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What is Medullary Thyroid Cancer?

Photo capture: thyroid gland

Medullary Thyroid Cancer, or MTC, is a rare form of cancer of the thyroid gland. This gland is part of the endocrine system as shown here. When there is no family history of the disease it is called sporadic MTC. 1 in 4 or 25% of cases of MTC occur as part of a rare disorder which can be passed down in families called Multiple Endocrine Neoplasia Type 2 (MEN2). All apparently sporadic MTC patients must be offered DNA screening (a gene test) in case theirs is the first case of a gene disorder in the family. AMEND has produced separate information booklets on the inherited forms of MTC (MEN2).

The thyroid gland is found at the front of the neck. This gland makes 3 hormones; thyroxine and tri-iodothyronine (essential for maintaining the body’s metabolism and mental and physical development), and calcitonin.

MTC starts in the C-cells of the thyroid which make the hormone calcitonin. An increase in the number of C-cells (C-cell hyperplasia) occurs before they become cancerous. MTC can spread to nearby lymph nodes. Even so, there may be no physical symptoms of this. As MTC grows, calcitonin levels increase.

If the thyroid and nearby lymph nodes are removed by surgery while the cancer is still contained within the thyroid (total thyroidectomy and central lymph node dissection), a patient is usually cured. If calcitonin levels are still raised after surgery, this shows that the cancer has spread (metastatic) or has not been completely removed. In this case further surgery and other therapies may be used to control it. As yet there is no complete cure for MTC that has spread; however, it is often slow-growing and can exist without symptoms for many years. Symptoms that develop can often be controlled by the use of radiotherapy, new drug therapies and very rarely chemotherapy (see How Is MTC Treated When It Has Spread?).

How is MTC Diagnosed?

In most cases, patients may notice a lump in the neck which was not there before, or this may be noticed by a partner or colleague. Sometimes MTC may cause diarrhea, although it is not immediately clear that this may be related to a problem in the neck. In some families there may be a history of MTC which warrants gene testing of other family members. A diagnosis of medullary thyroid cancer may be confirmed by a fine needle biopsy of the neck lump, and ultimately by surgery. A blood test to measure calcitonin is sometimes used to make the diagnosis of MTC, but levels may be raised for a variety of reasons other than MTC.

Children and MTC

It is rare for children to develop MTC. However, those that do should be seen by a genetics consultant to be tested for MEN2 (a disorder that can be passed down in families), as they are likely to have this condition and will need testing for other potential MEN-related problems. A referral to a genetics consultant at a Regional Genetics Service Centre should be made by your specialist or GP if appropriate.

For more information visit the AMEND website