What is Acute Lymphoblastic Leukemia?Acute Lymphoblastic Leukemia (ALL) is a malignant (cancerous) disease of the bone marrow in which lymphoblasts (immature white blood cells) proliferate and replace the normal hematopoietic (stem cells involved in the process of blood cellular component formation) cells in the marrow. Lymphoblasts are immature cells differentiated to form mature lymphocytes (mature white blood cells). In acute lymphoid leukaemia, lymphoblasts proliferate uncontrollably and are present in excessive numbers in the peripheral blood (blood flowing in veins and arteries). In acute lymphoblastic leukaemia, lymphoid precursor cells change in the early stage of development and do not go under the differentiation and maturation stage due to chromosomal abnormalities. This abnormal proliferation of lymphoblast decreases the number of other normal bone marrow precursor cells which involves the formation and maturation of red blood cells, platelets and neutrophils. This can result in anaemia (reduced oxygen carrying capacity of the blood due to decreased number of red blood cells), thrombocytopenia (decreased platelet count), and neutropenia (decreased neutrophil count). However, these symptoms are usually to a lower degree than how they are present in other forms of leukaemia. In acute lymphoblastic leukemia, the infiltration (accumulation) of lymphoblast can also occur outside the bone marrow specifically in the liver, spleen, and lymph nodes. This will often cause enlargement of these organs.
Epidemiology of Acute Lymphoblastic LeukemiaAmong the rare cancers and leukaemia, in the United States, ALL is of most common types that occur in children. It makes up for 74% of pediatric Leukemia cases and the median age of diagnosis is 16. When we look at the statistics of the reported cases, it is less common than acute myeloid leukaemia in adults. The relative estimated 5-year survival rate for ALL is 68.6%. Prognosis becomes poor with the increasing age and the median mortality age is 56 years. According to the global trend of the disease, Italy, the United States, Switzerland, and Costa Rica in Europe have the highest incidence rate of ALL, Annually, ALL of B-precursor cells grew by about 1 percent.
Causes and risk factors for Acute Lymphoblastic LeukemiaChildhood B cell precursor acute lymphoblastic leukaemia has multifactorial (having multiple factors) causation, a genetic predisposition (a tendency towards developing a disease) with exposure to certain infections plays a leading role in the development of ALL. In majority cases of the adult population, ALL has no known cause. Most cases of the secondary Lymphoblastic leukaemia presented with the previous history of Hodgkin lymphoma, small cell lung cancer, and ovarian cancer.
Signs and symptoms of Acute Lymphoblastic LeukemiaPatients with acute lymphoblastic leukaemia (ALL) present with signs and symptoms of direct invasion (multiplication and metastasis of malignant cells) by leukemic cells of the marrow or other organs, or with signs and symptoms of reduced production of normal marrow components. These are:
- Fever of unknown origin
- Decreased Neutrophil count
- Shortness of breath/difficulty in breathing and palpitation(fast irregular heartbeat) on mild exertion
- In 10% cases, there is Disseminated intravascular coagulation(DIC) with hemorrhagic and thrombotic complications
- Enlarged and palpable(able to touched or felt) lymph nodes
- Enlarged Liver and Spleen
- Shortness of breath associated with a large mediastinal mass
- Respiratory distress and altered mental status associated with Leukostasis (presence of lymphoblasts in excessive amounts in peripheral circulation).
Diagnosis for Acute Lymphoblastic LeukemiaSerological, radiological, and biopsy investigations are useful to diagnose. These are:
- Complete blood count (CBC) with peripheral smear and blood culture
- Blood coagulation profile
- LFT’s(Liver function tests) and RFT’s( Renal function tests)
- Bone marrow aspiration and biopsy
- Chest X-ray, CT chest
- MUGA and Echocardiography
- Lumbar Puncture
Treatment Options for Acute Lymphoblastic LeukemiaThe type of treatment used for Acute Lymphoblastic Leukemia varies depending on its stage, severity and behaviour.
ChemotherapyChemotherapy is the use of drugs to target and destroy cancer cells. It is effective against ALL because it stops cancer cells from dividing and spreading. Due to the stress chemotherapy may have on the body, it is often split up into several “session”. During a session, the drugs will be administered either orally or intravenously. Chemotherapy is known to cause side effects. These include:
- Nausea and vomiting
- Loss of appetite
- Loss of hair
- Fatigue and tiredness
- Increased risk of infection.