Currently, only pleural mesothelioma is described by the TNM staging system by the American Joint Committee on Cancer because the other types of mesothelioma are rarer. The TNM staging system for mesothelioma focuses on three important factors for understanding the spread and development of cancer.
TNM staging stands for:
T (tumor): This describes the size of the original tumor.
N (node): This indicates whether the cancer is present in the lymph nodes.
M (metastasis): This refers to whether the cancer has spread to other parts of the body.
Each factor is assessed and rated where 0 indicates there is no evidence of a tumor or spread and the increasing numbers correlate with increasing severity of that particular factor.
The stages of pleural mesothelioma are:
Stage I (stage 1 mesothelioma): The cancer is localized to either the right or left pleural lining. The cancer has not metastasized (spread) to any other sites or lymph nodes.
Stage II (stage 2 mesothelioma): The cancer affects either the right or left pleural lining and may have spread to a lung or the diaphragm. The lymph nodes are not affected.
Stage III (stage 3 mesothelioma): Other areas within the chest may now be involved. The cancer may extend into the chest wall and may or may not have spread to the lymph nodes.
Stage IV (stage 4 mesothelioma): The cancer may have spread across the chest. It has either metastasized to distant sites or the lymph nodes.
Next topic: How is mesothelioma diagnosed?