Mesothelioma Staging Systems

All cancers are described through a system called “staging.” Staging is based on the cancer’s severity – the higher the stage, the more severe it is – and allows doctors to make standardized assessments and prognoses of tumors. Since most cases of mesothelioma follow similar paths, knowing what stage the disease is currently in can help doctors estimate where it is going, and therefore how to treat it. Mesothelioma has many symptoms.

There are different systems used for staging mesothelioma, each with its own advantages and disadvantages. The following are the three staging systems currently used by doctors:

Read more in the book “100 Questions & Answers About Mesothelioma“

The Butchart System

The Butchart System is the oldest staging system used for diagnosing and treating malignant mesothelioma. It is based mainly on the size of the primary tumor mass, and can be broken down into the following four stages:

STAGE I: Mesothelioma is present in the right or left pleural mesothelium (lining of the chest cavity), and possibly in the diaphragm
STAGE II: Mesothelioma is present in the mesothelium of both the right and left pleura. The tumor may have moved into the heart, stomach, esophagus, or lymph nodes.
STAGE III: Mesothelioma is present in the abdominal cavity, and lymph nodes past the chest may have cancer cells in them.
STAGE IV: Mesothelioma has metastasized and spread through the bloodstream to other organs.

The TNM System

The TNM system is a system that is widely used for many forms of cancer. The stage of a malignant mesothelioma tumor is based on the variables of tumor size (T), how much the tumor has spread to lymph nodes (N), and whether or not it has metastasized (M). Each variable is assigned a number, and a stage is determined based on the three numbers. The following four stages are summaries of the possible TNM combinations:

STAGE I: Mesothelioma is present in the right or left pleura, and may have spread to the lung, the pericardium (the mesothelium surrounding the heart), or the diaphragm on the same side. Lymph nodes are not involved.
STAGE II: Mesothelioma has spread from the right or left pleura to nearby lymph nodes on the same side of the chest. It may have also spread to the pericardium, the lung, or the diaphragm on the same side.
STAGE III: Mesothelioma has spread into the chest wall, muscle, ribs, heart, esophagus, and/or other organs on the same side of the chest. It may have also spread to the lymph nodes on the same side of the chest as the primary tumor.
STAGE IV: Mesothelioma has spread to the lymph nodes on the opposite side of the chest, the tumor extends to the pleura or lung on the opposite side of the chest, or has invaded the organs in the abdominal cavity or neck. Any metastasis is considered Stage IV.

The Brigham System

The Brigham System is the most modern system, and is based on how easily the tumor can be cut out (resected). It also takes into account how involved the lymph nodes are. It is used more for other cancers than it is used for mesothelioma, since mesothelioma is so difficult to operate on.

STAGE I: Mesothelioma tumor is still resectable, and the lymph nodes are unaffected
STAGE II: Mesothelioma tumor is still resectable, but the lymph nodes are involved
STAGE III: Mesothelioma tumor is not resectable, and the tumor has penetrated the heart, chest wall, abdominal cavity, or diaphragm. Lymph nodes may or may not be involved.
STAGE IV: Mesothelioma tumor is not resectable and has metastasized.