Thyroid Cancer
What is it?
Thyroid cancer is a disease of the thyroid gland in
which the cells become abnormal and form tumors. Located
at the base of the throat, the thyroid gland makes
hormones that regulate heart rate, blood pressure, body
temperature, and metabolism. There are four different
types of thyroid cancer: papillary, follicular, medullary,
and anaplastic thyroid. The cancers grow at different
rates, so the aggressiveness of each cancer is different.
If left untreated, the cancer can spread to other parts of
the body.
Who gets it?
Thyroid cancer is three times as common in women as in
men. The rate of thyroid cancer is also higher in whites
than in African Americans. Most people who develop thyroid
cancer are 50 years of age or older, but the disease can
affect teenagers and young adults. Thyroid cancer accounts
for 1% of all cancers.
What causes it?
Although the exact cause of thyroid cancer has not been
determined, exposure to radiation during childhood is a
known risk factor for thyroid cancer. In the 1950s and
1960s, radiation was used to treat acne and to reduce
swelling and infection of organs in the neck, such as the
tonsils, adenoids, and lymph nodes. Recent studies prove
that people who received radiation to the head and neck
during their childhood have a higher than average chance
of developing thyroid cancer.
What are the 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.
How is it diagnosed?
Several tests, including x-ray examination,
transillumination of the gland, radioisotope scanning,
needle biopsy and ultrasonic examination, may be performed
by a doctor to determine size and location of the tumor
and to determine whether it is non-cancerous (benign) or
cancerous (malignant). If malignant, thyroid cancer can be
diagnosed as one of four types. The most common type of
thyroid cancer is papillary cancer, a slow-growing cancer
that can usually be treated successfully. The second type,
follicular cancer, also has a good cure rate. However, if
follicular cancer invades blood vessels or grows into
nearby structures in the neck, it may be difficult to
control. About 30-50% of thyroid cancers are follicular
cancers. Medullary cancers are more difficult to control
because they have a tendency to spread to other parts of
the body. About 5-7% of all thyroid cancers are medullary
cancers. Anaplastic cancer is the fastest growing of all
thyroid cancers, however only 2% of all thyroid cancers
are anaplastic.
What is the treatment?
Treatment of thyroid cancer depends on the type of
cancer and its stage. The most common treatments used are
surgical removal, radiation therapy, hormone therapy and
chemotherapy. If the cancer has not spread to distant
parts of the body, surgical removal is the usual
treatment. Radiation therapy may be used after surgery to
kill cancer cells and shrink tumors. Hormone therapy is
another treatment used to stop the cancer cells from
growing. If the cancer has spread to other parts of the
body and surgery is not possible, chemotherapy treatment
may be used to kill or slow the growth of cancer cells
throughout the body.
Self-care tips
Because most people with thyroid cancer have no known
risk factors, it is not possible to completely prevent
this disease. However, periodic follow-up examinations are
essential for patients who have had surgery for papillary
or follicular thyroid cancer, because recurrences
sometimes occur many years after apparently successful
surgery. In addition, the National Cancer Institute
recommends that a doctor examine anyone who has received
radiation to the head and neck during childhood at
intervals of one or two years.
This information has been designed as a comprehensive and quick reference
guide written by our health care reviewers. The health information written
by our authors is intended to be a supplement to the care provided by your
physician. It is not intended nor implied to be a substitute for
professional medical advice.
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