What Is Thyroid Cancer?
![Thyroid cancer largely affects people starting in middle age. Women (who are more susceptible to this cancer, in general) are usually in their 40s or 50s when diagnosed and men are usually in their 60s or 70s at diagnosis.](https://images.medicinenet.com/images/article/main_image/what-are-the-warning-signs-of-thyroid-cancer.jpg?output-quality=75)
Thyroid cancer occurs when cells in the thyroid gland grow out of control.
Anyone at any age can develop thyroid cancer but about two-thirds of cases of thyroid cancer are diagnosed in people aged 20 to 55 years. Anaplastic thyroid cancer is often diagnosed in patients after age 60. Infants 10 months and older and adolescents can develop medullary thyroid cancer (MTC), especially if they carry the RET proto-oncogene mutation.
What Are Symptoms of Thyroid Cancer?
Symptoms of thyroid cancer include:
- A lump or nodule in the neck
- Nodule may cause no symptoms
- In some cases, the tumor may have spread to lymph nodes in the neck, which may be enlarged
- Swelling in the neck
- Pain in the neck, jaw, or ear
- Difficulty breathing or swallowing if the nodule is large
- Hoarseness or other voice changes
- Persistent cough not due to a cold
What Causes Thyroid Cancer?
The cause of most thyroid cancers is unknown but the disease is linked with a number of inherited conditions.
Risk factors for developing thyroid cancer include:
- Gender: occurs about 3 times more often in women than in men
- Age: women are usually in their 40s or 50s when diagnosed and men are usually in their 60s or 70s at diagnosis
- Hereditary conditions
- About 20% of medullary thyroid cancers result from inheriting an abnormal gene (familial medullary thyroid carcinoma, or FMTC)
- Familial adenomatous polyposis (FAP)
- Cowden disease
- Carney complex, type I
- Familial nonmedullary thyroid carcinoma
- Family history
- Radiation exposure such as from medical treatments and radiation fallout from power plant accidents or nuclear weapons
- Being overweight or obese
- Iodine in the diet
- Follicular thyroid cancers are more common in parts of the world where diets are low in iodine
- The risk of papillary thyroid cancer is increased with diets high in iodine
How Is Thyroid Cancer Diagnosed?
Thyroid cancer is diagnosed with a patient history and physical examination and tests such as:
- Imaging tests
- Ultrasound
- Radioiodine scan
- Chest X-ray
- Computerized tomography (CT) scan
- Magnetic resonance imaging (MRI) scan
- Positron emission tomography (PET) scan
- Biopsy
- Fine needle aspiration (FNA) biopsy
- Core biopsy
- Surgical “open” biopsy to remove the nodule
- Lobectomy (removal of half of the thyroid gland)
- Molecular tests to check for gene changes
- Blood tests
- Thyroid-stimulating hormone (TSH)
- T3 and T4 (thyroid hormones)
- Thyroglobulin
- Calcitonin
- Carcinoembryonic antigen (CEA)
- Blood cell counts
- To check for bleeding disorders
- Liver and kidney function
- Tests for epinephrine (adrenaline) and norepinephrine
- Urine tests to check for the breakdown products of epinephrine (adrenaline) and norepinephrine (metanephrines)
- Vocal cord exam (laryngoscopy)
What Is the Treatment for Thyroid Cancer?
Treatment for thyroid cancer may involve one or more of the following:
- Surgery
- Thyroidectomy: removal of the thyroid gland
- Most common surgery for thyroid cancer
- After surgery, patients must take thyroid hormone replacement medication (levothyroxine) for life
- Lobectomy: removal of the lobe containing the cancer, usually along with the isthmus (the small piece of the gland that acts as a bridge between the left and right lobes)
- Lymph node removal if cancer has spread
- Thyroidectomy: removal of the thyroid gland
- Radioactive iodine (radioiodine) therapy
- RAI, also called I-131 collects mainly in thyroid cells, where the radiation can destroy the thyroid gland and any other thyroid cells (including cancer cells) that take up iodine
- Thyroid hormone therapy
- After thyroidectomy surgery, patients must take thyroid hormone replacement medication (levothyroxine) for life
- External beam radiation therapy
- Chemotherapy
- Targeted drug therapy
- Multikinase inhibitors: lenvatinib (Lenvima), sorafenib (Nexavar). vandetanib (Caprelsa), cabozantinib (Cometriq)
- RET inhibitors: selpercatinib (Retevmo) and pralsetinib (Gavreto)
- NTRK inhibitors: larotrectinib (Vitrakvi) and entrectinib (Rozlytrek)
- BRAF and MEK inhibitors: dabrafenib (Tafinlar) and trametinib (Mekinist)
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https://www.cancer.net/cancer-types/thyroid-cancer/risk-factors