Just like any other cancer which is basically an abnormal, uncontrolled cell growth, the human blood is not left out of this inferno. Blood cancer is literarily a condition whereby blood cells continue to proliferate uncontrollably.
What is Leukemia?
Leukemias are a heterogeneous group of malignant disorders which is characterized by uncontrolled clonal (single cell) proliferation of blast cells in the bone marrow and body tissues. To put it simply, imagine a pregnant woman delivering 100 premature babies every year whenever she gets pregnant!
Blast cells are immature blood cells. Blood cells go through about 5 stages before they become mature and are able to perform their functions. In leukemia, immature cells accumulate and are unable to reach their full matured state.
Blood cells produced in the bone marrow (the soft spongy center of long bones of the arms and legs) include; The Red Cells, White Cells, and Platelets.
While the red cells are responsible for carrying oxygen, providing nutrients to body cells and tissues to ensure their survivals as well as transporting waste products away from those same cells,
The white cells act as defense mechanisms of the body to fight and guard against infections. They are basically the B (The Myeloid cell line) and T cells (The Lymphoid cell line).
Anterior view of femur with cut bone morrow and cut blood vessel showing RBCs, WBCs, and platelets. REF: rendered from Zygote models, and 3D models.
Platelets are responsible for the formation of blood clots at sites of injury.
Stages of Blood Cells Production.
Leukemia can be Acute- (of short, quick and fatal onset) or Chronic- (continues over an extended period of time) while it is being managed.
Characterized by 20% or more of blast cells in the bone marrow. It is of abrupt onset and is rapidly fatal. The survival rate is <6 months without treatment. The more recent WHO classification of acute leukemia relates it with other Chromosomal Abnormalities E.g. Down Syndrome.
Acute Lymphoblastic Leukemia (ALL) is the most common Leukemia in children falling off by 10 years with a secondary rise after the age of 40 years. Its incidence is highest at 3 to 7 years while Acute Myeloid Leukemia is most common in adults.
Causes of Leukemias
There is no exact known cause but several risk factors of leukemia just like every other cancer, however, for Acute Leukemias;
- The first event is thought to occur in the fetus in utero due to environmental exposure during pregnancy.
- It may arise as a postnatal (after birth) mutation in early lymphoid cells in the bone marrow.
- The secondary event is precipitated by infection in childhood due to the mechanism of abnormal response of the child’s immune system to infection.
It is of utmost importance to exclusively breastfeed babies for the first six months of life this boosts the child’s immune system and the introduction of a balanced diet in complementary feeding.
Furthermore, children with high level of social activity like those attending day care have reduced incidence of ALL because of exposure to common infections boosting their immune system
Symptoms and Features of Acute Leukemia include:
- features of mouth, throat, skin and respiratory infections
- Marked cervical lymphadenopathy
- Testicular swelling
- Spontaneous bruises, purpura and bleeding gums.
1. Bone marrow infiltration checked with bone marrow biopsy
- Anemia (Reduced Blood hemoglobin concentration)
- Leucopenia (Reduced white cells count)
- Thrombocytopenia (Reduced platelet count)
- Hypercellular bone marrow with >20% blast cells.
- Infiltration of organs Liver, Spleen and lymph nodes.
2. Cerebrospinal fluid examination contains blast cells (CSF is meant to be a clear colorless fluid which cushions the brain)
3. Increase uric acid as a result of bone degradation with deranges Liver and renal function tests
4. Radiography may include lytic bone lesions
5. Other tests like a CT scan which may be needed for staging as well as other investigations depending on the salient signs
Supportive Therapy: Prompt treatment of any episode of fever, blood and blood products support.
Specific Therapy: Chemotherapy, Radiotherapy, Short and intensive courses of drugs.
The physician (Hemato-Oncologist) decides which is the best approach to treatment according to severity.
An unfortunate complication of acute leukemia is DIC Disseminated Intravascular Coagulation
- DIC is a disorder characterized by excessive inappropriate activation of coagulation and formation of small clots in the blood vessels. These clots block the flow of blood and are a leading cause of death in acute Leukemia.
- The activation of clot formation is caused by road- like clumps of granular materials in leukemic cells called Auer Rods. This can as well lead to bleeding from the digestive and respiratory tracts as all platelets are used up in the formation of these clots.
Could be chronic myeloid or chronic lymphoid leukemia according to the cell line affected. It is characterized by rapid proliferation and growth of MATURED blood cells within the bone marrow.
Hypercellularity (increased amount of cells) of any of the different blood cells (eg White Blood Cell or Red Blood Cell) is a diagnostic feature. It is mostly asymptomatic and detected mostly in routine blood checks. It is nominated according to the predominantly increasing cell;
- White cells increasing predominantly- Chronic Myeloid Leukemia or Chronic Lymphocytic Leukemia
- Red cells increasing predominantly- Polycythemia Rubra Vera
- If it’s the platelets increasing predominantly then we refer to as Essential Thrombocythemia
The Chronic leukemias account for about 15% of Leukemias and can occur at any stage.
Chronic Leukemia is managed appropriately at this hypercellular stage. It is stable indolent and slow progressing. All efforts by medical personnel managing the condition are aimed at not progressing from this stage into the accelerated phase where symptoms begin to manifest and ultimately to blastic transformation. (Transformation to the acute phase)
General Prevention of Leukemias
Prevention is aimed at reducing your risks of leukemia since there is no known cause for leukemia as well as other various types of cancers.
Risk factors include;
- Occupational exposures to certain chemicals such as benzene
- Smoking and other uses of tobacco products
- Exposure to large amounts of radiation
- Down Syndrome or other types of genetic abnormalities
- Smoking, other uses or exposure in pregnancy and in childhood to tobacco smoke (passive smoking).
The treatment for cancers are quite expensive and drain resources. This is even more so when the five-year survival rates aren’t encouraging, however, new treatments are emerging that can change the outcomes into a better prognosis.
Immunotherapy is the “treatment of disease by inducing, enhancing, or suppressing an immune response”. Immunotherapies designed to elicit or amplify an immune response are classified as activation immunotherapies, while immunotherapies that reduce or suppress are classified as suppression immunotherapies.
What holds true for most blood cancers is that the earlier you detect it, the better you can reign it in.
Mariam Mojisola Solate-Eshinlokun is a Medical Laboratory Scientist (B.MLS, AMLSCN) in Hematology and Immunohematology. She also has an M.Sc in view. She’s from Ogun state, a wife, mother and currently practice at the National blood bank, Khartoum Sudan.