What is the appropriate management for an adult thyroid nodule with a total ACR TI-RADS (Thyroid Imaging Reporting and Data System) score of 3?

Management of ACR TI-RADS 3 Thyroid Nodules

Important Clarification

The evidence provided discusses NI-RADS (Neck Imaging Reporting and Data Systems), which is a classification system for post-treatment head and neck cancer surveillance, NOT ACR TI-RADS (Thyroid Imaging Reporting and Data System) for thyroid nodules. These are completely different classification systems with different meanings for the number "3."

Management for ACR TI-RADS 3 Thyroid Nodules

For a thyroid nodule classified as ACR TI-RADS 3 (mildly suspicious), fine-needle aspiration biopsy is recommended only if the nodule measures ≥2.5 cm, otherwise ultrasound surveillance is appropriate. 1

Risk Stratification

• ACR TI-RADS 3 nodules carry a low risk of malignancy, with studies showing excellent negative predictive values of 94.6% for benign disease. 2
• The majority of TI-RADS 3 nodules are benign and do not require immediate biopsy unless they meet size criteria. 2

Size-Based Management Algorithm

For nodules <2.5 cm:

• Ultrasound follow-up is recommended rather than immediate biopsy. 1, 3
• This approach safely avoids unnecessary biopsies while maintaining appropriate surveillance. 4

For nodules ≥2.5 cm:

• Proceed with ultrasound-guided fine-needle aspiration biopsy. 1, 5
• Use local anesthesia (1-2% lidocaine) during the procedure. 5

Surveillance Strategy

• Perform follow-up ultrasound examinations at appropriate intervals to monitor for growth or development of more suspicious features. 3
• Document thyroid gland dimensions and characterize each nodule using standardized ACR TI-RADS features. 3
• Include cervical lymph node evaluation for suspicious features such as microcalcifications, cystic change, hyperechogenicity, abnormal vascular flow, or rounded shape. 3

Clinical Considerations

• Obtain serum TSH measurement before any thyroid imaging, as TSH levels determine the subsequent imaging strategy. 3
• If TSH is normal or elevated, ultrasound alone is sufficient for structural assessment. 3
• If TSH is suppressed, perform radioiodine uptake scan after ultrasound to clarify the cause of thyrotoxicosis. 3

Common Pitfalls to Avoid

• Do not biopsy TI-RADS 3 nodules smaller than 2.5 cm, as this leads to unnecessary procedures with minimal clinical benefit. 2, 4
• Be aware that false-negative results can occur in 5-10% of FNA biopsies, so maintain clinical suspicion if other concerning features are present. 5
• The ACR TI-RADS system has 98.8% specificity for identifying benign nodules, making it highly reliable for avoiding unnecessary biopsies. 4

Risk of Missed Malignancy

• Studies show that when ACR TI-RADS recommendations are followed, the risk of malignancy in TR3 nodules not recommended for biopsy is approximately 1.2%. 4
• Adjusting the size threshold from 2.5 cm to 1.0 cm would identify seven additional malignant nodules but would also result in 118 additional benign nodules undergoing follow-up, representing significant overtreatment. 6