Understanding CML Accelerated Phase
What's happening now? This is a really short, but critical transition phase. "Untreated, the acceleration phase progresses to blast crisis in an average of 1 1/2 to 2 years," says Bruno Medeiros, MD, assistant professor of hematology at Stanford University School of Medicine.
Blocks in blood cell differentiation allow abnormal blood cells to build up, he says. During this phase of CML, these so-called blast cells make up 10% to 19% of the cells in blood and bone marrow.
Symptoms like these may signal that something is wrong:
- Feeling ill, weak, or fatigued
- Loss of appetite or weight loss
- Fullness in your abdomen caused by a swollen spleen
You may also develop anemia from a lack of healthy red blood cells.
Many patients, however, have no symptoms at all during this phase. Instead, your doctor may see changes on your lab test results.
"When you're not feeling any worse, it's hard for you to understand that your disease has changed," Medeiros says. But grasping this is essential, because it greatly affects your treatment plan.
Understanding CML Blast Phase
The CML blast phase is really a continuation of what started in the acceleration phase, Radich says. More and more blasts build up and the numbers of normal blood cells in the bloodstream decrease.
The blast crisis occurs when blast cells make up more than 20% of the cells in your bone marrow and blood.
During this phase, infections and bleeding complications are common and can be fatal, Radich says. You may have symptoms such as:
- Fatigue or weakness
- Shortness of breath
- Stomach pain
- Bone pain
- Quick weight loss
- Fullness in the abdomen from an enlarged spleen
Treatment During CML Accelerated or Blast Phases
The goal of treatment during the CML accelerated phase or CML blast phase is to:
- Kill all cells that contain the BCR-ABL gene
- Return your disease to the chronic disease
Your doctor may first put you on a medication called targeted therapy. This therapy targets cancer cells without harming normal cells. Called tyrosine kinase inhibitors (TKI), the one you take now may be different than the one you've already taken. Your therapy may include:
- Imatinib mesylate (Gleevec)
- Dasatinib (Sprycel)
- Nilotinib (Tasigna)
- Bosutinib (Bosulif)
If a donor is available, view this therapy as a bridge to stem cell transplantation, Radich says. "With tyrosine kinase inhibitors, you can slow down progression in these phases, but you cannot cure the disease." If you are in acceleration or blast crisis, you need stem cell transplantation as soon as possible, he says. "And since that takes some time, you should be on a targeted kinase therapy or experimental agent until that time arises."
Even if you get a response to therapy in these phases, it's important to understand its stop-gap nature, Medeiros says. It's unlikely to provide a long-term benefit. "You try to maximize your response for the first few months of therapy while you're trying to identify a donor. And then you move forward to stem cell transplant as soon as possible. The sooner you do a transplant, the better your outcome tends to be."
During these phases, your doctor may recommend other types of treatment as well, including chemotherapy, hydroxyurea, or apheresis. There's a drug called Synribo (omacetaxine mepesuccinate) that can be used if the disease progresses after using two or more TKIs. Furthermore, some treatments may help to address symptoms you're experiencing.