Acute Lymphoblastic Leukaemia (ALL)
Acute lymphoblastic leukaemia is a type of blood cancer, responsible for affecting white blood cells. It can develop at a rapid rate and requires immediate treatment (Cannas, Thomas 2015).
Acute lymphoblastic leukaemia is a very rare disease, and in the UK 810 people are diagnosed with ALL each year (Yasmeen, Ashraf 2009).
Both adults and children can be affected, although it is the most common type of childhood leukaemia. The greatest incidence is among the age group of 2-5 years old (Inaba, Greaves et al. 2013).
What causes ALL?
The hallmark of ALL is characterised by chromosomal abnormalities as well a genetic changes in the stem cells which result in the immature white blood cells to be circulated in the bloodstream (Yokota, Kanakura 2016).
Scientists are unsure of the clear cause of the DNA mutation which takes place in the stem cells, however some of the known risk factors include:
• Genetic disorders; including fanconi anaemia, down’s syndrome and ataxia telangiectasia
• Past chemotherapy; including with drugs such as mitoxantrone, etoposide and idarubicin
• Environmental factors; including living near a power line or nuclear power station
• Weakened immune system; such as individuals who have AIDS or taking immunosuppressant’s
• Smoking; it has been found that smokers are at greater risk of developing ALL, and studies have shown that parents who smoke in home, may increase the risk of their children developing (Belson, Kingsley et al. 2007), (Greim, Kaden et al. 2014)
What are the symptoms of ALL?
ALL initially has a slow appearance, before it rapidly progresses as a result of shortages of normal white blood cells. The majority of symptoms appear as a consequence of immature white blood cells in the blood system, and a reduced number of healthy blood cells.
• Feeling tired and weak
• Weight and appetite
• Pale skin
• Frequent and persistent infections
• Swollen Lymph nodes
• Frequent bleeding, including nosebleeds and bleeding gums
• High fever of 38 C or above
(Esparza, Sakamoto 2005)
In a few individuals with ALL, the leukemic white blood cells spread from the blood stream to the central nervous system (CNS). This can result in series of neurological disorders, including;
• Nausea and vomiting
• Severe headaches
• Seizures and loss of consciousness
• Blurred vision
(Del Principe, Maurillo et al. 2014)
How does ALL develop?
ALL begins from the immature white blood cells, known as blastocytes in the bone marrow. This is soft inner part of the bone where new blood cells are produced.
Bone marrow makes specialised cells, known as stem cells, which have the capability to differentiate into three distinctive types of blood cells:
• Red blood cells- facilitate oxygen around the body
• White blood cells- help to combat infections
• Platelets- assist with stopping the bleeding (Terwilliger, Abdul-Hay 2017)
Under normal circumstances, the bone marrow does not release stem cells until, they are fully developed. However in patients with ALL, a great number of blasts are released in the blood system, instead of normal lymphocytes (Watt, Driskell 2010).
As a consequence this leads to a build up of blast cells in the blood system, and there is a decreased number of red blood cells and platelets. This results in symptoms of anaemia, including tiredness, breathlessness, as well a higher risk of excessive bleeding.
In addition, blast cells are less capable of fighting infections, than the mature white blood cells, leaving the individual more prone to infections (Maurillo, Buccisano et al. 2013).
What are the complications of ALL?
If the lymphoblastic leukaemia is not cured, then it can result in complications due to the insufficient number of healthy blood cells in the blood system. Complications can arise such as;
• Immunocompromised: the person’s immune system weakened and therefore less able to fight infections which can result to life threatening conditions.
• Excessive, uncontrolled bleeding: due to lack of platelets present in the blood stream
(Ju, Hong et al. 2014b)
What is the outlook for ALL?
The outlook for children with ALL is very positive and promising. According to the National Cancer Institute, the 5 year survival rate for children with ALL is significant 85%.
However the prognosis for adults aged 25-64, is less promising, with only 40% of the adults surviving for 5 years or more after diagnosis.
Promising future treatments such as “oncolytic virus therapy”, whereby viruses are designed to identify and destroy cancer cells, whilst the healthy cells remain intact are on the horizon of the medical field (Saletta, Wadham et al. 2014).
How is ALL treated?
Treatment of ALL begins almost immediately after diagnosis, as it can aggressively develop over a short period of time.
The treatment of ALL is divided into three phases:
• Remission Induction; the initial treatment aims to destroy the leukaemic cells in the bone marrow
• Consolidation therapy; targets any remaining leukaemic cells in the Central Nervous System, in order to prevent it from returning, also known as remission
• Maintenance therapy; is the last stage of treatment, whereby regular doses of chemotherapy drugs are given in order to keep leukaemia in remission.
(Park, Kim et al. 2003)
Chemotherapy is the mainstream method of treating ALL; however other treatments are available such as blood transfusions and the administration of antibiotics.
In some cases of ALL, a bone marrow transplant may be required in order to arrive to the point of being cured of the disease (Ju, Hong et al. 2014).
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