Primary Care Otolaryngology

Thyroid Cancer

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.

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