Mesothelioma Stages

What Are Mesothelioma Stages?

Once a patient has been diagnosed with malignant mesothelioma, doctors will attempt to determine how far their cancer has spread and how best to treat it through a process called cancer staging.

The stages of mesothelioma, ranging from stage 1 to stage 4, describes the extent of cancer spread in the body. Stage 1 is the earliest malignant mesothelioma stage with the least cancer spread, while stage 4 is the most advanced.

Each patient’s mesothelioma may behave in unique ways, but according to the American Cancer Society (ACS), similarly-staged mesothelioma tends to have a similar outlook and is often treated using the same methods.

Quick Facts About Mesothelioma Stages

• In the United States and many other countries, mesothelioma is staged using the Tumor Node Metastasis (TNM) System — a system used to stage nearly every type of solid tumor cancer.
• Pleural mesothelioma is the only type of mesothelioma that has been officially staged.
• Although it has no official staging, peritoneal mesothelioma is sometimes unofficially staged to help patients understand their disease outlook.

Pleural Mesothelioma Stages

According to the ACS, pleural mesothelioma patients make up roughly 80% of all mesothelioma cases. It is the only type of mesothelioma that has been well-researched enough to be officially staged.

Stage 1

• Remains on one side of the chest in the lining of the chest wall
• Pleura may be cancer-free
• May have spread to the pleura

Stage 2

• In lining of the chest wall and the lymph nodes on one side of the body
• May have also spread to the diaphragm and lungs
• Has not reached distant parts of the body

Stage 3

• Has spread past pleura into the deeper tissues
• May have reached areas such as the abdominal lining or spine
• May have spread to both sides of the body
• Has spread to the lymph nodes
• Has not reached distant parts of the body

Stage 4

• May or may not have grown into nearby tissues
• May or may not have spread to nearby lymph nodes
• Has spread to distant organs

This staging helps mesothelioma patients understand what to expect as their disease progresses and helps doctors create the most effective treatment plan for their patients.

Stage 1 Pleural Mesothelioma

Stage 1 mesothelioma is the earliest point in mesothelioma’s development. During this stage, the cancer has not spread very far.

Stage 1 has 2 sub-stages:

• Stage 1A: Mesothelioma remains in the pleura on one side of the chest cavity and may or may not have begun growing into the tissues of the lung or diaphragm. It has not spread to nearby lymph nodes or distant parts of the body.
• Stage 1B: Mesothelioma has grown into nearby tissues such as the lung and chest wall, but it remains on one side of the chest. The cancer still has not spread to nearby lymph nodes or distant parts of the body.

Stage 1 patients have the best prognosis and are usually good candidates for curative treatments such as surgery.

Stage 2 Pleural Mesothelioma

Stage 2 describes cancer that is still contained to one side of the body but has spread outside the pleura, into deeper tissues and nearby lymph nodes.

Stage 2 is still considered an early stage of mesothelioma when most curative surgeries can still be performed.

Stage 3 Pleural Mesothelioma

During stage 3, cancer has either spread deeper into surrounding tissues, spread to more lymph nodes, or both.

Stage 3 mesothelioma has 2 sub-stages:

• 3A: Mesothelioma has grown into nearby tissues and has invaded some tissues on the other side of the chest. It has only spread to lymph nodes on the side of the body where the main tumor originated. It has not spread to distant body parts.
• 3B: Mesothelioma either has spread to lymph nodes on the other side of the body or it has grown so deep into surrounding tissues that it can no longer be surgically removed. Regardless, it has not spread to distant parts of the body.

At this stage of mesothelioma, some patients may still be able to undergo curative treatments. However, doctors will likely recommend treatments to potentially control the cancer and help manage symptoms (palliative care).

Stage 4 Pleural Mesothelioma

The most advanced stage of mesothelioma is stage 4 mesothelioma. It marks the point when cancer cells have metastasized, traveling through the lymph nodes or blood vessels and taking root in distant parts of the body.

Even if the main tumor remains fairly small and mesothelioma has not reached the lymph nodes, it is considered stage 4 if metastasis has occurred.

At this stage, curative surgeries are nearly always unavailable to mesothelioma patients since the cancer is nearly impossible to completely remove. However, palliative treatments to potentially control the cancer and relieve symptoms may still improve a patient’s quality of life.

Peritoneal Mesothelioma Stages

There is no officially recognized staging system for peritoneal mesothelioma. This mesothelioma type makes up less than 10% of all cases,, so research on how it progresses is not as plentiful as it is for pleural mesothelioma.

Peritoneal mesothelioma also presents staging challenges because it advances in an unusual way, often remaining in the abdomen instead of spreading to other parts of the body.

Pericardial Mesothelioma Stages

Pericardial mesothelioma is a very rare form of mesothelioma. As a result, there is not enough known about the disease to properly stage it.

The disease may, instead, be described as localized, regional, or distant using the SEER staging system. Doctors may also simply determine whether the cancer can be surgically removed and/or if it has spread to other parts of the body.

Testicular Mesothelioma Stages

Testicular mesothelioma is extremely rare, so, like pericardial mesothelioma, it has no official staging system.

Doctors may look at whether or not a patient’s mesothelioma has metastasized to determine the individual’s outlook.

Mesothelioma Treatment

An important factor in determining a patient’s cancer outlook and treatment plan depends on which stage the cancer is in.

Most patients are diagnosed at a later mesothelioma stage, but as emerging treatment options like targeted therapy continue to improve and become available to more people, patients at all stages of mesothelioma may look forward to longer, healthier lives.