If malignant mesothelioma has been diagnosed, the next step is a process called staging. Staging is the process of assessing how severe malignant mesothelioma is and whether or not it has spread to other organs (metastasized) or remained in one place (localized). It is been used to estimate a victim’s prognosis and to determine the most suitable therapy.
Butchart System of Staging
The Butchart System is the oldest staging system for malignant mesothelioma is based on the tumor size. Malignant mesothelioma is divided into four stages:
Stage 1: Malignant mesothelioma has affected the right or left side of the chest cavity (pleura) and may be seen in the diaphragm.
Stage 2: Malignant mesothelioma has been found in the pleura on both sides of the body and may have also moved into the heart, stomach, or esophagus on both sides. Lymph nodes may be affected.
Stage 3: Malignant mesothelioma has reached the abdominal cavity (peritoneum). Lymph nodes past the chest may be affected.
Stage 4: Malignant mesothelioma has reached other organs and has entered the blood stream.
TNM System
The TNM System is based on the extent of the tumor, metastasis, and lymph node involvement. The TNM System divides malignant mesothelioma into four stages:
Stage 1: Malignant mesothelioma is present in the left or right chest cavity (pleura) and may have metastasized to the lung, the sac around the heart (pericardium) or the diaphragm on the same side. Lymph nodes at Stage 1 are not involved.
Stage 2: Malignant mesothelioma has reached from one side of the chest cavity to a lymph node near the lung area on the same side as the cancer. The cancer has metastasized to the diaphragm, pericardium (sac around the heart) or the lung on the same side as the original cancer.
Stage 3: Malignant mesothelioma has penetrated the chest lining, heart, esophagus, muscle, ribs and vital organs within the chest cavity on the same side as the cancer. Lymph nodes may or may not be involved during this stage.
Stage 4: Malignant mesothelioma has metastasized to the pleural area and the lymph nodes on the opposite side of where the cancerous tumor is located. It may also have reached the chest cavities or lungs on both sides, or may have spread to the abdomen.
Brigham System
The Brigham System looks at different variables such as the involvement of the lymph nodes and the surgical ability to remove a malignant mesothelioma tumor. It is not often used to stage mesothelioma; however, when used it divides malignant mesothelioma into four stages:
Stage 1: Malignant mesothelioma tumor is still resectable (able to be removed surgically) and the lymph nodes are not affected.
Stage 2: Malignant mesothelioma tumor is still resectable (able to be removed surgically) but the lymph nodes are now affected.
Stage 3: Malignant mesothelioma tumor is not resectable (able to be removed surgically) and the malignant mesothelioma has penetrated the heart, chest wall, abdominal cavity or diaphragm. Lymph nodes may or may not be affected.
Stage 4: Malignant mesothelioma tumor is not resectable (able to be removed surgically) and has completely metastasized (spread throughout the body).
Use of Imaging to Stage Mesothelioma
When mesothelioma is diagnosed, an imaging procedure is needed to determine the extent of the cancer and how far it has spread (metastasized). The imaging options your physician may use include:
- Chest x-ray
- CT scan of the chest and/or abdomen
- MRI (Magnetic Resonance Imaging) scan of the chest and/or abdomen
- PET (Positron Emission Tomography) scan of the chest and/or abdomen
Once the stage of mesothelioma is determined, a prognosis can be made and a plan formulated for treatment.
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