What are the stages of leukemia cancer? How does it progress?

Many variations. Leukemia can be Acute or Chronic. Further, it can be either Lymphatic(ALL , CLL) or Myeloid (AML)type. Since it is a blood cancer, it spreads into the blood very early on. So there is no staging system like we have for solid Cancers. But we can characterize it as Newly diagnosed(untreated) or Relapsed after prior treatment. The prognosis varies greatly among all the different varieties enlisted .