Oncologist-approved cancer information from the American Society of Clinical Oncology
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Mesothelioma

This section has been reviewed and approved by the Cancer.Net Editorial Board, 3/2013
Stages

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 in this guide, use the colored boxes on the right side of your screen, or click “Next” at the bottom.

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 determine 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 (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.

One tool that doctors use to describe the stage is the TNM system. TNM is an abbreviation for tumor (T), node (N), and metastasis (M). Doctors look at these three factors to determine the stage of cancer:

  • How large is the primary tumor and where is it located? (Tumor, T)
  • Has the tumor spread to the lymph nodes? (Node, N)
  • Has the cancer metastasized to other parts of the body? (Metastasis, M)

The results are combined to determine the stage of cancer for each person. There are four stages: stages I through IV (one through four). 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. 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 invaded the thin membrane that lines the lung and inner chest walls on one side of the body, called the pleura.

T1a: The tumor involves the parietal pleura (the thin lining around the chest wall) on one side of the body but has not grown into the visceral pleura (the thin lining around the lung).

T1b: The tumor has invaded the parietal pleura and the visceral pleura on one side of the body.

T2: The tumor involves any of the pleural surfaces on one side of the body and invades either the diaphragm (the muscle that separates the chest cavity from the abdomen) or the lung.

T3: The tumor involves any of the pleural surfaces on one side of the body, with at least one of the following: invasion of the membrane that surrounds the thorax, called the endothoracic fascia; invasion into the mediastinum (the area of the chest between the lungs); a single area of invasion into the muscles of the chest wall; or minimal invasion into the lining around the heart, called the pericardium.

T4: The tumor involves any of the pleural surfaces on one side of the body, with at least one of the following:

  • Invasion in several areas of the chest wall with or without involvement of rib
  • Invasion through the diaphragm to the abdominal cavity
  • Invasion of any mediastinal organ(s), such as large blood vessels
  • Extension to the pleura on the opposite side of the body
  • Invasion into the spine
  • Extension though the pericardium which may cause fluid buildup, or invasion of the heart.

Node. 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 (located within the lungs) on one side of the body and/or hilar lymph node(s) (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 one side of the body, including the internal mammary lymph nodes (near the breast bone) on one 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 one or both sides of the body.

Distant metastasis. The “M” in the TNM system indicates whether the cancer has spread to other parts of the body.

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 invaded the parietal pleura on one side of the body and may or may not have grown into the visceral pleura, but it has not spread to the lymph nodes or other parts of the body (T1, N0, M0).

Stage IA: The tumor has invaded the parietal pleura on one side of the body, but 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 invaded the parietal pleura on one side of the body and has grown into the visceral pleura, but 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), and cancer 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), and cancer 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 there is a recurrence, the cancer may need to be staged again (called re-staging) using the system above.

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 (2010) published by Springer-Verlag New York, www.cancerstaging.net.

Information about the cancer’s stage will help the doctor recommend a treatment plan for you. Choose “Next” (below, right) to continue reading about treatment options for this type of cancer. Or, use the colored boxes located on the right side of your screen to visit any section.

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