Staging
of Leukemia
Staging
Most cancer patients are assigned a clinical "stage" after undergoing a
diagnostic work-up. According to the system, staging is based
on the size of the tumor and how far it has spread from its original location in
the body.
Because leukemia starts in the bone marrow and often has spread to other
organs by the time it is detected, there is no need for traditional staging.
Instead, physicians rely upon cytologic (cellular) classification systems to
identify the type and subtype of leukemia. Cell classification systems, in turn,
help to predict the prognosis, or outcome, of specific forms of leukemia and the
likely response to treatment.
The most popular classification method for acute leukemia is the
French-American-British (FAB) system. According to FAB classification, acute
leukemia is divided into eight subtypes of acute myelogenous leukemia (AML) and
three subtypes of acute lymphocytic leukemia (ALL) (see Types of Leukemia). FAB
originally was based upon the microscopic appearance of leukemia cells; however,
in recent years, researchers have discovered that cellular characteristics such
as genetic make-up and numbers of specific cell types help to classify leukemia
and predict its outcome.
Chronic lymphocytic leukemia (CLL) is classified by one of two cytologic
staging systems, which known as Rai Classification and Binet Staging,
respectively.
Classification
This
Classification separates
chronic lymphocytic leukemia into low-, intermediate-, and high-risk categories,
which correspond with stages 0, I & II, and III & IV, respectively:
- Stage 0 patients are low risk and have lymphocytosis, a high
lymphocyte count defined as more than 15,000 lymphocytes per cubic millimeter
(> 15,000 /mm3).
- Stage I patients are intermediate risk and have lymphocytosis
plus enlarged lymph nodes (lymphadenopathy).
- Stage II patients are also intermediate risk but have
lymphocytosis plus an enlarged liver (hepatomegaly) or enlarged spleen
(splenomegaly), with or without lymphadenopathy.
- Stage III patients are high-risk and have lymphocytosis plus
anemia, a low red blood cell count (hemoglobin < 11 g/dL), with or without
lymphadenopathy, hepatomegaly, or splenomegaly.
- Stage IV patients are also high-risk but have lymphocytosis plus
thrombocytopenia, a low number of blood platelets
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