CML exists and progresses through multiple stages, distinguished by the number of blasts (immature leukemia cells) found in the blood and bone marrow, as well as the severity of symptoms (American Cancer Society, 2011b; National Comprehensive Cancer Network, 2011).
Chronic phase CML: Symptoms may be absent or mild. Few blasts exist in blood and bone marrow (< 10%). This phase may last months to years. Most cases are diagnosed in the chronic phase. The untreated chronic phase will eventually progress to the accelerated phase in three to five years.
Accelerated phase CML: Blasts increase to approximately > 10% to < 20% of cells. This phase can last weeks to months.
Blast phase, or blast crisis CML: Blasts account for more than 30% of cells. Blast cells may form tumors in bone or lymph nodes. CML has progressed to aggressive acute leukemia at this phase.
Prognostic Scoring of CML
Two systems exist (Sokal and Hansford) to stratify risk of patient with CML. The scores consist of a specific calculation that quantifies risk into low, intermediate, and high risk groups. Calculate the relative risk using the two systems.