Mesothelioma Staging: Staging Systems and Stages

Mesothelioma staging refers to the process in which doctors attempt to determine the severity and prognosis of a patient with this rare, asbestos-related cancer. There are four stages, each determined by the severity and spread of the cancer, as well as metastasis markers. Metastasis is the rate at which the cancer cells have or are multiplying to other, distant parts of the body. Mesothelioma staging is done in a hospital environment where various tests are ordered, many of which also assist with diagnosis and treatment plans. Historical information about the most common type of mesothelioma, pleural mesothelioma, is the basis for diagnosis, prognosis, and staging.

Mesothelioma Staging is Part of the Diagnosis\Prognosis Process

When a patient exhibits the symptoms of mesothelioma, has a history of exposure to asbestos and other conditions have been eliminated, a medical expert will order various tests and screening procedures to be completed on the patient.

Various images of the chest or abdomen are interpreted by a radiologist in an effort to identify the presence of tumors (groupings of cancerous cells). Doctors typically request imaging and test procedures to be performed on the patient during the initial diagnosis and again following each treatment to determine the exact location and severity of the cancer.

Common tests to identify the presence of cancer include:

•  Chest X-Rays
•  MRI (magnetic resonance imaging) scans
•  PET (positron emission tomography) scans
•  Blood tests
•  Biopsy

PET scans are often ordered at regular intervals for patients who are in remission – when the cancer is getting better or has, at least, stopped growing. Because mesothelioma often goes undetected until its later stages, however, most patients do not experience remission with malignant mesothelioma.

Biopsies provide an accurate mesothelioma staging tool by detecting which types of cancer cells are present. When one or more types of cancer cells are present, doctors know that the stage of mesothelioma is more advanced, the prognosis is worse, and the condition of the patient is likely to be quickly deteriorating. A biopsy is typically requested after imaging scans have shown that there may be the presence of tumors in the chest or abdominal cavities.

Mesothelioma Staging – Stages 1, 2, 3, and 4

Understanding the stage to which mesothelioma has progressed provides a better picture of the patients treatment options and prognosis (the outcome) of the disease for the individual patient. Stage 4 Mesothelioma is treated with more aggressive, invasive tactics and usually comes with a poor prognosis and life-expectancy of less than one year. Stage 1 Mesothelioma is treated as non-invasively as possible and the patient’s prognosis and life-expectancy is much greater if the patient responds well to treatment.

Mesothelioma staging is based largely on the study of pleural mesothelioma. Other types of mesothelioma (peritoneal and pericardial) are much less common, so oncology experts have been unable to derive statistics for them. Pleural mesothelioma is a malignant form of the cancer that begins in the lining of the lungs (the “pleura”) and, over time, may spread to other organs and tissues. The four stages of mesothelioma are:

The spread of cancer to distant parts of the body is called metastasis, which is the primary indicator used to determine advanced stages of mesothelioma. When mesothelioma has spread to other parts of the mesothelium, the stages incrementally increase in number. For example, mesothelioma that is only present in one area of the lungs is considered “Stage 1 Mesothelioma”. Alternatively, mesothelioma that has spread to distant organs and lymph nodes is considered “Stage 4 Mesothelioma”.

Other characteristics and indicators also assist in mesothelioma staging, such as the presence of pleural effusion (fluid in the chest) and the composition of the fluid. (Composition is determined through a special biopsy by placing a needle through the chest wall and between two ribs to draw a sample of fluid from the pleura.)

Doctors use a “staging system” to determine the classification and severity of mesothelioma cancers. There are two primary mesothelioma staging systems and all are based upon the statistical information available from case-studies of pleural mesothelioma.

Mesothelioma Staging – Butchart Staging System

The oldest mesothelioma staging system, the Butchart System, was developed as a classification for pleural mesothelioma and places the cancer patient’s condition into one of the following classes.

Mesothelioma Staging – TNM Staging System

The TNM staging system is the newest, most commonly used system to identify the progression of mesothelioma and was developed by the International Mesothelioma Interest Group. TNM is most aligned with all other cancer staging systems.

The TNM Staging System places malignant mesothelioma into four classifications as well:

The acronym “T.N.M.” represents the three primary markers used to determine mesothelioma staging:

•  T – Tumor; size and spread to immediate organs
•  N – Nodes; lymph nodes that have been affected by the mesothelioma
•  M – Metastasis; distant organs, tissues, and lymph nodes affected by the mesothelioma