Thyroid Nodule Evaluation and Management

Initial Evaluation and Diagnostic Approach

The American College of Endocrinology recommends that serum TSH measurement is the best initial test for assessing thyroid function and determining the subsequent diagnostic pathway 1
If TSH is low, radioiodine uptake scintigraphy should be performed to identify hyperfunctioning ("hot") nodules, which are rarely malignant and do not require fine-needle aspiration biopsy (FNAB) 1
If TSH is normal or high, ultrasonographic evaluation should be performed without radionuclide scanning 1
Routine serum calcitonin measurement is not recommended for all patients with thyroid nodules 1

The American Institute of Ultrasound in Medicine recommends that ultrasonography of the thyroid and central neck should be performed in all patients with palpable thyroid nodules 1
Lateral neck ultrasonography may also be performed 1
Suspicious ultrasonographic features require FNAB, including: microcalcifications 2, central hypervascularity 1, taller-than-wide shape 1, irregular margins 1, and hypoechoic appearance 1

The American Thyroid Association recommends that FNAB should be considered for nodules with suspicious ultrasonographic features, regardless of size 1
High-risk clinical features that lower the threshold for FNAB include: age <15 years or male sex 1, history of radiation exposure to the head and neck 3, and presence of cervical lymphadenopathy 3

The Society of Interventional Radiology recommends that thermal ablation is a minimally invasive surgical alternative for benign and malignant thyroid nodules, preserving thyroid function 3
Indications for thermal ablation include: clinical symptoms, cosmetic concerns, or maximum diameter ≥2 cm 3
Radiofrequency ablation (RFA) and microwave ablation (MWA) are the most commonly used techniques, with similar clinical outcomes 3

The American College of Endocrinology recommends that follow-up should start 1 month after the initial procedure, with evaluations at 3, 6, and 12 months in the first year 3, 2
Annual follow-up is recommended for benign nodules after the first year 2
If a nodule increases in size by ≥3 mm or develops new suspicious features, repeat FNAB should be performed 1

The International Society of Surgery recommends that follow-up should include: volume reduction rate (VRR), improvement in compression symptoms and cosmetic problems, presence of residual nodules, recurrence, metastasis, and complications, as well as thyroid function 4, 5
TSH suppression therapy is recommended after thermal ablation for malignant thyroid nodules, with a target TSH level of 0.5-2.0 mU/L for absolute indications and <0.5 mU/L for relative indications 4, 5