Leukemias

What are the types of Leukemia?

Leukemias make up approximately 10% of all cancers and are not gender or ethnic specific. Most commonly, leukemias present in younger children whose prognosis is considerably better than an adult's.

Leukemia is an uncontrolled proliferation of leukocytes. This means that normal bone marrow is replaced by immature and undifferentiated leukocytes or blast cells. These abnormal leukocytes then infiltrate the bloodstream and circulate in the blood, which takes them to the liver, spleen, lymph nodes, kidneys and other resting sites. The overcrowding of the leukocytes interrupts the maturation of other blood cells.

Leukemia is either acute, meaning they are rapidly spreading, or chronic, meaning they have a slow course. Acute leukemias involve immature poorly differentiated leukocytes, whereas chronic leukemias involve mature well differentiated leukocytes.

The types of leukemias are described below:

  1.   Acute Lymphocytic Leukemia

  • Rare but most common in children
  • Abnormal no. lymphoblasts (block in maturation causes crowding and immature circulation)
  • Mostly B-lymphocyte origin
  • Associated with a chromosomal abnormality, e.g. Philadelphia chromosome
  • Prognosis better in children
  • Signs: immature cells with large nuclei, coarse clumped chromatin, multiple nucleoli, lymphadenopathy (swelling of lymph nodes, particularly in the neck), splenomegaly, hepatomegaly and bone pain (high proliferation rate in bone marrow, diseased cells release enzymes which attack bone inside to out and cause fractures)
  • Symptoms: headaches, nausea/vomiting, papilledema (optic disc swelling) and seizures (all due to ALL cells crossing blood-brain barrier)


  2.   Chronic Lymphocytic Leukemia
  • Most common type of leukemia
  • Affects persons aged 50-80
  • Male predominance
  • Mature B-lymphocyte origin
  • Difficult to treat and high probability of progressing to a more severe form
  • Symptoms: fatigue, weight loss, anorexia and bacterial infections
  • Reasonably long survival (10 years)
  3.   Acute (Granulocytic) Myeloid Leukemia
  • Almost as common as chronic lymphocytic leukemia in Australia
  • Myeloid cells become cancerous and replace normal bone marrow cells → transported through blood to organs where they grow and divide
  • Affects adults with little survival time (1-3 years)
  • Bone marrow transplant is only curative treatment, with common relapse
  • Symptom: pale, fatigue, susceptible to infection, fever, bruise and bleed easily
  4.   Chronic Myeloid Leukemia
  • Similar prevalence to ALL in Australia
  • Affects adults, uncommon in children
  • Associated with a chromosomal abnormality, e.g. Philadelphia chromosome (part of chromosome no. 22 attached to no. 9)
  • Affects neutrophils, myelocytes, basophils and eosinophils
  • Symptoms: dragging abdomen

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