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Thyroid Cancer

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the remaining tissue, thus reducing the necessary dose. Therefore, total

thyroidectomy is the treatment of choice for follicular thyroid cancer.

Multifocal disease is less commonly seen in follicular carcinoma. Post-

operative treatment includes radioactive iodine and thyroid suppression.

Medullary Carcinoma

Medullary carcinoma accounts for 6–10 percent of all thyroid cancers.

There are

two forms: familial (10–20%) and sporadic.

In either case, the

parafollicular or C-cells

are the cells of origin, and the tumor tends to be

bilateral.

The familial form is a component of multiple endocrine neoplasms (MEN)

IIa and IIb. MEN IIa involves

parathyroid adenoma

, medullary carcino-

ma, and

pheochromocytoma.

MEN IIb does not have a parathyroid com-

ponent, but includes a

Marfanoid habitus

and mucosal neuromas. All

patients with medullary carcinoma should get a urinary

metanephrine

screen to determine whether there is an increase in circulating cate-

cholamines

If this test is positive, the pheochromocytoma should be locat-

ed and excised first. All

first-degree relatives

of patients with medullary

carcinoma should be tested for

calcitonin levels. Currently, it has been

demonstrated that the RET proto-oncogene is positive in most patients

with this disease. This oncogene can be detected by a blood test.

Surgical management of medullary thyroid cancer is somewhat conten-

tious. However, most surgeons elect to perform a total thyroidectomy with

paratracheal, central compartment neck dissections. In patients with a

neck mass, a modified neck dissection that encompasses all the involved

levels of disease should be performed. In patients with the familial form,

only abnormal parathyroid glands should be removed, but a total thyroi-

dectomy is always indicated. Thyroid C-cells do not absorb radioactive

iodine, so this common modality of adjuvant treatment in well-differenti-

ated thyroid cancers is seldom effective.

Anaplastic Carcinoma

Anaplastic thyroid cancer is a rare, aggressive cancer with a very poor

prognosis. The role of the surgeon is often limited to establishing diagno-

sis through open biopsy and securing the airway, which usually involves a

tracheotomy. These tumors are rarely resectable, and are often treated with

external beam radiation and systemic chemotherapy, since 50 percent of

patients will have pulmonary metastases at the time of diagnosis.