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WHAT IS CANCER |
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Cancer is an abnormal growth of body of cell or group
of cells. If it is not destroyed or removed, cancer can spread very repidly and
eventually lead to death. |
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LEUKAEMIA - A FORM OF CANCER
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Leukaemia means "white blood" but it is not, as Commonly
called, blood cancer. It is a cancer of the tissues in which blood is formed.
Bone marrow, the soft, spongy centre of the bone producesred blood cells, white
blood cells and platelets.
Red blood cells carry oxygen to cells throughout the body and, if there are too
few, symptoms such as anaemia, shortness of breath appear, white blood cells fight
infection, and platelets, which control blood clotting, prevent haemorrhaging.
The spleen and the lymph nodes produce a type of white blood cell called lymphocyte.
Lymphocytes produce antibodies, act against infection, and contribute the body's
own immune system.
All blood-forming tissues daily release millions of each type of cell into one
of the body's two circulatory systems-the blood vessel system and the lymph system.
when leukaemia strikes, millions of abnormal, immature white bood cells called leukocytes
are released into these circulatory systems.
Because these cells are immature, they cannot carry out
their basic fuction of fighting infection. In advanced leukaemia, the uncontrolled
multiplication of abnormal, I cells results in crowding out the production of normal
white cells to flight infections, of normal white cells to flight infections, of
platelets to control haemorrhaging and of red blood cellsto prevent anaemia.
There are several types of leukaemia, depending
on the white cell that is multiplying. About 90 percent of case are caused by two
types of leukocytes : lymphocytic leukaemia (also called lymphoblastic), involving
cells formed in lymphatic tissue and granulocytic leukaemia (also called myelocytic),
involving cells formed in bone marrow.
Both the lymphatic and granulocytic types have
acute or swift growing, and chronic or slowgrowing, forms. The two types of cells
and two rates of growth produce four main types of leukaemia in human beings: acute
lymphocytic, chronic lymphocytic, acute granulocytic and chronic granulocytic.
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RISK FACTORS |
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The causes of most cases of human leukaemia are unknown.
Excessive exposure to radiation and to certain chemicals, such as benzene, have
been linked to the development of leukaemia. Certain viruses are known to cause
leukaemia in animals, but this has not been proven so in humans. There is some evidence
of inherited susceptibility but none that the disease is transmitted directly from
parent to child. It is known that there is a higher them normal incidence of leukaemia
among children with down's syndrome(mongolism), and certain other hereditary abnormalities
may be linked to leukaemia.Age is a factor to the extent that the different types
of leukaemia generally strike different age groups.
Leukaemia strikes more children than any other form of cancer and is the leadingcauseof
death by disease among children aged 3 to 15. The type of leukaemia common among
children is acute lymphocytic leukaemia. Fortunately it is with this type of childhood
leukaemia that the greatest progress in treatment and survival is being made. Children
too get acute granulocytic leukaemia, but much less frequently.
The type of leukaemia most prevalent in young adults in acute granolocytic. Chronic
leukaemia, whether granulocytic or lymphocytic, generally appears after the age
of 40. Adults may also be struck by acute leukaemia-either granulocytic or lymphocytic.
More than half of all cases of leukaemia occur in persons over 60 years of age.
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