What is the standard treatment for thyroid papillary carcinoma?

Standard Treatment for Thyroid Papillary Carcinoma

Total or near-total thyroidectomy is the standard treatment for papillary thyroid carcinoma >1 cm, followed by selective radioactive iodine ablation, TSH suppression with levothyroxine, and appropriate surveillance. 1

Initial Surgical Management

Indications for Total Thyroidectomy

• Total thyroidectomy is recommended when any of these factors are present:
  • Tumor >4 cm in diameter 1
  • Known distant metastases 1
  • Cervical lymph node metastases 1
  • Extrathyroidal extension 1
  • Poorly differentiated histology 1
  • Prior radiation exposure (category 2B recommendation) 1

Indications for Thyroid Lobectomy

• Lobectomy plus isthmusectomy may be considered if ALL of the following criteria are met:
  • Tumor ≤4 cm in diameter 1
  • No prior radiation exposure 1
  • No distant metastases 1
  • No cervical lymph node metastases 1
  • No extrathyroidal extension 1

Lymph Node Management

• Perform therapeutic neck dissection of involved compartments for clinically apparent or biopsy-proven disease 1
• The benefit of prophylactic central node dissection in the absence of evidence of nodal disease is controversial 1
• Compartment-oriented microdissection of lymph nodes should be performed in cases of preoperatively suspected and/or intraoperatively proven lymph node metastases 1

Post-Surgical Management

Radioactive Iodine (RAI) Therapy

• RAI ablation is recommended after surgery for high-risk patients 1
• RAI is generally not indicated in very low-risk patients (unifocal T1 tumors <1 cm with favorable histology, no extrathyroidal extension, no lymph node metastases) 1
• RAI administration decreases the risk of locoregional recurrence and facilitates long-term surveillance based on serum thyroglobulin measurement 1

Thyroid Hormone Therapy

• Suppressive doses of levothyroxine should be administered to maintain serum TSH levels <0.1 μIU/ml (unless contraindicated) 2, 3
• TSH suppression prevents tumor growth by inhibiting endogenous thyroid-stimulating hormone 2

Management of Advanced Disease

RAI-Refractory Disease

• For metastatic disease that is RAI-refractory, consider systemic therapy with:
  • Sorafenib - FDA-approved for locally recurrent or metastatic, progressive differentiated thyroid carcinoma refractory to RAI treatment 4
  • Lenvatinib - indicated for differentiated thyroid cancer that can no longer be treated with RAI and is progressing 5

Bone Metastases Management

• Bone resorption inhibitors (bisphosphonates and denosumab) can be used for thyroid cancer-related bone metastases to manage pain and reduce skeletal-related events 2

Follow-Up Protocol

• Regular monitoring with serum thyroglobulin measurements to assess treatment response and detect recurrence 2
• Serial imaging studies including neck ultrasound and other modalities (MRI, CT, PET/CT) as indicated 2
• 2-3 months after initial treatment, thyroid function tests should be performed to check adequacy of levothyroxine suppressive therapy 1
• 6-12 months after initial treatment, screening with physical examination, neck ultrasound, and basal and stimulated serum thyroglobulin measurement with or without diagnostic whole-body scan 1

Clinical Considerations and Pitfalls

Surgical Complications

• In expert hands, surgical complications such as laryngeal nerve palsy and hypoparathyroidism are extremely rare (<1-2%) 1
• Vocal cord mobility should be examined in patients with abnormal voice, surgical history involving recurrent laryngeal or vagus nerves, invasive disease, or bulky disease of the central neck 1

Benefits of Total Thyroidectomy vs. Lobectomy

• Total thyroidectomy for PTC ≥1.0 cm has been shown to result in lower recurrence rates and improved survival compared to lobectomy 6
• Total thyroidectomy facilitates:
  • Treatment of potential multicentric disease (present in up to 80% of cases) 7
  • Maximal uptake of adjuvant radioactive iodine 8
  • Post-treatment follow-up by monitoring serum thyroglobulin levels 8

Special Pathologic Considerations

• Noninvasive follicular thyroid neoplasm with papillary-like nuclear features (NIFTP) has been reclassified and only lobectomy is needed 1