Cancer occurs
when there is uncontrolled abnormal cell growth and development. It disturbs
the normal life span of cells wherein they are formed, mature, carry out their
intended function, die, and are replaced by new cells which are constantly
regenerated in the body to maintain normal cellular function. Cancer represents
the disturbance of this process.
Leukaemia is
cancer of the white blood cells. The symptoms of leukaemia include:
* Breathlessness
* Having
repeated infections over a short space of time
* Pale skin
* Tiredness
In acute leukaemia, the condition progresses at a rapid and aggressive pace, and treatment needs to be administered immediately.
Bone marrow
Bone marrow is a
spongy material that is found inside the bones, and it produces all of the
blood cells. It also produces vital cells called stem cells that can create
other specialised cells that carry out essential functions. These specialised
cells are of three types:
* Red blood
cells which carry oxygen around the body
* White blood
cells which help fight infection
* Platelets
which help stop bleeding
Acute leukaemia
prevents the affected bone marrow from producing stem cells that mature into
adult blood cells. Instead it releases numerous immature blood cells called
blast cells. The immature white blood cells begin to rapidly disrupt the normal
balance of cells in the blood, limiting the presence of red blood cells or
platelet cells in the body. This can lead to tiredness and other symptoms of
anaemia, and also increase risk of excessive bleeding. The patient also becomes
more vulnerable to infection as the white blood cells are not properly formed
and thus ineffective in fighting
bacteria and viruses.
Types of acute leukaemia
There are two
main types of white blood cells classified according to the type of white blood
cells that are affected by cancer:
* Lymphocytes
which are mostly used to fight viral infections
* Myeloid cells
which fight bacterial infections defend the body against parasites and prevent
the spread of tissue damage
The two main types of acute leukaemia are:
* Acute
lymphoblastic leukaemia, which is cancer of the lymphocytes
* Acute myeloid
leukaemia, which is cancer of the myeloid cells
Acute myeloid leukaemia
It is more
common in older people, especially when over 50 years of age, and more common
in males than females, though it is not clear why. The causes of acute
leukaemia are uncertain, but known risk factors include:
* Exposure to
high levels of radiation
* Exposure to
benzene, a chemical that is used in manufacturing and is also found in
cigarettes
The lack of
healthy blood cells in the blood supply causes most of the symptoms of acute
leukaemia, which usually begin slowly before rapidly escalating in severity as
the number of blast cells in the blood increases.
Outlook
The outlook for
people with AML depends on the sub-type of AML, with some subtypes being more
challenging to treat than others. The cure rate thus varies, and some sub-types
have a 75 per cent cure rate, while others have a 20 per cent cure rate. The
outlook also favours younger people as compared to older people. The treatment
usually includes a combination of chemotherapy and radiation, or a bone marrow
transplant in some cases.
Acute lymphoblastic leukaemia
ALL is the most
common type of cancer found in children, though it is uncommon on an overall
basis. Approximately one in every 2,000 children will develop ALL. The majority
of cases develop in the age group of two to five year olds, and 85 per cent develop
in children below the age of 15.
Outlook
The outlook for
children with ALL is optimistic, as almost all of them will achieve a remission
from their symptoms. 85 per cent of children will be completely cured, whereas
only 40 per cent of adults will be completely cured.
Treatment for AML involves two
stages:
* Induction: The
aim of the initial stage of treatment is to kill the leukaemia cells in the
bone marrow, restore the blood to proper working order and resolve any symptoms
that may be present.
* Consolidation:
This stage aims to kill any remaining leukaemia cells that may be present in
the central nervous system.
Treatment for ALL involves three stages:
* Induction
* Consolidation
* Maintenance,
which involves taking regular doses of chemotherapy tablets to prevent the
leukaemia returning. This seems to be the most effective stage.
Other treatments
The other
treatments that are used in some circumstances are:
* Radiotherapy
* Stem cell
transplant
* Targeted
therapies
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