Mesothelioma Stages

If the diagnosis is mesothelioma, your doctor will need to know the stage of your disease. Staging defines how far the cancer has spread from its original location to other parts of the body.

Staging can be clinical or pathological. Clinical staging relies on scanning tests and x-rays. Pathological staging refers to staging done at surgery.

Malignant mesothelioma moves through four stages, each one more serious than the next. The cancer is described as localized if it is found only on the lining surface where it originated. If the cancer has spread beyond the original site to other parts of the body, such as the lymph nodes, chest wall, or abdominal organs, it is considered as advanced.

The stage of the cancer will determine treatment options and helps determine the prognosis of the disease. Pleural mesothelioma is the only mesothelioma that has a staging system. But the clinical staging systems are considered inadequate due to the way the disease spreads.

The staging systems used include:
• The Brigham System, the latest system, which stages mesothelioma according to the ability to surgically remove it and lymph node involvement.
• The Butchart Staging System, based upon how far the disease has spread to and invaded other organs.
• The TNM system, which considers variables of tumor mass and spread, involvement of lymph nodes, and metastasis.

Mesothelioma tends to grow and spread in unusual ways compared to other tumors. Rather than forming a lump, mesothelioma tends to extend from the pleural lining to press against the lung or abdominal organs. It also grows along the pleural lining, eventually forming a hard casing around the lung (like the peel of an orange). This makes taking a deep breath difficult.

Mesothelioma generally does not spread widely to other organs. It tends to involve the chest and lungs or abdominal cavity before spreading to other distant organs, late in the course of the disease. If the disease is detected early, when only limited growth on the pleural lining has occurred (stage I), the tumor is considered potentially curable, and an attempt can be made to surgically remove the entire tumor. Usually, however, the tumor is detected later, when it more extensively involves the pleural lining and has possibly invaded surrounding normal structures. In these advanced stages (stages II, III, and IV), the cancer may not be considered curable and is generally treated to extend survival and improve symptoms and quality of life.

Assuming a diagnosis of mesothelioma is confirmed, staging of the disease remains extremely difficult and is an obstacle to effective treatment. Staging techniques require knowledge about where the tumor is located, how extensive it is and whether it is still locally contained or whether it has metastasized to organs or adjacent tissues.

Since staging is essential to selecting the appropriate treatment, much effort has been invested in developing an accurate pre-operative staging technique. Because of the difficulty of imaging the extent of mesothelioma and its presence or absence in the lymph nodes, staging pre-operatively remains a fairly imprecise process. Several recent attempts have been made to establish a standard process.

Both the International Mesothelioma Interest Group and Brigham & Women's Hospital have developed staging systems based upon a common set of variables. These are:
• T or tumor staging - what is the size and location of the tumor in relation to nearby organs and structures?
• N or nodal staging - are lymph nodes positive or negative for meso?
• M or metastatic staging - is there evidence of metastasis?

Each variable above is expressed as a number and the final combination is compared to a table to establish staging. Negative nodes and metastasis is represented as N0 and M0 Regardless of the staging system used, patients with stage 3 or higher disease are almost always only considered for chemotherapy. This is because stage 3 implies that the tumor is no longer locally contained and cannot be removed (resected) by surgical means.

Recent studies with genomics have added an additional set of considerations to outcome. An assay of the markers of genetic damage in a population of patients seems to co-relate certain genotypes to a better prognosis or outcome. While most of this material is just now being published, it may soon be possible to examine mesothelioma cells for DNA markers that can forecast whether the patient would benefit from aggressive surgical treatment or not.

Stage 1 and 2 patients tend to be surgical candidates, while stage 3 and stage 4 patients are generally offered chemotherapy in combination therapies. Radiation is rarely offered as a primary treatment since it has little effect on its own. Staging, therefore, has a pivotal role in choosing treatment options and determining the prognosis for mesothelioma patients.

Stage 1: Mesothelioma is localized - detected in the pleura of one of the two lungs, but not both. May also affect the pericardium (lining of heart)
Stage 2: Cancer spreads from lung to the lymph nodes
Stage 3: Tumor spreads to peritoneal, chest wall, heart, ribs or other chest organs on the same side as the originally afflicted lung
Stage 4: Cancer has metastasized, which means it has spread throughout the rest of the body through the blood stream.

Currently, there is no known cure for mesothelioma. In the United States, 2,000 to 3,000 new cases are diagnosed each year. Because the disease has an extremely long incubation period, up to 50 years in some instances, the cancer is usually not detected until the very advanced stages. Approximately 75% of victims die within a year of being diagnosed. However, there are several treatment options doctors may use to contain the cancer and prolong the victim’s life. The most common treatments include surgery, chemotherapy, and radiation therapy. Doctors are constantly working on new experimental treatments as well.

Mesothelioma is a devastating and lethal disease made even more disturbing by the fact that many companies deliberately covered up information known about the ill effects of asbestos. Mining companies had definitive proof of the lethal effects of airborne asbestos particles before asbestos reached the peak of its popularity. Not wanting to lose a cheap and extensively utilized additive, officials in some companies falsified reports and even forced company doctors to purposely misdiagnose mesothelioma sufferers with lung or chest cancer.