Screening of Organ-Specific Autoantibodies in a Large Cohort of Patients with Autoimmune Thyroid Diseases

Background: Autoimmune diseases tend to cluster in the same individual or in families. Four types of autoimmune polyglandular syndromes (APS) have been described based on the combination of endocrine and/or non-endocrine autoimmune diseases. In particular, type-3 APS is defined by the association of an autoimmune thyroid disease (ATD) and other autoimmune diseases and has a multifactorial etiology. The natural history of autoimmune diseases is characterized by three stages: potential, subclinical, and clinical. Methods: To determine the prevalence of organ-specific autoantibodies (anti-adrenal, anti-ovary [StCA], anti-pituitary [APA], anti-parietal cells [PCA], anti-tissue transglutaminase [tTGAb], anti-mitochondrial [AMA], anti-glutamic acid decarboxylase [GADA], anti-nicotinic acetylcholine receptor) in patients with ATD and to define the stage of the disease in patients with positive autoantibodies. From January 2016 to November 2018, 1502 patients (1302 female; age 52.7 ± 14.7 [mean ± standard deviation] years, range 18-86 years) with ATD (1285/1502 [85.6%] with chronic autoimmune thyroiditis and 217/1502 [14.4%] with Graves' disease) were prospectively enrolled. Results: The most common organ-specific autoantibodies were PCA (6.99%) and GADA (2.83%), while the prevalence of the remaining autoantibodies was ≤1%. All autoimmune diseases, but celiac disease, were predominant at the potential stage. Sex, ATD type, smoking habit, and coexistence of other autoimmune diseases correlated with the susceptibility to develop chronic atrophic gastritis (CAG) or autoimmune diabetes mellitus. Conclusions: The association between ATD and CAG was the most common manifestation of type-3 APS, mainly at the potential stage, that could lead to appropriate follow-up for early detection and timely treatment of the disease.

Baseline serum TSH levels predict the absence of thyroid dysfunction in cancer patients treated with immunotherapy

PURPOSE

Immunotherapy against immune checkpoints has significantly improved survival both in metastatic and adjuvant setting in several types of cancers. Thyroid dysfunction is the most common endocrine adverse event reported. Patients who are at risk of developing thyroid dysfunction remain to be defined. We aimed to identify predictive factors for the development of thyroid dysfunction during immunotherapy.

METHODS

This is a retrospective study including a total of 68 patients who were treated with immune checkpoint inhibitors (ICIs) for metastatic or unresectable advanced cancers. The majority of patients were treated with anti-PD1 drugs in monotherapy or in combination with anti-CTLA4 inhibitors. Thyroid function and anti-thyroid antibodies, before starting immunotherapy and during treatment, were evaluated. Thyroid ultrasound was also performed in a subgroup of patients at the time of enrolment in the study.

RESULTS

Eleven out of 68 patients (16.1%) developed immune-related overt thyroid dysfunction. By ROC curve analysis, we found that a serum TSH cut-off of 1.72 mUI/l, at baseline, had a good diagnostic accuracy in identifying patients without overt thyroid dysfunction (NPV = 100%, p = 0.0029). At multivariate analysis, both TSH and positive anti-thyroid antibodies (ATAbs) levels, before ICIs treatment, were independently associated with the development of overt thyroid dysfunction during immunotherapy (p = 0.0001 and p = 0.009, respectively).

CONCLUSIONS

Pre-treatment serum TSH and ATAbs levels may help to identify patients at high risk for primary thyroid dysfunction. Our study suggests guidance for an appropriate timely screening and for a tailored management of thyroid dysfunctions in patients treated with ICIs.

Calcitonin Levels in Thyroid Disease Are Not Affected by Autoimmune Thyroiditis or Differentiated Thyroid Carcinoma

INTRODUCTION

Association between hypercalcitoninemia and pathological conditions such as autoimmune thyroiditis (AIT) or differentiated thyroid carcinoma (DTC) has been addressed, with conflicting results. We evaluated the prevalence and the clinical relevance of elevated basal serum calcitonin (CT) levels in non-neoplastic (nodular goiter [NG] and AIT) and neoplastic thyroid diseases (DTC).

METHODS

We retrospectively evaluated 3,250 consecutive patients with thyroid nodular disease who underwent fine-needle aspiration cytology with adequate sample. After exclusion of medullary thyroid cancer (MTC) patients were divided according to the presence/absence of thyroid autoimmunity into NG or nodular autoimmune thyroiditis (N-AIT) and, according to cytological results, in benign or suspicious/malignant nodules.

RESULTS

One hundred ninety-seven/3,250 patients (6.0%) showed CT level >10 pg/mL. In 11/3,250 (0.3%) cases, a final histological diagnosis of MTC was made, while the remaining 186/3,250 patients (5.7%) had non-MTC-related hypercalcitoninemia (CT > 10 pg/mL). According to cytological diagnosis, the rate of hypercalcitoninemia was similar in class II and class V-VI groups (5.4 vs. 6.9%, p = 0.4). The occurrence of hypercalcitoninemia was significantly higher in patients with NG (166/2,634 [6.3%]) than in patients with N-AIT (20/605 [3.3%]) (p = 0.004). However, after matching by sex, no difference was found between the 2 groups (NG and N-AIT). These results were confirmed in 598 patients submitted to surgery.

CONCLUSIONS

AIT and DTC seem not to affect serum CT levels in patients with thyroid nodules. Therefore, hypercalcitoninemia, in these patients, should be submitted to the same diagnostic workup than patients without AIT or DTC.

Validation of American Thyroid Association Ultrasound Risk-Adapted Approach for Repeating Cytology in Benign Thyroid Nodules

Background: The 2015 American Thyroid Association (ATA) ultrasound (US) risk stratification system is used to identify thyroid nodules in which fine-needle aspiration cytology (FNAC) should be performed. In addition, this system is used to plan the long-term follow-up of patients with cytological benign thyroid nodules. The aim of our study was to evaluate the ATA US risk-adapted approach for repeating cytology in a large retrospective cohort of consecutive benign nodules with a second FNAC repeated after a median follow-up of 3.8 years (range 1.0-14.2 years). Methods: We retrospectively evaluated 1010 thyroid nodules, with an initial benign cytological diagnosis, that underwent at least one repeat FNAC during the follow-up. Results: The rate of missed cancer in the whole cohort of thyroid nodules was 1.0%, and it increased along by the US risk class (0.8% in very low/low-risk, 1.2% in intermediate-risk, and 3.1% in high-risk nodules). The 2015 ATA US risk stratification system showed a very high accuracy in selecting nodules that did not require a second FNAC (negative predictive value = 99.1%). In addition, the rate of missed cancer significantly increased along with the increase in the US risk class in nodules that showed an enlarged volume (0.4% in the low-risk class and 6.4% in the high-risk class, p = 0.005), while it was very low and not associated with the US features in the subgroup of thyroid nodules that did not grow during the follow-up (p = 0.96). Conclusions: Our results confirm the accuracy of the ATA recommendations in selecting benign nodules for FNAC repetition during the follow-up. An additional cytological evaluation maybe avoided in benign thyroid nodules with low-risk US features, regardless of the evidence of growth during the follow-up. While the utility of the routine repeat FNAC in all benign nodules with high-risk US features remains to be defined, based on our results, repetition of FNAC seems to be indicated in nodules with evidence of growth during the follow-up.