What is the difference between CLL stage (Rai or Binet) and SLL stage (Ann Arbor)? Why does the same disease have two different staging systems?
Dr. Richard Furman writes: The purpose of a staging system is to help clinicians better determine prognosis and plan treatment for a patient’s disease. Although chronic lymphocytic leukemia (CLL) and small lymphocytic lymphoma (SLL) are the same disease, they were not recognized as the same disease until 1994. Since then they have been combined into one entity, CLL/SLL.
For historical reasons, CLL was staged based upon the Rai or Binet scheme (see below) and SLL was staged using the Ann Arbor lymphoma staging scheme (see below). Today most CLL specialists use the Rai stage because it is more clinically helpful. Using the Ann Arbor classification to stage SLL is problematic in scenarios where the disease has spread to the bone marrow. A person with SLL in their lymph nodes and bone marrow would immediately be characterized as an Ann Arbor stage IV, but their prognosis and treatment plan would be far better indicated as measured by the Rai stage I. Therefore the Rai stage, even without lymphocytosis, provides better prognostic and therapeutic information for a physician to treat their patient.
0: lymphocytosis (an increase in number of lymphocytes in the blood).
I: Lymphocytosis + lymphadenopathy, (enlarged lymph nodes).
II: Lymphocytosis + splenomegaly (enlargement of the spleen) +/- lymphadenopathy
III: Lymphocytosis + anemia (decrease in red blood cells) +/- splenomegaly +/- lymphadenopathy
IV: Lymphocytosis + thrombocytopenia (decrease in platelets) +/- anemia +/- splenomegaly +/- lymphadenopathy
Ann Arbor Stages
I: Disease found in one group of lymph node
II: Disease found in two or more groups of lymph nodes on the same side of the diaphragm.
III: Disease found in two or more groups lymph nodes on both sides of the diaphragm.
IV: Extranodal disease (found outside of the lymph nodes), including bone marrow, liver, or other organs)
Note: if only one isolated area or organ involvement is present, then it would be a stage I, except for bone marrow.