Undifferentiated thyroid cancer

Disease Description (Causes and Symptoms)

• Definition: Anaplastic/undifferentiated thyroid cancer is a rare but highly aggressive cancer that develops in the thyroid. It accounts for approximately 1% of all thyroid cancers and occurs mainly in older adults.
• Pathophysiology/Causes: It often develops when a pre-existing differentiated thyroid cancer (papillary or follicular cancer) undergoes dedifferentiation over a long period. Molecular genetic abnormalities (e.g., BRAF mutations) may also be present.
• Main symptoms: A rapidly enlarging mass (nodule) in the front of the neck, difficulty breathing, a foreign-body sensation in the neck, voice changes (hoarseness), and difficulty swallowing (dysphagia). Even when detected early, local invasion or distant metastasis (to the lungs, bones, etc.) is common.
• Course/Prognosis: It progresses very rapidly, and in many cases there is local invasion or distant metastasis at diagnosis, resulting in a poor prognosis (average survival of several months).

Treatment Methods (Standard Treatment, Medication, Surgery, Lifestyle Management, and Precautions)

• Treatment goals: When possible, prolong survival and relieve symptoms (such as difficulty breathing and swallowing) while maintaining quality of life. Depending on the stage and overall condition, the possibility of curative treatment is limited.
• Surgery: When the disease is localized and can be resected, complete resection (curative surgery) may improve survival. However, few patients are eligible for surgery at diagnosis (approximately 10% according to the literature).
• Radiation therapy: External-beam radiation therapy may be performed for local control and symptom relief. It is used as adjuvant treatment after surgery or as local treatment for unresectable lesions.
• Chemotherapy: It is used as palliative or combination therapy, and the effectiveness of monotherapy is limited. Traditional agents such as doxorubicin or taxane agents such as paclitaxel may be used.
• Targeted therapy/Molecularly targeted therapy: When a BRAF V600E mutation is confirmed, combination treatment with a BRAF inhibitor and a MEK inhibitor (e.g., dabrafenib + trametinib) is effective and is currently considered one of the standard treatment options (molecular testing is recommended).
• Symptom-relieving treatment: If airway compression is severe, airway management (tracheostomy or stent placement) may be needed; nutritional support (such as tube feeding) and specialized palliative care (including hospice care) may be provided to relieve pain and difficulty breathing.
• Radioactive iodine therapy: It generally has little to no effect in anaplastic thyroid cancer.
• Lifestyle management and precautions:
  • Thyroid hormone replacement therapy is needed after total or partial thyroidectomy, with the dose adjusted through medication management and testing (such as TSH).
  • Visit the emergency room immediately if difficulty breathing or rapid worsening of symptoms occurs.
  • A prior consultation with the medical team is needed regarding the treatment plan (surgery, radiation, and medication), side effects, and goals (life prolongation and symptom relief).
  • Risk of complications: Airway obstruction, aspiration, bleeding, and nerve paralysis due to invasion of the airway, esophagus, or nerves (vocal cords), among others.

Outpatient Visit Checklist (Including Preparation Items and Example Questions)

• Preparation items (tests and records):
  • List of medications currently being taken (including prescriptions, OTC medications, and supplements)
  • Previous test results (thyroid ultrasound, fine-needle aspiration (FNA)/biopsy reports, CT/PET-CT, and blood test results)
  • A record of when symptoms began and how they have progressed (such as difficulty breathing, difficulty swallowing, and voice changes)
  • History of previous surgery or radiation therapy and coexisting conditions (such as cardiovascular or pulmonary disease)
• Information that is helpful to report during the outpatient visit:
  • When the symptoms began and how quickly the mass grew
  • The severity of difficulty breathing (differences at rest and during activity), and whether coughing or aspiration occurs when swallowing
  • Weight loss, fever, and changes in overall condition
• Possible preliminary tests to request: Thyroid ultrasound, CT or MRI (neck and chest), PET-CT, blood tests, biopsy (or repeat biopsy), and molecular genetic testing (such as BRAF)

Examples of General Questions to Ask the Doctor

• "What exactly does my current stage mean? Is surgery possible?"
• "What are the expected benefits (prolonging survival and improving symptoms) and major side effects of each treatment option?"
• "Should I have molecular testing (such as BRAF)? How would the treatment change depending on the results?"
• "How should I respond if difficulty breathing or swallowing worsens during treatment?"
• "Is palliative treatment (symptom management) or participation in a clinical trial possible?"

Examples of Disease-Specific Questions

• "Has it been confirmed whether my biopsy shows a BRAF V600E mutation? Depending on the test results, can I receive targeted therapy such as dabrafenib + trametinib?"
• "The mass in my neck is compressing my airway. Would it be appropriate to control it first with airway management (tracheostomy or stent placement) or radiation instead of curative resection?"

(Note: This information is intended to support diagnosis and treatment decisions. Individual treatment should be determined in consultation with the treating physician.)