What are the guidelines for managing thyroid nodules?

Guidelines for Managing Thyroid Nodules

Thyroid nodules should be evaluated with a complete thyroid ultrasound, thyroid function tests (TSH), and fine-needle aspiration biopsy (FNAB) for suspicious nodules, with thermal ablation techniques recommended as first-line treatment for symptomatic benign nodules. 1

Initial Evaluation and Diagnosis

Diagnostic Workup

• Complete thyroid ultrasound is essential for all thyroid nodules 1
• Thyroid function tests (TSH) should be performed 1
• Assessment of glycemic control (HbA1c) in patients with diabetes 1

Risk Stratification Based on Ultrasound Features

Nodules can be categorized into risk groups based on sonographic features:

Suspicion Level	Ultrasound Features
High suspicion	Hypoechogenicity, microcalcifications, irregular borders, solid composition, absence of peripheral halo [1,2]
Low suspicion	Cystic or spongiform appearance [2]

Indications for Fine-Needle Aspiration Biopsy (FNAB)

FNAB is the gold standard for diagnosis of thyroid nodules 1:

Nodule Size	Recommendation
<1.0 cm	Monitor with ultrasound if no suspicious characteristics
1.0-1.4 cm	Consider FNAB if suspicious characteristics present
≥1.5 cm	FNAB recommended [1]
≤5 mm	Should be monitored rather than biopsied [3]

Management Options

Benign Nodules

• Most thyroid nodules are benign (90%) and do not require treatment 2
• Levothyroxine suppressive therapy is not recommended 3
• For symptomatic benign nodules:
  • Percutaneous ethanol injection (PEI) is first-line for relapsing, benign cystic lesions 3
  • Thermal ablation techniques (radiofrequency ablation, microwave ablation, laser ablation, high-intensity focused ultrasound) are recommended for solid or mixed symptomatic benign nodules 1, 3

Suspicious or Malignant Nodules

• Surgery remains the treatment of choice 1, 3
• Total thyroidectomy is preferred over hemithyroidectomy for confirmed malignancy during pregnancy 1

Follow-up Protocol

Surveillance Schedule

• Initial follow-up at 1 month
• Subsequent follow-ups at 3,6, and 12 months during the first year
• Annual follow-up thereafter 1

Follow-up Assessment

• Ultrasound to assess volume reduction
• Thyroid function tests
• Symptom assessment 1

Special Considerations

Indeterminate Cytology

• Nodules with indeterminate cytology may benefit from molecular testing 2, 4
• For nodules with negative molecular testing:
  • Surveillance ultrasound is recommended
  • Initial surveillance ultrasound typically at 13 months (range 11-19 months) 4
  • For "negative but limited" samples, repeat FNAB should be performed 4

Pregnancy

• Thyroid nodules discovered during pregnancy should be evaluated to ensure the best possible outcomes for both mother and fetus 1

Patients with History of Thyroid Cancer

• Regular ultrasound monitoring is recommended
• Those with rising thyroglobulin or thyroglobulin antibodies should undergo ultrasound evaluation 1

Complications of Thermal Ablation and Prevention

• Potential complications include bleeding, voice change due to recurrent laryngeal nerve injury, nodule rupture, vasovagal reflex, neck edema, pain, and fever (incidence 0.04-1.42%) 1
• Prevention strategies:
  • Hydrodissection technique
  • Transisthmic approach
  • Continuous monitoring of needle tip position 1
  • NSAIDs may be considered for prevention or treatment of nodule rupture 1

Common Pitfalls to Avoid

• Inappropriate antibiotic use and premature open biopsy should be avoided 1
• Overtreatment of small, asymptomatic nodules with low suspicion features
• Failure to perform FNAB on nodules with suspicious ultrasound features regardless of size
• Relying solely on size rather than considering both size and ultrasound characteristics for management decisions