Common Thyroid Disorders
Thyroid Cancer:
Every year in the United States, over 20,000 cases of thyroid cancer are diagnosed. There are several types of thyroid cancer:
- Papillary Cancer (most common)
- Follicular Cancer and Follicular Variant of Papillary Cancer
- Hurthle Cell Cancer
- Medullary Cancer
- Poorly Differentiated and Anaplastic Cancer
- Lymphoma
Some of these cancers can be diagnosed with a needle biopsy and some require surgery for diagnosis. With the exception of Lymphoma and perhaps Anaplastic Cancer, most Thyroid Cancer is treated with Surgery as the primary modality of treatment. Conventional Radiation Therapy and Chemotherapy are rarely indicated, however, many patients do require Radioactive Iodine taken as a pill following surgery. Although Thyroid Cancer may be life threatening, most patients with Thyroid Cancer will be detected early and will be cured, or will live many years before the disease recurs if appropriately treated.
Papillary and Follicular Cancer: Detailed Information
These account for over 80-85% of all thyroid cancers and are sometimes referred to as well-differentiated thyroid cancer (carcinoma). Their appearance under a microscope is responsible for their names and occasionally some contain elements of both (follicular variant of papillary carcinoma).
Papillary Carcinoma and its follicular variant may occur at any age. Certainly, any thyroid mass in a child or teenager should be considered highly suspicious for thyroid cancer. Most papillary cancers present as a thyroid nodule, although some present as a mass in the neck representing a lymph node involved by papillary cancer. Papillary cancer may be multicentric (affecting multiple sites within the thyroid gland) and tends to preferentially metastasize to regional lymph nodes in a high percentage of cases, more commonly in those tumors which are larger, i.e. over 3 - 4cm. Fortunately, it less commonly spreads to other organs. The first group of lymph nodes usually involved lie along the trachea below the thyroid gland (paratracheal lymph nodes) and the second group lie in the lateral neck along the jugular vein and behind it (cervical nodes). While not necessary in all patients, complete removal of the lymph node compartments containing thyroid cancer can control it in most patients. The side effects of this type of surgery can be minimized in most patients.
In general, the best treatment for papillary and follicular thyroid cancer involves total thyroidectomy (complete removal of the thyroid gland) with or without an associated removal of the regional lymph nodes. In selected cases, radioactive iodine ( a radioactive pill) is given following the surgery to identify and destroy any remaining thyroid cancer cells not removed by surgery, or that may have escaped to other sites.
A whole body scan follows administration of this drug, to determine if there are any foci of unrecognized disease. The patient can then be followed periodically by the thyroid specialist by examination, blood tests and occasionally ultrasounds and scans to be certain that the thyroid cancer has not recurred.
Follicular Cancer affects women somewhat more frequently than men and behaves somewhat differently than papillary cancer. It rarely spreads to lymph nodes but may spread via the bloodstream to other organs. Its treatment is not much different however from papillary cancer, although lymph nodes only rarely have to be removed.
Hurthle Cell cancer is most often a variant of follicular cancer although some are variants of papillary cancer. Hurthle Cells have a unique appearance under the microscope. However, their behavior and treatment is not much different than that for papillary and follicular cancer.
Medullary Thyroid Cancer:
This cancer arises from so called “C-Cells,” or nests of non-thyroidal cells, located within the thyroid gland. These cells produce a hormone called Calcitonin which assists in regulating calcium metabolism. Far more rare than papillary or follicular cancer, Medullary cancer occurs as both a sporadic non-hereditary event and as an inherited disease. Most commonly, it occurs with no known family history. Those that are inherited are often part of Hereditary syndromes known as Multiple Endocrine Neoplasia (MEN), either type 1 or 2. Details of these is beyond the scope of this brief essay. Suffice to say, when there is a defined family history of MEN, medullary cancer can be detected and aggressively treated early in life to improve the patient’s chance for survival. All Medullary cancers produce an excessive amount of Calcitonin and can be identified and followed using the blood level of this hormone.
Nowadays, sophisticated genetic testing can also be done for those suspect of having the familial form of the disease. Medullary thyroid cancer can spread both to lymph nodes and via the bloodstream to distant organs, and thus mandates aggressive treatment. Total thyroidectomy with removal of regional lymph nodes is indicated for most patients. Careful pot-operative monitoring of calcitonin is then done by the thyroid specialist. Radioactive iodine is not indicated for this cancer, but occasionally radiation therapy or specific targeted therapies may be given for more advanced disease.
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