Like any cancer, mesothelioma has stages as well. Staging, in cancer, is the process of determining how far the cancer has spread, or how advanced it is. For mesothelioma, this is accomplished by utilizing the results of a number of imaging studies, like x-rays, CT scans, and MRI scans. There are two staging systems that are widely accepted: the Butchart System and the TNM Staging System.
The Butchart staging system divides mesothelioma into four stages and is based mostly on the extent of the mass of the primary tumor.
Stage One
In stage one, mesothelioma is seen in the tests in the right pleura or the left pleura, but not both. The tumor may also involve part of the lungs, the pericardium, and the diaphragm on the same side as the affected pleura. The diaphragm is the large, involuntary muscle that separates the chest cavity from the abdominal cavity.
Stage Two
During this stage, mesothelioma has invaded the chest wall or started to involve the esophagus, heart, or the formerly unaffected pleura on the other side. In addition, the lymph nodes located in the chest can also have little tumors in them. When mesothelioma invades the esophagus, swallowing and the conveyance of food from the mouth to the stomach may become difficult.
Stage Three
By this point, mesothelioma cells have worked their way through the diaphragm and into the peritoneum (the lining of the abdominal cavity). The cells may also have spread from the lymph nodes in the chest to those located elsewhere in the body.
Stage Four
Stage four is the last phase of mesothelioma. In this phase, there is evidence, sometimes extensive, of metastases throughout the body. These metastases are new pockets of mesothelioma that have been spread throughout the body via the bloodstream to other organs.
Recently, another system for classifying the stages of mesothelioma has been developed by the American Joint Committee on Cancer (AJCC). This system is similar to the staging systems used for most cancers in that it analyzes the tumor, lymph node, and metastases information into one big picture that is grouped into a roman numeral system from one through four. While it is very similar to the Butchart staging system, there are still minor differences between the two systems.
This newer system is much more detailed and precise than the older system; however, the original Butchart system is still used more frequently.
