Thyroid Cancer Diagnosis
Getting an accurate diagnosis is the first step in successful thyroid cancer treatment. At MD Anderson¡¯s Endocrine Center, our experts are among the most experienced and skilled in recognizing, staging and treating thyroid cancer.
Most cases of thyroid cancer are found by chance during routine medical imaging. If an image shows a growth on the thyroid your doctor will conduct a thorough exam. This involves asking questions about your symptoms, overall health and your family¡¯s medical history. If anyone in your family has had thyroid cancer, parathyroid disease or adrenal tumors, be sure to tell your doctor.
One or more of the following tests may be used to find out if you have cancer and if it has spread. These tests may also be used to find out if treatment is working.
Imaging exams: Imaging exams allow doctors to look inside the body for cancerous growths. Ultrasound is the most common exam used to help diagnose thyroid cancer. Other imaging techniques, such as CT and PET scans, may be used after a diagnosis to determine the extent of the disease. These additional exams are usually ordered when an aggressive form of thyroid cancer has been found.
Biopsy: During a biopsy, a small tissue sample is removed and examined under a microscope for cancer cells. This is the only way to definitively diagnose thyroid cancer. Doctors may order a biopsy when an initial imaging exam shows a growth on the thyroid, called a nodule.
Thyroid biopsies are performed by a radiologist using ultrasound to guide a needle to the thyroid nodule. The patient receives local anesthesia. Only around 12% of thyroid nodules that are biopsied are cancer. The rest are benign (not cancerous) growths.
Radioactive iodine thyroid scan: In the case of well differentiated thyroid cancer, a radioactive iodine thyroid scan may be used after thyroid surgery. This helps determine if any cancer remains or has spread to other parts of the body. During this procedure, the patient takes a liquid form of radioactive iodine (usually contained in several capsules). Since thyroid cells absorb iodine, they can then be identified using a scanner similar to a Geiger counter. Neither medullary thyroid cancer nor anaplastic thyroid cancer absorbs iodine, so this test is not useful for those diseases.
Blood tests: When thyroid cancer is suspected, doctors typically test the hormones related to thyroid function. This can help them understand the nature of the suspected cancer, the health of the thyroid gland itself and the effects of future treatment. The thyroid gland¡¯s ability to function properly is not necessarily impacted by the presence of thyroid cancer, though. People with thyroid cancer usually have a normally functioning thyroid. Most people with abnormally functioning thyroid glands do not have thyroid cancer.
Genetic testing: People with medullary thyroid cancer should undergo a blood test to determine if they carry a genetic mutation that causes the hereditary form of the disease. If the test is positive, the patient¡¯s children, siblings and parents may also have the mutation. They should be tested, too. More than 90% of people who have the genetic mutation will eventually develop the hereditary form of medullary thyroid cancer.
If a child has the gene, doctors often suggest removing the thyroid. Although children rarely develop MTC before age five, one type of hereditary MTC can occur within the first year of life. Doctors will help determine the best time for surgery. If the thyroid is removed, that person will need to take thyroid medication daily for the rest of his or her life.
Genetic testing of the tumor and blood can also be used to identify treatment options, including clinical trials, for patients with aggressive thyroid cancers. These include medullary thyroid cancer, poorly differentiated thyroid cancer and anaplastic thyroid cancer.
Thyroid biopsy: Purpose, process and recovery
The thyroid is a butterfly-shaped gland in the front of your lower neck. A thyroid biopsy is a procedure that helps diagnose or rule out thyroid cancer.
As an oncologic endocrinologist at MD Anderson, I often perform thyroid biopsies and order thyroid biopsies to be performed by radiologists. Here, I¡¯ll answer some of the most common questions I get about them.
Why would my doctor order a thyroid biopsy?
A doctor usually orders a thyroid biopsy?to evaluate a?thyroid nodule further. A thyroid nodule is a lump that grows within the thyroid gland.
When you have a thyroid biopsy, the doctor uses a small needle to remove a tissue sample from the thyroid nodule. The sample will then be examined to see if it¡¯s cancerous.
Can you see thyroid nodules?
It depends on the size of the nodule and where it¡¯s located in the thyroid gland.
A nodule on the front of the thyroid can pop out enough to be seen. But if the nodule is in the middle or the back of the thyroid, you won¡¯t be able to see it unless it grows large enough to push your whole thyroid out. In this case, it may look like an enlarged thyroid.
