What is malignant mesothelioma?
Malignant mesothelioma is a rare form of cancer (uncontrolled growth and spread of abnormal cells) that begins in the mesothelium. The mesothelium is a thin, protective layer of cells that lines the wall of the chest and abdomen. These cells also cover most of the internal organs, including the lungs and heart.
Malignant mesothelioma is almost always caused by exposure to asbestos. Asbestos is a natural mineral that resists heat. Before the 1970s, asbestos was commonly used in the United States to make insulation and to make many products safer against fire. While asbestos is still in use today, exposure limits were set by the federal government in 1972.
What is leukemia?
Leukemia is a cancer that affects the blood and bone marrow, the soft, spongy material in the center of bones where blood cells are made. Leukemia causes the uncontrolled growth of abnormal white blood cells. There are many subtypes of leukemia, including those that are fast growing (acute) and those that are slow growing (chronic). The four main subtypes of leukemia are:
- Acute lymphocytic leukemia
- Acute myelogenous leukemia
- Chronic lymphocytic leukemia
- Chronic myelogenous leukemia
Most cases of leukemia are caused when the DNA, the substance within a cell that controls the way the cell works, is damaged. The reasons for this are not totally understood. Some cases of leukemia are caused by long-term exposure to certain chemicals. Over time, this exposure will cause changes to occur inside the cells.
What is an occupational cancer?
An occupational cancer is a cancer that is caused by exposure to known cancer-causing substances, called carcinogens, while at work. Occupational exposure is “any contact between the body and a potentially harmful substance or environment in the workplace.” It has been shown that excess exposure to certain carcinogens, which can occur if you work with or around them for a long time, can result in cell changes. These changes lead to the uncontrolled growth of abnormal cells. The abnormal cells then attack healthy tissue and kill it.
How common are occupational cancers?
The US Centers for Disease Control and Prevention estimate that 4 percent to 10 percent of cancers in the United States are caused by occupational exposure. About 20,000 deaths and 40,000 new cancer cases each year are attributable to occupational cancers.
The FDA, EPA and OSHA have all established safety standards that have reduced occupational exposure to known cancer-causing agents dramatically in the last few decades. However, many occupational cancers are very slow in developing, so workers who are now retired or no longer exposed are also still at risk.
How are malignant mesothelioma and leukemia occupational cancers?
Along with lung cancer, malignant mesothelioma and leukemia are the most common and most studied occupational cancers. Other cancers, including bladder cancer and colorectal cancer, have also been linked to occupational exposure but are less common.
As stated, malignant mesothelioma is mainly caused by exposure to asbestos. Asbestos was widely used in many industries in the United States during the 1940s, 1950s and 1960s. One study estimates that over half of the workers who were exposed to asbestos on the job between 1940 and 1970 may be currently living with an asbestos-related cancer.
Leukemia is linked to exposure to ionizing radiation, as well as to chemicals such as benzene, ethylene oxide, formaldehyde and many herbicides and cytotoxic drugs.
What jobs are linked to malignant mesothelioma?
Since 1940, millions of American workers have been exposed to asbestos in many industries. Some include:
- Shipbuilders
- Asbestos miners and millers
- Asbestos products manufacturers
- Insulation workers in construction
- Demolition workers
- Drywall removers
- Asbestos removal workers
- Firefighters
- Automobile workers
- Tire repair workers
- Soybean farmers
What jobs are linked to leukemia?
Among the jobs linked to leukemia are:
- Boot and shoe manufacturers
- Long-time radiology workers
- Underground miners
- Uranium processors
- Painters
- Printers
- Petroleum manufacturers
- Chemical manufacturers
- Rubber manufacturers
How are occupation-related malignant mesothelioma and leukemia related?
Some studies link the development of leukemia to exposure to asbestos. Workers in many industrial settings are considered to be at high risk for developing leukemia because of exposure to toxic substances. One of these substances is asbestos. One study done in 2005 linked the development of malignant mesothelioma and leukemia together in the same patient to asbestos exposure. However, more research is needed to support this causal link.