Outcome of thyroid gene expression classifier testing in clinical practice.

Area of Science:

• Endocrinology
• Surgical Oncology
• Molecular Diagnostics

Background:

• Fine-needle aspiration cytology (FNAC) often yields indeterminate results for thyroid nodules (Bethesda III or IV).
• Diagnostic surgery is frequently performed for these indeterminate nodules, leading to potential overtreatment.
• Gene expression classifiers offer a molecular approach to risk stratification.

Purpose of the Study:

• To evaluate the safety and efficacy of gene expression classifier testing in reducing diagnostic surgery for indeterminate thyroid nodules.
• To determine the negative predictive value of gene expression classifiers in this patient cohort.

Main Methods:

• Retrospective review of 520 patients undergoing ultrasound-guided FNAC for thyroid nodules.
• Analysis of 32 cases with indeterminate FNAC (Bethesda III or IV) that proceeded to gene expression classifier testing.
• Assessment of malignancy rates and surgical outcomes.

Main Results:

• The indeterminate FNAC rate was 9%, with a 21% malignancy prevalence.
• Gene expression classifier testing was performed on 32 patients: 14 benign, 15 suspicious, 3 no result.
• A 100% negative predictive value was observed for benign classifier results.

Conclusions:

• Gene expression classifier testing demonstrated a 100% negative predictive value for benign nodules.
• In this series, 14 out of 29 patients with indeterminate FNAC were spared diagnostic surgery.
• Molecular testing can safely reduce the need for diagnostic surgery in select patients with indeterminate thyroid nodules.