Mesothelioma Staging Techniques

Mesothelioma Diagnosis

Mesothelioma Staging: Has the Cancer Spread?

Once you have been diagnosed with mesothelioma, your doctor will want to learn the extent of the disease and whether the cancer has spread to various parts of the body or to the lymph notes. Finding out this information is called staging. Knowing the phase or stage of mesothelioma will help your doctor plan treatment. For example, mesothelioma patients in early stages of the disease may be eligible for surgery. Once the mesothelioma is more advanced, pain reduction or palliative treatment may be the best course of action (see J Thorac Cardiovasc Surg. 1996 Apr; 111(4): 815–25, National Cancer Institute: Treatment by Stage, and Mesothelioma Treatment: Surgery). The decision is up to you and your doctor, but may be strongly influenced by your stage of mesothelioma.

Generally, mesothelioma is considered localized if the cancer is found only on the membrane surface where it originated. It is classified as advanced if it has spread beyond the original membrane surface to other parts of the body, such as the lymph nodes, lungs, chest wall, or abdominal organs.

There is no standard staging system for peritoneal mesothelioma. There are two staging systems for pleural mesothelioma—the TNM system, which is concerned with tumor size, lymph node analysis, and how far the tumor has spread (metastasis), and the older Butchart system, based on the extent of the primary tumor. Most cancer centers are using the TNM system in preference to the Butchart system of staging.

The TNM System of Mesothelioma Staging

Also known as the International Mesothelioma Interest Group staging system, the TNM system of mesothelioma consists of four stages (American Cancer Society, How is Mesothelioma Staged). In Stage I, the mesothelioma is in the membrane lining the chest (the right or left pleura), and has not spread to the lymph nodes. In stage II, the mesothelioma involves the right or left pleura lining the chest. It has also spread from the lining of the chest into the outer lining of the lung, into the diaphragm, or into the lung.

Besides involving the chest pleura, Stage III mesothelioma has spread into the first layer of the chest wall, part of the mediastinum (the chest cavity behind the breastbone that lies between the lungs), or a single place in the chest wall. It may also have spread to the outer covering layer of the heart or to lymph nodes on one side of the chest. In Stage IV mesothelioma, the disease has advanced to other organs in the body such as the liver, brain or bone or to lymph nodes on both sides of the chest.

Mesothelioma Staging Using the Butchart System

The Butchart system of staging also consists of four stages. In Stage I, mesothelioma is present on only one side of the chest pleura. In Stage II, the disease is also present in the chest wall, heart, or esophagus (the food passage connecting the throat to the stomach). It may also be in the pleura on the other side of the chest as well as in the chest lymph nodes. In Stage III, mesothelioma has entered the diaphragm and the peritoneum (lining of the abdominal cavity) or has spread to lymph nodes beyond those in the chest. In Stage IV, mesothelioma has spread to many organs.

How Mesothelioma Staging is Accomplished

Imaging using computed tomography scans (CT), magnetic resonance imaging (MRI), or positron emission tomography scans (PET) helps determine the mesothelioma stage. CT scans are most commonly used, although PET scans have grown in importance. See PET Use in Mesothelioma Diagnosis and Staging.