Leukaemia
Leukaemia is a type of cancer which affects the blood and bone marrow (where blood cells are made), and immature blood cells become cancer cells. Leukaemia occurs most often in adults older then 55 years, but is also the most common cancer in children younger than 15 years (National Cancer Institute, 2017).
The development and spreading of blood cancers are quite different to those of the solid tumours. Solid tumours have methods to evade the body's immune system cells which normally identify and kill cancer cells. Leukaemias originate and develop in bone marrow or lymph glands, where the immune system cells develop and reside and where anti-cancer immune responses are initiated. This suggests a suppressed immune system function is a factor in the development of these blood cancers (Curran, Godfrey & Kline, 2017).
Leukaemia can be classified depending on which type of white blood cell is involved - lymphocytes or myeloid cells - and whether the illness develops quickly (acute) or slowly (chronic). Lymphocytic leukaemias develop from cells which give rise to T-lymphocytes, B-lymphocytes or natural killer (NK) cells. Myeloid leukaemias develop from cells that give rise to white blood cells called granulocytes and monocytes. In acute leukaemia the cancer cells are immature and incapable of performing their normal actions. Chronic leukaemia cancer cells develop in more mature cells and they can perform some of their duties, but not very well (Memorial Sloan Kettering Cancer Centre, 2017). A treatment for leukaemia depends on which type it is and whether it is acute or chronic. There are over 12 types of leukaemia, with the four primary types being (Jin, Xu, An & Wang, 2016; (Memorial Sloan Kettering Cancer Centre, 2017):
The symptoms of leukaemia can vary, depending on the type, but can include the following (National Cancer Institute, 2017; Memorial Sloan Kettering Cancer Centre, 2017; Osiecki, 2012, p415):
The risk factors of Leukaemia include the following (Jin, Xu, An & Wang, 2016; Osiecki, 2012, p416):
The development and spreading of blood cancers are quite different to those of the solid tumours. Solid tumours have methods to evade the body's immune system cells which normally identify and kill cancer cells. Leukaemias originate and develop in bone marrow or lymph glands, where the immune system cells develop and reside and where anti-cancer immune responses are initiated. This suggests a suppressed immune system function is a factor in the development of these blood cancers (Curran, Godfrey & Kline, 2017).
Leukaemia can be classified depending on which type of white blood cell is involved - lymphocytes or myeloid cells - and whether the illness develops quickly (acute) or slowly (chronic). Lymphocytic leukaemias develop from cells which give rise to T-lymphocytes, B-lymphocytes or natural killer (NK) cells. Myeloid leukaemias develop from cells that give rise to white blood cells called granulocytes and monocytes. In acute leukaemia the cancer cells are immature and incapable of performing their normal actions. Chronic leukaemia cancer cells develop in more mature cells and they can perform some of their duties, but not very well (Memorial Sloan Kettering Cancer Centre, 2017). A treatment for leukaemia depends on which type it is and whether it is acute or chronic. There are over 12 types of leukaemia, with the four primary types being (Jin, Xu, An & Wang, 2016; (Memorial Sloan Kettering Cancer Centre, 2017):
- Acute lymphoblastic leukaemia (ALL) - is the most common type in children.
- Acute myeloid leukaemia (AML) - is the most common type in older adults, with men being more affected than women.
- Chronic lymphocytic leukaemia (CLL) - is the most common chronic type in older adults, affecting twice as many men as women.
- Chronic myeloid leukaemia (CML) - is more common in men with an average age of 65 years at diagnosis.
The symptoms of leukaemia can vary, depending on the type, but can include the following (National Cancer Institute, 2017; Memorial Sloan Kettering Cancer Centre, 2017; Osiecki, 2012, p415):
- Fever, night sweats
- Shortness of breath
- Easy bruising or bleeding, from low levels of platelets (needed for blood clotting and wound healing)
- Pinpoint spots under the skin, caused by bleeding (called petechiae)
- Fatigue, weakness or feeling tired
- Weight loss or loss of appetite
- Anaemia
- Increased infections, resulting from low levels of disease-fighting white blood cells
- Increased white blood cells (called leukocytosis), often seen in CML
- Bone or joint or abdominal pain
- Enlarged spleen, lymph nodes or liver.
The risk factors of Leukaemia include the following (Jin, Xu, An & Wang, 2016; Osiecki, 2012, p416):
- Ethnicity - there are differences in rates of some types of leukaemia in the ethnic groups. For example the ALL rates in Caucasian children are double that of African-American children, or for AML, it is three times as prevalent.
- Age - the prevalence rates of the different leukaemia types vary by age. Also, the parental age at childbirth is linked to an increase in childhood leukaemia rates.
- Ionising radiation - this is significantly linked to childhood leukaemia, especially AML, depending on the dose of radiation and duration of exposure. Such radiation can come from nuclear electricity plants or spills, x-rays from medical investigations, or similar sources.
- Infections - many viruses are known to cause cancer, including the human T-cell leukaemia virus.
- Smoking and alcohol - maternal consumption of alcohol and smoking during pregnancy shows an increased risk of AML during childhood. Pre-pregnancy and gestational use of marijuana results in a ten-fold risk increase of AML in childhood. Many leukaemia-causing chemicals can be found in tobacco smoke.
- Immunosuppressive medications - people who receive immunosuppressive medications after organ transplants, or who have received radiation therapy or chemotherapy, have higher risk of leukaemia.
- Environmental chemicals – exposure to hydrocarbon chemicals such as benzene and others (used in paints, fossil fuels, solvents, and other household and industrial products) has been shown in research to increase leukaemia risk. This can occur before conception in the child's parents, during gestation or after birth. Exposure to pesticides in pregnant women is also a risk factor.
- Genetics – genetic mutations can increase leukaemia risk, as can having some genetic diseases including Down's syndrome and others.