Mesothelioma: Stages I, II, III, IV

After mesothelioma has been diagnosed, certain tests are done to find out if cancer cells have spread to other parts of the body. The process used to find out if cancer has spread outside the pleura or peritoneum is called staging. The information gathered from the staging process determines the stage of the disease. It is important to know whether the cancer has spread in order to plan treatment. The following stages are used for malignant mesothelioma:

Stage I (Localized) - Stage I is divided into stages IA and IB:

1. In stage IA, cancer is found in one side of the chest in the lining of the chest wall and may also be found in the lining of the chest cavity between the lungs and/or the lining that covers the diaphragm. Cancer has not spread to the lining that covers the lung.
2. In stage IB, cancer is found in one side of the chest in the lining of the chest wall and the lining that covers the lung. Cancer may also be found in the lining of the chest cavity between the lungs and/or the lining that covers the diaphragm.

Stage II (Advanced) - In stage II, cancer is found in one side of the chest in the lining of the chest wall, the lining of the chest cavity between the lungs, the lining that covers the diaphragm, and the lining that covers the lung. Also, cancer has spread into one or both of the following:

1. Lung tissue.
2. Diaphragm.

Stage III (Advanced) - In stage III, either of the following is true:

1. Cancer is found in one side of the chest in the lining of the chest wall. Cancer may have spread to: A) the lining of the chest cavity between the lungs; B) the lining that covers the diaphragm; C) the lining that covers the lung; D) the lung tissue; E) the diaphragm.
2. Cancer has spread to lymph nodes where the lung joins the bronchus, along the trachea and esophagus, between the lung and diaphragm, or below the trachea.
3. Cancer is found in one side of the chest in the lining of the chest wall, the lining of the chest cavity between the lungs, the lining that covers the diaphragm, and the lining that covers the lung.
4. Cancer has spread into one or more of the following: A) Tissue between the ribs and the lining of the chest wall. B) Fat in the area between the lungs. C) Soft tissues of the chest wall. D) Sac around the heart.

Stage IV (Advanced) - In stage IV, cancer cannot be removed by surgery and is found in one or both sides of the body. Cancer may have spread to lymph nodes anywhere in the chest or above the collarbone. Cancer has spread in one or more of the following ways: A) Through the diaphragm into the peritoneum (the thin layer of tissue that lines the abdomen and covers most of the organs in the abdomen). B) To the tissue lining the chest on the opposite side of the body as the tumor. C) To the chest wall and may be found in the rib. D) Into the organs in the center of the chest cavity. E) Into the spine. F) Into the sac around the heart or into the heart muscle. G) To distant parts of the body such as the brain, spine, thyroid, or prostate.

Source: National Cancer Institute