Stages of Malignant Mesothelioma

Cancer stage describes the extent of cancer in the body.

Cancer stage describes the extent of cancer in the body, such as the size of the tumor, whether it has spread, and how far it has spread from where it first formed. It is important to know the stage of mesothelioma to plan the best treatment.

There are several staging systems for cancer that describe the extent of the cancer. Malignant mesothelioma staging usually uses the TNM staging system. The cancer may be described by this staging system in your pathology report. Based on the TNM results, a stage (I, II, III, or IV, also written as 1, 2, 3, or 4) is assigned to your cancer. When talking to you about your diagnosis, your doctor may describe the cancer as one of these stages.

Learn about tests to stage mesothelioma. Learn more about Cancer Staging.

The following stages are used for malignant mesothelioma of the lung:

Stage I (also called stage 1) malignant mesothelioma

Stage I is divided into stages IA and IB:

• In stage IA, cancer is found in the inside lining of the chest wall on one side of the chest. On the same side of the chest, cancer may also be found in one or more of the following:
  • the thin layer of tissue that covers the lung
  • the thin layer of tissue that covers the organs between the lungs
  • the thin layer of tissue that covers the top of the diaphragm
• In stage IB, cancer is found in the inside lining of the chest wall, and in each of the thin layers of tissue that cover the lung, the organs between the lungs, and the top of the diaphragm on one side of the chest. On the same side of the chest, cancer has also spread into one or more of the following:
  • diaphragm
  • lung tissue
  • tissue between the ribs and the inside lining of the chest wall
  • fat in the area between the lungs
  • soft tissues of the chest wall
  • sac around the heart

Stage II (also called stage 2) malignant mesothelioma

In stage II, cancer is found in the inside lining of the chest wall on one side of the chest. On the same side of the chest, cancer may also be found in one or more of the following:

• the thin layer of tissue that covers the lung
• the thin layer of tissue that covers the organs between the lungs
• the thin layer of tissue that covers the top of the diaphragm

Cancer has spread to lymph nodes along the center of the chest on the same side of the chest as the tumor.

or

Cancer is found in the inside lining of the chest wall, and in each of the thin layers of tissue that cover the lung, the organs between the lungs, and the top of the diaphragm on one side of the chest. On the same side of the chest, cancer has also spread into one or both of the following:

• diaphragm
• lung tissue

Cancer has spread to lymph nodes along the center of the chest on the same side of the chest as the tumor.

Stage III (also called stage 3) malignant mesothelioma

Stage III is divided into stages IIIA and IIIB.

• In stage IIIA, cancer is found in the inside lining of the chest wall, and in each of the thin layers of tissue that cover the lung, the organs between the lungs, and the top of the diaphragm on one side of the chest. On the same side of the chest, cancer has also spread into one or more of the following:
  • tissue between the ribs and the inside lining of the chest wall
  • fat in the area between the lungs
  • soft tissues of the chest wall
  • sac around the heart

  Cancer has spread to lymph nodes along the center of the chest on the same side of the chest as the tumor.

• In stage IIIB, cancer is found in the inside lining of the chest wall, and may also be found in the thin layers of tissue that cover the lung, the organs between the lungs, and/or the top of the diaphragm on one side of the chest. On the same side of the chest, cancer may have also spread into one or more of the following:
  • diaphragm
  • lung tissue
  • tissue between the ribs and the inside lining of the chest wall
  • fat in the area between the lungs
  • soft tissues of the chest wall
  • sac around the heart

  Cancer has spread to lymph nodes above the collarbone on either side of the chest or cancer has spread to lymph nodes along the center of the chest on the opposite side of the chest as the tumor.

  or

  Cancer is found in the inside lining of the chest wall, and in each of the thin layers of tissue that cover the lung, the organs between the lungs, and the top of the diaphragm on one side of the chest. Cancer has also spread to one or more of the following:

  • the chest wall and may be found in the rib
  • through the diaphragm into the peritoneum
  • the tissue lining the chest on the opposite side of the body as the tumor
  • the organs in the area between the lungs (esophagus, trachea, thymus, blood vessels)
  • the spine
  • through the sac around the heart or into the heart muscle

  Cancer may have spread to lymph nodes.

Stage IV (also called stage 4) malignant mesothelioma

In stage IV, cancer has spread to the tissue covering the lung or the lung on the opposite side of the chest, peritoneum, bones, liver, lymph nodes outside the chest, or to other parts of the body.

Stage IV malignant mesothelioma is also called metastatic mesothelioma. Metastatic cancer happens when cancer cells travel through the lymphatic system or blood and form tumors in other parts of the body. The metastatic tumor is the same type of cancer as the primary tumor. For example, if malignant mesothelioma spreads to the liver, the cancer cells in the liver are actually malignant mesothelioma cells. The disease is called metastatic mesothelioma, not liver cancer. Learn more in Metastatic Cancer: When Cancer Spreads.

Malignant mesothelioma can recur (come back) after it has been treated.

Recurrent malignant mesothelioma is cancer that has come back after it has been treated. If mesothelioma comes back, it may come back in the chest or in other parts of the body, such as the liver, lungs, or both. Tests will be done to help determine where the cancer has returned. The type of treatment for recurrent mesothelioma will depend on where it has come back.

Learn more in Recurrent Cancer: When Cancer Comes Back. Information to help you cope and talk with your health care team can be found in the booklet When Cancer Returns.