From the Guidelines
For TIRADS 4 thyroid nodules, fine-needle aspiration (FNA) biopsy is recommended for nodules ≥1.5 cm or larger, as this approach balances the risk of missing a clinically significant cancer against avoiding unnecessary procedures for what are still predominantly benign nodules 1. The management of TIRADS 4 thyroid nodules is guided by the American College of Radiology (ACR) Thyroid Imaging, Reporting and Data System (TI-RADS), which provides a standardized approach to thyroid nodule evaluation and risk stratification.
Key Considerations
- For nodules 1.0-1.4 cm, FNA should be considered based on additional risk factors such as family history of thyroid cancer or concerning ultrasound features 1.
- Follow-up ultrasound is appropriate for nodules <1.0 cm, typically at 6-12 month intervals initially.
- If the nodule is biopsied and returns indeterminate results, molecular testing may be considered to further stratify risk.
- After initial evaluation, if the nodule is benign on FNA, follow-up ultrasound is recommended at 12-24 months.
Rationale
TIRADS 4 nodules carry a moderate suspicion for malignancy (15-20% risk), which justifies this more aggressive surveillance compared to lower TIRADS categories.
- Patient factors including age, comorbidities, and preferences should also influence the final management decision 1.
- The NCCN Guidelines for Thyroid Carcinoma provide recommendations for management of the different types of thyroid carcinoma, including papillary, follicular, Hürthle cell, MTC, and ATC 1.
Additional Recommendations
- Molecular testing for DTC may be conducted for diagnostic, prognostic, and/or predictive purposes, and can be useful for evaluating suspicious thyroid nodules so that appropriate treatment options can be determined 1.
- The expanding role of molecular testing for DTC, implications of the new pathologic diagnosis of noninvasive follicular thyroid neoplasm with papillary-like nuclear features (NIFTP), and the addition of a new targeted therapy option for BRAF V600E–mutated ATC should be considered in the management of TIRADS 4 nodules 1.
From the Research
Recommendations for Thyroid Imaging, Reporting and Data System (TI-RADS) 4
- The American College of Radiology (ACR) Thyroid Imaging Reporting and Data System (TI-RADS) is a classification system used to standardize thyroid ultrasound reports and predict the probability of malignancy in thyroid nodules 2.
- A TI-RADS score of 4 indicates a higher risk of malignancy, with a positive predictive value (PPV) of 2.8% compared to Bethesda scoring and 6.1% compared to histopathology 3.
- Patients with small (<1.5 cm) TI-RADS 4 nodules should be appropriately counseled for fine-needle aspiration (FNA) to exclude cancer 3.
- A study found that a TI-RADS score of ≥4 had an 84% PPV for malignancy, and TI-RADS categories 4 and 5 have high PPV for malignancy in thyroid nodules 4.
- The ACR TI-RADS recommendations for FNA biopsy are based on the TI-RADS score and nodule size, with a score of 4 or 5 indicating a higher risk of malignancy and recommending FNA biopsy 2, 3.
- However, some malignant nodules may not meet ACR TI-RADS criteria for FNA, and adjusting size thresholds to decrease the number of missed malignant nodules would result in a substantial increase in the number of benign nodules undergoing follow-up 5.