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Leukaemia is a serious malignancy affecting the blood and bone marrow. The cancer is characterized by an abnormal and excessive proliferation of white blood cell precursors blocked at the stage of differentiation.
These immature blood cells turn into malignant cells and invade blood and bone marrow. This haematological disorder leads to inadequate production of red blood cells responsible for anaemia; decreased white blood cell count, and low platelet count (thrombocytopenia) a major cause of spontaneous bleeding.
Rare, leukaemic cells can invade other organs such as the lymph nodes, spleen, liver, testes or central nervous system, depending on the severity of the disease. Leukaemia can be acute or chronic. The most common forms of leukaemia include:
- Acute lymphoblastic leukaemia (ALL).
- Acute myeloid leukaemia (AML).
- Chronic lymphocytic leukaemia (CLL).
- Chronic myeloid leukaemia (CML).
1. Statistics.
Leukaemia is very common over the world. Worldwide, leukaemia accounts for 3% of cancer deaths. In the United States alone, 265,000 people live with leukaemia. According to the American Cancer Society, estimates that 44,790 men and women (25,630 men and 19,160 women) were diagnosed with leukaemia in 2009; nearly 21,870 men and women died of it.
The incidence varies with age and sex from 2002 to 2006. The median age at diagnosis for leukaemia was 66 years of age; thus, the percentages and ages of people diagnosed were about:
- 1% were under age 20;
- 7% between 20 and 34;
- 5% between 35 and 44;
- 1% between 45 and 54;
- 0% between 55 and 64;
- 8% between 65 and 74;
- 3% between 75 and 84;
- 5% 85+ years of age.
2. Causes.
Apart from occupational exposure to chemicals that are known causative for acute leukaemia or chronic myeloid leukaemia. The causes of the disease are unknown. but, here are some possible causatives:
Benzene – Pieces of research, shows that prolonged exposure to the organic chemical compound can cause leukaemia in children. Studies have shown that children living around a gas station or any place where fuel is sold have four times more risk of developing leukaemia than other children do.
Foods – Studies have been conducted on Hot Dog by many scientists such as Sara and David A. Sarasua, Savitz of the University of North Carolina at Chapel Hill; they have found that children who eat more than 12 hot dogs per month have nine times more chance of having leukaemia.
But, the problem lies in the ingredients contained in hot dogs; Hot dog has a preservative substance called nitrite, a form of a salt which can be found in vegetables.
In its natural form, nitrite is not harmful to the body. but, during the cooking, nitrites combine with amines naturally present in meat to form “N-nitroso”, a highly potent carcinogenic agent.
Tobacco – Tobacco has always been known as the number one cause of oral cancer. but, regular use of tobacco increases the risk of acute myeloid leukaemia in adults.
According to the Canadian Council for Tobacco Control, tobacco use (including chewing tobacco and cigarette smoke) seems to participate in the development of plasma cell myeloma and acute myelogenous leukaemia.
Ionizing radiation – numerous studies have shown that the risk of leukaemia is two times higher among individuals who are constantly exposed to ionization radiation. In addition, ionization radiation can also cause other types of cancer such as skin cancer.
Genetic – Most patients with myeloid leukaemia, scientists have found an abnormality in chromosome 22 called Philadelphia chromosome or Philadelphia translocation. This disorder occurs in almost all cases of chronic myelogenous leukaemia, which leads to the belief that genetics plays a role in having leukaemia.
Virus – certain viruses such as Human T-lymphotropic virus appears to play a role in the occurrence of leukaemia; this assumption remains controversial.
3. Symptoms.
The majority of leukemics patients do not suspect any clinical signs of the disease. They often learn they have leukaemia during a blood test or medical exams done for other medical condition. In general, the disease is often diagnosed mostly when the disease becomes chronic. Leukaemia symptoms may include:
Weight loss.
Decreased appetite.
Fever or chills.
Shortness of breath.
Bone pain or tenderness.
Excessive night sweats.
Easy bleeding or bruising.
Enlargement of the spleen (splenomegaly).
Joint pain (arthralgia).
Liver enlargement (hepatomegaly).
Weakness and fatigue.
Physical weakness and loss of strength (asthenia).
Small red spots on the skin (petechiae).
4. Diagnosis.
Along with a physical exam, many tests and medical exams are used to diagnose leukaemia:
- Physical examination – this is a simple examination during which your physician will search your body for signs and symptoms of leukaemia: pinprick bleeds, bruises, skin paleness (due to anaemia), swollen lymph nodes, etc.
- Blood tests – your doctor may take your blood sample for laboratory analysis. In general, a high concentration of immature white blood cells and an abnormally low number of red blood cells and platelets is an indication of leukaemia.
- Immunophenotype – This test is a powerful tool in the diagnosis and monitoring of most haematological malignancies such as lymphoblastic leukaemia and myeloblastic leukaemia. It helps to discover not only leukaemia cells but also to differentiate chronic lymphocytic leukaemia cells from other types of leukaemia and lymphoma.
- Cytogenetic Analysis – this cytogenetic exam is a study of genetic phenomena in the chromosomes in order to detect Philadelphia chromosome. The most common techniques of cytogenetic analysis include karyotype analysis, Fluorescent In-Situ Hybridization (FISH), and DNA microarray analysis (DNA chip).
