Thyroid Cancer

What is thyroid cancer?

Thyroid cancer arises from genetic changes in the cells of the thyroid gland, which is located at the base of the neck. This gland is responsible for producing hormones that regulate metabolism, controlling important functions such as heart rate, body temperature, and the rate at which the body burns calories.

There are different types of thyroid cancer, classified based on the specific cells that become cancerous. The main subtypes include:

• papillary carcinoma: the most common type, accounting for about 80% of cases. It usually grows slowly and has a good prognosis
• follicular carcinoma: the second most common type, also tends to grow slowly. It is more likely to spread to other parts of the body compared to papillary carcinoma
• medullary carcinoma: accounts for about 4% of cases and may be hereditary (common in the same family). It is associated with specific genetic mutations
• anaplastic carcinoma: very rare and aggressive, representing about 2% of cases. It grows rapidly and is more difficult to treat
• thyroid lymphoma: rarer and develops in immune system cells within the thyroid

Each type of thyroid cancer has different characteristics and behaviors, which influence treatment and prognosis. Therefore, it is important to be evaluated by a healthcare professional.

Symptoms

Thyroid cancer symptoms can vary, and often the disease may not present symptoms in its early stages. Some common signs include:

• neck lump: presence of a lump or swelling in the neck area, which may be palpable or identified through imaging tests
• neck pain: which may radiate to the ears
• hoarseness: changes in the voice, including persistent hoarseness
• difficulty swallowing: a feeling of tightness when swallowing
• difficulty breathing: a sensation of shortness of breath or noisy breathing
• persistent cough: not related to a cold or other common illness

Causes

Several factors may contribute to the development of thyroid cancer. The main ones include:

• radiation exposure: exposure to high levels of radiation, such as X-rays, especially during childhood
• family history: having a family history of thyroid cancer or associated genetic syndromes (such as multiple endocrine neoplasia type 2 – MEN2, familial adenomatous polyposis, Werner syndrome, or Cowden syndrome)
• age and gender: women and individuals over the age of 40 are at higher risk
• previous thyroid conditions: conditions such as goiter and thyroid nodules may increase the risk

Diagnosis

Diagnosing thyroid cancer usually involves a series of tests and procedures, such as:

• physical examination: palpation of the neck area to check for nodules or swelling
• ultrasound: an imaging test that uses sound waves to visualize the thyroid and identify nodules, as well as their size and blood flow
• fine-needle aspiration biopsy (FNAB): a procedure that removes a sample of cells from the nodule for laboratory analysis
• blood tests: to measure hormone levels and substances that may indicate the presence of a tumor (tumor markers)
• thyroid scintigraphy: determines the functional status of a nodule. Patients with multiple thyroid nodules may benefit from this test to identify those that are underactive (hypofunctioning) and therefore candidates for FNAB
• CT scan and MRI: imaging tests used to assess the extent of the disease and check for metastases (spread of cancer to other organs)
  
   

Treatment

The treatment of thyroid cancer depends on the type and stage of the disease, as well as the patient’s overall health. The main treatment options include:

• surgery: partial removal (lobectomy) or total removal of the thyroid gland (thyroidectomy)
• radioactive iodine therapy: a treatment that uses radioactive iodine to destroy any remaining thyroid cells after surgery
• hormone therapy: the use of synthetic hormones to replace natural ones and suppress the production of thyroid-stimulating hormone (TSH), which could encourage cancer growth
• radiation therapy: the use of high-energy radiation to destroy cancer cells, typically used in more advanced cases
• chemotherapy: the use of anti-cancer drugs, although it is less commonly used in the treatment of thyroid cancer
• targeted therapy: drugs that target specific genes or proteins in cancer cells (also known as TKIs – tyrosine kinase inhibitors), used in cases of iodine-refractory disease, advanced thyroid cancer, or metastatic disease (when cancer has spread to other organs)

Einstein’s Oncology and Hematology offers comprehensive care from diagnosis through treatment. Learn more.

Prevention

Some measures can help reduce the risk of developing thyroid cancer, such as:

• avoid unnecessary radiation exposure: especially during childhood. Avoid unnecessary imaging tests and follow safety guidelines when exposed to radiation sources
• monitor thyroid conditions: have regular check-ups with a healthcare professional if you have existing thyroid conditions, such as goiter or thyroid nodules
• maintain a proper diet: a diet rich in iodine can help maintain thyroid health. Foods like fish, dairy products, and iodized salt are good sources of iodine
• do not smoke: smoking is associated with an increased risk of several types of cancer, including thyroid cancer
• eegular screenings: especially for people with a family history of thyroid cancer or associated genetic syndromes. Regular exams can help detect the disease in its early stages, when it is more treatable

References

National Cancer Institute – INCA

Brazilian Society of Surgical Oncology

By Einstein Editorial Board