What is thyroid cancer metastasis? Symptoms and treatment!

What does thyroid cancer metastasis mean?

Metastatic or advanced thyroid cancer is a condition in which cancer cells have broken away from the thyroid gland and spread to other parts of the body. Most patients with thyroid cancer have their disease confined to the thyroid gland at the time of diagnosis. About 30 percent of patients have metastases (spread of cancer). Treating metastatic thyroid cancer is more difficult than treating cancers confined to the primary site (i.e., the thyroid gland) and usually requires a combination of several treatment methods.

Pathways of Thyroid Cancer Spread

Thyroid cancer spreads to other parts of the body in two main ways. The pattern of metastasis can vary depending on the specific type of thyroid cancer (such as papillary, follicular, or anaplastic) and the individual characteristics of the patient. The two pathways of thyroid head metastases are:

1. Spread through the lymphatic system: This is the most common way thyroid cancer spreads. Cancer cells first enter the lymph vessels near the thyroid gland and then travel to the lymph nodes in the neck. Swollen or enlarged lymph nodes in the neck are usually the first sign of this type of spread.
2. Spread through the bloodstream: In cases where the cancer is more advanced or has not spread through the lymphatic system, cancer cells can enter the bloodstream and reach distant organs. This type of spread usually indicates a more advanced stage of the disease and requires a more comprehensive treatment approach.

Areas of thyroid cancer metastasis

Different types of thyroid cancer metastasize in different ways. Papillary and follicular cancers usually spread slowly throughout the body; however, anaplastic thyroid cancer behaves more aggressively and spreads more rapidly.

The most common sites of thyroid cancer metastasis are:

1. Thyroid cancer metastasizes to the lymph nodes

The first place thyroid cancer spreads to is the lymph nodes in the neck. This condition usually appears as swollen or enlarged lymph nodes during an exam or imaging.

2. Thyroid cancer spreads to the lungs

Some cancers, especially follicular types and some advanced papillary types, may metastasize to the lungs. In many of these cases, this initial spread is very small (microscopic) and is detected during follow-up checkups and scans done to ensure health.

3. Thyroid cancer spreads to the bones

Bone metastases occur in more aggressive or advanced types of thyroid cancer, especially after a long time. Patients may experience bone pain or even spontaneous fractures, depending on the extent of bone involvement.

4. Thyroid cancer metastasis to distant organs (rare)

In very advanced cases of the disease, thyroid cancer can also spread to distant organs such as the liver or brain; however, this is rare. Early diagnosis and regular check-ups help doctors choose the best treatment.

Symptoms of thyroid cancer metastasis

The symptoms of thyroid cancer metastasis depend entirely on the location of the disease. Note that in many cases, the patient does not experience any specific symptoms and metastasis is only detected through imaging during routine follow-ups. For this reason, regular monitoring and periodic examinations are a vital part of the management and treatment of this disease.

If symptoms occur, the symptoms are based on the location of the involvement as follows:

• Symptoms of metastasis to the lymph nodes in the neck: The most common sign of involvement in this area is the presence of a swollen or palpable lymph node in the neck.
• Symptoms of lung metastasis: If cancer spreads to the lungs, it causes symptoms such as shortness of breath or difficulty breathing, a dry, persistent cough, and coughing up blood (coughing up blood).
• Symptoms of bone metastasis: Bone involvement is accompanied by symptoms such as bone pain, increased risk of fractures, decreased bone density (bone destruction), and pressure on the spinal cord (a very serious symptom).
• Symptoms of metastasis to other organs: The spread of the disease to distant organs such as the liver leads to general and digestive symptoms; including abdominal pain, unexplained weight loss, feeling unwell, and general discomfort in the body.

Note: A definitive diagnosis of thyroid cancer metastasis to other areas of the body is only possible by a specialist using clinical examinations and imaging.

The importance of diagnosing thyroid metastasis

Early diagnosis of thyroid cancer metastasis has a direct impact on the outcome of treatment. The earlier the spread of cancer is detected, the more treatment options the doctor can begin to deal with the disease and the higher the chance of success of the treatment. Early detection of metastases also helps the doctor to prevent further damage to vital organs, reduce side effects of treatment, and maintain the patient’s quality of life during the treatment process. For this reason, thyroid cancer patients should undergo regular follow-up even after the end of initial treatment so that the fastest possible action can be taken if the disease returns or spreads.

Methods for diagnosing metastases in thyroid cancer

The process of diagnosing metastases usually includes the following steps:

Initial evaluation and screening:

The doctor evaluates the possibility of thyroid cancer and its spread by examining the patient’s symptoms and asking questions about the medical history.

