Mesothelioma Life Span

Although the disease of mesothelioma ultimately will cause the death of anyone diagnosed with this virulent form of cancer, there is no way to determine uniformly the life span of a mesothelioma patient.
The primary reason for this is simple: The process of mesothelioma begins when someone first inhales or ingests asbestos fibers, and it's not always clear when that exposure occurred. That exposure, when combined with repeated incidents, as happens during many on-the-job exposures, set the stage for a disease that doctors have yet figured out how to cure.

Determining Life Span
There are a number of factors and mitigating circumstances that must be examined from patient to patient. Among them are: how far along the cancer is when it is detected; the cell type of the cancer; the patient's overall health; and past health, such as whether the patient was a smoker. In one way or another, all those variants affect the life span of someone battling this lethal ailment.
 One important factor when assessing the life span of mesothelioma patients is its inordinately long latency period. Once asbestos fibers are in place to render a human body unhealthy, the mesothelioma they sometimes create can lie dormant for a period of 20 to 50 years. That is the typical time between asbestos exposure that begins the syndrome and its eventual diagnosis. That means that the true life span of a mesothelioma victim can be measured in decades; decades in which there are no symptoms, no pain or discomfort, and no detectable signs of the disease.
It is true that once mesothelioma is diagnosed, the medical prognosis is usually bleak. Pleural mesothelioma, if untreated, has an average life expectancy that ranges between four months and 18 months after symptoms appear. Peritoneal mesothelioma yields a five- to 13-month outlook, on average, if not treated.

Other Factors of Life Span
Another important factor that needs to be understood when assessing these statistics, and which has the tendency to skew them downward, is the relatively advanced age of the average mesothelioma patient. Most people diagnosed with mesothelioma are between 50 and 70 years old, with about 75 percent of patients in their mid-60s.
Therefore, the life expectancy for these individuals is understandably much shorter than for those who have other types of cancers and who may be much younger when their ailments are initially diagnosed.

Sources:

"100 Questions & Answers About Mesothelioma" by Harvey I. Pass, Amy Metula & Susan Vento; ISBN -13:978-0-7637-7123-2. Published by Jones and Bartlett Publishers, LLC - 2010.
"Fatal Deception – The Terrifying True Story of How Asbestos is Killing America." By Michael Bowker; ISBN: 0743251431. Published by Simon & Schuster - 2003.
National Comprehensive Cancer Network. NCCN Guidelines for Patients | Malignant Pleural Mesothelioma. Version 1.2011. Retrieved from: http://www.nccn.com/files/cancer-guidelines/mpm/index.html#/26/
National Institutes of Health. Mesogthelioma – malignant. (June 2, 2010). Retrieved from: http://www.nlm.nih.gov/medlineplus/ency/article/000115.htm
American Cancer Society. Malignant Mesothelioma. How is malignant mesothelioma staged? Retrieved from: http://www.cancer.org/Cancer/MalignantMesothelioma/DetailedGuide/malignant-mesothelioma-staging
American Lung Association. Understanding Mesothelioma. Retrieved from: http://www.lungusa.org/lung-disease/mesothelioma/understanding-mesothelioma.html