The latency of mesothelioma has been one of its greatest problems and may partly explain why a connection with asbestos exposure took so long to be accepted as the primary cause. Mesothelioma latency isn’t known exactly since exposure to asbestos doesn’t always equate directly or immediately to an insult to the tissues. Consequently, estimates of latency vary widely with mesothelioma patients being reported in age ranges from early teens to octogenarians.
Assuming a diagnosis of mesothelioma is confirmed, staging of the disease remains extremely difficult and is an obstacle to effective treatment. Mesothelioma 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.
Progression of Mesothelioma
Stage 1 and 2 mesothelioma 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. The stages of mesothelioma, therefore, have a pivotal role in choosing treatment options and determining the prognosis for mesothelioma patients. Treatment options and outcomes are discussed in detail under the mesothelioma treatment section of this web site.
If you have more questions or are looking for personalized information, contact our Patient Services Director for resources and critical information to help you make sense of your mesothelioma diagnosis
Standardizing the Mesothelioma Staging Process
Since staging is essential to selecting the appropriate mesothelioma treatment, much effort has been invested in developing an accurate pre-operative mesothelioma 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. Read about progress in this area here.
Both the International Mesothelioma Interest Group and Brigham & Women’s Hospital have developed systems used to identify the stages of mesothelioma 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 mesothelioma staging system used, patients with stage 3 or higher disease are almost always only considered for chemotherapy. This is because stage 3 mesothelioma 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.
Progression of Meso and Life Expectancy
Since symptoms are often misdiagnosed or even absent during early stages, the rate of mesothelioma progression is also a guess. The most commonly available figures pertain to median survival time from the date of diagnosis but many mesothelioma experts believe the tumor may be in existence for quite some time before diagnosis.
Even survival times vary widely with no clear consensus emerging. On the low side, survival times of 4 to 8 months are reflected in the information to be gleaned from obituaries and tributes paid to the afflicted. On the high side, 12 to 18 months is considered the norm, although this number is demonstrating some upward movement and tends to become differentiated when mesothelioma types, categories and treatments are considered as part of the assessment.
