Mesothelioma is a thin, fast-spreading tumor of the pleura, peritoneum or pericardium. These are tissues that surround and encase internal organs. It almost always arises from exposure to asbestos, either on the job or in the home, and can take many years to develop. About 3,000 people are diagnosed with malignant mesothelioma in the United States every year.
Because mesothelioma is such a rare cancer, many published studies focus on a single notable case or a small group of cases. A new study conducted by the Texas Occupational Medicine Institute attempts to paint a bigger picture of mesothelioma by analyzing a larger number of cases. The Texas researchers report on the findings of 238 cases of malignant mesothelioma from a private medical practice. Most of the cases had a history of exposure to asbestos at work. Their observations included the following:
Latency – Despite isolated cases of short latency (such as the recent case of a woman who contracted mesothelioma just 8 years after exposure), this cancer usually takes at least 20 years to develop. The Texas researchers found a mean latency in their study of 48.5 years. The disease took longer to develop in woman than it did in men. They also found that people who were exposed to smaller amounts of asbestos tended to develop the disease later that those who had higher exposure.
Patient Characteristics – Primarily because of this long latency, mesothelioma is normally a disease of the elderly. The mean age at diagnosis in the Texas study was 70. Men appear to be more likely to contract mesothelioma than women, even with the same level of exposure.
Survival – Mesothelioma remains a difficult disease to treat. The Texas researchers found an overall survival among study participants of just 8.8 months. On the positive side, those who underwent treatment did live longer – about 11.3 months as opposed to 6.4 months without treatment. The analysis also confirmed that mesothelioma patients with the epithelioid variety survive longer and do better with treatment than do patients with the sarcomatoid or biphasic varieties.
The analysis was published in the journal Industrial Health.
Haber SE, Haber JM, “Malignant Mesothelioma: A clinical study of 238 cases”, December 16, 2010, Industrial Health. Epub ahead of print.
Bitchatchi E, Kayser K, Perelman M, Richter ED, “Mesothelioma and asbestosis in a young woman following occupational asbestos exposure: Short latency and long survival: Case Report”, December 16, 2010. Diagnostic Pathology. Epub ahead of print.