Medullary Cancer

Medullary tumors are the third most common type of thyroid cancer.

In contrast to follicular and papillary thyroid cancers, medullary cancers arise from the parafollicular cells (also called C cells) of the thyroid. The aforementioned thyroid cancer types arise rather from thyroid hormone producing cells. These C cells, from which medullary cancers arise, make a different hormone. This hormone is called calcitonin. This hormone has nothing to do with regulating the metabolism the way thyroid hormones do. The production of this particular hormone, calcitonin, may be measured after surgery to see if there is any indication of the cancer still present or growing. Medullary cancer has a low cure rate when compared to papillary and follicular cancer, which are far more differentiated or distinct. When the entire disease is confirmed to have not spread beyond the thyroid gland a 10-year survival rate can be expected with up to 90% certainty. If the disease has spread to cervical lymph nodes then a 10-year survival rate can be expected with up to 70%. It becomes a 20 % certainty if the disease has been diagnosed in distant areas.

Characteristics of Medullary Thyroid Cancer

Medullary Thyroid Cancer Occurs in Four Clinical Settings:

1. Sporadic- The onset of the disease occurs in the 40 – 60 years of age group. Occurs more in females than males by a ration of 3 to 2. This setting accounts for approximately 80% of all the cases of medullary thyroid cancer. Typically unilateral and not connected to any presence of the disease in other endocrine glands. One third of the patients will be present with intractable diarrhea. Diarrhea is brought on by increased gastrointestinal secretions and excessive movement due to hormones that are secreted by the tumor.

2. MEN 2A (also referred to as Sipple Syndrome). Multiple endocrine neoplasia syndromes are a group of disorders associated with the endocrine system. These disorders occur together and are usually inherited. A “syndrome" is a medical condition which occur in groups of three. Sipple syndrome or MEN 2A has:

This syndrome is inherited due to a defect in the DNA that plays a part in controlling the healthy growth of the endocrine tissues. The syndrome is then passed on to the children who inherit the gene. This would be about 50% of all offspring of a patient with the defect in the gene or DNA. Due to this fact, males and females are affected equally. Peak occurrences of medullary cancer in these patients occur between those that fall between the ages of 30 and 40 years.

3. MEN 2B. This syndrome also has:

Instead, these patients have an unusual appearance, which is characterized by tumors inside the mouth. This is referred to as mucosal ganglioneuromas and a Marfanoid habitus. Inheritance is autosomal dominant or non-sex determining (as in MEN 2A) can present itself sporadically. It does not have to be inherited. MEN 2B patients normally get medullary cancer in their 30's. The ration of men to women that contract the disease is equal. Pheochromocytomas has to be detected prior to any surgery. The aim is to remove the pheochromocytoma first in order to eliminate any risk of severe hypertensive episodes (as in severe increase in blood pressure) while operating on the thyroid or the parathyroid.

4. Inherited medullary carcinoma (without any associated endocrinopathies. This type of medullary cancer is the least malignant. Like the other types of thyroid cancer, peak occurrence is between age 40 and 50.

Medullary Thyroid Cancer Management

When compared to papillary and follicular thyroid cancer, there is less controversy regarding management and treatment of the medullary type of thyroid cancer. Once and endocrinologist has assessed treatment for any associated endocrine condition, the general practice is for all patients receive a complete or full thyroidectomy. This is a total removal of lymph nodes and fatty tissues located in the central part of the neck or the side of the neck where tumors may have been found.

The Use of Radioactive Iodine Post-Operatively

Thyroid cells are the only type that can absorb iodine but medullary thyroid cancer does not spring from thyroid cells. Due to this fact, radioactive iodine therapy would be useless as a form of treatment for medullary thyroid cancer. In addition, if the medullary cancer should spread to distant areas in the body iodine scanning will never find the cancer cells it in the same way it can be found in patients who have papillary or follicular cancer that spreads.

The Long-Term Follow Up

All patients should receive an annual chest x-ray. They should also get calcitonin levels checked. Serum calcitonin is extremely helpful in follow up appointments for medullary thyroid cancer sufferers because they aren’t any other cells in the body that can make this hormone.

If the serum calcitonin level is high when it had previously been low after surgery to remove cancerous parts of the thyroid, then this is indicative of possible recurrence. Surgery can remove the entire thyroid and lymph nodes in the neck area, which still show signs of the cancer. In the best-case scenario, post-surgery calcitonin levels drop to zero. However, this is often not the case. Calcitonin levels will remain elevated, but not as high as before surgery. Calcitonin levels should be checked every 6 months. If they start to rise, a more thorough examination is required for diagnosis as to the source of the rising level.