Leukemia--Chronic Myeloid (Myelogenous) Overview

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Early Detection, Diagnosis, and Staging TOPICS

Staging for chronic myeloid leukemia

Staging is the process of finding out how far a cancer has spread. Most types of cancer are staged based on the size of the tumor and how far it has spread from where it started. This system does not work for leukemias because they do not often form a solid mass or tumor. Also, leukemia starts in the bone marrow and, in many people, it has already spread to other organs when it is found.

For someone with chronic myeloid leukemia (CML), the outlook depends on other factors such as features of the cells shown in lab tests, and the results of imaging studies. This information helps guide treatment decisions.

Phases of chronic myeloid leukemia

CML is divided into 3 phases that help predict the patient’s outlook. Doctors call these phases rather than stages. The phases are based on the number of immature white blood cells, called blasts, that are seen in the blood or bone marrow. From less to more serious, they are:

  • Chronic phase
  • Accelerated phase
  • Blast phase (also called acute phase or blast crisis)

Most patients are diagnosed in the chronic phase. These patients usually have rather mild symptoms (if any).

Patients in the accelerated phase often have more symptoms, like fatigue, fever, poor appetite, and weight loss. They do not respond to treatment as well as during the chronic phase.

In the blast phase, patients often feel even worse. At this point the CML acts much like an aggressive acute leukemia.

Not all doctors agree with these cutoff points for the different phases. If you have questions about your CML phase, ask your doctor explain it to you.


Last Medical Review: 08/13/2013
Last Revised: 02/10/2014