Thyroid Cancer - Symptoms & Treatment

Thyroid cancer is cancer of the thyroid gland. There are four forms: papillary, follicular, medullary and anaplastic.

• Papillary carcinoma accounts for about half of thyroid cancer in adults. It can occur at any age but is most common in young adult females. Usually multifocal and bilateral, it metastasizes slowly into regional nodes of the neck, mediastinum, lungs, and other distant organs. It is the least virulent form of thyroid cancer.
• Less common, follicular carcinoma is more likely to recur and metastasize to the regional lymph nodes and spread through blood vessels into the bones, liver, and lungs.
• Medullary (solid) carcinoma, this type of cancer tends to run in families. The symptoms may mimic those of Cushing's syndrome. It does not involve thyroid hormone-producing cells and accounts for 5 to 10 per cent of thyroid cancers.
• Anaplastic carcinoma (giant and spindly cell cancer) resists radiation and is almost never curable by resection. This cancer metastasizes rapidly, causing death by invading the trachea and compressing adjacent structures.

Causes

Besides exposure to radiation, suspected causes of thyroid cancer include prolonged secretion of thyroid-stimulating hormone (TSH) through radiation or heredity, familial predisposition, and chronic goiter.

Signs and Symptoms

The most common symptom of thyroid cancer is a lump or nodule in the thyroid gland that can be felt in the neck. Occasionally, a patient will have a swollen lymph node in the neck and hoarseness due to pressure from the tumor on the nerve to the voice box (recurrent laryngeal nerve). A patient may also have difficulty swallowing or breathing due to a tumor obstructing the esophagus or windpipe.

Diagnostic tests 

Diagnosing thyroid cancer involves a number of tests, including:

• Physical examination
• Blood tests
• Ultrasound scans
• Examination of the vocal cords
• Tissue biopsy.

Treatment

Surgery is recommended initially for all forms of thyroid cancer, but the extent of surgery and the postoperative treatments vary. Ideally before surgery, the patient should have normal thyroid function (euthyroid) as demonstrated by normal thyroid function tests, pulse rate, and electrocardiogram.

Treatment may include one or a combination of the following:

• total or subtotal thyroidectomy with modified node dissection (bilateral or homolateral) on the side of the primary cancer (for papillary or follicular cancer)
• total thyroidectomy and radical neck excision (for medullary or anaplastic cancer)
• radioisotope (131I) therapy with external radiation(Sometimes postoperatively in lieu of radical neck excision) or alone (for metastasis)
• adjunctive thyroid suppression (with exogenous thyroid hormones suppressing TSH production) and simultaneous administration of an adrenergic blocking agent such as propranolol, to increase tolerance to surgery and radiation therapy
• chemotherapy limited to treating symptoms of wide­spread metastasis, as a palliative measure; doxorubicin has some antitumor activity in about 20% of cases.

Prevention

Because most people with thyroid cancer have no known risk factor, it is not possible to completely prevent this disease. However, inherited cases of medullary thyroid cancer can be prevented and radiation to the neck is avoided. If a family member has had this disease, the rest of the family can be tested and treated early.