Hurthle Cell Cancer Long-Term Follow-Up: Why Do I Need It?
- To make sure that your thyroid hormone levels in your blood are at the right level for you! It is possible you may not require any thyroid hormone pill or supplement, however most hurthle cell cancer patients during follow-up are maintained on thyroid hormone pills. There are several different types of thyroid hormone pills and you should discuss this with your endocrinologist to make sure that you are feeling well and your hormone levels are right for you. Your thyroid hormone should not be too low or too high for your specific needs. The amount of thyroid hormone that you may need may change throughout your lifetime due to many reasons including age, body weight, pregnancy, and more.
- To determine whether all of your hurthle cell cancer was completely removed. If thyroid hurthle cell cancer is still evident in your neck following your initial surgery, this is called persistent hurthle cell cancer. Unfortunately, this is more common than we would like to recognize. Persistent thyroid cancer occurs in nearly 11% of patients with the earliest forms of differentiated thyroid cancer (follicular thyroid cancer and papillary thyroid cancer). Persistent hurthle cell cancer is largely preventable in almost all patients. After the initial hurthle cell cancer surgery, determining whether there is persistent cancer can be difficult because of all the changes associated with the surgery and the healing process. Don’t worry and don’t be in a hurry! But don’t make the same decisions that lead you to this issue. Make sure your next evaluation and surgery is performed by a thyroid cancer team that is truly expert in evaluating and managing huthle cell cancer. We have written a complete section on persistent hurthle cell cancer just for you so you can understand this issue and how best to approach it.
- To determine whether your hurthle cell cancer has come back. If your hurthle cell cancer has been gone for a period of time and comes back, this is called recurrent hurthle cell cancer. We have written a complete section on recurrent hurthle cell cancer just for you. Important questions that need to be asked:
- How old are you?
- What does the hurthle cell cancer look like under the microscope?
- Where has the recurrent hurthle cell cancer been found?
- What treatment (s) have you had for your hurthle cell cancer?
Thyroid Hurthle Cell Cancer Patient Follow-Up-Who Should Do It?
The hurthle cell cancer patient follow-up can be performed by surgeons, endocrinologist, oncologists and others. But what is most important is that those individuals which are following the hurthle cell cancer patient are truly experts in the management, evaluation, and treatment of the disease. The Clayman Thyroid Cancer Center believes that the hurthle cell cancer patient follow-up is best managed by an endocrinologist with defined expertise in the evaluation, management, and follow-up of hurthle cell cancer patients. Communication between the interdisciplinary team of endocrinologists, surgeons, radiologists, and other members of the hurthle cell cancer team is critical. This is the absolute foundation of the Clayman Thyroid Cancer Center approach.
Hurthle Cell Cancer Follow-Up: What Factors Influence How Often and What Studies Should Be Obtained?
Hurthle cell cancer patients who have completed treatments, the timing of follow-up appointments and the types of studies obtained in the follow up of their hurthle cell cancer depends upon:
- The age of the hurthle cell cancer patient-when they were diagnosed.
- The hurthle cell cancer treatment(s) the patient received.
- The location(s) the hurthle cell cancer was found in the body.
- Thyroid gland only
- The soft tissues of the neck
- The neck lymph nodes only (rare)
- Sites outside of the neck (distant spread of the hurthle cell cancer).
- Whether the hurthle cell cancer patient was ever considered free of disease.
- The hurthle cell cancer pathology (What was found when looking under the microscope at the hurthle cell cancer surgery specimen)? We have written a whole section on this for you to better understand your hurthle cell cancer. This is called Pathology of Hurthle Cell Cancer Staging (TNM staging)
- How big was the hurthle cell cancer within the thyroid gland?
- What did the hurthle cell cancer cells look like under the microscope?
- Did the hurthle cell cancer grow out of the confines of the thyroid gland itself?
If it did grow out, what did it grow into?
- The muscle which lays over the thyroid gland?
- The breathing tube (trachea)
- The swallowing tube (esophagus)
- Did the hurthle cell cancer grow into blood vessels or lymphatic vessels?
- Did the hurthle cell cancer grow into nerves or other nearby structures?
- Did the hurthle cancer spread into neck lymph nodes?
- Did the hurthle cell cancer spread to other areas of the body outside of the neck? Meaning is there distant spread of the cancer?
- Other sites
Hurthle Cell Cancer Follow-Up: How Frequent and What Studies Should Be Obtained?
Follow-up of hurthle cell cancer patients is usually accomplished by an endocrinologist every six months for the first year and then annually thereafter if there is no evidence of disease.
- Free T4 level
- TSH (Thyroid Stimulating Hormone)
- Thyroglobulin antibody
Physical examination:This will include examination of the neck and thyroid bed and examination of the voice box if there is concern over changes in voice or swallowing
Ultrasound of the neck (see ultrasound of the neck for hurthle cell cancer)
Blood tests for:
This is the blood level of the major hormone normally produced by the thyroid gland. It is also a direct measurement of the most commonly prescribed thyroid hormone pill, levothyroxine. The dose of thyroid hormone pill will be based upon the blood thyroid stimulating hormone (TSH) level described below.
