What is the treatment for thyroid cancer?

Treatment for Thyroid Cancer

The standard treatment for thyroid cancer is total or near-total thyroidectomy followed by radioactive iodine (RAI) therapy for most patients, with the exception of very low-risk cases. 1

Treatment Algorithm Based on Thyroid Cancer Type

Differentiated Thyroid Cancer (DTC) - 90% of cases

1. Initial Surgical Management:

   • Total or near-total thyroidectomy for tumors ≥1 cm, or with metastatic, multifocal, or familial disease 1
   • Lobectomy may be considered for selected low-risk tumors (T1a-T1b-T2, N0) 1
   • Lymph node dissection:
     • Central neck dissection may improve regional control for invasive tumors (T3-T4) 1
     • Lateral neck dissection for patients with positive preoperative imaging 1

2. Post-Surgical RAI Therapy:

   • Low-risk patients (unifocal T1 tumors <1 cm with favorable histology): RAI not recommended 1
   • Intermediate-risk patients: RAI with 30-100 mCi (1.1-3.7 GBq) 1
   • High-risk patients: RAI with 100 mCi (3.7 GBq) 1
   • RAI preparation: recombinant human TSH (rhTSH) administration while on levothyroxine therapy 1

3. TSH Suppression Therapy:

   • Complete remission: maintain TSH in low-normal range (0.5-2 μIU/ml) 1
   • Intermediate to high-risk with incomplete response: mild TSH suppression (0.1-0.5 μIU/ml) 1
   • Persistent structural disease: TSH suppression (<0.1 μIU/ml) 1

Medullary Thyroid Cancer (MTC)

1. Surgery: Total thyroidectomy with bilateral prophylactic central lymph node dissection 1
2. Post-surgical monitoring: Serum calcitonin (CT) and carcinoembryonic antigen (CEA) measurements 1
3. Advanced/metastatic disease: Consider vandetanib (FDA and EMA approved) 1

Anaplastic Thyroid Cancer (ATC)

1. Surgery: Complete resection when possible 1
2. Adjuvant therapy: High-dose external beam radiotherapy (EBRT) with or without chemotherapy 1

Follow-Up Protocol

1. 2-3 months post-treatment:

   • Thyroid function tests (FT3, FT4, TSH) to check adequacy of levothyroxine therapy 1

2. 6-12 months post-treatment:

   • Physical examination
   • Neck ultrasound
   • Serum thyroglobulin (Tg) measurement 1
   • Optional: diagnostic whole-body scan (WBS) 1

3. Long-term follow-up for disease-free patients:

   • Annual physical examination
   • Annual basal serum Tg measurement
   • Annual neck ultrasound 1

Management of Recurrent or Metastatic Disease

1. Locoregional recurrence:

   • Surgery combined with RAI therapy 1
   • External beam radiotherapy if surgery is incomplete or there is lack of RAI uptake 1

2. Distant metastases:

   • RAI therapy for RAI-avid lesions 1
   • For RAI-refractory disease: consider targeted therapies 1, 2
     • Cabozantinib for locally advanced or metastatic DTC that has progressed following prior VEGFR-targeted therapy and is RAI-refractory 2
     • Other options include sorafenib, lenvatinib, dabrafenib 3

Special Considerations

• Microcarcinomas (≤1 cm): Observation without surgical resection can be considered 3
• Pregnancy planning: RAI therapy should be avoided in pregnant women; women should wait at least 6 months after RAI before conception 4
• RAI safety: Despite multiple treatments, no long-term effects on fertility have been documented 4

Common Pitfalls to Avoid

1. Overtreatment of very low-risk patients (unifocal tumors <1 cm) with RAI therapy
2. Inadequate surgery leading to incomplete resection and higher recurrence rates
3. Insufficient TSH suppression in high-risk patients with persistent disease
4. Delayed treatment of recurrent disease
5. Overlooking the need for lifelong follow-up, as recurrences can occur even 20 years after initial treatment 1

Thyroid cancer treatment requires a risk-stratified approach based on tumor characteristics, with most patients achieving excellent outcomes when appropriate treatment protocols are followed.