Treatments for chronic myelogenous leukemia

If you have chronic myelogenous leukemia (CML), your healthcare team will create a treatment plan just for you. It will be based on your needs and may include a combination of different treatments. When deciding which treatments to offer for CML, your healthcare team will consider:

• your age
• the phase of CML
• other prognostic factors, including blood cell counts and chromosome changes
• if there is a matched stem cell donor
• your overall health

During treatment for CML, your healthcare team will monitor you closely for response to treatment. They watch your blood cell counts closely. They also check the blood and bone marrow to see if any cells have the Philadelphia chromosome.

Often, instead of searching for the Philadelphia chromosome , the polymerase chain reaction (PCR) test for the BCR-ABL translocation may be done. This test is very sensitive. It can find small amounts of the BCR-ABL fusion gene, which is created by the Philadelphia chromosome and leads to the development of CML.

Your healthcare team will develop a plan to monitor the CML during treatment. Monitoring may include:

• complete blood count (CBC) every week until the blood cell counts are stable, and then less frequently
• sometimes, cytogenetic tests (analysis of the cells) on the bone marrow after the start of treatment
• PCR or reverse transcriptase PCR (RT-PCR) tests on the blood at diagnosis and about every 3 months during treatment

Your healthcare team uses these tests to look for hematologic, cytogenetic and molecular responses to treatment. About 70% of people have a complete cytogenetic response within 1 year of starting targeted therapy. After 1 year, even more people will have a complete cytogenic response. Many of these people will also have a complete molecular response. The healthcare team can’t tell if the CML is cured based on these responses, so targeted therapy is usually continued indefinitely.

The hematologic response usually occurs within the first 3 months of starting treatment.

Complete hematologic response means that:

• the blood cell counts have returned to normal
• there are no leukemia cells in the blood
• the spleen has returned to a normal size

Partial hematologic response is similar to a complete response, but all 3 conditions have not been met.

The cytogenetic response may take several months or longer to occur. It is based on how many cells in the blood or bone marrow have the Philadelphia chromosome.

Complete cytogenetic response means that no cells that have the Philadelphia chromosome are found in the blood or bone marrow.

Partial cytogenetic response means that less than 35% of cells have the Philadelphia chromosome.

Major cytogenetic response is sometimes used to refer to either a complete or partial cytogenetic response.

Minor cytogenetic response means that 35%–90% of cells have the Philadelphia chromosome.

Molecular response is based on PCR test results.

Complete molecular response means that the BCR-ABL fusion gene is not found in any cells in the blood.

Major molecular response means that only a small number of cells in the blood have the BCR-ABL fusion gene.