The potential risk of your hurthle cell cancer coming back or spreading will determine the amount of thyroid hormone that will be prescribed to you in the replacement of your thyroid hormone. The American Thyroid Association has guidelines for the blood level of TSH which should be sought based upon the risk of the hurthle cell cancer recurring. That risk may be low, intermediate or high risk and each is associated with a different range of TSH blood levels.
- In low-risk patients, the 2015 American Thyroid Association Guidelines recommend that the goal for initial TSH level usually be 0.5 to 2.0 mU/L, which is within the normal range. For some patients, the goal is 0.1 to 0.5 mU/L, which is just below or near the low end of the normal range.
- In intermediate-risk patients, the initial TSH goal is 0.1 to 0.5 mU/L. This goal may change to a normal range of TSH following long term follow-up and no detectable thyroglobulin.
- For high-risk patients, the thyroid hormone dose will be high enough to suppress the thyroid stimulating hormone (TSH) below the range that is normal for someone not diagnosed with hurthle cell cancer. The goal is to prevent the growth of hurthle cell cancer cells while providing essential thyroid hormone to the body. At first, TSH levels will probably be suppressed to below 0.1 mU/L. The level may later change to 0.1 to 0.5, depending on your body’s response to the treatment and time.
Thyroglobulin is a protein produced by thyroid cells (both hurthle cell cancer as well as normal cells) that can be measured in your blood. After removal of the entire thyroid gland, thyroglobulin can be used as a "cancer marker." Its number should be as low as possible. Sometimes this is termed "undetectable.” After your surgery with or without radioactive iodine, it may take months or even years for the thyroglobulin number to come down to zero or undetectable.
Generally speaking, hurthle cell cancers produce a lot of thyroglobulin. So for most hurthle cell cancer patients, thyroglobulin is a very effective tool to monitor for the prescence and the pace of persistent or recurrent disease. A detectable thyroglobulin test indicates that either hurthle cell cancer cells or normal thyroid cells are still present in your body. Depending on the level of thyroglobulin in your blood, your doctor may want to monitor you more closely with other tests or scans and/or prescribe additional treatment.
If you had a thyroid lobectomy rather than a total thyroidectomy, your remaining thyroid lobe will almost always produce some amount of Thyroglobulin. However, it may still be helpful to follow your Thyroglobulin levels over time. If significant changes in Thyroglobulin levels occur over time, your doctor may recommend further imaging studies to locate the source.
Not only do hurthle cell cancers produce thyroglobulin, they actually produce a lot of it compared to other thyroid cancers. Some thyroid cancers as they begin looking more angry under the microscope (called dedifferentiation or becoming poorly differentiated), they may lose the ability to produce thyroglobulin. Most hurthle cell cancers, however aggressive they may become, usually produce thyroglobulin and allow this blood measurement to be an effective means of monitoring their cancer.
From time to time, your doctor may recommend what is called a “stimulated Thyroglobulin” measurement. This means that your TSH is elevated, by withdrawal from thyroid hormone or by receiving injections of the drug called Thyrogen, and then your Thyroglobulin is measured. Thyroglobulin testing can be more accurate when your TSH level is elevated.
Some people produce a very large protein that for some reason recognizes the normal thyroglobulin protein as being “abnormal”. These very large proteins are called anti-thyroglobulin antibodies. These are not harmful but are a sign of an autoimmune disease where the body recognizes itself as being abnormal. The presence of Thyroglobulin antibodies makes Thyroglobulin a largely useless (insensitive) blood test for monitoring hurthle cell cancer. Sometimes the Thyroglobulin antibodies may disappear over time following surgery for hurthle cell cancer. Although that does not commonly occur even in hurthle cell cancer patients which are cured.
Hurthle cell cancer patients with medium risk or high risk of their cancer recurring may require additional studies including:
Radioactive Iodine Whole Body Scanning
This is generally performed with elevated blood levels of TSH. Elevated TSH levels can be obtained by withholding thyroid hormone and making the patient hypothyroid or by giving the patient TSH injections called Thyrogen. Both methods of raising TSH levels are equal in delivering radioactive iodine. A low iodine diet is required for at least two weeks before this examination.
CT scanning of the neck and or chest
In hurthle cell cancer patients with extensive angioinvasion (blood vessel invasion), soft tissue extension or spread to neck lymph nodes, above 50 years of age, a baseline CT scan of the chest should routinely be obtained and periodically re-examined approximately once annually. The baseline CT scan can be used in comparison if Thyroglobulin levels are shown to be increasing during the period of follow-up or recurrence is ever discovered.
A PET scan is a special imaging study using a specially designed sugar that “lights up” on nuclear imaging and when combined with a CT scan is called a PET/CT scan. PET/CT scan is expectantly useful for hurthle cell cancer follow-up when there is:
- an “angry appearing” hurthle cell cancer microscopically
- distant spread in the body of the follicular thyroid cancer
- neck recurrence of the hurthle cell cancer
- significant elevation of thyroglobulin levels above what would be anticipated for the known disease
- when there is known recurrent cancer but no detectable thyroglobulin.
MRI scanning is particularly beneficial for examination of the brain, spinal column, or bones when there has been a history or concern for involvement of hurthle cell cancer in those sites. This study does not produce any radiation effect and is given with an intravenous contrast agent called gadolinium. There is no iodine present in gadolinium and therefore it does not conflict with radioactive iodine scanning.