FREE ESSAY ON THYROID CANCER

THYROID CANCER

Cancer of the Thyroid
Statistics
Cancer of the thyroid may be one of the less frequently occurring forms of cancer, but it
is the most common malignancy of the endocrine system. Each year, more than 1,100
Americans are diagnosed with thyroid cancer and most of them can expect to live a normal
life span (Health Conn. html). The overall incidence of being diagnosed with thyroid
cancer is about 1 out of every 1,000 people (Health Answers. html). As with other thyroid
conditions, more than twice as many women as men develop thyroid cancer. Most men and
women who are diagnosed with this type of cancer are between the ages of twenty-five and
sixty-five years (Health Conn. html).
General Description
Cancer is a disease in which abnormal cells in some organ or tissue go out of control,
growing and increasing in number. Normal cells reproduce themselves throughout life, but
in an orderly and controlled manner. When normal cell growth occurs, worn out tissues are
replaced and wounds are healed. But when cells grow out of control, they form a mass
called a tumor. Some tumors grow and enlarge only at the site where they began. These
types of tumors are referred to as benign tumors. Other tumors not only enlarge locally,
but they also have the potential to invade and destroy the normal tissues around them and
to spread to other regions of the body. These types of tumors are called malignant tumors
or cancer.(Mediconsult html)
Malignant tumors of the thyroid gland tend to develop gradually and remain localized. The
tumors usually appear as nodules or lumps of tissue growing on or inside the gland
itself. Most lumps on the neck, however, are usually caused by thyroid conditions such as
goiters.(Mediconsult html)
There are four main types of thyroid cancers: papillary, follicular, medullary, and
anaplastic (also referred to as
undifferentiated) (Graylab html). These tumors are identified by the type of cells seen
under the microscope. Papillary thyroid tumors occur most often. This type of thyroid
cancer develops on one or both sides of the gland and remains confined for several years.
Follicular tumors, on the other hand, grow only on one side of the gland. Medullary
thyroid tumors are usually uncommon, and like papillary tumors, they grow on one or both
sides of the gland . Anaplastic tumors, though extremely rare, develop on either side of
the thyroid gland and spread rapidly to other parts of the body (Thyroid Cancer
Overview).
Causes The only known risk for thyroid cancer in some people is
external radiation to the head and neck areas. From the early 1920's to the late 1950's,
thousands of children received x-ray treatments to the head and neck areas (Health Conn.
html).Back then x-ray therapy was used to treat inflammation of the tonsils and adenoids,
ringworm of the scalp, ear infections, acne, and other non-cancerous conditions (Health
Answers html). At the time physicians had no indications that external radiation
treatment could lead to thyroid cancer. Several years later, thyroid tumors began to
appear in people who had received this type of radiation therapy. Fortunately most of the
tumors were slow-growing and not malignant (Health Conn. html).Other risks factors for
thyroid cancer include patients with a family history of thyroid cancer and patients who
experience chronic goiters (National Cancer Institute html).
Symptoms
Malignant thyroid tumors may develop without any detection for many years after its
original formation. Aside from a slightly enlarged thyroid gland or lump located in the
neck region, there are no early signs or symptoms that indicate this type of cancer. If
the malignant tumor is left undetected and untreated, the later stages of thyroid cancer
might cause more obvious symptoms (UPHS Health html). Such symptoms could possibly be
hoarseness or a slight change in the voice due to pressure from the tumor on the nerve
connected to the voice box or, difficultly in swallowing or breathing due to a tumor
obstructing the esophagus or windpipe (Thyroid Cancer Overview html). Other signs of
thyroid cancer are chronic coughing or coughing accompanied by bleeding, or diarrhea or
constipation (American Cancer Clinic html).
Diagnosis
The diagnosis of cancer is terrifying for most patients because it has become associated
with extreme pain and suffering (Brochlure.1 html). But what the patients do not realize
is that there are a number of tests that can be performed to determine the existence of a
malignant or benign thyroid tumor, and most of these tests cause little pain or
disability (Mediconsult html). Most cases of thyroid cancer are found during a routine
physical examination. If the gland appears to be enlarged, the physician may order
further tests to diagnose or rule out cancer (CRHA html). These tests include:
* Thyroid scan- a patient is given radioactive iodine to drink. After the iodine has been
absorbed by the thyroid, the patient must lie on his or her back with the neck region
positioned under a scanner. The information received by the scanner is then sent to a
computer that displays a 2-dimensional image of the thyroid and any tumors that have
absorbed the iodine. There is no discomfort felt during this testing, and slight nausea
due to the iodine mixture is the only reported reaction to this testing. A thyroid scan
is about 80 to 85% accurate, and it costs an estimated $50- $120, plus any hospital stay
and extra computer costs. (Health Answers html)
* Thyroid ultrasound- The ultrasound uses high-frequency sound waves that are emitted and
received by a transducer (a hand-held instrument) that is passed over the neck region.