- Bone marrow biopsy – your doctor may recommend a bone marrow biopsy to confirm the diagnosis and determine the type of leukaemia you have. In general, the specialist will use a needle to withdraw the marrow samples and then analyze it under a microscope to look for leukaemia cells.
5. Treatment.
Your oncologist will consider your age and the type of leukaemia you have this to enable him or her to recommend an appropriate treatment. Leukaemia treatment is generally less intensive in patients aged over 60 years.
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Chemotherapy.
Chemotherapy in the treatment of chronic lymphocytic leukaemia, mild chemotherapy can be used to reduce the number of white blood cells, reduce the size of lymph nodes, and spleen.
Treatment of acute, myeloid and lymphoid leukaemia is based on Anti-mitotic Drugs (anti-mitotic chemotherapy); certain substances that are often used in the chemotherapy of these types of leukaemia include vincristine and vinblastine. Those medications inhibit mitotic cell division and prevent the damage of the disease in the body.
However, the treatment destroys not only the tumour cells but also the normal cells in your bone marrow, which makes you susceptible to infections, bleeding and anaemia.
A bone marrow transplant may also be considered. Sometimes the therapy requires prolonged hospitalization.
Certain types of leukaemia, when detected early, can be treated effectively with chemotherapy drugs. However, chemotherapy is a systemic treatment that affects both healthy cells and cancer cells, which often causes side effects. Adverse effects vary from one person to another and depending on drugs usage and their dosage.
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Chemotherapy Side Effects.
All anti-cancer drugs affect cell division and the immune system (white blood cells). This is why, during cancer treatment, cancer patients are more prone to infections, anaemia, fatigue, hair loss, nausea and vomiting, Intestinal disorders or even lesions in the mouth (mucositis).
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Radiotherapy (Radiation Therapy).
Radiation therapy is a regional treatment consisting of using ionizing radiation to kill leukaemia cells. It can be administered externally (external beam radiotherapy) or internally (brachytherapy or internal radiation therapy). Your oncologist will use the method that thinks will be more effective. Although rare in the treatment of leukaemia, both external beam radiotherapy and internal radiation therapy can be used.
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Radiation Therapy Side Effects.
Radiotherapy can be effective in some types of leukaemia; however, it tends to cause severe blood changes including a drop in production of new blood cells, nausea, anaemia, vomiting, and other short/long-term side effects.
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Immunotherapy (Biological Therapy).
Immunotherapy is a cancer treatment aims at stimulating the natural defence of the body (the immune system) to fight against leukaemia cells and destroy them. Several molecules are currently used in leukaemia immunotherapy; the most common are kinase inhibitors: Imatinib, Dasatinib, Nilotinib and Bevacizumab.
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Stem Cell Transplant.
This method consists of replacing leukemic cells with healthy cells which can be either from your own healthy cells (autologous stem cell transplant) or a healthy donor (allogeneic stem cell transplant). The stem cell transplant is often used in case of failure of other treatments: chemotherapy, radiotherapy, immunotherapy, etc.
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Bone Marrow Transplant.
This is a complex medical procedure consists of replacing leukemic marrow with leukaemia-free marrow (healthy bone marrow). Your own narrow can be used (autologous transplant) or that of an individual who does not have leukaemia (allogeneic transplant). A bone marrow transplant is often associated with massive doses of chemotherapy and/or radiation. Although bone marrow transplant is a serious medical intervention, it often brings good result in the fight against leukaemia.
6. Prognosis.
The prognosis for leukaemia depends on several factors: age, stage of cancer or organs affected the state of health of the patient, etc. That is, the sooner you are diagnosed with leukaemia the more likely you are to survive.
In addition, your survival chances depend on the type of leukaemia that you have. For example, nearly 60 per cent of patients with myeloid leukaemia can be cured with a bone marrow transplant; 50 to 60 per cent of young patients with acute lymphatic leukaemia can be cured by chemotherapy. However, when it comes to leukaemia, chances of recovery are much more favourable in children.
Survival rates also vary by race and sex. The overall 5-year relative survival rate for 1999-2005 from 17 SEER geographic areas was 53.1%. Five-year relative survival rates by race and sex were:
- 8% for white men;
- 0% for white women;
- 5% for black men;
- 1% for black women.
7. Preventions.
Since the causes of leukaemia are not well known, it is not easy to establish preventive measures. While it is not always possible to prevent cancer, the risk can be reduced.
To prevent the occurrence of all cancers including leukaemia, it is important to have a healthy lifestyle and live in a healthy environment. An unhealthy environment may promote the breeding of cancerous cells in your body.
Some risk factors such as age, sex and genetic are impossible to Change; but some risk factors can be changed:
- Avoid tobacco smoke, including second-hand smoke
- Maintain a healthy weight;
- Limit your alcohol intake
- Reduce your exposure to toxic chemicals
- Reduce your exposure to ultraviolet (UV) radiation
- Regular Exercise.
- Practice safe sex
Adopt a healthy diet: a diet containing 5 to 10 servings of fruits and vegetables a day may help prevent the occurrence of many cancers, including leukaemia. Increase the following foods in your diet:
a) Avocados
b) Blueberries
c) Black Raspberries
d) Curcumin
e) Flax
f) Garlic
g) Papaya
h) Pomegranate juice
i) Tomatoes
j) Soy products
k) Grapefruits, oranges and other citrus fruits
l) Cruciferous vegetables (broccoli, cauliflower, kale, Brussels sprouts, and cabbage).
