Thyroid cancer is a type of cancer that begins in the cells of the thyroid. The thyroid is the organ in the body that controls metabolism. Chemicals are produced in the thyroid that regulate blood pressure, body temperature, weight, and heart rate. Approximately 200,000 people are newly diagnosed with thyroid cancer worldwide each year. Although thyroid cancer isn’t common in the United States, rates have been increasing. Thyroid cancer can be deadly, but is highly treatable when caught early.
Causes of Thyroid Cancer
Although the cause of thyroid cancer is not known, anything causing an abnormality in cell DNA puts a patient at risk for development of cancer. Family history of certain types of thyroid cancer can alert doctors to the possibility of a patient developing the disease. Patients that have been exposed to radiation also run a higher risk of being diagnosed with thyroid cancer.
Types of Thyroid Cancer
There are four main types of thyroid cancer:
The most common types of thyroid cancer are papillary and follicular, accounting for about 90 percent of all cases of thyroid cancer. These types tend to grow slowly and the cells act much like ordinary thyroid cells. Papillary and follicular thyroid cancers typically respond well to treatment if caught early, and almost 90 percent of those diagnosed with one of these types of thyroid cancer survive. Treatments may vary according to the health condition of the patient and the stage of the cancer.
Medullary thyroid cancer only accounts for about six percent of all cases of thyroid cancer. If it is discovered that the patient has familial medullary thyroid cancer, all immediate family members should be tested for genetic factors that may lead to development of medullary thyroid cancer. Nearly 100 percent of patients that are found to have the genetic mutation associated with this disease will develop medullary thyroid cancer. Removing the thyroid is the best way to treat this type of cancer, and is an effective preventative measure if the genetic mutation is discovered. Medullary thyroid cancer is not as treatable as papillary or follicular cancer, and may recur or continue to grow after treatment.
Anaplastic thyroid carcinoma is the least common type of thyroid cancer, and is often seen in patients that have another type of thyroid cancer. Anaplastic thyroid cancer is the most aggressive type of thyroid cancer, and often spreads to other areas of the body rapidly. Anaplastic thyroid cancer is difficult to control and treat.
Diagnosis of Thyroid Cancer
A delayed diagnosis of thyroid cancer is common because the disease often shows no symptoms in early stages. Positively diagnosing thyroid cancer requires the results of a biopsy, which doctors do not perform unless thyroid cancer is suspected. Screening tests for thyroid cancer are limited to examination of the neck for lumps or swelling, and have not been shown to increase the chances of catching thyroid cancer early. If a lump in the throat is detected, the doctor may order further testing to establish the presence of cancerous cells.
Symptoms of thyroid cancer are also commonly mistaken for other diseases:
- Pain in the neck or ears
- Lump in the neck
- Trouble breathing
- Hoarseness or cough
- Trouble swallowing
Blood tests can indicate the level of thyroid stimulating hormone in the body, but this does not necessarily indicate thyroid cancer. If blood tests do show elevated levels of this hormone, a biopsy will be ordered to test for thyroid cancer. Ultrasounds may also be used to examine lumps or nodules within the throat, but these are not considered to be definitive without the results of a biopsy. During a biopsy, a small piece of the thyroid is removed surgically, and the tissue is examined.
Misdiagnosis of Thyroid Cancer
Diseases that are often misdiagnosed as thyroid cancer include:
- Lyme Disease
- Thyroid disorders
- Neck cancer
- Thyroid nodules
- Benign multinodular goiter
- Graves Disease
These diseases can all exhibit similar symptoms which may lead to an incorrect diagnosis of thyroid cancer. A biopsy may also show cancer cells within the thyroid that may not necessarily have originated there, changing the way that the cancer should be treated. A misdiagnosed patient may suffer greatly. The condition that the patient actually has is not being treated, and may spread or worsen, while thyroid cancer treatment may harm the patient that does not have the disease.
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