Patient Info

Thyroid Cancers

Cancers that arise in the thyroid are categorized based on their histologic appearance. Pathologists examine thyroid cancer and are able to determine which category a particular tumor belongs to. The different forms of thyroid cancer have different clinical characteristics.

Learn about the major types of thyroid cancer and how new cancer drugs are developed. Expand your understanding of the importance of participation in clinical trials.

Anaplastic Thyroid Cancer (ATC)

Anaplastic thyroid cancer (ATC) is the rarest form of thyroid cancer, accounting for 1-2% of all thyroid cancer diagnoses. There are approximately 400-500 cases of ATC diagnosed annually in the United States. Patients with ATC generally present with a rapidly enlarging mass in the neck. Patients with ATC may experience difficulty breathing (due to tracheal invasion), coughing, changes or difficulty with swallowing, a change in their voice or hoarseness. Due to the aggressiveness of this cancer, ATC patients require urgent diagnostic evaluation and treatment planning by an experienced team of thyroid cancer specialists.

Anaplastic thyroid cancer is sometimes diagnosed from a fine needle aspiration biopsy but more commonly an excisional or core biopsy is needed to make a definitive diagnosis. Diagnostic evaluation by experienced endocrine pathologists is recommended due to the rarity of the disease and difficulty in making an accurate diagnosis. Furthermore, ATC can have many different synonyms such as “undifferentiated,” “sarcoma,” “sarcomatoid,” “squamous type,” and “spindle cell” thyroid cancer.

ATC patients often have disease that is advanced and a complete surgical resection may not be possible. It is important to have expert evaluation by a thyroid surgeon to make this decision. External beam radiation therapy is an important modality for patients with unresectable disease. Thyroid cancer treatment should be individualized by a team of specialists to ensure the best possible outcome. BRAF mutations are the most common mutation found in ATC tumors. Testing of the tumor to determine if there are genetic mutations, which can be targeted with chemotherapy should be considered.

Follicular Thyroid Cancer

The second most common form of thyroid cancer, this accounts for 5-10% of all thyroid cancer.

This form of thyroid cancer is more common among women and older adults. Iodine deficiency, which is common in developing countries, plays a role in the etiology of this cancer. With effective therapy, long term survival rates exceed 90-95% for most patients with this form of thyroid cancer. Follicular thyroid cancer arises from mutations in specific genes.

A FNA may suggest the possibility of a follicular cancer. Further testing using molecular diagnostics or surgery is often required to make a definitive diagnosis. Surgery is the mainstay of treatment for confirmed follicular thyroid cancer. Thyroidectomy should be performed by an experienced thyroid surgeon. Endocrinologists play a key role in diagnosing and managing patients with thyroid cancer. Most patients will require replacement therapy with thyroid hormone (T4) which requires monitoring.

Some patients may benefit from treatment with radioactive iodine. This decision is best made in consultation with an endocrinologist or nuclear medicine specialist. Follicular thyroid cancers usually produce thyroglobulin that can be measured by a blood test.

Up to 25% of patients with follicular thyroid cancer may have spread of disease (metastasis) to other parts of the body such as the lungs or bones. Some forms of follicular thyroid cancer, such as Hurthle cell carcinoma, are associated with more aggressive diseases. Patients with symptoms due to metastatic thyroid cancer or growth of thyroid cancer in other organs may benefit from consultation with a medical oncologist specializing in thyroid cancer and consideration of targeted therapy or participation in clinical trials.

Medullary Thyroid Cancer (MTC)

Accounts for 3-5% of all thyroid cancer cases. 20% of MTC patients may have hereditary disease, and all patients with newly diagnosed MTC should be tested for a germline mutation in the RET gene. 80% of MTC is sporadic and no other family members are at risk for disease.

Patients with MEN2 may have other non-cancerous medical conditions, such as over active parathyroid glands (hyperparathyroidism) or other endocrine cancers such as pheochromocytoma, and require evaluation for these conditions. Medullary thyroid cancer arises from mutations in specific genes, such as RET.

