Medullary Thyroid Cancer: Long-Term Follow-Up
Medullary Thyroid Cancer Long-Term Follow-Up: Why Do I Need It?
You may have heard or experienced one of the following:
- You didn’t know you had medullary thyroid cancer until after your thyroid surgery.
- Your medullary thyroid cancer was not completely removed (this is called persistent medullary thyroid cancer).
- Your medullary thyroid cancer has come back! (this is called recurrent medullary thyroid cancer).
- Your medullary thyroid cancer is located in other sites of your body other than your neck (this is distant spread of your cancer or distant metastases)
- You had a medullary thyroid cancer and underwent removal of all of your thyroid gland-called a total thyroidectomy.
- Your blood marker for your medullary thyroid cancer (called calcitonin) is detectable or elevated.
- Your blood marker for your medullary thyroid cancer (called CEA) is elevated.
If you had a medullary thyroid cancer and completed all of your treatment (s), life-long follow-up is strongly encouraged among all experts in thyroid cancer for three reasons:
- To make sure that your thyroid hormone levels in your blood are at the right level for you! 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 medullary thyroid cancer was completely removed. If medullary thyroid cancer is still evident in your neck following your initial surgery, this is called persistent medullary thyroid 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 medullary thyroid cancer is likely much more likely than the more favorable thyroid cancers to be persistent. Persistent medullary thyroid cancer in the neck is largely preventable in almost all patients. After the initial medullary thyroid 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 medullary thyroid cancer. We have written a complete section on persistent medullary thyroid cancer just for you so you can understand this issue and how best to approach it.
- To determine whether your medullary thyroid cancer has come back. If your medullary thyroid cancer has been gone for a period of time and comes back, this is called recurrent medullary thyroid cancer. We have written a complete section on recurrent medullary thyroid cancer just for you. Important questions that need to be asked:
- How old are you?
- How long do you know the cancer has been there?
- Where has the recurrent medullary thyroid cancer found?
- What treatment (s) have you had for your medullary thyroid cancer?
For medullary thyroid cancer patients with recurrence in the sides of the neck or recurrences in the central area of the neck which are invading the soft tissues of the breathing tube or swallowing tube, are significantly associated with the risk of the medullary thyroid cancer to spread to distant sites. It is possible that early diagnosis and effective definitive treatment of recurrent medullary thyroid cancer may effect the patient’s ability to be cured and survive their cancers. Therefore, early diagnosis of recurrent medullary thyroid cancer is very important.
Medullary Thyroid Cancer Patient Follow-Up-Who Should Do It?
The medullary thyroid 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 medullary thyroid cancer patient are truly experts in the management, evaluation, and treatment of the disease. The Clayman Thyroid Cancer Center believes that the medullary thyroid cancer patient follow-up is best managed by an endocrinologist with defined expertise in the evaluation, management, and follow-up of medullary thyroid cancer patients. Communication between the interdisciplinary team of endocrinologists, surgeons, radiologists, geneticists, counselors and other members of the medullary thyroid cancer team is critical. This is the absolute foundation of the Clayman Thyroid Cancer Center approach.
Medullary Thyroid Cancer Follow-Up: Factors Influencing How Often and What Studies Should Be Obtained
Medullary thyroid cancer patients who have completed treatments, the timing of follow-up appointments and the types of studies obtained in the follow up of their medullary thyroid cancer depends upon:
- The medullary thyroid cancer treatment(s) the patient received.
- Whether the medullary thyroid cancer patient was ever considered free of disease.
- What was the lowest amounts that were achieved in the blood tests for post operative calcitonin and how has it changed?
- What was the lowest amounts that were achieved in the blood tests for post operative CEA and how has it changed?
- The medullary thyroid cancer pathology (What was found when looking under the microscope at the medullary thyroid cancer surgery specimen)? We have written a whole section on this for you to better understand your follicular thyroid cancer. This is called Pathology of Medullary Thyroid Cancer Staging (TNM staging)
- How big was the medullary thyroid cancer within the thyroid gland?
- Did the medullary thyroid 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)
- The nerve to the voice box
- Did the medullary thyroid cancer grow into blood vessels or lymphatic vessels?