The sound waves penetrate the body, and by electronic readings, the sound waves are
arranged on a computer screen into a picture image of the thyroid gland and any tumors. A
thyroid ultrascan is completely harmless, and it is about 80 to 97% accurate. The costs
range anywhere from $75-$100. (Health Answers html)
* Thyroid excisional biopsy- the test is done in a hospital operating room under a
general anesthesia. A sedative is usually given by an injection about one hour before the
procedure. An intravenous line is placed in a vein in the arm. Throughout the procedure,
the patient is given a mixture of anesthetic gas and oxygen through a hollow tube that is
inserted through the mouth and into the trachea. A small incision is made in the neck,
and either side of the thyroid or the entire lump is removed. The sample is sent to a
laboratory to be examined. If thyroid cancer is detected, the thyroid is removed. The
incision is then stitched up. A patient who undergoes a thyroid excisional biopsy will
experience drowsiness, a mild sore throat, and some discomfort from the incision. The
test is highly accurate and costs any where from $300 to $1,000. (Health Answers html)
* Laryngoscopy- it is the examination of the interior of the larynx with either the aid
of a small mirror held against the back of the palate or a flexible viewing tube called a
laryngoscope. This type of testing may cause a sore or hoarse throat. It is 50 to 75%
accurate and costs around $65. (Health Answers html)
Cancer development
Once the cancer of the thyroid is diagnosed, more tests can be done to find out if cancer
cells have spread to other parts of the body. This is called staging. A physician needs
to determine which stage the cancer is in order to plan the proper treatment (American
Cancer Clinic html). There are four main stages in each of the types of thyroid cancer
except for anaplastic (undifferentiated) cancer.
In the stage I of papillary thyroid cancer, the cancer is located only in the thyroid and
may be found in one or both of the lobes. In stage II if the patients are younger than 45
years of age, the cancer has spread beyond the thyroid. But if the patient is older than
45 years of age, the cancer is only in the thyroid and is larger than 1 centimeter. In
stage III, the cancer is usually found in patients older than 45 years of age and has
spread outside of the thyroid or has spread to the lymph nodes but not outside of the
neck. In stage IV, the cancer is again usually found in patients over the age of 45. It
most likely has spread to other parts of the body such as the lungs or bones. (Graylab
hmtl)
In stage I of follicular thyroid cancer, the cancer is only found in the thyroid gland on
one of the lobes. In stage II if the patient is younger than 45 years of age, the cancer
has spread beyond the thyroid to the lymph nodes. If the patient is older than 45 years
of age, the cancer is only in the thyroid and is larger than 1.5 centimeters. In stage
III, the cancer is usually found in patients older than 45 and has spread to beyond the
thyroid into other areas of the neck and maybe outside of the neck. Stage IV of follicle
thyroid cancer is very similar to stage IV of papillary thyroid cancer in that the cancer
has probably spread to the lungs and various bones. (Graylab html)
Medullary thyroid cancer is quite uncommon. In stage I, the is located in one or both of
the thyroid glands and is about 1 centimeter in size, but throughout the last three
stages of medullary thyroid cancer, the tumor grows by 1-4 centimeters and continuously
spreads to other parts of the body. (Graylab html)
There is no staging system for anaplastic cancer of the thyroid. This cancer is located
in either of the lobes and spreads faster than any of the other types. (Graylab html)
Treatment
There are basically four different types of treatments used on patients with cancer of
the thyroid: surgery, radiation therapy, hormone therapy, and chemotherapy (National
Cancer Institute html). Each treatments are widely used in fight against thyroid cancer,
but not all yield the same results.
Surgery the most common treatment for cancer of the thyroid. A physician can remove the
cancer by using one or several operations. A lobectomy removes only the side of the
thyroid where the cancer is found. A near-total thyroidectomy removes all of the thyroid
except for a small portion. A total thyroidectomy removes the entire thyroid, and a lymph
node dissection removes lymph nodes in the neck that contain cancer. Complications of
surgery include: hemorrhage, damage to the parathyroid glands, and temporary or permanent
damage to the vocal chords. Any type of surgery for thyroid cancer is followed up by a
series of oral doses of radioactive iodine. The concentrations of iodine destroy any
residual thyroid tissue or tumor.
Radiation therapy uses high-energy x-rays to kill cancer cells and shrink tumors.
Radiation for cancer of the thyroid may come from a machine outside of the body (external
radiation therapy) or from drinking a liquid that contains radioactive iodine. Because
the thyroid absorbs the iodine, the radioactive iodine collects in any thyroid tissue
remaining in the body and kills the cancer cells. Side effects of radiation therapy
include: edema, increased skin pigment, skin itching, desquamation( shedding of outer
layer of skin), nausea, vomiting, hair loss, and possible fetal damage in women.
Hormone therapy uses hormones to stop cancer cells from growing. In treating cancer of
the thyroid, hormones can be used to stop the body from making other hormones that might
make cancer cells grow. The hormones are usually ingested orally in the form of a pill.
There are generally no side effects to hormone therapy other than slight nausea,
vomiting, and diarrhea.
Chemotherapy uses drugs to kill cancer cells. Chemotherapy may be taken by a pill, or it
may be put into the body by a needle in the vein or muscle. Chemotherapy is called a
systemic treatment because the drug enters the blood stream, travels through the body,
and can kill the cancer cells outside of the thyroid. Chemotherapy causes similar side
effects to those of radiation therapy.
Prognosis
Fortunately in most cases, people with the cancer of the thyroid are usually treated
successfully. Papillary cancer of the thyroid is not associated with a high degree of
progression so many people maintain a normal life expectancy ,if diagnosis is made early.
Follicular cancer of the thyroid is often fast growing and may invade other tissues, but
the probable outcome is still good. The outcome of medullary cancer of the thyroid
varies. Women under the age of 40 have a better chance of a good outcome. The number of
people who live at least 10 years after diagnosis is 46%.Anaplastic cancer of the thyroid
has the worst prognosis. The expected life span of anyone diagnosed with this type of
thyroid cancer is anywhere from 6 months to 3 years.