Most types of cancer are classified by a process known as staging. Staging assigns numbered stages to cancers based on tumor size and how far the cancer spreads from the original site. Leukemia, however, is not staged because it involves all the bone marrow in the body. In many cases, it spreads to other organs through the bloodstream.

Diagnostic tests focus on establishing the type and subtype of leukemia. This information is then used to determine the prognosis and predict which treatments will be most effective. Subtypes of AML respond to treatment differently and their prognoses vary.

The classification of these subtypes is based on a classification system known as the French-American-British (FAB) Classification of AML. Based on the type of cell from which the leukemia developed, this system consists of eight subtypes including:

In addition to these subtypes, certain prognostic factors have been identified to help a physician determine if a patient requires more or less treatment. Adult AML prognostic factors include:

• Age. Patients over the age of 60 have a worse prognosis than younger patients.
  
  
• White blood cell count. Patients with a white blood cell count above 100,000 have a worse prognosis.
  
  
• Having a prior preleukemic condition. Patients who have a prior preleukemic condition (e.g., myelodysplastic syndrome) have a worse prognosis.  
  
  
• Having secondary AML. Patients who develop AML after receiving chemotherapy or radiation therapy for another cancer have a worse prognosis.
  
  
• Having an unfavorable chromosome abnormality. Analysis of abnormalities in the chromosomes (cytogenics) may be the best predictor of a patient’s response to treatment.
  
  
• • Whether the AML has spread to the brain or spinal cord. Patients with AML that has infiltrated the brain or spinal cord have a worse prognosis.
    
    
  • Whether the AML has been treated previously. Patients who have been treated for AML have a poorer prognosis.