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Advanced Thyroid Cancer

Diagnosing Advanced Thyroid Cancer

Getting to a diagnosis begins with a history and physical examination. If a thyroid lump has been present for a long time and it is getting larger, you’re having difficulty breathing, your vocal cords aren’t moving so well or anything in your history and physical exam raises the suspicion for thyroid cancer, your doctor should consider the possibility of starting a cancer work-up. As with most cancers in the head and neck, this will include some combination of biopsy and imaging tests.

Imaging

Imaging refers to radiologic studies, or scans, that create pictures of the structures (and even function) inside your head and neck. They give more information about the tumor location and possible spread to regional lymph nodes. Spread into other structures will influence what treatment your doctor recommends for you.

The two main techniques of cross-sectional imaging used in the U.S. are computed tomography (CT) scans and magnetic resonance imaging (MRI) scans. However, for thyroid cancer, the main imaging modality is ultrasound. Ultrasound is a quick and inexpensive way to get information about nodules in the thyroid gland and/or in the neck. For thyroid cancer, ultrasound is the preferred method to evaluate the thyroid gland (along with the lateral compartments of the neck to look for lymph nodes). This might be followed by either a CT scan or an MRI if necessary. PET scans are studies that look at the function of cells in the body, and they are being used more and more in oncology. PET scans can be combined with other imaging methods such as CT scans to get more information. PET scans are not used very often in thyroid cancer (see below).

Thyroid and neck ultrasound (including the lateral and central compartments): An ultrasound is a way to look at vessels surrounding and inside of thyroid nodules, structures and lymph nodes all over the body, particularly in the neck and thyroid gland. You are not exposed to any radiation, and it doesn’t hurt.

A technician or a radiologist will place some cold jelly over the area to be examined and rub a plastic probe over the area to take pictures. The technician can see enlarged lymph nodes and nodules deep in the neck, and he or she can even describe details about them, such as whether they have fluid inside, have many blood vessels around or there is evidence of calcium deposits.

At the same time as he or she is performing an ultrasound, the doctor can place a needle into a lymph node or nodule and draw off cells (this is an ultrasound-guided biopsy).

CT scan: This is a quick series of X-rays that can show very good detail of the anatomy. It is helpful in seeing the extent of the main tumor mass and what structures it has invaded. It can also help pick up spread into the neck.

  • Advantages: A CT scan is a quick test that is readily available and gives a great deal of useful information.
  • Disadvantages: A CT scan involves radiation, and the images can be degraded by movement and dental work. It only shows late changes associated with invasion into nerves (such as destruction of the bone where the nerve enters the skull).
  • Important points: A CT scan looking for throat tumors should be done with contrast injected into your veins, unless there is some reason that you cannot receive contrast.
  • What to expect: First, a nurse will insert an intravenous line into a vein to allow for contrast injection. Then you will have to lie flat on a table with your head in a little holster to help keep it totally still. CT scans are typically open, so you shouldn’t feel enclosed. You will then get an injection of contrast, and soon after, the scanner will start moving and taking pictures; this part should take only one or two minutes. Try not to swallow, speak or move during this quick test.

MRI: This test uses magnets to create a picture of the inside of the neck. It is good for showing more subtle details of how extensive the main tumor mass is. It can also help pick up spread of cancer to lymph nodes in the neck.

  • Advantages: There is no radiation involved, and the details of the soft tissues are better than that of a CT scan.
  • Disadvantages: An MRI takes much longer than a CT scan and is more expensive. Some people feel enclosed inside the MRI machine. Images can be degraded with movement and dental work. There can be loud banging inside the machine, which can be uncomfortable.
  • Important points: This test should be done with and without contrast injected into your veins, unless there is some reason you can’t have contrast. Closed MRI machines usually give better pictures than open MRI machines.
  • What to expect: First, a nurse will insert an intravenous line into a vein to allow for contrast injection. Then you will have to lie flat on a table with your head in a holster to help keep it totally still. You will then enter the scanner, and the MRI machine will start moving and taking pictures. This can take 30 to 60 minutes, depending on how the scan is done. Try to stay as still as possible throughout the test. If you are prone to claustrophobia, you should ask your doctor to prescribe a sedative to help you relax.

Positron Emission Tomography (PET): Doctors are still studying the most appropriate uses of PET scans for head and neck cancer. Currently, the main uses of PET scans are to see if there is spread to sites in the neck or other parts of the body or to help find a primary tumor when the only evidence of cancer is a lymph node that has cancer in it. It is often combined with a CT scan (or in some cases an MRI) to help pinpoint the location of active cells. PET scans are not used in the vast majority of thyroid cancers because well-differentiated thyroid cancers are not very active and don’t light up like other cancers. In cases of rare, aggressive thyroid cancers, your doctor might consider a PET scan.

Neck ultrasound: An ultrasound is a way to look at vessels, structures and lymph nodes all over the body, particularly in the neck and thyroid gland. You are not exposed to any radiation, and it doesn’t hurt. Basically, a technician or a radiologist will place some cold jelly over the area he or she is examining and rub a plastic probe over the area to take pictures. The technician can see enlarged lymph nodes and nodules deep in the neck and describe details about them such as whether they have fluid inside, have a lot of blood vessels around and so on. At the same time as he or she is performing an ultrasound, a doctor can place a needle into a lymph node or nodule and draw off cells (this is an ultrasound-guided biopsy).

