Treatment
Thyroid Cancer
What is Thyroid Cancer?
Thyroid cancer develops in the thyroid gland (located at the base of the neck) and is one of the most treatable cancers, with rising incidence rates globally due to improved detection. Here’s a focused, clinically relevant overview:
- Types & Key Features
Type | Frequency | Behavior | Key Characteristics |
Papillary | 80–85% | Slow-growing | Follicular cells; BRAF mutations; spreads via lymph nodes |
Follicular | 10–15% | Moderate aggression | Vascular invasion; RAS mutations; distant mets (lungs/bone) |
Medullary (MTC) | 2–5% | Aggressive | Parafollicular C-cells; RET mutations; linked to MEN2 syndrome |
Anaplastic | <2% | Highly aggressive | Rapid growth; resistant to treatment; poor prognosis |
- Symptoms
- Early:Often asymptomatic; found incidentally on imaging.
- Later:
- Neck lump/nodule(palpable in 90% of cases).
- Hoarseness(recurrent laryngeal nerve invasion), dysphagia.
- Lymph node swelling(lateral neck).
- Medullary-specific: Diarrhea, flushing (calcitonin secretion).
🔍 Note: Most thyroid nodules are benign (95%). Suspicious features: rapid growth, firm fixation, voice changes.
- Risk Factors
- Gender/Age:
- Women 3× > men (papillary); peaks at 40–50 yrs (medullary: 50–60 yrs).
- Radiation Exposure:
- Childhood head/neck radiation (↑ papillary risk).
- Genetics:
- Medullary:RET proto-oncogene mutations (MEN2A/2B).
- Follicular/Papillary:BRAF, RAS, familial syndromes (Cowden, FAP).
- Iodine Deficiency:↑ Follicular cancer risk (rare in iodine-sufficient areas).
- Gender/Age:
- Diagnosis
- Ultrasound (US):
- First-line for nodules; assesses size, margins, microcalcifications, vascularity.
- Fine-Needle Aspiration (FNA) Biopsy:
- Guided by US; classifies nodules using Bethesda System(I–VI).
- Lab Tests:
- TSH(suppressed in toxic nodules).
- Calcitonin(elevated in medullary cancer).
- Carcinoembryonic Antigen (CEA)(MTC marker).
- Molecular Testing:
- BRAF, RET, RAS, *PAX8/PPARγ* for indeterminate nodules (Bethesda III/IV).
- Advanced Imaging:
- CT/MRI:For large/invasive tumors.
- FDG-PET:For aggressive/recurrent disease.
- Ultrasound (US):
- Treatment
Differentiated (Papillary/Follicular)
- Surgery:
- Lobectomy:For low-risk, <1 cm nodules.
- Total Thyroidectomy:For tumors >1 cm, multifocal, or with metastases.
- Radioactive Iodine (RAI) Ablation:
- Post-op to destroy residual tissue (for intermediate/high-risk cases).
- TSH Suppression:
- Levothyroxine to suppress TSH (slows tumor growth).
- Targeted Therapy (Advanced Cases):
- Lenvatinib, sorafenib (for RAI-resistant tumors).
- Surgery:
Medullary (MTC)
- Total Thyroidectomy + Central Neck Dissection.
- RET Inhibitors: Cabozantinib, vandetanib for metastatic disease.
- Monitor calcitonin/CEA for recurrence.
Anaplastic
- Aggressive Multimodal Approach:
- Surgery (if resectable) → Chemoradiation (docetaxel/doxorubicin).
- Immunotherapy/Targeted Trials: Dabrafenib/trametinib for *BRAF V600E+*.
- Aggressive Multimodal Approach:
- Prognosis
Type | 10-Year Survival | Key Prognostic Factors |
Papillary | 95–99% | Age <55, size <4 cm, no distant mets |
Follicular | 85–90% | Minimal vascular invasion, no mets |
Medullary | 75–85% | Early stage, RET mutation status |
Anaplastic | <10% | Rapid treatment initiation, resectability |
- Prevention & Screening
- Genetic Testing:
- RETtesting for all MTC patients/families (prophylactic thyroidectomy for RET+ carriers).
- Radiation Avoidance:
- Minimize unnecessary neck radiation, especially in children.
- Self-Exams:
Check neck for lumps; voice changes warrant evaluation.