- Did the medullary thyroid cancer grow into nerves or other nearby structures?
- Did the medullary thyroid cancer spread into neck lymph nodes?
- The lymph nodes along the breathing tube or swallowing tube- called the central compartment lymph nodes?
- The lymph nodes on the side of the neck- called the lateral neck?
- Did the medullary thyroid cancer spread to other areas of the body outside of the neck? Meaning is there distant spread of the cancer?
- Other sites
- If it did grow out, what did it grow into?
Medullary Thyroid Cancer Follow-Up: How Frequent and What Studies Should Be Obtained
Follow-up of medullary thyroid 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.
The following section in a yellow box!!!!
Every medullary thyroid cancer patient should have the following examinations included in generally every follow-up appointment:
- 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 medullary thyroid cancer)
- Blood tests for :
1) Free T4 level
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.
2) TSH (Thyroid Stimulating Hormone)
The risk of the medullary thyroid cancer coming back or spreading has likely no relationship, whatsoever, to the TSH level since the parafollicular C cells of the thyroid do not have a “receptor” for TSH (unlike the follicular cells of the thyroid which give rise to the more common papillary thyroid cancers and follicular thyroid cancers). Therefore, the goal for initial TSH level usually be 0.5 to 2.0 mU/L, which is within the normal range. Obviously, the endocrinologist also wants their patients to feel well and normal and thus some adjustments are sometimes made to optimize patient’s sense of well being.
Calcitonin is a protein produced by parafollicular C cells of the thyroid that can be measured in your blood. After removal of the entire thyroid gland, calcitonin can be used as a "cancer marker." Its number should be as low as possible. Sometimes this is termed "undetectable.” After your surgery, because of the long half life of this protein, most thyroid cancer experts wait about three months to determine the first baseline level.
A detectable calcitonin test indicates that either medullary thyroid cancer cells or normal thyroid parafollicular C cells are still present in your body. Actually, even a third possibility exists because some other tumors can also potentially produce calcitonin including the neuroendocrine tumors of the adrenal and pancreas organs as well as some bowel tumors. Depending on the level of calcitonin in your blood, your doctor may want to monitor you more closely with other tests or scans and/or prescribe additional treatment.
- CEA (carcinoembryonic antigen)
CEA is a protein produced by neuroendocrine carcinomas, the category to which medullary thyroid cancer belongs. Other neuroendocrine derived normal cells of the body also produce this protein thus it is not anticipated that CEA will ever be unpredictable.
Several other tumors, both benign and cancerous can also produce CEA. Significantly increasing CEA levels in relation to calcitonin levels, in medullary thyroid cancer patients, is considered a general adverse predictor of a more aggressive cancer. Depending on the level of CEA in your blood, your doctor may want to monitor you more closely with other tests or scans and/or prescribe additional treatment.
Medullary thyroid cancer patients with medium risk or high risk of their cancer recurring may require additional studies including:
- CT scanning of the neck, chest, and abdomen
CT scanning of the neck is obtained for medullary thyroid cancer patients when there have been surgical or pathology findings of the medullary thyroid cancer which suggest a high risk of recurrence in locations that ultrasound has limitations. This includes the voice box (larynx), trachea (breathing tube) and esophagus as well as deeper structures in the neck and below the collar bones or chest wall. CT scan of the neck should be obtained with contrast otherwise its use is extremely limited.
In medullary thyroid cancer patients with extensive angioinvasion (blood vessel invasion) or soft tissue extension or the history of 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 calcitonin or CEA levels are shown to be increasing during the period of follow-up or recurrence is ever discovered.
- PET/CT scanning
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. Medullary thyroid cancer is not always a routine cancer that will be PET positive. Medullary thyroid cancer follow-up may include this scan when there is:
- an “angry appearing” medullary thyroid cancer under the microscope
- distant spread in the body of the medullary thyroid cancer
- neck recurrence of the medullary thyroid cancer
- significant elevation of calcitonin levels above what would be anticipated for the known disease
- when there is known recurrent cancer but no detectable thyroglobulin.
- MRI scanning
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 medullary thyroid cancer in those sites. This study does not produce any radiation effect and is given with an intravenous contrast agent called gadolinium