Radioactive iodine test: In this test, you will be given a drink of radiolabeled iodine. Depending on the form of radioactive iodine given to you, the test will either be used for diagnosis of thyroid cancer cells in your body or for treatment of thyroid cancer cells all over your body. If you previously had a CT scan with contrast for evaluation of the thyroid cancer before surgery, your doctors will delay administering radioactive iodine to help with its accuracy. Radioactive iodine is not generally administered prior to thyroid cancer surgery because the thyroid gland will take up most of the radioactive iodine, and the scan will not be as good as finding small areas of thyroid cells in other parts of your body. Therefore, this is used in cancer only after a total thyroidectomy.

Chest X-ray: This is a quick, inexpensive and easy way to look for signs of spread of cancer into the lungs or the possibility of a different cancer in the lungs.

Biopsy

A biopsy is the removal of a small piece of tissue to examine under a microscope to see if it is cancerous.).

Three ways to confirm a diagnosis of thyroid cancer are:

  • Biopsy of the thyroid gland
  • Biopsy of a neck lymph node
  • Removal of half your thyroid gland

The first type of biopsy should almost always be a fine needle aspiration biopsy [FNAB].

  • Fine needle aspiration biopsy: The most common and easiest way to biopsy is fine needle aspiration biopsy (FNAB), in which a tiny needle is placed into the tumor and some cells are drawn out through a syringe. The pathology doctor, known as a cytologist or cytopathologist, will then immediately look at the cells under the microscope and let your doctor know if there were enough cells to make a diagnosis. A number of “passes” might be done to increase the likelihood that there are enough cells to make a diagnosis. The final diagnosis may take a few days to come back, so be patient.

Different Types of Fine Needle Aspiration Biopsies

By Feel” FNAB Ultrasound-Guided FNAB
When your doctor might use this technique If the lump can be easily felt by your doctor If your doctor thinks it will be difficult to get the needle directly into the lump with certainty
What to expect Your doctor will feel the lump and place a tiny needle directly into it to extract some cells. Your doctor will use a gentle probe on your face or neck, identify the tumor with the ultrasound and then watch the needle go directly into the tumor on the ultrasound machine.
  • Core biopsy: Core biopsy is an alternative to fine needle aspiration. A core biopsy is done in the same way as an FNA biopsy, but it uses a larger needle and removes a core of tissue from the tumor rather than just a few cells. The likelihood of false positives and false negatives is much lower with a core needle biopsy than with a fine needle biopsy, but it is not always clear which patients should have core biopsies rather than FNA biopsies.
  • Open neck biopsy: An open biopsy involves making an incision over the tumor and removing a piece or all of the tumor to make a diagnosis. An open biopsy of a neck mass is performed through an incision over the lump, and either a piece (incisional open neck biopsy) or the entire lump (excisional open neck biopsy) is removed to make a diagnosis. Except in a few special circumstances (such as if the tumor is likely a lymphoma or if other methods of diagnosis have not worked), this method should not be used to find the diagnosis of a thyroid cancer.

Serology

Serology involves checking your blood for certain proteins.

Your doctor will probably perform a number of blood tests before and/or after diagnosis of thyroid cancer. These might include looking for antibodies that are a sign of auto-immune thyroid disease, thyroid stimulating hormone (which tells you of the functional status of your thyroid gland) and thyroglobulin.

If you have (or there is concern for) medullary thyroid cancer, your doctor will need to do a number of additional tests such as:

  • Calcitonin levels
  • CEA levels
  • Screening for other endocrine problems such as pheochromocytoma
  • Calcium levels
  • Genetic screening for certain mutations
References

1 SEER Fast Facts. http://seer.cancer.gov/statfacts/html/thyro.html Accessed February 2013.

2 Hundahl SA, Fleming ID, Fremgen AM, et al.: A National Cancer Data Base report on 53,856 cases of thyroid carcinoma treated in the U.S., 1985-1995. Cancer. 1998;83:2638-2648.

3 Salerno P, De Falco V, Tamburrino A, Nappi TC, Vecchio G, Schweppe RE, Bollag G, Santoro M, Salvatore G. Cytostatic activity of adenosine triphosphate-competitive kinase inhibitors in BRAF mutant thyroid carcinoma cells. J Clin Endocrinol Metab. 2010;95(1):450-455.

4 Referenced with permission from The NCCN Clinical Practice Guidelines in Oncology (NCCN Guidelines®) for Thyroid Carcinoma V.2.2013. © National Comprehensive Cancer Network, Inc 2013. All rights reserved. Accessed July 24, 2013. To view the most recent and complete version of the guideline, go online to www.nccn.org. NATIONAL COMPREHENSIVE CANCER NETWORK®, NCCN®, NCCN GUIDELINES®, and all other NCCN Content are trademarks owned by the National Comprehensive Cancer Network, Inc.

5 Cooper, D.S., G. M. Doherty, et al. (2009). “Revised American Thyroid Association Management Guidelines for Patients with Thyroid Nodules and Differentiated Thyroid Cancer: the American Thyroid Association (ATA) Guidelines Taskforce on Thyroid Nodules and Differentiated Thyroid Cancer.” Thyroid 19(11): 1167-1214.

6 Ries LAG, Young JL, Keel GE, Eisner MP, Lin YD, Horner M-J (editors). SEER Survival Monograph: Cancer Survival Among Adults: U.S. SEER Program, 1988-2001, Patient and Tumor Characteristics. National Cancer Institute, SEER Program, NIH Pub. No. 07-6215, Bethesda, MD, 2007.