What are the effects and treatment options for a patient with a dominant thyroid nodule?

Management of Dominant Thyroid Nodules

Thermal ablation is the recommended treatment for benign dominant thyroid nodules that cause clinical symptoms such as compression or cosmetic concerns, or for nodules ≥2 cm that are gradually increasing in size. 1

Evaluation of Thyroid Nodules

Initial Assessment

• Ultrasound evaluation is the cornerstone of thyroid nodule assessment
• Risk factors that increase suspicion of malignancy include:
  • Age <15 years or male gender
  • History of head/neck radiation
  • Family history of thyroid cancer
  • Associated syndromes
  • Concerning physical findings (fixed nodule, vocal cord paralysis)

Ultrasound Classification

• Suspicious ultrasound features include:

  • Solid composition
  • Hypoechogenicity
  • Irregular margins
  • Microcalcifications
  • Central hypervascularity 2

• TI-RADS classification system stratifies nodules based on ultrasound characteristics:

  • TI-RADS 2: Benign appearing nodule with very low risk of malignancy (<2%)
  • Higher TI-RADS scores (3-5) indicate increasing risk of malignancy 2

Fine-Needle Aspiration (FNA)

• FNA should be performed for:
  • Any thyroid nodule >1 cm
  • Nodules <1 cm with suspicious clinical or ultrasound features 1, 2
• FNA is the most reliable and cost-effective method for distinguishing benign from malignant nodules, with diagnostic accuracy approaching 95% 3, 4
• Limitations of FNA include:
  • Nondiagnostic yield (inadequate samples)
  • Indeterminate results (follicular neoplasia) 3

Management Options for Benign Dominant Thyroid Nodules

Thermal Ablation

• Indicated for:

  • Nodules causing compression symptoms
  • Nodules affecting appearance (cosmetic concerns)
  • Nodules ≥2 cm with gradual increase in size
  • Autonomously functioning thyroid nodules
  • Recurrent nodules after chemical ablation 1

• Advantages of thermal ablation over surgery:

  • Simple operation
  • Short procedure time
  • No neck scarring
  • Low complication rates
  • Outpatient treatment
  • Preservation of thyroid function
  • Usually no need for lifelong medication 1

• Thermal ablation techniques include:

  • Radiofrequency ablation (RFA)
  • Microwave ablation (MWA)
  • Laser ablation (LA)
  • High-intensity focused ultrasound (HIFU) 1

Surgical Management

• Total or near-total thyroidectomy is indicated for:

  • Nodules ≥1 cm with confirmed malignancy
  • Any size tumor with metastatic disease
  • Multifocal disease
  • Familial differentiated thyroid carcinoma 1, 2

• Less extensive surgical procedures may be considered for:

  • Unifocal differentiated thyroid carcinoma diagnosed after surgery for benign thyroid disorders
  • Small, intrathyroidal tumors with favorable histology 1

Surveillance

• For benign nodules without symptoms:
  • Regular monitoring with thyroid function tests annually
  • Ultrasound follow-up at 6-12 month intervals initially, then annually if stable 2
  • Optional follow-up ultrasound at 12-24 month intervals to confirm stability 2

Special Considerations

Multinodular Goiter

• FNA has limited utility in multinodular goiter, with sensitivity as low as 17% for detecting carcinomas (26% if microcarcinomas are excluded) 5
• Clinical criteria should be prioritized over FNA results in multinodular goiter 5

Malignant Nodules

• Standard treatment for differentiated thyroid carcinoma is:

  • Total or near-total thyroidectomy
  • Followed by radioactive iodine (RAI) ablation in appropriate cases
  • Subsequent thyroid hormone suppression therapy 2

• RAI therapy is:

  • Recommended for high-risk patients
  • May be considered for low-risk patients
  • Not indicated for very low-risk patients (unifocal T1 tumors <1 cm, favorable histology, no extrathyroidal extension, no lymph node metastases) 2

Pitfalls to Avoid

• Overtreatment of micropapillary carcinomas: 60-80% of newly detected thyroid carcinomas are micropapillary (<1 cm) with excellent prognosis 2

• Inappropriate use of RAI: Not all patients benefit from RAI therapy; very low-risk patients should be spared unnecessary radiation exposure 2

• Insufficient follow-up: Differentiated thyroid carcinoma can recur even 20 years after initial treatment, necessitating long-term surveillance 2

• Limited ultrasound evaluation: Ultrasound has limitations in evaluating retrosternal extension, invasion of deep structures, and certain lymph nodes; CT or MRI should be considered for fixed, bulky, or substernal lesions 2

• Inadequate pre-ablation preparation: Before thermal ablation, patients should be fully informed about advantages and limitations, and anticoagulant medications should be discontinued 1