Thy 3F and 3a malignancy rate, a multisite regional retrospective case series.

Area of Science:

• Endocrinology
• Oncology
• Pathology

Background:

• Thyroid nodules require accurate risk stratification for malignancy.
• The Thy system categorizes nodules, with indeterminate categories (Thy3, Thy3a, Thy3f) posing diagnostic challenges.
• Recent subdivisions of the Thy3 category aim to refine risk assessment and guide management.

Purpose of the Study:

• To determine the incidence of thyroid cancer in patients classified as Thy3, Thy3a, or Thy3f.
• To compare malignancy rates across different Thy subcategories and between multiple UK tertiary centers.

Main Methods:

• Retrospective case series analysis of 395 patients with thyroid nodules.
• Patients were categorized using the Royal College of Pathologists modified British Thyroid Association and Royal College of Physicians Thy system.
• Data collected included final diagnoses (benign, malignancy, specific cancer types).

Main Results:

• Overall thyroid malignancy rate was 28.8% (111 out of 395 patients).
• Malignancy rates for Thy3, Thy3a, and Thy3f categories were 24.7%, 30.4%, and 29.2%, respectively.
• Significant variation in malignancy incidence was observed between the four participating centers, particularly for the Thy3f category (18-54%).

Conclusions:

• The utility of the Thy3a and Thy3f subcategories in improving thyroid cancer detection compared to the original Thy3 category is debatable.
• Observed variations in malignancy rates across centers suggest that local data may be more informative for treatment decisions than national averages.
• Further research is needed to optimize the classification and management of indeterminate thyroid nodules.