Thyroid Cancer: Symptoms, Causes, And Treatment
What is Thyroid Cancer?
Thyroid cancer develops when a mutation in thyroid cells cause abnormal growth of thyroid cells resulting in the formation of a tumor. The thyroid gland is butterfly shaped and is located at the base of the neck. The hormones secreted by thyroid gland are essential for maintaining blood pressure, heart rate, body weight and body temperature.
They are five different types of thyroid cancers, papillary thyroid cancer, follicular thyroid cancer, medullary thyroid cancer, anaplastic thyroid cancer and thyroid lymphoma.
Thyroid cancer is rare cancer. In India, less than 1 million cases of thyroid cancer are reported. It is more common in middle-aged and elderly individuals. Thyroid cancer can be treated, and in most cases, it can be treated completely. After treatment, most of the individuals have a normal lifespan.
What are the Symptoms of Thyroid Cancer?
In the initial stages, thyroid cancer does not exhibit any signs and symptoms. As the disease progress, the patient might experience the following symptoms:
- Sore throat
- A lump in the neck
- Difficulty swallowing
- Pain in neck and throat
- Swollen lymph nodes in the neck
What are the Causes of Thyroid Cancer?
The thyroid cancer is caused when a mutation in the thyroid cells cause abnormal division of cells. This abnormal growth results in accumulation of the cells resulting in the formation of the tumor.
What are the Risk Factors for Thyroid Cancer?
Risk factors increase the chances of an individual to experience a medical condition. The various risk factors for thyroid cancer are:
- Gender: Thyroid cancer is more common in women than male. Women have thrice more chance of developing thyroid cancer than men.
- Exposure to Radiation: Individuals who are exposed to high levels of radiation are at high risk of developing thyroid cancer. Source of exposure include radiation therapy, fallout material from nuclear reactions etc.
- Inherited Syndromes: Few inherited conditions like medullary thyroid cancer, familial adenomatous polyposis, Carney complex (type 1), Cowden disease and familial non-medullary thyroid carcinoma increase the risk of thyroid cancer.
- Family History: Individuals whose close relatives have thyroid cancer are at high risk of developing thyroid cancer.
- Low Iodine Levels: Low levels of iodine in the body might increase the risk of developing thyroid cancer. Studies have shown that some types of thyroid cancers are common in places where there is iodine deficiency.
- Other Thyroid conditions: Other thyroid conditions, such as Inflammation of thyroid gland (thyroiditis) or enlarged thyroid gland (goitre) increases the possibility of thyroid cancer.
- Obesity: Obesity also increases the risk of experiencing thyroid cancer.
What are the Complications of Thyroid Cancer?
Thyroid cancer recurrence is the most common complication of thyroid cancer. The thyroid cancer can return despite treatment. In few cases, it can even reappear when the thyroid gland is even removed. This happens when the thyroid cancer cells have spread beyond the thyroid gland. It can reappear in the lymph nodes, thyroid tissue left after surgery and other parts of the body.
How to Diagnose Thyroid Cancer?
A physician might diagnose thyroid cancer by observing the symptoms or by doing a physical examination. However, to confirm the diagnosis of thyroid cancer the physician might do one of the following diagnostic tests:
- Physical Examination: A physical examination is done to determine if the patients have any lumps in the neck. The physician might also ask questions about the exposure to radiation and about family history of thyroid cancer.
- Blood Tests: Blood test is done to find out if the thyroid gland is functioning normally. The levels of thyroid hormones, thyroid stimulating hormones, calcitonin and thyroglobulin are determined.
- Biopsy: In thyroid biopsy, a small piece of tissue from the thyroid nodule is removed, and it is sent to the laboratory for testing.
- Imaging Tests: Imaging test such as computerised tomography (CT) scan, ultrasound scan and positron emission tomography (PET) scan are done to see if the thyroid cancer has spread to other parts.
- Genetic Testing: Genetic testing is done to find out if the patient has any of the genes that increase the possibility of thyroid cancer.
- Laryngoscopy: In laryngoscopy, the vocal cord is examined has sometimes the thyroid cancer might also affect the vocal cords. The vocal cords are examined by using a laryngoscope, a narrow tube with light and mirror at the end.
How is Thyroid Cancer Treated?
Most of the cases of thyroid cancer can be treated. The treatment depends on the type and stage of the thyroid cancer. The various treatment options for thyroid cancer are:
Surgery: Surgery is the most common option for treating thyroid cancer. In surgery, either thyroid gland is completely removed (thyroidectomy) or partially removed (one lobe). In few cases, tissue around the thyroid gland and lymph nodes are also removed.
Chemotherapy: Chemotherapy involves administration of drugs either orally or intravenously to inhibit the growth of cancer cells.
Radioactive Iodine Therapy: In radioactive iodine therapy, a radioactive form of iodine is administered orally. It is absorbed by the normal or the cancerous cells of thyroid gland so, it does not cause harm to the other cells.
Radioactive iodine treatment is given after thyroidectomy to destroy the left out portion of thyroid cancer or to remove the remaining healthy thyroid tissue. It is also preferred in thyroid cancer recurrence or metastasis (a spread of thyroid cancer to other parts) cases.
Radiation Therapy: In radiation therapy, high energy x-rays or protons are used for killing the cancer cells. It is the preferred option when surgery cannot be done or in cases when cancer recurs after radioactive iodine therapy or when there is a high risk of cancer recurrence.
Targeted Drug Therapy: Targeted drug therapy is the preferred option for advanced thyroid cancer. The drugs administered during this therapy acts by blocking the signals that cause the cancer cells to grow.
Thyroid Hormone Therapy: After surgery, thyroid hormone cannot be produced in the body due to the removal of the thyroid gland. So, thyroid hormone therapy is required, which involves administration of thyroid hormone pills. It restores normal metabolism of the body and also stops thyroid cancer recurrence.
How can we Prevent Thyroid Cancer?
As exact cause of thyroid cancer is not known preventive measures are not defined for individuals who have an average risk of thyroid cancer. In individuals who are at risk of developing thyroid cancer due to genetic cause or exposure to radiation, the following preventive measures can be taken:
- Exposure to Radiation: Individuals who live in proximity to nuclear power plants are administered with potassium iodide as it combats the effect of radiation.
- Inherited Genes: Individuals who have inherited genes that increase the risk of developing thyroid cancer are recommended to have thyroid surgery.