Staging And Outcomes

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. (t)

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. (q) (r) (s) 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. Treatment options and outcomes are discussed in detail under the treatment section of this web site.