Thyroid cancers typically do not cause any symptoms early in the disease. As the cancer grows, it may cause:

• A lump (nodule) in the neck, which may grow quickly
• Hoarseness or other voice changes
• A constant nagging cough
• Swollen lymph nodes in your neck
• Pain in the neck and throat
• Trouble breathing
• Difficulty in swallowing

• The exact cause of thyroid cancer is not known
• Thyroid cancer occurs when cells in thyroid undergo genetic changes known as mutations. These mutations allow the cells to grow and multiply rapidly. These mutant cells also lose their ability to die resulting in an accumulation of abnormal thyroid cells which form a tumor
• The abnormal cells can invade nearby tissues and can later on spread to other parts of the body

Factors that may increase the risk of thyroid cancer include:

• Females are at higher risk than males
• Radiation therapy treatments to the head and neck especially during childhood
• Certain inherited genetic syndromes like familial medullary thyroid cancer, multiple endocrine neoplasia, Cowden’s syndrome and familial adenomatous polyposis

Thyroid cancers are classified into types based on the type of cells found in the tumor by fine needle aspiration cytology. Types of thyroid cancers include:

• Papillary thyroid cancer: This is the most common form of thyroid cancer, arises from the follicular cells which produce and store thyroid hormones. It can occur at any age, but is most often found in people around 30 to 50 years of age. This type of Thyroid cancer has the best prognosis

• Follicular thyroid cancer: Follicular thyroid cancer also arises from the follicular cells of the thyroid and usually affects people older than 50 years

• Anaplastic thyroid cancer: This is a rare type of thyroid cancer originating in the follicular cells and grows rapidly. It typically occurs in adults aged 60 years and older and is very difficult to treat. This type of Thyroid cancer has a bad prognosis

• Medullary thyroid cancer: Medullary thyroid cancer begins in thyroid parafollicular cells called C cells, which produce the hormone calcitonin. Elevated levels of calcitonin in the blood can indicate medullary thyroid cancer at a very early stage. Certain genetic syndromes increase the risk of medullary thyroid cancer

• Other rare types include thyroid lymphoma and thyroid sarcoma

After a detailed medical history and physical examination, the following tests are advised,

• Blood tests- Thyroid function tests
• Ultrasound imaging- The appearance of thyroid on the ultrasound helps determine whether a thyroid nodule is likely to be noncancerous or whether there’s a risk that it might be cancerous
• Fine needle aspiration cytology – Samples of suspicious thyroid tissue are aspirated and analyzed in the laboratory to look for cancer cells
• Other imaging tests like CT scan may be advised to assess the spread of cancer beyond the thyroid
• Genetic testing may be recommended in few patients with medullary thyroid cancer

Thyroid cancer treatment depends on the type and stage of thyroid cancer and the overall health. Most thyroid cancers can be cured completely with treatment. The treatment options include:

1. Surgery–The operation to be performed depends on the type, size, extent of thyroid cancer and ultrasonography of the thyroid. Operations used to treat thyroid cancer include:

• Removing the entire thyroid (Total thyroidectomy): This is the surgery of choice when the tumor is more than 2cm and/or has extended beyond the thyroid gland
• Removing half of the thyroid (Hemithyroidectomy): This type of surgery is recommended if the tumor is slow-growing thyroid cancer, measuring less than 2cm, limited to one part of the thyroid with no suspicious nodules in other areas of the thyroid
• Additionally, removing lymph nodes in the neck (Lymph node dissection): During thyroidectomy, adjacent lymph node compartments in the neck may be dissected

2. Thyroid hormone therapy

• To Replace the deficient thyroid hormone following total thyroidectomy and to suppression production of thyroid stimulating hormone from the pituitary gland

3. Radioactive iodine therapy

• Following total thyroidectomy to destroy any remaining healthy thyroid tissue and residual microscopic thyroid cancer cells
• To treat recurrent and metastatic thyroid cancer  

4. External beam radiation therapy- Selectively recommended in cases where surgery isn’t an option and the cancer continues to grow even after radioactive iodine treatment

5. Chemotherapy- Selectively recommended to treat anaplastic thyroid cancers

6. Targeted drug therapy- Selectively recommended in advanced thyroid cancers

Thyroid cancer patients require long term follow-up at regular intervals to ensure that the cancer has not recurred. Follow up visits include physical examination, Blood tests (Serum thyroglobulin and anti thyroglobulin)  and ultrasonography of neck if indicated