Multiple Causation Theory Of Leukemia Essay, Research Paper
Leukemia is a malignant disease of the bone marrow and blood. It is characterized by the uncontrolled growth of blood cells. The term leukemia has a Latin derivation. Leuko means white and heme is blood. Therefore the word leukemia literally means white blood. The common types of leukemia are divided into four major categories: myelogenous and lymphocytic, which can then be divided into acute or chronic. Thus, the four major types of leukemia are acute or chronic myelogenous leukemia and acute or chronic lymphocytic leukemia.
Acute leukemia involves the most primitive types of leukemia cells. It is a rapidly progressing disease that results in the accumulation of immature cells in the marrow and blood that do not function. In most cases, the marrow can no longer produce enough normal red and white blood cells and platelets. This class of cancer leads to an overproduction of blood cells that have similar characteristics, which mean that they are clones. Cloned cells share two common features that lead to the symptoms of leukemia. The first is that the cells divide without control and fail to respond to the signals that tell them to stop. The second is that these cells have a longer life than normal cells and gradually accumulate in the bone marrow (www.leukemia.org).
This uncontrolled production of long lived cells leads to the replacement of the normal cells in the bone marrow with leukemic clones. Since the space is limited in the marrow, the normal cells are crowded out by these clones (www.meds.com). All the normal blood-forming elements are eventually affected if the leukemia goes unchecked. This means that the white cells, platelets and red blood cells are all eventually depleted. The lower number of normal white blood cells makes leukemic patients more vulnerable to infection. The depletion of normal platelets interferes with the patients clotting ability and makes the patient more susceptible to abnormal bleeding and bruising. Anemia is caused by the decreased production of normal red blood cells. Leukemic cells are actually abnormal white blood cells. As these cells clone themselves they increase the concentration of white blood cells in the blood stream. Chronic leukemia seems to progresses more slowly and permits greater numbers of more mature functional cells to be made.
Now that I have presented the background for the disease itself, it?s time to look at it from the ?Multiple Causation Theory.? This theory has five basic categories: biological/genetic, demographic, environmental, psychological, and social interaction. Before I discuss these categories, I must first present the information that the theory is concerned with. And that is a) the incidence of new cases and b) the prevalence or total number of illness within a given population.
It was estimated that there would be 30,200 new cases of leukemia in the United States in 1999. There would be equal proportions are acute leukemia and chronic types (www.leukemia.org). Most cases occur in older adults; more than half of all cases occur after the age of 60. Leukemia is expected to strike ten times as many adults as children in 1999. About 27,900 cases compared with 2,300 in children, ages 0-14. The most common types of leukemia in adults are acute myelogenous leukemia (AML), with an estimated 10,100 new cases annually; and chronic lymphocytic leukemia (CLL), with some 7,800 new cases in 1999. The most common form of the leukemia in children is acute lymphocytic leukemia (ALL). It accounts for about 3,100 new cases of leukemia in 1999, with 1,500 of these new cases occurring among children. Chronic myelogenous leukemia (CML) strikes about 4,500 persons each year. Other forms of leukemia strike about 4,700 persons each year.
The first category that I will talk about is biological/genetic. This category refers to an inherent bio-physiological state that predisposes certain persons to particular illnesses as a result of physical inheritance. But as stated in the article, there is no evidence that any form of cancer can be inherited. Even in the very rare cases of cancer being present at birth, the disease has developed as a result of cell damage, which happened in the uterus. In the vast majority of cases of leukemia and other forms of cancer there is no evidence that relatives of the patient are at greater risk than any one else (www.cancernews.com).
There are some inherited conditions in which the risk of developing cancer is increased. Examples include Down?s syndrome and a condition called ataxia telangiectasia. This condition affects the ability of the cell to repair damage to the genes and because of this many different cancers are seen more frequently than in the general population. In other cases, including Down?s syndrome the reasons are not well understood (www.cancernews.com).
The second category is the demographic of the disease. This refers to social status characteristics such as age, sex, social class, race, income, and education. The characteristics of social class, income, and education don?t really come into play with the different leukemia types because everyone is susceptible. Age plays a big part in which type of leukemia a person will develop. There are a few types of cancer, which occur more commonly in childhood than in adults. One of these is acute lymphoblastic leukemia, which is more common between the ages of 2 and 5 years than at any other age. This is known as the childhood peak of leukemia. Some diseases, such as myeloma and chronic lymphocytic leukemia, are almost never seen in young people (www.leukamia.demon.co.uk). The leukemia death rate for children in the U.S. has declined 57 percent over the last three decades. Nonetheless, in children under age 15, leukemia causes more deaths in the U.S. than any other disease. There were approximately 550 deaths from childhood leukemia in 1999 (www.cancernews.com).