Typically, you can¡¯t see a nodule that is less than 1 to 2 centimeters in size. Thyroid nodules are often easier to see in people with a thin neck because there is less tissue covering the thyroid. People who have lost a lot of weight might notice a thyroid nodule for the first time.
Sometimes, doctors can feel a thyroid nodule during a physical exam. It¡¯s pretty common for thyroid nodules to be found incidentally when people have medical imaging done for an unrelated reason.
What can a thyroid biopsy tell you?
A thyroid biopsy can help diagnose thyroid cancer. It can also tell us if there is metastasis from cancer that started in another part of the body and spread to the thyroid.
Thyroid nodules are very common. Most of the time, they are not cancer. A thyroid biopsy could show other thyroid conditions, such as:
Hashimoto¡¯s disease
This is an autoimmune disease in which the immune system attacks the thyroid, resulting in an underactive thyroid.
Graves¡¯ disease
This is an autoimmune disease that causes an overactive thyroid, which means the thyroid makes too much hormone.
Thyroiditis
This is inflammation of the thyroid, which can cause an underactive or overactive thyroid.
What percentage of thyroid biopsies are cancerous?
MD Anderson pathologists will classify a thyroid sample in one of four broad categories:
- Benign: Noncancerous
- Malignant: Cancerous
- Insufficient: There was not enough of the sample to make a diagnosis.
- Indeterminate: We cannot tell whether it¡¯s cancer because it may have some uncommon features or abnormal cells, but not enough to make a cancer diagnosis.
At MD Anderson, 60% to 70% of our thyroid biopsies come back benign; 5% come back as cancerous. The other 25% to 35% are indeterminate.
We offer Rapid On-site Evaluation (ROSE), a practice that helps our pathologists ensure there is enough tissue to make a diagnosis. Using this method, pathologists analyze the sample immediately. If there is not enough sample to make a diagnosis, your doctor may obtain more sample tissue to make the diagnosis.
If biopsy results are indeterminate, your doctor may order molecular testing for gene mutations or fusions. This helps predict which nodules are cancerous versus noncancerous. Molecular testing has been found to reduce the number of unnecessary surgeries. If you have an indeterminate biopsy that is unlikely to be cancer, your doctor will continue to monitor the nodule.
What can I expect during a thyroid biopsy?
There¡¯s nothing specific you need to do to prepare for a thyroid biopsy. Tell your doctor if you are taking any blood thinners; they may want you to stop taking them before the biopsy. This is because blood thinners may increase the chance of bleeding during the biopsy, which can affect your results and increase the chance of bruising at the biopsy site.
The procedure
On the day of your appointment, you will go to the hospital or clinic and be asked to change into a gown. Then, you will lie down on your back, and the doctor will cleanse the skin over the thyroid gland with an antiseptic. The doctor will then put gel on your neck and use the ultrasound to find and measure the thyroid nodule. After that, the doctor will give a local anesthetic to numb the area.
Once the area is numb, your doctor will carefully put a small needle through your skin and into the thyroid nodule, using the ultrasound to guide them. The doctor will then use a syringe to take a small sample of cells from the nodule. This is called an ultrasound-guided thyroid biopsy. Most people do not feel pain during the procedure. After the needle is removed, your doctor will press on your neck and cover the area with a bandage or gauze. After that, you are free to go home.
Recovery after the procedure
We recommend leaving the bandage on for four hours. You should not shower or allow the area to get wet for 24 hours after the biopsy.
You can resume your normal activities the same day. If you have any pain once the anesthesia wears off, we recommend taking acetaminophen or applying an ice pack to the area for 20 minutes at a time.
Getting your results
A pathologist will analyze the sample, which can take a few days up to 2 weeks. Once the results are ready, the pathologist will share the results with your doctor. Your doctor will then go over the results with you. If the results show that the nodule is benign, your doctor will monitor it regularly to check for any changes. Your doctor may recommend another biopsy if the nodule grows, or if anything concerning is found.?
If the biopsy shows cancer, your doctor will discuss a treatment plan with you. When thyroid cancer is caught early, it is often successfully treated with surgery. In some cases, the plan may also include thyroid hormone therapy and radioactive iodine treatment. For more advanced thyroid cancer, your doctor may suggest targeted therapy, immunotherapy or external beam radiation therapy.
, is an oncologic endocrinologist who specializes in ultrasound-guided thyroid biopsies.
or call 1-877-632-6789.