Thyroid Cancer

Diagnosis

When detected early, cancer of the thyroid gland is highly treatable. Mayo Clinic doctors consider the following when diagnosing thyroid tumors.

• Physical exam. Your doctor will look for physical changes in your thyroid and ask about your risk factors, such as excessive exposure to radiation and a family history of thyroid tumors.
• Blood tests. Blood tests determine if the thyroid gland is functioning normally. In some people with thyroid cancer, blood tests may be useful in monitoring tumor extent and progression.
• Fine-needle aspiration. Fine-needle aspiration gathers cells to view under a microscope (biopsy) and is generally the first test to distinguish between benign and malignant tumors.
• Imaging tests. You may have one or more imaging tests, such as X-rays, magnetic resonance imaging (MRI), computerized tomography (CT) scans, positron emission tomography (PET) or ultrasound. These tests can help detect whether the cancer has spread. In tests that involve radiation, specialists carefully monitor doses to avoid the risk of radiation overexposure.
• Genetic testing. Thyroid cancers are most often not inherited, but some people with medullary thyroid cancer may have genetic changes that can be associated with other endocrine cancers. Most people with medullary thyroid cancer and their families should undergo genetic testing.

Read more about magnetic resonance imaging (MRI), computerized tomography (CT) scans, positron emission tomography (PET) and ultrasound.