The risk of developing leukemia increases with age. The increased numbers of cases of many types of cancer in older people is probably simply a result of the accumulation of genetic damage to cells over the years. Much of the time damage to the cell will result in cell death but with over 3 million new blood cells being produced every second it is inevitable that some cells will accumulate damage to genes over the years. Over the last 20 years, death rates for leukemia have fallen 21 percent for U.S. men and women under the age of 65.
In total, 22,100 persons died from leukemia in 1999 in the U.S., approximately 12,400 males and 9,700 females. Incidence rates for all types of leukemia are higher among males than among females and higher among whites than African Americans. The five-year survival rate for African American patients with leukemia is 31 percent (www.meds.com). These statistics that have been presented show that it is possible for anyone to develop this form of cancer.
The third category is environmental. In this category, we look at what people may have been exposed to in their home and occupational environments. The cause of leukemia is not known. But scientists have formed many ideas. The most common chemical exposure linked to leukemia is probably cigarette smoking, which has been shown to be a significant risk factor for acute myeloid leukemia. It has been estimated that as many as a quarter of all cases may be caused by smoking (www.leukemia.org). Another cause of leukemia could come from benzene. Benzene in high concentrations is known to cause leukemia and it is possible that other, similar organic chemicals, may increase the risk of leukemia and related diseases. There are very small amounts of benzene present in unleaded petrol but this is not considered high enough to be a leukemia risk. In some groups of workers, for example farmers and agricultural workers, there appears to be an increased risk of certain conditions, for example myeloma and lymphoma (www.cancernews.com).
Ionizing radiation is another idea to the cause of the disease. This is radiation given off by X-ray machines or by radioactive materials. High doses of radiation can definitely increase the risk of leukemia. Most experts believe it is extremely unlikely that very low levels of radiation can cause leukemia (www.cancernews.com). Some years ago it was reported that children who had been exposed to medical X-rays before birth were more likely to develop leukemia. The introduction of ultrasound has virtually eliminated the need to use X-rays during pregnancy. Modern X-ray machines deliver a much smaller dose and on the very rare occasions when a pregnant woman needs to be X-rayed special precautions are taken to reduce the risk even further. Some studies have suggested that there appears to be an increased risk of leukemia in children who live near electrical power-lines or other electrical facilities. It is suggested that electromagnetic fields may be capable of causing leukemia or accelerating the development of the condition (www.cancernews.com).
The fourth category is psychological. This category refers to how the patients see themselves and to what they do once they have the disease. Psychologically, in the beginning, the patient has no idea that they have leukemia. The initial symptoms that they feel can easily be associated with other conditions. So their first response is not to go to the doctor to get checked out. At first they would try home remedies until the symptoms persist for a long period of time. This is the point in which the patient will seek the help of a qualified physician. Once they have been diagnosed with the disease the patient begins to feel that their life is over. This is because the overall survival rate for the disease is only 5-7 years. This means that if you are diagnosed in the beginning stages of the disease, doctors are only giving you up to 7 years to live even with treatment (www.leukemia.org). It is very hard for these patients to return to their normal roles in society because only 65 percent of the people diagnosed go into complete remission. But with treatment and a strong support system, patient?s ability to cope with this disease is very high. They have a very good sense of personal competence and they do not have to rely solely on others.
The last category is social interaction. In this category, you have to look at how the patient?s participate in social activities. In the first and last stages of this disease, it is very hard for the patient to be social at all. In the first stages, the patient is beginning their treatment in the hospital setting. This means that they will have to spend 3-4 weeks in the hospital while they receive their chemotherapy treatments (www.cancernews.com). At this time, the patient is very weak and ill and it is virtually impossible for them to be social at this time. The middle stages are a lot better for most patients. At this time, their disease is in some form of remission so they have a chance to be more active with friends and family members. In the last stages, the patients are back in the hospital and they are confined to their beds. It is sometimes very hard for them to talk because they are so weak and in turn they no longer have a strong sense of social interaction.
The ?Multiple Causation Theory? is a way to classify the cause of illness into five basic categories which together explain the origin and distribution of illness. I hope that by me using this theory and it ?s five categories, you are able to see this trend in the social epidemiology of leukemia.
Multiple Causation Theory of Leukemia