Thyroid Cancer Diagnosis
Tests and Exams to Diagnose Thyroid Cancer
In order to accurately diagnose and treat thyroid cancer, your doctor thoroughly reviews your complete medical history, which may include information about family members who may have had a thyroid cancer, benign tumor, or multiple endocrine neoplasia. The doctor performs a physical examination and orders tests such as blood work.
During the physical exam, the doctor palpates (feels) your neck, which may require you to swallow and flex and bend your neck. He or she will pay particular attention to the thyroid gland and surrounding tissues, such as the lymph nodes. The number, size, shape, and firmness of the nodule(s) are carefully examined. The doctor correlates the physical findings with your medical history and reported symptoms, such as pain or hoarseness.
Fact: The American Thyroid Association reports that while thyroid lumps (nodules) are common, fewer than 1 in 10 is cancer. 1
Family History as Part of Thyroid Cancer Diagnosis
If you have a family history of medullary thyroid cancer, the doctor will test your blood calcitonin and calcium levels. Calcitonin is a hormone important to calcium and phosphorus metabolism and bone growth. An elevated calcitonin level can indicate cancer.
Laboratory Tests to Diagnose Thyroid Cancer
Blood is drawn to test your thyroid gland function. Results from a thyroid-stimulating hormone (TSH) test either confirms or rules out hypothyroidism (too low) or hyperthyroidism (too high) levels. If your thyroid gland does not function normally, a T3 or Free T3 (triiodothyronine) and T4 (thyroxine) test is run to determine your thyroid hormone activity levels. It is important to remember that thyroid function tests are not indicators of thyroid cancer and most people with thyroid cancer have normal thyroid function.
A thyroid scan, or nuclear medicine scan, tests the gland's function. After a radioactive tracer is injected, a special camera captures images of the thyroid gland and measures the amount of dye the gland (nodules) absorbs.
Normal and abnormal test results are reported as functioning (normal), cold (underactive), or hot (overactive). Suspicious cold nodules can be further evaluated by a procedure called fine needle aspiration (needle biopsy). Hot nodules do not generally require biopsy.
Ultrasound Guided BiopsyFine Needle Aspiration (FNA)
Fine needle aspiration (FNA) is one way of diagnosing thyroid cancer. A local anesthetic may be injected into/around the neck area. Using ultrasound to guide needle placement, your doctor takes several samples of the nodule or tumor. The samples are sent to pathology for microscopic evaluation.
Some fine needle aspiration biopsy results are indeterminate. This means it is not exactly known if the nodule or tumor is benign (noncancerous) or malignant (cancer). To help patients avoid unnecessary thyroid surgery, new molecular testing (gene expression classification) may be performed to help confirm an accurate diagnosis.
Undergoing FNA can be a distressing time for patients. Questions you may want to ask your doctor can help put your mind at ease.
- Where will my FNA be performed?
- How long does the test take?
- Is FNA painful?
- How many of these procedures do you performed each month?
- What are the risks? Bleeding, infection?
- Should I stop taking any over-the-counter or prescription medications before the test?
- How soon until I have the results of the test?
- If I have thyroid cancer, what's next?
Results from imaging studies may assist your doctor in confirming your thyroid cancer diagnosis. Different types of imaging studies include x-ray, computed tomography (CT scan), magnetic resonance imaging (MRI), and positron emission tomography (PET scan).
Depending on your tumor's characteristics, and the close proximity of your thyroid gland to your voice box (larynx), your doctor may recommend laryngoscopy. A laryngoscope is a lighted and flexible tube with magnification used to examine your larynx.
After your doctor has evaluated each piece of information about your health, including test results, he makes his diagnosis and outlines a treatment plan for your thyroid cancer.