Staging is important because it defines the treatment plan and the prognosis. Staging is the process which describes the stage of progression that the cancer is at. Staging involves evaluating whether the cancer has spread to the lymph nodes or to other parts of the body (known as metastasis).
CT and MRI scans are useful for determining local spread of the disease. However, clinical staging based on the x-rays and the symptoms is very difficult.
At the time of first surgical diagnosis through thoracoscopy, exploration of the pleural cavity by camera can determine the extent of the local disease.
As with many types of cancer, the staging process of mesothelioma involves 4 stages. These range from stage 1 which is the best prognosis, to stage 4 which means that the cancer has spread to other parts of the body. Stage 4 has the worst prognosis.
Pleural Mesothelioma Staging
Staging the pleural mesothelioma involves assessing the size of the tumour and whether it has spread. It is also important to establish whether the cancer has spread to the lymph nodes.
Involvement of the lymph nodes is important in relation to prognosis. Spread to the lymph nodes confirms the disease at stage 3 and that it has progressed significantly. The lymph nodes are small pea shaped structures found throughout the body, and they are part of the immune system. Their job is to attach bacteria. Lymph nodes are connected by a system of vessels called lymphatic vessels. These connect the lymph nodes and allow the flow of lymph (the fluid is made up of excess tissue fluid and protein). The lymph nodes often enlarge in the presence of cancer. The only way to have an accurate staging is via biopsy that takes samples of the lymph nodes. This procedure is called a mediastinoscopy. This is a surgical procedure prepared under general anaesthetic via small incision into the chest, and the insertion of a scope (called a mediastinoscope) to obtain tissue samples.