Thyroid cancer affects approximately 60,000 Americans each year. Thyroid cancers are defined as either poorly-differentiated, which are highly aggressive, or well-differentiated, which respond well to treatment.
Well-Differentiated Thyroid Cancers
Papillary Thyroid Carcinoma
Papillary thyroid carcinoma accounts for approximately 85 percent of all well-differentiated thyroid cancers. This form of thyroid cancer is most often seen in women between 25 to 55 years of age. Additional risk factors include a family history of the disease as well as a history of radiation exposure. Symptoms typically include a palpable mass within the thyroid gland, hoarseness, difficulty swallowing, and shortness of breath. Treatment involves removing the thyroid gland followed by thyroid hormone replacement medication. Depending on the circumstances, removal of lymph nodes in the neck and follow-up radioactive iodine therapy may also be required.
Follicular Thyroid Carcinoma
This is the second most common form of thyroid cancer. It also affects more women than men but tends to occur in middle-aged individuals. Unlike papillary thyroid carcinoma, it rarely affects the lymph nodes, but it can spread to the bones or lungs. The treatments used to treat follicular thyroid carcinoma are essentially the same as those for papillary thyroid carcinoma.
Poorly-Differentiated Thyroid Cancers
Medullary Thyroid Carcinoma
Approximately 3 to 4 percent of thyroid cancers are medullary carcinomas. As many as one-quarter of these cancers are familial in nature, and they are often linked to other types of endocrine tumors. Anyone with this form of thyroid cancer should receive regular screenings for additional endocrine tumors. The most common symptom of medullary thyroid carcinoma is a palpable mass in the neck. In many cases, the cancer has spread to nearby lymph nodes by the time that the mass is discovered. Treatment involves removing the entire thyroid gland along with any affected lymph nodes. Radioactive iodine therapy is not used in treating this form of thyroid cancer.
Anaplastic Carcinoma
This highly aggressive form of thyroid cancer accounts for less than 2 percent of thyroid cancer diagnoses. Anaplastic carcinoma most often affects the elderly and typically involves the esophagus and other structures in the vicinity of the thyroid gland. The patient may present with a neck mass that is fast-growing along with hoarseness and difficulty swallowing and breathing. Because of the airway involvement, a tracheostomy may be necessary to enable the patient to breathe. Early-stage tumors may be treated with surgery or external beam radiotherapy.
Lymphoma
Less than 5 percent of thyroid cancers are attributed to lymphoma arising from the lymph nodes or the thyroid gland itself. The thyroid mass will typically be fast-growing, and the patient may present with hoarseness, a persistent cough, shortness of breath, and difficulty swallowing.
When diagnosed early through a CT or PET scan, primary lymphoma affecting the thyroid can often be cured with radiation or chemotherapy.
The majority of thyroid nodules are benign with carcinomas accounting for only 5 percent of nodules. Patients noticing a mass in their neck along with hoarseness or difficulty swallowing or breathing should consult an ear, nose and throat specialist to rule out malignancy and for appropriate treatment.