HT, while cytology of right-side nodule displayed sheets of plasmacytoid cells and frequent scattered large bizarre and pleomorphic cells, lymphoglandular bodies and pale eosinophilic material. The differential diagnosis of MTC with co-existent HT or high-grade lymphoma was considered. To establish the diagnosis, serum calcitonin and ancillary studies on aspirated material were carried out. High serum calcitonin (7251 pg/mL), Congophilia on smears, and CD 45-ve; CD56+ve expression of tumor cells on flowcytometric analysis established the diagnosis of MTC over lymphoma. This diagnosis was further confirmed upon histopathology. Ancillary studies on aspirated material established the diagnosis of MTC and excluded the diagnosis of lymphoma. Establishing the correct diagnosis was cardinal in such a scenario as these diseases have extremely diverse management.

Expressions of IL-17 and TNF-α in patients with Hashimoto's disease combined with thyroid cancer before and after surgery and their relationship with prognosis

OBJECTIVE

This study aimed to investigate expressions and clinical significance of IL-17 and TNF-α after surgery in patients with Hashimoto's disease (HD) combined with thyroid cancer (TC).

PATIENTS AND METHODS

From June 2010 to October 2012, 38 patients with HD combined with TC admitted to the oncology department of Tongji Hospital were selected as an experimental group, including three males and 35 females, aged 24-78 years. Forty adults undergoing physical examination during the same period were selected as a control group. All patients in the experimental group were given total endoscopic TC resection. Real-time fluorescence quantification (qRT-PCR) and enzyme-linked immunosorbent assay (ELISA) were used to detect the expression levels of serum IL-17 and TNF-α before and 14 days after surgery. Patients with HD combined with TC were divided into high and low expression groups according to the median values of preoperative IL-17 mRNA and TNF-α mRNA. The relationship between IL-17, TNF-α, and prognosis of patients was analyzed through K-M survival curve.

RESULTS

The concentrations of IL-17 and TNF-α in serum were also higher than those in control group 14 days after surgery (p < 0.05). qRT-PCT showed that the relative expressions of IL-17 and TNF-α in serum 14 days after surgery were higher than those in control group (p < 0.05). According to the relative expression median of mRNA in IL-17 and TNF-α before surgery, they were divided into high and low expression groups. It was found that the survival rate of high expression groups of IL-17 and TNF-α was lower than that of low expression groups (IL-17, p = 0.028; TNF-α, p = 0.014).

CONCLUSIONS

The protein and mRNA of IL-17 and TNF-α in serum of HD patients with TC are higher than those of healthy control group. Expressions of IL-17 and TNF-α can be reduced by surgical resection of focal tissue. IL-17 and TNF-α may be used as potential prognostic indicators of HD patients with TC.

Reactive C cell hyperplasia as an incidental finding after thyroidectomy for papillary carcinoma

The biologic and clinical significance of reactive C cell hyperplasia (CCH), adjacent to differentiated thyroid cancers, remains unknown. Our aim was to investigate the presence of CCH in thyroidectomy specimens with papillary thyroid carcinomas (PTC) and discuss its epidemiology and histology. In total, 413 patients were prospectively included in the study (189 benign goiters, 224 PTC). Reactive CCH was observed in 9.8% of PTC cases (32% males, 68% females, mean age 48.3 ± 16.4 years) and usually ipsilateral to the primary tumor (91%). Histologically, CCH was either focal (91%) or diffuse (9%) and almost always (92%) found in the middle or upper thirds of the thyroid lobes. Patients with PTC/CCH were generally younger than patients with benign goiters (0.027). On the other hand, patients with PTC and with PTC/CCH did not differ in terms of age, gender, basal calcitonin levels, primary tumor size, multifocality, extrathyroidal invasion, or lymph node metastasis. Thyroiditis, however, was more frequent in cases with PTC/CCH compared to PTC alone. Reactive CCH is considered a physiological response of the C cells to various stimuli, differentiated thyroid cancer among others. It bears no malignant potential and requires no additional treatment, following thyroidectomy.

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.

Consanguinity and the Risk of Hashimoto's Thyroiditis

BACKGROUND

Hashimoto's thyroiditis (HT) is the most common autoimmune thyroid disease that may lead to hypothyroidism due to progressive destruction of the thyroid. The etiology of HT is unclear. However, it is associated with multiple genetic predispositions. Consanguinity has been associated with an increased susceptibility to different inherited conditions. This study investigated the association between consanguinity and risk of HT for the first time.

METHODS

Using a case-control study design, 298 HT patients were compared with two subject groups: (i) 299 participants with non-HT hypothyroidism, and (ii) 298 healthy control participants. The three groups were age and sex matched. Presence of consanguinity among the parents was compared in these groups, and odds ratios (OR) were calculated to establish a correlation.

RESULTS

Consanguinity significantly increased the risk of HT (compared with healthy subjects; OR = 3.3; p < 0.0001). In addition, consanguinity was a significant risk factor for HT compared with non-HT hypothyroidism patients (OR = 2.8; p < 0.0001). However, the prevalence of consanguinity was not significantly different in non-HT hypothyroidism patients and healthy subjects.

CONCLUSIONS

The results suggest that the risk for HT is increased in consanguineous unions, but no significant increase in the risk of non-HT hypothyroidism was observed. However, for more precise risk estimates, larger studies that include different populations may be helpful. These findings highlight the health impact of consanguinity and have applications in empiric risk estimations in genetic counseling, particularly in countries with high rates of consanguineous marriages.