From the Guidelines
Thyroid nodule follow-up should be based on the initial ultrasound findings and fine needle aspiration (FNA) results if performed, with a focus on identifying potentially malignant nodules while minimizing unnecessary procedures for benign nodules, as recommended by the most recent guidelines 1. The follow-up approach should consider the size and characteristics of the nodule, as well as the patient's overall risk profile.
- For benign nodules, repeat ultrasound is recommended at 12-24 months, with subsequent follow-up intervals extending if the nodule remains stable.
- Nodules with very low suspicion features (spongiform or purely cystic) may be followed less frequently, every 3-5 years.
- For nodules with indeterminate cytology (atypia of undetermined significance or follicular lesion of undetermined significance), repeat FNA is typically recommended in 3-6 months, or molecular testing may be considered.
- Suspicious nodules that don't meet criteria for immediate surgery should be monitored more closely, with repeat ultrasound in 6-12 months.
- Growing nodules (increase of 20% in two dimensions or 50% in volume) warrant reassessment with FNA regardless of initial benign cytology. During follow-up, attention should be paid to changes in echogenicity, margins, shape, and vascularity, not just size, as these features can be indicative of malignant potential 1. The use of serum thyroglobulin (Tg) measurement and diagnostic radioiodine whole body scan (WBS) can also be useful in the follow-up of patients with a history of thyroid cancer, particularly those who have undergone radioiodine ablation 1. Overall, a tailored approach to thyroid nodule follow-up, taking into account the individual patient's risk profile and nodule characteristics, can help balance the need to detect potentially malignant nodules with the need to avoid unnecessary procedures and minimize harm.
From the Research
Guidelines for Follow-up of Thyroid Nodules
The follow-up of thyroid nodules is crucial for identifying the small subgroup of nodules that harbor a clinically significant cancer, cause compressive symptoms, or progress to functional disease 2. The main goal of initial and long-term follow-up is to determine the need for treatment and the type, frequency, and length of subsequent follow-up.
Factors to Consider for Follow-up
Several factors should be considered when determining the follow-up of thyroid nodules, including:
- Ultrasound characteristics, such as solid composition, hypoechogenicity, irregular margins, and microcalcifications 2, 3
- Cystic content of the nodule, which is a significant independent predictor of nondiagnostic cytology 4
- Patient age, gender, nodule size, and location 4
- Serum concentrations of thyroid stimulating hormone (TSH) and peripheral thyroid hormones 5
Follow-up Intervals
The optimal follow-up intervals for thyroid nodules are unclear, but one study suggests that there is no difference between >4- versus 1- to 2-year intervals to first follow-up ultrasound in the likelihood of malignancy 6. However, follow-up ultrasound at >4 years was associated with increased likelihood of ≥50% nodule growth, repeat fine needle aspiration, and thyroidectomy.
Management
Management of thyroid nodules includes:
- Simple observation 2, 3
- Local treatments 2
- Surgery 2, 5
- Conservative therapy or treatment with radioactive iodine 5
Diagnostic Procedures
Diagnostic procedures for thyroid nodules include: