Most types of cancer are staged to communicate the size of the tumor and how far the cancer has spread. But leukemia rarely causes tumors. And because it is in your bone marrow and blood, the leukemic cells are always circulating through your body. Instead of stages, doctors describe chronic myeloid leukemia (CML) in terms of phases: chronic phase, accelerated phase, and blast phase.
Here are brief descriptions of each:
During this phase, you have fewer than 10% blasts, which are immature white blood cells, in your blood or bone marrow. You usually have relatively mild symptoms (if any) and respond to standard treatments.
During this phase, you have more than 10% but fewer than 20% blasts, which are the immature white blood cells. You may have a fever, poor appetite, and weight loss. During this phase, your symptoms and blood counts may not respond as well to treatment. Your leukemia cells may have developed other chromosomal changes, in addition to the Philadelphia chromosome.
During this phase, you have more than 20% of the immature blasts in your blood or bone marrow. These blast cells often spread to other areas of your body outside the bone marrow. When tiredness, fever, and an enlarged spleen occur during the blastic phase, it is called blast crisis. This phase is considered aggressive.