Imaging techniques:

In case of clinical suspicion, advanced imaging methods are used to examine internal organs and find signs of metastases. These methods include:

• Ultrasound: This is often the first step to examine the thyroid gland and lymph nodes in the neck.
• MRI and CT scan: These methods provide detailed images of soft tissues and internal organs and are very effective for detecting metastases in organs such as the lungs, liver, or brain.
• Chest X-ray: A very simple and effective tool for the initial investigation of metastases in the lungs.

Biopsy for definitive confirmation:

After identifying areas of suspected metastases through imaging, a sample (biopsy) of those tissues is taken. Laboratory analysis of the biopsy sample confirms the definitive diagnosis of metastases.

Blood tests:

may be prescribed to check the levels of thyroid hormones or tumor markers (such as thyroglobulin), which can help monitor and evaluate the response to treatment in patients with metastases.

Is there a definitive treatment for thyroid cancer metastases?

Contrary to popular belief, the diagnosis of thyroid cancer metastases does not mean that treatment is impossible. In many cases, this condition is controllable and patients can have a quality life with proper management, because thyroid cancer progresses more slowly than most other cancers. The final outcome of treatment depends on several factors, such as the type of thyroid cancer, the location of the spread, and the stage at diagnosis. If the metastasis is limited to the lymph nodes, the likelihood of complete control of the disease is high. If the cancer has spread to organs such as the lungs or bones, the main goal of treatment is to prevent further progression and reduce complications. For this reason, ongoing follow-up and close cooperation with a specialist doctor are very important to manage this condition.

Treatment of thyroid cancer metastasis

The treatment of thyroid cancer metastasis depends on several factors, including the type of cancer (papillary, follicular, medullary, or anaplastic), the location of the disease, previous treatments, and the genetic characteristics of the cancer cells.

• For metastasis to the lymph nodes in the neck, surgery and removal of the involved nodes is the most effective treatment. In these cases, choosing a specialist and experienced doctor in neck surgery plays a decisive role in the success of the treatment.
• In cases where the cancer has spread to the bones and is causing pain or a risk of fracture, surgical intervention by a specialist orthopedic surgeon is recommended. External radiation therapy is also used in rare cases such as brain metastases.
• Radioactive iodine is one of the common methods for treating less aggressive thyroid cancers such as papillary and follicular, which have the ability to absorb iodine. This method is used to destroy cancer cells remaining after surgery. However, the response rate to treatment varies in different patients.
• Targeted therapy is used in advanced or treatment-resistant cases. These drugs inhibit the growth and spread of cancer cells by identifying and attacking specific characteristics of cancer cells. Decisions for these treatments require careful specialized examination and consideration of the genetic characteristics of the tumor.
• Kinase inhibitors are one of the most important classes of drugs in the treatment of thyroid cancer metastases. These drugs help control the disease by blocking enzymes that stimulate the uncontrolled growth of cancer cells. A well-known example is vandatinib, which is used to treat metastatic medullary thyroid cancer with a RET gene mutation.
• Chemotherapy is not usually the first choice in the treatment of thyroid cancer metastases; however, in very advanced cases, especially anaplastic cancer that has not responded to other treatments, it may be used as part of a combination approach.
• Some metastases, such as small lung lesions that have not grown on periodic imaging, do not require immediate intervention and can only be monitored regularly.

The bottom line

Metastatic thyroid cancer is a serious and worrisome condition; but the results of treatment are often better than expected; Especially when the disease is diagnosed early and followed up properly. Understanding how metastases spread, recognizing common sites, and interpreting imaging results correctly are all important in the long-term management of the disease. If you are in the follow-up phase after thyroid cancer treatment, being aware of this information and working with a specialist is one of the most important things you can do for your health.

Frequently Asked Questions

1. Where does thyroid cancer usually metastasize?

Thyroid cancer often spreads first to areas close to the gland; including the muscles or blood vessels of the neck, esophagus, and nearby lymph nodes. In more advanced cases, the cancer may also spread to the bones, liver, lungs, or brain.

2. What is the survival rate for patients with metastatic thyroid cancer?

Survival rates for metastatic thyroid cancer depend on the stage of the disease at the time of diagnosis. People whose disease is detected in the early stages have a chance of recovery of about 99.5 percent. However, in more advanced stages of metastasis, the five-year survival rate varies between 4 and 74%.

3. At what stage does thyroid cancer metastasize?

In stage 1, the tumor is completely confined to the thyroid gland. From stage 2 onwards, cancer cells begin to invade surrounding tissues. In stage 4, the cancer has spread to distant parts of the body.