Clinical Characteristics, Diagnostic Approach and Outcome of Thyroid Incidental Findings vs. Clinically Overt Thyroid Nodules: An Observational Single-Centre Study

Rates of diagnostic and therapeutic procedures in a cohort of patients undergoing first endocrine consultation for thyroid nodular disease

PURPOSE

This study aimed to evaluate the rates of necessary diagnostic and therapeutic procedures in a cohort of patients undergoing their first endocrine consultation for thyroid nodular disease.

METHODS

This was an observational study conducted between January 1 and June 30, 2023, on patients undergoing their first endocrine consultation for thyroid nodular disease. Data were collected, including age, thyroid-stimulating hormone (TSH) concentration, reasons for performing thyroid ultrasound (US), and thyroid US reports. The US was performed at the time of the endocrine consultation according to the American College of Radiology Thyroid Imaging, Reporting and Data System (ACR-TIRADS) risk stratification system. Patients underwent further investigations/treatment or simple US follow-up as necessary.

RESULTS

A total of 373 patients with thyroid nodules were evaluated. Reasons for undergoing thyroid US were unrelated to suspected thyroid disease in 126 (33.8%), incidentalomas in 91 (24.4%), dysfunction or positivity for thyroid antibodies in 67 (18%), symptoms or visible nodules in 61 (16.3%), and family history of thyroid disease in 28 (7.5%). A total of 193 diagnostic or therapeutic procedures were performed in 133 (35.7%) patients [fine-needle aspiration (FNA): 121 (62.7%), surgery: 28 (14.5%), percutaneous ethanol injection: 20 (10.4%), scintigraphy: 10 (5.2%); thermal ablation: 7 (3.6%), and radioactive treatment: 7 (3.6%)].

CONCLUSIONS

In the present study only one-third of the patients undergoing endocrine consultation with first detected thyroid nodules required any diagnostic or therapeutic procedures.

Integrated Diagnostics of Thyroid Nodules

Thyroid nodules are common findings, particularly in iodine-deficient regions. Our paper aims to revise different diagnostic tools available in clinical thyroidology and propose their rational integration. We will elaborate on the pros and cons of thyroid ultrasound (US) and its scoring systems, thyroid scintigraphy, fine-needle aspiration cytology (FNAC), molecular imaging, and artificial intelligence (AI). Ultrasonographic scoring systems can help differentiate between benign and malignant nodules. Depending on the constellation or number of suspicious ultrasound features, a FNAC is recommended. However, hyperfunctioning thyroid nodules are presumed to exclude malignancy with a very high negative predictive value (NPV). Particularly in regions where iodine supply is low, most hyperfunctioning thyroid nodules are seen in patients with normal thyroid-stimulating hormone (TSH) levels. Thyroid scintigraphy is essential for the detection of these nodules. Among non-toxic thyroid nodules, a careful application of US risk stratification systems is pivotal to exclude inappropriate FNAC and guide the procedure on suspicious ones. However, almost one-third of cytology examinations are rendered as indeterminate, requiring "diagnostic surgery" to provide a definitive diagnosis. 99mTc-methoxy-isobutyl-isonitrile ([99mTc]Tc-MIBI) and [18F]fluoro-deoxy-glucose ([18F]FDG) molecular imaging can spare those patients from unnecessary surgeries. The clinical value of AI in the evaluation of thyroid nodules needs to be determined.