There are four stages of mesothelioma. Each of these stages corresponds with how much the cancer has metastasized.
Stage one has the least amount of metastasis, and stage four has the highest amount. What stage of the disease a patient affects the type of treatment a patient can receive.
Currently, there is not a standard staging system for mesothelioma.
However, the most common staging system for pleural mesothelioma is the American Joint Committee on Cancer (AJCC) TNM system, which looks at the size of the original tumor (T), whether it has spread to any nearby lymph nodes (N), and if it has metastasized (M) to distant sites.
The other two staging systems are Brigham and Butchart.
Stages 1 and 2
In stages 1 and 2 of pleural mesothelioma, the cancer has only spread locally. Meaning, while the patient might have the disease in their diaphragm or local lymph nodes, it is still unilateral — that is it has remained on one side of the body.
In stages 1 and 2, most treatment methods like surgery are still viable options.
In stage 3 the disease has spread further. The disease may have spread to the esophagus, on to the surface of the pericardium, to the lymph nodes above the collarbone or on to the other side of the body. In stage 3 it has not spread to a distant organ such as the liver or the other lung.
At this point, surgery might still be an option to remove the mesothelioma. However, patients will likely also receive chemotherapy or radiation therapy to improve their survival rate.
By stage 4 pleural mesothelioma, the cancer has spread further in the body to locations such as bones, the other lung or the lining of the abdomen.
At this point, all treatments are palliative and designed to make the patient as comfortable as possible and to increase their life expectancy.