If you are in the chronic phase of chronic myeloid leukemia (CML), the aim is to prevent you from reaching what's called the "accelerated phase". About 90% of CML patients are in the chronic phase when they are diagnosed. On the other hand, there are some patients who are diagnosed in the accelerated phase of CML, or who may progress to the accelerated phase. These patients may already be dealing with a number of symptoms, and worse blood counts, than patients who are in the chronic phase.

Like everyone with chronic myeloid leukemia, your treatment options and outlook, along with your recommended treatment goals, may all be affected by the CML phase you're in.

When you're in the accelerated phase, the cancer cells grow faster, so tests show more of them.
Blast cells may already have undergone changes, producing other mutations beyond the
Philadelphia chromosome. Increasing white blood cell (WBC) counts aren't affected by treatment. Your spleen may be enlarged. Overall, the disease—while still treatable—is less responsive to treatment in the accelerated phase. The goal of your oncologist—with you as an active partner—is to develop a treatment plan to get you back to the chronic phase.