There are four stages of mesothelioma, each defined by certain disease characteristics.
Early stage mesothelioma patients have more treatment options and a better prognosis.
Advanced, late stage mesothelioma can often only be treated palliatively.
Pleural mesothelioma is the only type with an approved staging system.
Mesothelioma staging is the process of classifying how far the cancer has spread throughout a patient’s body. An oncologist determines a mesothelioma patient’s specific stage using a combination of diagnostic tests including physical exams, biopsies, and imaging tests. Pleural mesothelioma is the only type with a formal staging system, but there are other ways that allow oncologists to determine the cancer’s stage for patients with peritoneal or pericardial mesothelioma.
Determining the stage of malignant mesothelioma happens during a patient’s diagnosis and largely informs both the patient’s treatment options and prognosis. For mesothelioma, there are four stages (1-4), and patients with early stage mesothelioma generally have the most treatment options and a more favorable prognosis. Read on to learn more about the characteristics of the four stages according to various cancer staging systems and how the stage of mesothelioma at diagnosis affects a patient’s treatment plan.
- No metastasis or lymph node involvement
- Curative treatment options
- Best prognosis
- Tumor has metastasized with minimal spread to lymph nodes
- Curative treatment is an option
- Localized to one side of the body
- Tumor has spread to nearby organs and lymph nodes
- Treatment options are usually palliative and non-surgical
- Spread to both sides of the body
- Tumor has spread to multiple organs, lymph nodes, and blood vessels
- Treatment is generally palliative
Pleural Mesothelioma Staging Systems
Malignant pleural mesothelioma, the most common type of mesothelioma, is the only type of mesothelioma that has an approved staging system at this time. Like many other cancers, the stages of pleural mesothelioma can be either stage 1, 2, 3, or 4. Each stage is defined by a particular set of criteria. As the stage becomes higher in number, the disease is generally more advanced, more difficult to treat, and carries a worse life expectancy. Also, treatment options for early stage disease are typically intended to be curative, while advanced stage disease is generally limited to palliative treatments that are non-curative. Patients with late stage disease typically experience worsening symptoms, like chest pain and fluid accumulation in the abdomen, so palliative care seeks to lessen these symptoms and improve quality of life.
Many staging systems have been developed and used over the last several decades for pleural mesothelioma. Each staging system possesses specific criteria for the different stages.
TNM Staging System
The most common staging system for pleural mesothelioma is known as the American Joint Committee on Cancer (AJCC) TNM staging system. It may also be referred to as the International Mesothelioma Interest Group (IMIG) staging system. Both the AJCC and IMIG have approved the staging system for universal use.
The TNM acronym represents the following: Tumor, Node, and Metastasis. Following each letter in the TNM acronym, a number is assigned to designate the extent of disease in that particular category. The information identified by TNM is then collectively used to assign a corresponding stage. For example, a person with T1N0M0 disease represents a tumor that is confined to the site of origin (T1) and is without nodal (N0) or metastasis (M0). The TNM information in this example corresponds to a stage 1.
Refers to disease which is confined to the primary site, or site of origin. The lymph nodes are free of disease and there are no metastases present. Most often, treatment for stage I mesothelioma consists of surgical resection, or removal, of the disease.
Refers to disease which is confined to one site. While the lymph nodes are still free of disease and there are no metastases present, the tumor extends into the deeper pleural surfaces on the same side as the tumor as well as at least one of the following: the diaphragm or the lung.
Refers to disease which either has spread to lymph nodes on the same side as the tumor; or, a tumor which is extensive and involves the deeper pleural surfaces as well as at least one of the following: chest wall, thoracic fascia, sac around the heart, or mediastinal fat. The tumor is still considered resectable by surgery. There is no metastasis present.
Refers to disease in which one of the following occurs: the tumor is too extensive for surgery, there is distant lymph node involvement on the opposite side from the tumor, or there is distant metastasis present.
