Mesothelioma: Stages

Approved by the Cancer.Net Editorial Board, 05/2016

ON THIS PAGE: You will learn about how doctors describe a cancer’s growth or spread. This is called the stage. To see other pages, use the menu.

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 metastasized 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.

Here are more details on each part of the TNM system for pleural mesothelioma:

Tumor (T)

Using the TNM system, the "T" plus a letter and/or number (0 to 4) is used to describe the stage of the tumor. Some stages are also 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:

T1: The tumor has grown into the thin membrane that lines the lung and inner chest walls, called the pleura, on 1 side of the body.

T1a: The tumor has grown into the parietal pleura on 1 side of the body. The parietal pleura is the thin lining of tissue around the chest wall. The tumor has not grown into the visceral pleura, which is the thin lining around the lung.

T1b: The tumor has grown into the parietal pleura and the visceral pleura on 1 side of the body.

T2: The tumor has grown into any of the pleural surfaces on 1 side of the body and has grown into either the lung or the muscle that separates the chest cavity from the abdomen called the diaphragm.

T3: The tumor has grown into any 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 any 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

  • The spine

  • Though the pericardium which may cause fluid buildup, or growth to the heart

Node (N)

The “N” in the TNM staging system stands for lymph nodes, the tiny, bean-shaped organs that 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.

N2: Cancer has spread to the subcarinal lymph node(s) surrounding the windpipe and/or the mediastinal lymph node(s) located in the center of the chest between the lobes of the lungs on 1 side of the body, including the internal mammary lymph nodes near the breast bone on 1 side of the body and the peridiaphragmatic lymph nodes surrounding the diaphragm.

N3: Cancer has spread to the mediastinal lymph nodes on both sides of the body, the internal mammary lymph nodes and/or supraclavicular lymph node(s) above the collar bone on 1 or both sides of the body.

Metastasis (M)

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 I: The tumor has grown into the parietal pleura on 1 side of the body and may or may not have grown into the visceral pleura. It has not spread to the lymph nodes or other parts of the body (T1, N0, M0).

Stage IA: The tumor has grown into the parietal pleura on 1 side of the body. It has not grown into the visceral pleura or spread to the lymph nodes or other parts of the body (T1a, N0, M0).

Stage IB: The tumor has grown into the parietal pleura on 1 side of the body and the visceral pleura. It has not spread to the lymph nodes or other parts of the body (T1b, N0, M0).

Stage II: The tumor is defined as T2 (see above). It has not spread to the lymph nodes or throughout the body (T2, N0, M0).

Stage III: Any of the following conditions:

  • The tumor is defined as T1 or T2 (see above). Cancer has spread to the lymph nodes described above as N1 or N2 but not to other parts of the body (T1 or T2, N1 or N2, M0).

  • The tumor is defined as T3 (see above). It may or may not have spread to lymph nodes and has not spread to other parts of the body (T3, N0-2, M0).

Stage IV: Any of the following conditions:

  • The tumor is defined as T4 (see above). Cancer may or may not have spread to the lymph nodes and has not spread to other parts of the body (T4, any N, M0).

  • Cancer has spread to lymph nodes described above as N3 but not to other parts of the body (any T, N3, M0).

  • 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 Joint Committee on Cancer (AJCC), Chicago, Illinois. The original source for this material is the AJCC Cancer Staging Manual, Seventh Edition published by Springer-Verlag New York, www.cancerstaging.net.

Information about the cancer’s stage will help the doctor recommend a specific treatment plan. The next section in this guide is Treatment Options. Or, use the menu to choose another section to continue reading this guide.