ON THIS PAGE: You will learn about how doctors describe a cancer’s growth or spread. This is called the stage. Use the menu to see other pages.
Staging is a way of describing where the cancer is located, if or where it has spread, and whether it is affecting other parts of the body.
Doctors use diagnostic tests to find out the cancer's stage, so staging may not be complete until all the tests are finished. Knowing the stage helps the doctor to decide what kind of treatment is best and can help predict a patient's prognosis, which is the chance of recovery. There are different stage descriptions for different types of cancers.
This section describes the staging system for pleural mesothelioma. Currently, there is no standard staging system for peritoneal mesothelioma. Your doctor will talk to you about the extent of disease and what it means.
TNM staging system
One tool that doctors use to describe the stage is the TNM system. Doctors use the results from diagnostic tests and scans to answer these questions:
Tumor (T): How large is the primary tumor? Where is it located?
Node (N): Has the tumor spread to the lymph nodes? If so, where and how many?
Metastasis (M): Has the cancer spread to other parts of the body? If so, where and how much?
The results are combined to determine the stage of cancer for each person. There are 4 stages: stages I through IV (1 through 4). The stage provides a common way of describing the cancer, so doctors can work together to plan the best treatments.
Staging can be clinical or pathological. Clinical staging is based on the results of tests done before surgery, which may include physical examinations and imaging tests. Pathological staging is based on what is found during surgery. In general, pathological staging provides the most information to determine a patient’s prognosis.
Here are more details on each part of the TNM system for pleural mesothelioma.
Using the TNM system, the "T" plus a letter and/or number (0 to 4) is used to describe the stage of the tumor. Tumor size is measured in centimeters (cm). A centimeter is roughly equal to the width of a standard pen or pencil.
Stage may also be divided into smaller groups that help describe the tumor in even more detail. This helps the doctor develop the best treatment plan for each patient. Specific tumor stage information is listed below:
TX: The primary tumor cannot be evaluated.
T0 (T plus 0): There is no evidence of a primary tumor.
T1: The tumor is only in the thin membrane that lines the lung and inner chest walls, called the pleura, on 1 side of the body. It may or may not have grown into visceral pleura, mediastinal pleura, or diaphragmatic pleura. These are the thin membranes that line the lungs, the chest, and the muscle called the diaphragm that separates the chest cavity from the abdomen.
T2: The tumor has grown into all of the pleural surfaces on 1 side of the body and has grown into either the lung or the diaphragm.
T3: The tumor has grown into all of the pleural surfaces on 1 side of the body, with at least 1 of the following:
Growth to the membrane that surrounds the thorax, called the endothoracic fascia
Growth to the area of the chest between the lungs, called the mediastinum
Growth to a single area of the muscles of the chest wall
Minimal growth to the lining around the heart, called the pericardium
T4: The tumor has grown into all of the pleural surfaces on 1 side of the body, and has grown to at least 1 of the following areas:
Several areas of the chest wall with or without growth into the rib
Through the diaphragm to the abdominal cavity
Any mediastinal organ(s), such as large blood vessels
The pleura on the opposite side of the body
Though the pericardium which may cause fluid buildup, or growth to the heart
The “N” in the TNM staging system stands for lymph nodes. These tiny, bean-shaped organs help fight infection. Lymph nodes near the chest are called regional lymph nodes. Lymph nodes in other parts of the body are called distant lymph nodes.
NX: The regional lymph nodes cannot be evaluated.
N0 (N plus zero): Cancer has not spread to the regional lymph nodes.
N1: Cancer has spread to the bronchopulmonary lymph nodes that are located within the lungs on 1 side of the body and/or hilar lymph node(s) that are located near the larger airways of the lungs. It may have also spread to other the lymph nodes in the chest on 1 side of the body, including the internal mammary lymph nodes near the breast bone, the peridiaphragmatic lymph nodes surrounding the diaphragm, the intercostal lymph nodes between the ribs, or the fat surrounding the heart.
N2: Cancer has spread to the mediastinal lymph nodes on both sides of the body, the internal mammary lymph nodes, and/or the supraclavicular lymph node(s) above the collar bone on 1 or both sides of the body.
The “M” in the TNM system indicates whether the cancer has spread to other parts of the body, called distant metastasis.
M0 (M plus zero): Cancer has not spread to other parts of the body.
M1: Cancer has spread to other parts of the body.
Cancer stage grouping
Doctors assign the stage of the cancer by combining the T, N, and M classifications.
Stage IA: The tumor has grown into the pleura on 1 side of the body and may or may not have grown into the visceral pleura, mediastinal pleura, or the diaphragmatic pleura. It has not spread to the lymph nodes or other parts of the body (T1, N0, M0).
Stage IB: The tumor is defined as T2 or T3 (see above). It has not spread to the lymph nodes or other parts of the body (T2 or T3, N0, M0).
Stage II: The tumor is defined as T1 or T2 (see above). It has not spread to the lymph nodes or throughout the body (T1 or T2, N0, M0).
Stage IIIA: The tumor is defined as T3 (see above). Cancer has spread to the lymph nodes described above as N1 but not to other parts of the body (T3, N1, M0).
Stage IIIB: Any of the following conditions:
The tumor is defined as T1, T2, or T3 (see above). Cancer has spread to the lymph nodes described above as N2 but not to other parts of the body (T1, T2, or T3, N2, M0).
The tumor is defined as T4 (see above). Cancer may or may not have spread to the lymph nodes but has not spread to other parts of the body (T4, any N, M0).
Stage IV: Cancer may or may not have spread to the lymph nodes and has spread to other parts of the body (any T, any N, M1).
Recurrent: Recurrent cancer is cancer that has come back after treatment. It may return in the chest or in another part of the body. If the cancer does return, there will be another round of tests to learn about the extent of the recurrence. These tests and scans are often similar to those done at the time of the original diagnosis.
Used with permission of the American College of Surgeons, Chicago, Illinois. The original and primary source for this information is the AJCC Cancer Staging Manual, Eighth Edition (2017) published by Springer International Publishing.
Information about the cancer’s stage will help the doctor recommend a specific treatment plan. The next section in this guide is Types of Treatment. Use the menu to choose a different section to read in this guide.