What are the indications for total thyroidectomy?

Indications for Total Thyroidectomy

Total thyroidectomy is indicated for any thyroid cancer with one or more of the following characteristics: tumor >4 cm, extrathyroidal extension, cervical lymph node metastases, distant metastases, aggressive histological variants, or bilateral disease. 1

Primary Indications for Total Thyroidectomy

Differentiated Thyroid Carcinoma (Papillary and Follicular)

• Tumor size >4 cm 1
• Extrathyroidal extension 1
• Cervical lymph node metastases 1
• Known distant metastases 1
• Bilateral thyroid disease/nodularity 1
• Aggressive histological variants (tall cell, columnar cell, poorly differentiated features) 1
• Macroscopic multifocal disease 1
• Age <15 years or >45 years (for papillary carcinoma) 1
• History of radiation exposure 1

Medullary Thyroid Carcinoma

• All medullary thyroid cancers >5 mm 2
• Hereditary MTC (MEN 2A/2B) - prophylactic thyroidectomy recommended by age 5 for MEN 2A and in first year of life for MEN 2B 1
• Elevated calcitonin levels 1

Other Indications

• Anaplastic thyroid carcinoma (when resectable with good performance status) 2
• Graves' disease with palpable nodule(s) or ophthalmopathy 3
• Large multinodular goiter with minimal normal thyroid tissue (particularly in endemic regions) 3

Decision Algorithm for Thyroidectomy Extent

Total Thyroidectomy Required (Any Present)

1. Tumor >4 cm
2. Extrathyroidal extension
3. Cervical lymph node metastases
4. Distant metastases
5. Aggressive histological variants
6. Bilateral disease
7. Multifocal disease
8. Family history of thyroid cancer
9. Prior radiation exposure (category 2B) 1

Total Thyroidectomy or Lobectomy Acceptable (All Present)

1. Tumor ≤4 cm
2. No prior radiation exposure
3. No distant metastases
4. No cervical lymph node metastases
5. No extrathyroidal extension 1

Lymph Node Management with Total Thyroidectomy

• Central compartment neck dissection (level VI) should be performed for clinically apparent/biopsy-proven disease 1
• Lateral neck dissection (levels II-IV) should be performed for patients with metastases in the lateral compartment 2
• Prophylactic central neck dissection is not routinely recommended for papillary thyroid cancer without clinical or radiological evidence of lymph node involvement if the patient meets all criteria: classical type papillary thyroid cancer, <45 years old, unifocal tumor <4 cm, no extrathyroidal extension on ultrasound 2

Complications and Considerations

• Major complications include recurrent laryngeal nerve injury (0.8-1.6% permanent) and hypoparathyroidism (1.6-3.9% permanent) 3, 4
• Risk reduction strategies:
  • Complete exposure of parathyroid glands with preservation or autotransplantation
  • Meticulous identification and preservation of recurrent laryngeal nerves
  • Referral to high-volume thyroid surgeons 4

Post-Thyroidectomy Management

• Radioactive iodine (RAI) ablation is recommended for most patients with tumors >1 cm who have undergone total thyroidectomy 2
• Thyroid hormone therapy should be initiated after surgery (levothyroxine 2 μg/kg) 2
• TSH suppression is recommended for high-risk thyroid cancer patients 1
• Follow-up includes serum thyroglobulin measurement, neck ultrasound, and clinical examination 2

Total thyroidectomy provides the advantage of facilitating RAI therapy and follow-up with thyroglobulin monitoring, while eliminating the risk of recurrence in the contralateral lobe. However, the trend has shifted toward more conservative approaches (lobectomy) for low-risk differentiated thyroid cancers <4 cm without other high-risk features 5.