Thyroid fine-needle aspiration and The Bethesda Classification System.

Area of Science:

• Endocrinology
• Surgical Pathology
• Oncology

Background:

• Fine-needle aspiration (FNA) is crucial for diagnosing thyroid nodules.
• The current Danish FNA classification system is broad, particularly the "Suspicious" category.
• The Bethesda Classification System (TBCS) offers a more detailed international standard.

Purpose of the Study:

• To apply the TBCS to the Danish "Suspicious" FNA group.
• To determine the malignancy risk within individual Bethesda groups (BG) derived from the Danish "Suspicious" category.

Main Methods:

• A descriptive study utilizing a prospective cohort from the THYKIR database.
• Inclusion of 479 patients with "Suspicious" FNA and subsequent surgical treatment.
• Classification of FNA according to TBCS based on pathology records, with malignancy confirmed by histological diagnosis.

Main Results:

• The Danish "Suspicious" FNA group was categorized into Bethesda groups I-VI.
• Malignancy risks within these groups were: BG I (36.4%), BG II (13.3%), BG III (17.2%), BG IV (16.1%), BG V (55.3%), and BG VI (88.2%).

Conclusions:

• The Danish "Suspicious" FNA category comprises a wide range of Bethesda groups with disparate malignancy risks.
• Standardization of Danish FNA classification is necessary.
• National adoption of the TBCS could establish an internationally comparable standard for thyroid nodule diagnosis.