The cause of this cancer is not known. However, often it appears to be related to the presence of an abnormal chromosome called the Philadelphia chromosome. CML develops mainly in people who are middle-aged and sometimes in people who are older. Men and women are affected equally. The symptoms vary a lot.
Some people have no symptoms.
Your health care provider may discover the disease during a routine blood test. Or during a physical exam your provider may find that you have an enlarged spleen. The disease can have a chronic phase and an accelerated phase. In about 1 person in 4 the chronic phase develops into an accelerated phase, which is more serious. With frequent checkups, your health care provider will recognize a change in phases.