Symptoms of Mesothelioma

Staging is a process which allows physicians to evaluate the local extension and the distant diffusion of a tumor. It is one of the most important factors in the choice of a treatment and in making a prognosis. In the case of MMe, the only staging systems available are for the most popular pleural mesothelioma. The information needed to determine the stage of a pleural mesothelioma come through imaging techniques. The staging systems most commonly used today are The Butchart System and the most recent TNM System.

The Butchart System
It is based solely on the extension of the primitive tumoral mass and is able to distinguish four different stages. Stage I: tumor confined within the right or left pleura, which can affect the lung, the diaphragm, or the external portion of the homolateral pericardium (on the same side of the primitive mass). Stage II: the tumor invades the chest wall, the mediastinum and the structures it contains (esophagus, trachea, great vessels), the heart or both sides of the pleura. Even the intrathoracic lymph nodes are implicated. Stage III: Tumor that infiltrates the diaphragm and affects the peritoneum and/or the extra parietal spaces. Invasion of extra thoracic lymph nodes. Stage IV: the presence of distant metastasis.

TNM Staging System
This classification was drafted by the American Joint Committee on Cancer and it takes in to account three main variables: variable T, which describes the size of the primitive mass and its extension into neighboring structures; variable N, which evaluates a possible invasion into the lymph nodes; and the variable M, which considers the possible presence of metastases of distant organs. The union of these three parameters allows for staging. Such stages can therefore describe the exact extent of the neoplasm: Stage I: tumor confined only to the right and left pleura. It can affect the lung, the pericardium or the homolateral diaphragm. Lymph nodes are not implicated. Stage II: the tumor extends into the peribronchial and/or homolateral ilary lymph nodes. Lungs, diaphragm or homolateral pericardium could already be affected. Stage III: The tumor invades the muscles of the chest wall, ribs, the heart, the esophagus or other organs found inside the homolateral chest wall with or without invasion of the sub-carinal and/or homolateral mediastinal lymph nodes. Stage IV: tumor that has invaded the heterolateral intrathoracic lymph nodes (on the opposite side of the primitive mass) and/or tumor that involves through direct extension: heterolateral pleura and/or lung, peritoneum and/or abdominal organs-structures of the neck and any tumor showing a distant metastasis. In the TNM classification, the first stage configures a localized MMe, while the following three stages reflect advanced stages of the disease.

Prognostic factors
Besides the extension of the illness, other factors are associated with the prognosis of peritoneal mesothelioma.
Age at the time of the diagnosis, a good performance status (functional condition of the patient), and the absence of weight loss, are all predictors of a better course of the illness. Another important prognostic factor is the histological type. The course of epithelial MMe is much less severe than fibrosarcomatoid MMe. Mixed cell Mme, however, has a prognosis.