Thyroid Cancer

Thyroid cancer is the abnormal proliferation of malignant cells that begins in the thyroid gland. This gland, located at the base of the neck below the Adam’s apple, is responsible for producing essential hormones that regulate vital body functions such as growth, heart rate, blood pressure, weight, and body temperature.

Depending on the type of cells affected, the following types of thyroid cancer are distinguished:

• Differentiated thyroid cancer: This cancer originates in follicular cells, which produce and store thyroid hormones. Cancerous cells of this type have mature structures and functions, their microscopic appearance resembles healthy cells, and they tend to grow and spread more slowly.
• Papillary thyroid cancer: The most common type. It generally originates in a single lobe of the gland and often spreads to nearby lymph nodes. Nevertheless, it usually has a favorable prognosis.
• Follicular thyroid cancer: It rarely spreads to the lymph nodes but can metastasize through the bloodstream, affecting other parts of the body such as the lungs or bones. It also has a high cure rate.
• Hürthle cell cancer: A rare and aggressive thyroid cancer, making it more difficult to detect and treat.
• Medullary thyroid cancer: This type originates in the thyroid's C cells, which produce calcitonin, the hormone that regulates blood calcium levels. It can spread to the lymph nodes, lungs, or liver. A hereditary variant of medullary thyroid cancer exists.
• Anaplastic thyroid cancer (undifferentiated): A very rare, highly aggressive, and difficult-to-treat cancer. It sometimes originates from an existing papillary or follicular cancer.
• Thyroid lymphoma: A rare neoplasm that originates in the immune system cells within the thyroid and grows rapidly.
• Thyroid sarcoma: An extremely rare primary tumor with a tendency to metastasize to distant sites. It has a very poor prognosis.
• Parathyroid cancer: This cancer originates in the parathyroid glands, four small glands attached to the back of the thyroid that help regulate calcium levels. It is very rare.

Symptoms

Most thyroid cancers do not cause symptoms in the early stages. As the cancer grows, the following may occur:

• A hard lump (nodule) in the front of the neck. In some cases, it grows rapidly.
• Swelling in the lymph nodes.
• Neck and throat pain that may radiate to the ear.
• Hoarseness or other persistent voice changes.
• Difficulty swallowing and breathing.
• Persistent cough.

Causes

Thyroid cells begin to reproduce uncontrollably when a change or mutation occurs in their DNA, activating their reproductive process or disabling cellular destruction mechanisms. In hereditary medullary cancer, this is due to a mutation in the RET or BRAF gene. The exact cause of these mutations is unknown, but they are believed to be influenced by a combination of environmental and genetic factors.

Risk Factors

These conditions increase the likelihood of developing thyroid cancer:

• Age: In women, it typically occurs between 30 and 50 years old. In men, between 60 and 80 years old.
• Sex: Like most thyroid disorders, it is more common in women.
• Personal history of goiter.
• Family history of thyroid disease or thyroid cancer.
• Previous exposure to radiation.
• Iodine deficiency.
• Obesity.
• Hereditary disorders, such as multiple endocrine neoplasia, Cowden syndrome, Carney syndrome, or familial adenomatous polyposis.

Complications

Although thyroid cancer usually has a very good prognosis, complications may arise. These include:

• Recurrence: The cancer may return after treatment if it is an aggressive type or has spread. It typically reappears in the lymph nodes, in residual thyroid tissue left after surgery, in the lungs, or in the bones.
• Metastasis: Although uncommon, thyroid cancer can sometimes spread to the lymph nodes, lungs, bones, brain, liver, or skin, reducing the chances of a cure.

Prevention

The only effective way to prevent thyroid cancer is through genetic testing to confirm the presence of mutations in genes associated with medullary thyroid cancer. If a mutation is detected, surgical removal of the thyroid gland may be performed.

Which Doctor Treats This Disease?

Thyroid cancer is evaluated and treated by specialists in endocrinology, medical oncology, and radiation oncology.