The Brigham Staging System
The Brigham staging system is another older staging system for pleural mesothelioma. It is primarily focused on whether or not a tumor is able to be surgically removed. Attention is also given to whether or not the cancer has spread to the lymph nodes. Stages 1 and 2 represent tumors which are amenable to surgical resection, while stages 3 and 4 represent more advanced disease states that are not amenable to surgical resection. Patients who undergo surgical resection have a better prognosis than patients who do not undergo surgical resection.
At this point, mesothelioma is resectable and there is no lymph node involvement.
Mesothelioma is still respectable during stage II, but the lymph nodes are now involved.
This stage involves the presence of unresectable mesothelioma extending into the chest wall, heart, or through the diaphragm or peritoneum; with or without extra-thoracic lymph node involvement.
This stage indicates distant metastatic disease (widespread cancer throughout the body).
The Butchart Staging System
The Butchart staging system is the oldest staging system. It is based mostly on extent of the primary tumor. This system is limited in that researchers developed it from a small sample of patients. Additionally, it was developed prior to the use of modern imaging methods, such as CT scans.
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.
Mesothelioma has invaded 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 once the cancer reaches Stage II.
Mesothelioma has penetrated through the diaphragm into the lining of the abdominal cavity or peritoneum. Lymph nodes beyond those in the chest may also be affected.
There is evidence of metastasis (the spreading of the mesothelioma) through the bloodstream to other organs.
Staging Peritoneal, Pericardial, and Testicular Mesothelioma
Unlike pleural mesothelioma, peritoneal, pericardial, and testicular mesotheliomas do not currently have a universally accepted staging system. This is because there are not enough cases each year to develop and validate a formal staging system. Without a large sample of patients, it becomes increasingly difficult to develop and validate both staging systems and treatment options.
In the absence of a formal staging system, peritoneal mesothelioma is most often treated according to whether or not it is confined to the abdomen. If the mesothelioma tumors are confined to the abdomen, surgical removal is often attempted with the possibility of delivering heated chemotherapy directly into the abdomen during the surgery in a procedure called HIPEC (hyperthermic intraperitoneal chemotherapy).
If the disease is not confined to the abdomen, chemotherapy, radiation therapy to specific sites of metastases, or both may be administered. Prognosis for peritoneal mesothelioma is generally poor. Patients who are able to undergo surgical removal and HIPEC have a greater prognosis with median survival around three years.
Pericardial mesothelioma is rarer than even peritoneal mesothelioma, and therefore has very limited information available regarding staging and very limited treatment options. The size of the tumor on the pericardium, or sac surrounding the heart, often determines the type of treatment that is carried out.
Surgery involving the pericardium carries significant risk. Smaller tumors may be appropriate for surgical removal, whereas larger tumors often cannot be safely removed. Treatment options outside of surgical removal are limited and prognosis for pericardial mesothelioma is universally poor with many patients surviving between six and ten months from diagnosis.
Testicular mesothelioma is also a very rare type of mesothelioma. Staging is often determined by whether the mesothelioma cells are localized to one site of the testis, or has spread outside of the area of the primary disease site. Surgical removal of tumors that are confined to the abdomen or are limited to nearby lymph nodes provides the best opportunity for survival. Prognosis for testicular mesothelioma is around two years.
Developing a Treatment Plan After Staging
In conclusion, mesothelioma is a complex disease requiring careful assessment and diagnosis. Discussing the specifics of mesothelioma staging with a cancer doctor is important in order to fully understand the meaning of a disease stage. Following staging, a treatment plan can be determined, taking into account type and cell type, staging, prognosis, and overall health of the patient.
Financial Help For Mesothelioma Patients
The process of staging and determining a treatment plan come with burdensome medical costs. There also may be costs associated with losing income if you need to take time off work following a diagnosis. If you or someone you know has been diagnosed with mesothelioma, there are options to help ease or fully cover treatment and related expenses.