While MTC is occasionally diagnosed by fine needle aspiration of a thyroid nodule, many patients with sporadic MTC learn of the diagnosis after thyroidectomy. Surgery is the mainstay of treatment for medullary thyroid cancer. Thyroidectomy should be performed by an experienced thyroid surgeon. Endocrinologists play a key role in diagnosing and managing patients’ with thyroid cancer. Most patients will require replacement therapy with thyroid hormone (T4) which requires monitoring.

Radioactive iodine is not used for treatment of medullary thyroid cancer.

Medullary thyroid cancers usually produce hormone such as calcitonin and CEA that can be monitored by blood tests. Patients with persistently elevated calcitonin or CEA after thyroidectomy may have residual or metastatic disease.

The FDA has approved two targeted therapies for treatment of patients with progressive medullary thyroid cancer. Patients with metastatic disease should be followed by an experienced endocrinologist, oncologist, or surgeon. Some patients with medullary thyroid cancer may have distant spread of disease (metastasis) to lung, liver, or bones.

Papillary Thyroid Cancer

The most common form of thyroid cancer, accounts for 80-90% of all thyroid cancer. The incidence of papillary thyroid cancer is rising in the U.S. This form of thyroid cancer is more common among women. Radiation exposure during childhood is a risk factor for the development of this form of thyroid cancer. With effective therapy, long term survival rates exceed 95-98% for most patients with this form of thyroid cancer. Thyroid cancer arises from mutations in specific genes.

Papillary thyroid cancer is usually diagnosed by a fine needle aspiration biopsy of a thyroid nodule. Surgery is the mainstay of treatment for papillary thyroid cancer. Thyroidectomy should be performed by an experienced thyroid surgeon.

Endocrinologists play a key role in diagnosing and managing patients with thyroid cancer. Most patients will require replacement therapy with thyroid hormone (T4) which requires monitoring. Some patients may benefit from treatment with radioactive iodine. This decision is best made in consultation with an endocrinologist or nuclear medicine specialist. Papillary thyroid cancers usually produce thyroglobulin that can be measured by a blood test.

Some subtypes of papillary thyroid cancer, such as the tall cell variant, are more aggressive. Many patients with papillary thyroid cancer may have disease that has spread to lymph nodes in the neck. More rarely, papillary thyroid cancer can spread (metastasize) to other organs in the body, such as lungs and bones.

Poorly Differentiated Thyroid Cancer

This is an uncommon form of thyroid cancer, accounting for less than 5% of all cases. This form of thyroid cancer may co-exist with differentiated (papillary or follicular) thyroid cancer.

Poorly Differentiated thyroid cancer may be diagnosed from a fine needle aspiration biopsy of a thyroid nodule. Surgery is the mainstay of treatment for Poorly Differentiated thyroid cancer. Thyroidectomy should be performed by an experienced thyroid surgeon. Endocrinologists play a key role in diagnosing and managing patients with thyroid cancer. Most patients will require replacement therapy with thyroid hormone (T4) which requires monitoring. Some patients may benefit from treatment with radioactive iodine. This decision is best made in consultation with an endocrinologist or nuclear medicine specialist. Thyroid cancer treatment should be individualized by a team of specialists to ensure the best possible outcome. Poorly differentiated thyroid cancers may or may not produce thyroglobulin that can be measured by a blood test.

Poorly Differentiated thyroid cancer tends to be more clinically aggressive than differentiated thyroid cancers. It commonly spreads to regional lymph nodes, lungs, and bones. Poorly differentiated thyroid cancers may require treatment with external beam radiation therapy if they have spread to structures outside the thyroid.

Thyroid Cancer Clinical Trials

Clinical trials are carefully controlled experiments that are conducted to discover more effective therapies. Some patients with advanced disease may be candidates for participation in clinical trials. Physicians that specialize in care of patients with advanced thyroid cancer can help identify whether you may be an appropriate candidate for participation in a clinical trial. Consultation with a thyroid cancer specialist to consider new forms of therapy for thyroid cancer is encouraged for patients with advanced disease.

For more information visit www.clinicaltrials.gov