The stage of a cancer tells us how far a cancer has spread. Tests used to diagnose your cancer often provide information about the stage of the disease, too. Knowing the stage of a cancer is important to helping doctors know what treatment approach will work best for you.

At Memorial Sloan Kettering, our mesothelioma experts use the TNM (tumor, node, metastasis) system to begin the process of staging pleural mesothelioma.

• T: the position and size of the primary tumor
• N: whether the cancer cells have spread to nearby lymph nodes
• M: whether the cancer cells have spread (metastasized) to other parts of the body

Stages of Pleural Mesothelioma

By combining TNM information with other things we learn about your condition, we give you information about the stage of your pleural mesothelioma.

• Stages I and II: when the cancer is limited to the pleura in one of your lungs
• Stage III: when the cancer has spread to your mediastinum (the area between your lungs) or involves your lymph nodes
• Stage IV: when the cancer has spread to your chest wall or other parts of your body

Stages of Peritoneal Mesothelioma

At this point there is no widely accepted system for staging peritoneal mesothelioma.