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NH Environmental Public Health Tracking Program
Thyroid Cancer

Thyroid cancer is a cancer that starts in the thyroid gland, which is situated under the Adam's apple in the front part of the neck. In most people, it cannot be seen or felt. It is butterfly shaped, with two lobes--the right lobe and the left lobe--joined by a narrow isthmus. Thyroid cancer has a lower fatality rate than most cancers. Since 1973, a 2.4-fold increase in the incidence of this disease has occurred. Much of this is attributable to improved detection of the disease by thyroid ultrasound and ultrasound-guided fine needle aspiration. The American Cancer Society (ACS) estimates that about 37,340 new cases of thyroid cancer will be diagnosed in the United States in 2008. Thyroid cancer is much more likely to occur in women. ACS states that "nearly 2 out of 3 cases are found in people between the ages of 20 and 55."

Thyroid Cancer and the Environment

The excessive risk for thyroid cancer associated with exposure to external ionizing radiation has been well established. No other environmental chemicals or physical agents have been associated with this cancer. Other risk factors for this cancer include:

Exposure and Risk

Although a person with thyroid cancer may have a risk factor, the degree to which that risk factor contributes to the cancer may be difficult to determine. A few risk factors that increase the likelihood to develop thyroid cancer have been established. These include:

Reduce Your Risk

Most people with thyroid cancer have no known risk factors; therefore it is not possible to prevent the disease in those instances. Because of the availability of genetic blood tests, most of the familial cases of MTC can be either prevented or treated early. If the disease is diagnosed, the patient's family members can be tested also. If a family history of MTC exists, a doctor who is familiar with the latest advances in genetic counseling and genetic testing for this disease should be consulted. Removing the thyroid gland in children who carry the abnormal gene will prevent a cancer that might be fatal.

Environmental Public Health Tracking Program
NH Department of Health and Human Services, Division of Public Health Services
29 Hazen Drive, Concord, NH 03301
Tel: (603) 271-4988 800-852-3345 ext.4988

copyright 2009. State of New Hampshire