Once you have been diagnosed with mesothlioma, it is important to determine the spread of the disease. This is called staging and it is based on imaging studies from X-Ray scans, CT scans, MRI scans, PET scans and pathology results. Although there are three types of Mesothelioma (pleural, peritoneal and pericardial), only pleural mesothelioma (the most frequent of the three and the most studied) is staged. No classification or staging exists for peritoneal and pericardial mesethlioma. Staging is important since it helps in the prognosis and for the determination of the treatment plan. There are three types of staging systems:
- Butchart Staging System
- TNM Staging System
- Brigham Staging System
This Butchart staging system is both the oldest of the three and the most commonly used staging system. This system divides mesothelioma into four stages and it is mainly based on the primary tumor mass. The spread of mesothelioma increases from stage 1 to stage 4. If mesothelioma is diagnosed to be at stage 4, this may mean that there is evidence of metastasis (spreading of the mesothelioma through the bloodstream to other organs). This is the worst case scenario and such mesothelioma is extremely difficult to cure.
The TNM System is divided into four stages and takes into account three variables or components: the tumor (T), the lymph nodes (N) and metastasis (M). Metastasis (spread of mesothlioma to other organs through the bloodstream). As we advance through the stages the more is the spread of the tumour and the more is the chance that the lymph nodes are involved. Stage 4 is the worst case scenario where the disease may have spread through other organs through the bloodstream.
The Brigham system is the most recently devised. Mesothelioma is also divided into four stages and it is staged according to resectability (the ability to remove the tumor by surgery) and according to the involvement of the lymph nodes. The more the stages are reached, the more is the difficulty to remove the tumor and the more are the lymph nodes involved.