There is no staging system for leukemias, except for the chronic lymphocytic form (CLL). With CLL there are several staging classifications, the most frequently used being the RAI and the International. Both systems are based on the presence or absence of enlarged lymph nodes , liver or spleen and, most important, on the degree of anemia or low platelet counts.
Staging in the RAI system varies from Stage 0 to Stage IV, with average survivals ranging from over 12 years in the early stage to about a year in the late. Average survivals are comparable in the International classifications of A, B and C.
The RAI system has been modified by grouping Stage I as a low-risk group, Stage II as an intermediate-risk and Stage III and IV combined as a high-risk group. This offers a comparable grouping of average survival to the International classification of A, B and C groups.
