Mesothelioma Metastasis

Metastatic Mesothelioma

Once mesothelioma tumors have formed, the microscopic cells that make up the tumor can spread throughout the body. These cells form new tumors in the body. At this point, a patient’s disease is said to be metastatic.

When mesothelioma spreads to a different organ it is still considered to be mesothelioma. For example, mesothelioma that spreads to the liver is not considered liver cancer. The cells in the newly developed tumor are still of a mesothelial type.

Metastasis corresponds with how advanced the mesothelioma is, which is denoted by staging. There are 4 stages of mesothelioma—stages 3 and 4 are considered metastatic mesothelioma.

• Stage 3 Mesothelioma

  Mesothelioma is still confined to one side of the body, but tumors have spread to nearby organs and lymph nodes.

• Stage 4 Mesothelioma

  Mesothelioma has metastasized to both sides of the body and has invaded multiple, possibly distant, organs. This is the most advanced form of mesothelioma.

Usually, the extent of a patient’s metastasis is used to estimate how advanced the diagnosis is, but there isn’t a standard staging system accepted for mesothelioma yet. This means that different doctors may have different criteria for what is considered stage 3 or 4.

Some doctors may favor a staging system based on the type of treatment acceptable for certain patients as well. This makes finding a specialist an absolute must for patients with advanced mesothelioma.

How Does Mesothelioma Spread?

Mesothelioma cells can metastasize to both local and distant organs. Localized metastasis happens when mesothelioma cells continue to grow uncontrollably and latch onto nearby organs and lymph nodes.

The main channels of metastasis, however, are the blood vessels and lymphatic system. These systems are like an interstate for mesothelioma cells and make distant metastasis of mesothelioma possible.

Distant metastases are rare, but they can occur in the right scenario. Mesothelioma originates on the outer linings of the lung or abdomen and begins invading those organs first.

When these cells reach the blood vessels or lymph vessels, they can travel to other areas of the body and form new tumors. Though rare, there have been cases of mesothelioma spreading to the:

• Brain
• Bone
• Abdomen (in pleural patients)
• Liver
• Adrenal glands
• Ovaries

Mesothelioma and the Lymphatic System

The lymphatic system is structurally similar to the vascular system (blood vessels), but also consists of nodes that are designed to trap harmful cells and bacteria. These nodes act like checkpoints for most cancers, including mesothelioma, and are an essential component of the immune system. Swollen lymph nodes can be a red flag for metastatic mesothelioma.

Cell Type and Metastasis

The cell type of a mesothelioma patient is one of the biggest factors in how fast metastasis occurs. Some patients experience more rapid metastasis due to a more aggressive cell type. Metastasis also affects a patient’s prognosis because the faster mesothelioma spreads, the faster it can overtake the patient.

• Epithelioid mesothelioma

  Spreads to nearby organs and lymph nodes. May continue to spread through lymphatic system.

• Sarcomatoid mesothelioma

  Tumors themselves grow faster and larger, spreading mostly through the blood vessels rather than the lymphatic system.

• Biphasic mesothelioma

  Mesothelioma made up of both epithelioid and sarcomatoid cell types, typically takes on the characteristics of the most prevalent cell type.

Through a quick examination of the behavior of these cell types, it’s easy to see why they have such an effect on prognosis. On the one hand, epithelioid cells tend to group together more than sarcomatoid cells do, resulting in less rapid metastasis. Sarcomatoid cells, on the other hand, tend to travel farther than epithelioid cells due to their preferred method of using blood vessels to travel, resulting in more rapid metastasis.

Distant metastasis is more common in sarcomatoid mesothelioma because it mainly spreads through the blood vessels, which lack nodes to prevent the cancerous cells from traveling any further.

Treating Advanced Metastatic Mesothelioma

Treatment options for advanced mesothelioma get more limited the farther the disease spreads. Generally, treatment options at this point are mainly palliative—they are designed to make the patient comfortable.

Palliative treatments are used to ease the symptoms associated with mesothelioma. Most of these symptoms range from shortness of breath to chest pain and can be solved with minor procedures to drain fluid buildup in the lungs or abdomen.

Aggressive treatments, like surgery, aren’t used as often in advanced stage patients, but there are many new drugs being developed to inhibit the metastasis of mesothelioma.

Exploring clinical trials for advanced mesothelioma can open new pathways for treatment and improve life expectancy. Get connected to the top recruiting clinical trials and explore your treatment options.