MESOTHELIOMA STAGES

Treatment options are often determined by the stage of mesothelioma a patient is in. There are three staging systems currently in use for pleural mesothelioma and each one measures somewhat different variables; peritoneal mesothelioma is not staged.
Staging is the term used to describe the extent of a patient's cancer, based on the primary tumor and its spread in the body. It can help the medical team plan treatment, estimate prognosis and identify clinical trials for which the patient may be eligible.
Staging is based on a knowledge of how the cancer develops, from the primary tumor, to the invasion of nearby organs and tissues, to distant spread or metastasis. Staging systems have evolved over time, and they continue to change as scientists learn more about cancer. Some staging systems cover many different types of cancer, while others focus on more specific cancers. The TNM (primary tumor, regional lymph nodes, distant metastasis) is the most common staging system for mesothelioma.
Some elements common to most staging systems are:

• Location of the primary tumor.
• Size and number of the tumors.
• Lymph node involvement.
• Cell type and tumor grade.
• Metastasis.

Many cancer registries, such as the National Cancer Institute's Surveillance, Epidemiology, and End Results Program (SEER) use summary staging, a system used for all types of cancer. Summary staging groups cancer into five main categories:

• In situ - cancer that is present only in the layer of cells in which it began.
• Localized - cancer that is limited to the organ in which it began with no evidence of spread.
• Regional - cancer that has spread from the primary site to nearby lymph nodes or organs.
• Distant - cancer that has spread from the primary site to distant lymph nodes or organs.
• Unknown - cases where not enough information exists to indicate stage.

Several types of testing may be used to help doctors determine stage, and to formulate a treatment plan.

• Physical examinations. The doctor examines the body by looking, feeling and listening to anything out of the ordinary.
• Imaging techniques. Procedures such as x-rays, CT scans, MRIs and PET scans may show the location, size of the tumor and whether the cancer has spread.
• Laboratory tests. Studies of blood, urine, fluid and tissue can provide information about the cancer. Tumor markers, sometime elevated when cancer is present, may provide information.
• Pathology reports. Results of the examination of tissue samples can include information about the size of the tumor(s), extension into adjacent structures, type of cells and grade of the tumor. Results of the examination of cells in fluid, such as that from a mesothelioma-related pleural effusion, may also provide information.
• Surgical reports. Observations about the size and appearance of the tumor(s), lymph nodes and nearby organs.

Staging information should be provided to the patient by his doctor so that potential treatment plans can be discussed. Stage of the mesothelioma, as well as consideration of other factors such as age, health status and the patient's wishes may dictate different treatment options.
The oldest staging system and the one most often used is the Butchart System which is based mainly on the extent of primary tumor mass and divides mesotheliomas into four stages. The more recent TNM system considers variables of tumor in mass and spread, lymph node involvement, and metastasis. The Brigham System is the latest system and stages mesothelioma according to resectability (the ability to surgically remove) and lymph node involvement.