Medullary Thyroid Cancer
Medullary tumours are the third most common of all thyroid cancers – unlike differentiated thyroid cancer which usually affects women, medullary thyroid cancer (MTC) affects women and men equally. Unlike papillary and follicular thyroid cancers which arise from thyroid hormone producing cells, medullary cancer of the thyroid originates from the parafollicular cells (also called C cells) of the thyroid. These C cells make a different hormone called calcitonin which has nothing to do with the control of metabolism the way thyroid hormone does. This cancer has a much lower cure rate than does the “well differentiated” thyroid cancers (papillary and follicular), but cure rates are higher than they are for anaplastic thyroid cancer. Overall 10 year survival rates are 90% when all the disease is confined to the thyroid gland, 70% with spread to cervical lymph nodes, and 20 when spread to distant sites is present.
Types of Medullary Thyroid Cancer
Sporadic
- Sporadic medullary thyroid cancer is a non-hereditary type of medullary cancer, since there is no family history of medullary thyroid cancer
- This means that the patient who develops this disease will not pass it on to their children
MEN (Multiple Endocrine Neoplasia) associated
- MEN stands for Multiple Cndocrine Neoplasia, which are a group of tumours affecting hormone glands that are passed on from one generation to the next
- MEN associated medullary thyroid cancer usually occurs in younger patients
- Although there are several different types of MENs, MEN2A and MEN 2B are the ones associated with medullary thyroid cancer
- MEN 2A is a hereditary syndrome in which affected patients suffer from medullary thyroid cancer, tumours of the adrenal gland and tumours of the parathyroid glands
- MEN 2B patients usually have medullary thyroid cancer and tumours of the adrenal gland, but do not have problems with their parathyroid glands – instead these patients all have characteristic bumps (called mucosal neuromas) on the end of their tongue, the undersurface of the eyelid and throughout the gut. These patients also have thickened lips and eyelids
Familial
- The fourth type of medullary thyroid cancer is called familial type, which means that the thyroid cancer is passed genetically through a family, but not in association with the other endocrine tumors that occur in the MEN syndromes
- The non-MEN familial and the sporadic types occur usually in patients in their 40s or 50s
Treatment
- MTC tends to involve both lobes of the thyroid gland with multiple tumours in the hereditary forms of the disease, the operation of choice is a total thyroidectomy plus lymph node dissection both in the centre of the neck as well as the side(s)
- The best prognosis is associated with the familial form of the disease, the worst with the MEN 2B associated form, while the MEN 2A and sporadic forms have prognoses somewhere in between
- There is an 80% 10 year survival for the very earliest forms of disease that are confined to the thyroid gland without metastasis, but that figure drops to about 25% for patients whose disease has spread to lymph nodes or distant sites such as the lung, liver and bone
- For people who undergo thyroid surgery for C-cell hyperplasia (which is the precursor to medullary thyroid cancer), the survival is 100%. An important issue in the discussion of medullary thyroid cancer is the question of whether future family members may develop this form of cancer, since three out of the four types of medullary thyroid cancer are hereditary.
- After your operation, you will be followed by careful physical examination, as well as blood tests to determine your calcitonin and CEA levels – if these levels rise, a repeat operation may be needed when new neck lymph nodes have been invaded by cancer.
If you have any questions about thyroid symptoms or thyroid surgery, you should speak to your local doctor, who will arrange to contact your thyroid surgeon.
