Typical survival despite surgery is between 12 and 21 months depending on the stage of disease at diagnosis with about 7.5% of people surviving for 5 years.Women, young people, people with low-stage cancers, and people with epithelioid cancers have better prognoses. Negative prognostic factors include sarcomatoid or biphasic histology, high platelet counts (above 400,000), age over 50 years, white blood cell counts above 15.5, low glucose levels in the pleural fluid, low albumin levels, and high fibrinogen levels. Several markers are under investigation as prognostic factors, including nuclear grade, and serum c-reactive protein. Long-term survival is rare.Pericardial mesothelioma has a 10-month median survival time.In peritoneal mesothelioma, high expression of WT-1 protein indicates a worse prognosis. Epidemiology
Although reported incidence rates have increased in the past 20 years, mesothelioma is still a relatively rare cancer. The incidence rate varies from one country to another, from a low rate of less than 1 per 1,000,000 in Tunisia and Morocco, to the highest rate in Britain, Australia and Belgium: 30 per 1,000,000 per year. For comparison, populations with high levels of smoking can have a lung cancer incidence of over 1,000 per 1,000,000. Incidence of malignant mesothelioma currently ranges from about 7 to 40 per 1,000,000 in industrialized Western nations, depending on the amount of asbestos exposure of the populations during the past several decades. Worldwide incidence is estimated at 1-6 per 1,000,000.
Indeed, the relationship between asbestos and mesothelioma is so strong that many consider mesothelioma a "signal" or "sentinel" tumor. A history of asbestos exposure exists in most cases. Pericardial mesothelioma may not be associated with asbestos exposure.Asbestos was known in antiquity, but it was not mined and widely used commercially until the late 19th century. The dangers were not unknown in antiquity. Pliny the Elder, a Roman author and naturalist, observed that quarry slaves from asbestos mines tended to die young. Its use greatly increased during World War II. Since the early 1940s, millions of American workers have been exposed to asbestos dust. Initially, the risks associated with asbestos exposure were not publicly known. However, an increased risk of developing mesothelioma was later found among naval personnel (e.g., Navy, Marine Corps, and Coast Guard), shipyard workers, people who work in asbestos mines and mills, producers of asbestos products, workers in the heating and construction industries, and other tradespeople. Today, the official position of the U.S. Occupational Safety and Health Administration (OSHA) and the U.S. EPA is that protections and "permissible exposure limits" required by U.S. regulations, while adequate to prevent most asbestos-related non-malignant disease, are not adequate to prevent or protect against asbestos-related cancers such as mesothelioma. Likewise, the British Governments Health and Safety Executive (HSE) states formally that any threshold for exposure to asbestos must be at a very low level and it is widely agreed that if any such threshold does exist at all, then it cannot currently be quantified.