Doctors employ the use of “stages” in both cancer diagnoses and monitoring to determine the progress of an individuals’ disease.  Staging takes a close look at cancers, like Mesothelioma, and determines to what extent it has developed and/or spread.  Most importantly, staging helps determine the course of treatment.

Currently, though there are three types of Mesothelioma – pleural, peritoneal, and pericardial – staging has thus far been established for the most frequently occurring form of this cancer - pleural - and not for the others. The three systems that stage this disease are the Butchart, TNM, and Brigham systems. 

Butchart is the oldest system and is still the most commonly used.  Its four stages are based on the extent of primary tumor mass.

Stage I: Mesothelioma is present in the right or left pleura (the thin, transparent membrane which covers the lungs and lines the inside of the chest walls) and may also involve the diaphragm (the muscle separating the chest from the abdomen) on the same side.

Stage II: Mesothelioma invades the chest wall or involves the esophagus (food passage connecting the throat to the stomach, heart, or pleura on both sides. Lymph nodes in the chest may also be involved.

Stage III: Mesothelioma has penetrated through the diaphragm into the lining of the abdominal cavity or peritoneum. Lymph nodes beyond those in the chest may now be affected as well.

Stage IV: There is evidence of metastasis (the spreading of the Mesothelioma) through the bloodstream to other organs.

The TNM System looks at three components: the tumor (T), the lymph nodes (N), and the spreading of the disease, otherwise known as metastasis (M).  It is also divided into four stages.

Stage I: Mesothelioma involves right or left pleura and may also have spread to the lung, pericardium (the fluid filled sac that surrounds the heart), or diaphragm on the same side. Lymph nodes are not involved.

Stage II: Mesothelioma has spread from the pleura on one side to nearby lymph nodes next to the lung on the same side. It may also have spread into the lung, pericardium, or diaphragm on the same side.

Stage III: Mesothelioma has now invaded the chest wall, muscle, ribs, heart, esophagus, or other organs in the chest on the same side. It may or may not have spread to lymph nodes on the same side as the primary tumor.

Stage IV: Mesothelioma has spread into the lymph nodes in the chest on the side opposite the primary tumor, or extends to the pleura or lung on the opposite side, or directly extends into organs in the abdominal cavity or neck. Any distant metastasis is included in this stage.

The most recent system to be devised is the Brigham System.  It stages the disease according to the ability to surgically remove the tumor (resectability) and the involvement of the lymph nodes.  It, too, is divided into four stages.

Stage I: Mesothelioma is resectable and no lymph node involvement.

Stage II: Mesothelioma is resectable but with lymph node involvement.

Stage III: Presence of unresectable Mesothelioma extending into the chest wall, heart, or through the diaphragm or peritoneum; with or without extra-thoracic lymph node involvement.

Stage IV: Distant metastatic disease (widespread cancer throughout the body).

Diagnosis is achieved in a number of ways, especially because other diseases may possess similar symptoms to those presented by Mesothelioma.  A wide variety of imaging techniques may be used in diagnosis, such as CT scans, MRI, and conventional x-rays.  Some doctors also choose to test the pleural fluid for malignant cells. 

Biopsy, however, is by far the most accurate way to diagnose Mesothelioma.  Needle biopsies, done under local anesthetic, may be used but provide only small tissue samples.  That means the accuracy rate might be less than desirable.  The preferred course of action in suspected Mesothelioma is an “open” biopsy, which provides a larger tissue sample.  This type of biopsy is performed in a hospital setting under general anesthesia.

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