Stages of mesothelioma

Once you receive a diagnosis of malignant mesothelioma, more tests will be done to determine whether cancer cells have spread to other parts of the body. This is called "staging". Your doctor will need to know the stage of the cancer in order to plan treatment.

Staging is the process by which doctors judge how dangerous a cancer is in a patient. When staging a cancer, doctors investigate where the cancer is located, the size of the cancerous tumor, whether the cancer has spread to other body parts, and if the cancer is affecting other bodily functions. By running a series of diagnostic tests, including tomography and radiographic imaging, doctors ascertain the information they need to plan an effective treatment and judge the patient’s prognosis.

It is important that doctors have a common system for staging cancer so they can easily exchange information about patients. Although there are many different kinds of cancer, the TNM system, developed by the American Joint Committee on Cancer (AJCC) is the system used for most varieties of cancer. (Cancers of the spinal cord or brain, as well as lymphoma, do not warrant use of the TNM system). When using the TNM system, doctors assign a numeric value to a “T”, “N”, and “M” category.

The “T” category is used to classify the original tumor. Doctors assign a numerical value between 0 and 4 to the tumor, with 4 indicating a large tumor that has grown deep into adjacent structures. The “T” value of the tumor can also be an “Tx” meaning the tumor can’t be measured, or a “Tis,” which indicates the tumor is in situ (the tumor has not grown into nearby tissues).

The “N” category measures if, and to what extent, the cancer has spread to neighboring lymph nodes. Like the “T” category, the “N” category is assigned a value of 0-4, with the higher “N” values indicating a larger area of affected lymph nodes. A “Nx” value means the nearby lymph nodes cannot be evaluated.

The “M” category is used to tell whether the cancer has generated any distant metastases. Distant metastases are areas far from the site of the tumor that show signs of cancerous cells. Usually, the presence of distant metastasis indicates the cancer has entered the bloodstream. The “M” category only has three possible values: “Mx” (metastasis can’t be evaluated), “0” (no distant metastases) and “1” (metastasis has occurred).

When all three TNM values have been found, doctors then assign the cancer a stage value of 0-IV. (Some stages are subdivided into categories like IIIa or IIIb as well.) Once the stage is determined, a doctor can give a prognosis and decide on the most effective treatment.

The standard for staging mesothelioma is as follows:

Localized malignant mesothelioma

Stage I: The cancer is located in the lining of the chest cavity near the lung and heart, or in the diaphragm or the lung.

Advanced malignant mesothelioma

Stage II: The cancer has spread beyond the lining of the chest to lymph nodes in the chest.

Stage III: The cancer has spread into the chest wall, center of the chest, heart, through the diaphragm, or abdominal lining, and in some cases, into nearby lymph nodes.

Stage IV: The cancer has spread to distant organs or tissues.

Recurrent malignant mesothelioma

Recurrent disease means that the cancer has come back after it has been treated. It may come back in the lining of the chest or abdomen or in another part of the body.

The difference between metastatic cancer and advanced cancer.

Three types of mesothelioma – epithelioid, sarcomatoid and biphasic