The term "leukemia" refers to a cancer that affects a patient's blood and bone marrow. It occurs most commonly in men and women over 66 years of age. The Leukemia & Lymphoma Society Center estimated that approximately 43,050 people were diagnosed with the disease in 2010. Specific causes are unknown; however, particular risk factors have been associated with the disease, including environmental factors such as exposure to toxic substances like asbestos.
Repeated exposure to hazardous substances appears to be one risk factor for this type of cancer. Workers in industrial settings, such as asbestos workers, tire repair workers and soybean farmers, are considered to be at an especially high risk for developing the cancer because of occupational exposure to toxic materials. Many of these work environments have been known to contain varying levels of toxic substances including asbestos. Workers who have been exposed to asbestos over an extended period have shown an increased development of related diseases.
Determining whether or not a person has leukemia, as well as the specific type that is present, requires a specialized medical professional to perform either a bone marrow aspiration or a bone marrow biopsy. A number of risk factors also help doctors diagnose the disease, including: family history of leukemia, presence of certain blood disorders or genetic diseases, smoking, and exposure to high levels of radiation and certain chemicals that may include asbestos.
This relationship is supported by a 2001 study titled "Occupation and leukemia: A population-based case-control study in Iowa and Minnesota," in which the authors conclude that workers among specific industries had an increased risk of developing leukemia than those who did not work in such environments. These industries include agricultural settings, nursing, janitorial environments, as well as a wide host of others. The belief is that some substances that are present in the mentioned work environments can yield harmful effects.
Acute forms of the disease tend to progress quickly when untreated and are signified by the presence of blast cells (immature cells produced by bone marrow). Few or no blast cells are present in cases of chronic leukemia, which tends to progress more slowly than acute forms of the disease.
One of the first studies to associate asbestos exposure with leukemia was published in 1979 and involved three patients with heavy occupational exposure to asbestos. Of the three, two of whom were also diagnosed with asbestosis, all were found to have chronic lymphocytic leukemia. The culmination of these two relatively rare illnesses caused some consideration of a common cause for the conditions.
A 2005 study explored a similar question after a patient with leukemia developed mesothelioma as the result of heavy asbestos exposure. The only common substance found in both the bone marrow and the mesothelioma sample was asbestos.
Additionally, two case studies were taken into account for a 1988 report on the potential causal relationship between asbestos and acute myelocytic leukemia. The patients were both found to have elevated levels of asbestos bodies (asbestos fibers wrapped in an iron-rich coating) in their lungs. The first patient exhibited 39,800 of the fibers in every 5 grams of lung tissue, while 15,800 bodies were found in every 5 grams of lung tissue in the second patient.
Almost all of these fibers were found to be crocidolite asbestos, which is thought to cause cancer more often than some other forms of asbestos. The patients with leukemia – but not the patients in the control group – were also found to have asbestos bodies lodged in their bone marrow, which suggested that the lymphatic route may transport asbestos once it has entered the body. This hypothesis requires further analysis to give a concrete correlation between asbestos and leukemia. In another study by the same researchers that analyzed the relationship between malignancy and asbestos, five out of 10 cases of leukemia were associated with asbestos exposure.
Multiple studies demonstrate some form of an association between asbestos and the disease that further suggest that asbestos fibers contribute to cancerous changes once they reach the lymph nodes. However, several studies have yet to find concrete evidence for a relationship between the two. With that being said, further research is necessary to better understand any potential association.
As more research is performed on the causes and treatment of leukemia, it becomes vital for anyone that may have the risk factors or signs of this disease to get the most relevant information on the topic. Furthermore, seeking guidance from a medical professional is always advised, as they may be able to determine what risk factors, such as asbestos exposure, may have contributed to the development of the disease. As with many asbestos-related illnesses, symptoms and signs may not be noticeable for decades. Therefore, proactive screening and creating a regular dialog between you and a medical professional is always recommended.
Joining the team in February 2008 as a writer and editor, Michelle Whitmer has translated medical jargon into patient-friendly information at Asbestos.com for more than eight years. Michelle is a registered yoga teacher, a member of the Academy of Integrative Health & Medicine, and was quoted by The New York Times on the risks of asbestos exposure.
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