Monday, May 29, 2006

thyroid symptoms: Thyroid cancer treatment

Diagnosis Thyroid

The doctor may use several tests to confirm a diagnosis of thyroid cancer. The size and location of the lump has to be identified and it has to be determined whether the lump is non-cancerous (benign) or cancerous (malignant). Blood tests, such as the thyroid stimulating hormone (TSH) test, may be ordered to check how well the patient's thyroid is functioning.

A test known as the calcitonin test may be ordered if medullary thyroid cancer is suspected. Calcitonin is a hormone produced by the C cells (also called the parafollicular cells) of the thyroid gland, in response to rising levels of calcium in the blood. This hormone lowers calcium levels in blood serum by slowing the rate at which the bones absorb it and increasing the rate at which the kidneys discharge it. When the parafollicular cells of the thyroid become cancerous, they produce too much calcitonin. Because increased serum levels of the calcitonin hormone are characteristic of medullary thyroid cancer, the calcitonin test, which measures serum levels of calcitonin, can be used to confirm a diagnosis of medullary thyroid cancer.

Imaging tests such, as a computed tomography scan (CT scan) or an ultrasound scan, may be used to produce a picture of the thyroid. In ultrasonography, high-frequency sound waves are bounced off the thyroid. The pattern of echoes that is produced by these waves is converted into an image by a computer. This test can determine whether the lumps found in the thyroid are fluid-filled cysts or solid malignant tumors.

A radioactive scan can be used to identify any abnormal areas in the thyroid. The patient is given a very small amount of radioactive iodine, which can either be taken by mouth or injected into the thyroid. Since the thyroid is the only gland in the body that absorbs iodine, the radioactive iodine accumulates there. A x-ray image can then be taken or an instrument called a "scanner" can be used to identify areas in the thyroid that do not absorb iodine normally. These abnormal spots are called "cold spots" and further tests are performed to check whether the cold spots are benign or malignant tumors. If a significant amount of radioactive iodine is concentrated in the nodule, then it is termed "hot" and is usually benign.

The most accurate diagnostic tool for thyroid cancer is a biopsy. In this process, a sample of thyroid tissue is withdrawn and examined under a microscope. The tissue samples can be obtained either by drawing out a sample of tissue through a needle (needle biopsy) or by surgical removal of the nodule (surgical biopsy). If thyroid cancer is diagnosed, further tests may be done to learn about the stage of the disease and help the doctors plan appropriate treatment.

Thyroid Treatment

Treatment for thyroid cancer depends on the type of cancer and its stage. Cancer staging considers the size of the tumor, whether it has grown into surrounding lymph nodes, and whether it has spread to distant parts of the body (metastasized). The patient's age and general health status are also taken into account. Four types of treatment are used: 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. The surgeon may remove the side or lobe of the thyroid where the cancer is found (lobectomy) or all of it (total thyroidectomy). If the adjoining lymph nodes are affected, they may also be removed during surgery.

Radiation therapy uses high-energy x rays to kill cancer cells and shrink tumors. The radiation may come from a machine outside the body (external beam radiation) or the patient may be asked to swallow a drink containing radioactive iodine. Because the thyroid cells take up iodine, the radioactive iodine collects in any thyroid tissue remaining in the body and kills the cancer cells.

Hormone therapy uses hormones to stop the cancer cells from growing. When the thyroid gland is removed and levels of thyroid hormones fall, the pituitary gland starts producing a hormone called "thyroid stimulating hormone" (TSH). TSH stimulates the thyroid cells to grow. This stimulation would also induce growth of the cancerous thyroid cells. To prevent cancerous growth, the natural hormones that are produced by the thyroid are taken in the form of pills. Thus, their levels remain normal and inhibit the pituitary from making TSH.

If the cancer has spread to other parts of the body and surgery is not possible, the treatment is aimed at killing or slowing the growth of cancer cells throughout the body. Chemotherapy may be used, either in a pill or an injection through a vein in the arm.

Prognosis

Like most cancers, cancer of the thyroid is best treated when it is found early. More than 90% of patients who are treated for papillary or follicular cancer will live for 15 years or longer after having had thyroid cancer. Eighty percent of patients with medullary thyroid cancer will live for at least 10 years after surgery. The fourth type of thyroid cancer, anaplastic, is usually fatal. Only 3-17% of patients with this cancer survive for 5 years.
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. If a family member has had this disease, the rest of the family can be tested.

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. The neck and the thyroid should be carefully examined for any lumps or enlargement of the nearby lymph nodes. Ultrasonography may be used for people at risk for thyroid cancer.

Gale Encyclopedia of Medicine. Gale Research, 1999.

Comments:
During the cancer diagnosis doctors look for the site of origin of the tumor and the type of cells. Cancers arise in any organ. The body site, where cancer develops first, is the primary site. The tumor spreads (metastasizes) then. Common cancers include skin, lungs, breasts, prostate, colon and uterine tumors. There are many signs and symptoms of cancer. Doctors may find tumors directly, by X-ray or MRI imaging, or through lab tests.

However, these signs and symptoms of cancer may mimic other diseases. Weight loss and abdominal pain may mean stomach cancer or an ulcer. Weight loss and swollen lymph nodes may mean lymphoma or AIDS or tuberculosis. Blood in urine is a sign of bladder or kidney cancer or a kidney infection. Blood in stool is a sign of many bowel problems, not just cancer. Benign looking skin mole may be deadly melanoma. Doctors often need a biopsy (microscopic check of tissues samples) to diagnose cancer. The cancer type is found by microscopic examination. If the type is different from surrounding tissue, the cancer came from another primary site. Metastases can spread directly or through blood vessels, and lymphatic vessels. Biopsy helps to find the primary site. Treatment also depends on the cancer cell type. Cells could be more or less differentiated and originate from different layers of the same organ. If the cancer cells resemble healthy, mature cells, they are differentiated. Undifferentiated cells look like very immature primitive cells. Checking the differentiation allows doctors to know how aggressive the cancer is. Grade one cancer is less aggressive than grade four usually.

Also doctors classify cancers by stage. Stage depends on the size and spreading of the tumor. Stage determines the mode of treatment - Whether it is surgical, radiation, chemotherapy and so on. RDoctor.com.
 
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