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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
You may be offered the following treatments for CML.
Targeted therapy drugs called tyrosine kinase inhibitors are first-line therapy for most people with CML.
Stem cell transplant
A stem cell transplant is rarely used as a first-line therapy for CML in the chronic phase. More often, it may also be used if CML becomes resistant to treatment with targeted therapy or biological therapy.
Stem cell transplant and the chemotherapy drugs used in preparation for a stem cell transplant can cause serious side effects, so not everyone can have this treatment. A reduced-intensity transplant may be an option for some people.
Donor lymphocyte infusion
Before a stem cell transplant, blood cells are removed from the donor’s blood. If a relapse occurs after a stem cell transplant, the lymphocytes are given to the person through one or more infusions. This is called a donor lymphocyte infusion (DLI).
Biological therapy with interferon alfa (Intron A, Wellferon) used to be the first-line therapy for CML. It is now occasionally offered to people who cannot cope with the side effects of targeted therapy or whose CML is resistant to targeted therapy.
Chemotherapy used to be one of the main treatments for CML. It is still used in preparation for a stem cell transplant and may also be used to treat people when targeted therapy has stopped working.
Sometimes surgery is used to remove the spleen (called a splenectomy) if it is larger than normal, or enlarged. Surgery may be done if the enlarged spleen is painful, and chemotherapy or radiation therapy does not shrink it. The spleen may also be removed to help improve blood cell counts.
Radiation therapy may be used to:
- shrink an enlarged spleen when chemotherapy does not work
- treat CML that may have spread outside the bone marrow
- relieve pain caused by the buildup of leukemia cells in the bone marrow
- treat the whole body (called total body irradiation) before a stem cell transplant
Supportive therapy is given to treat complications that usually happen with treatments for CML and the disease itself. Supportive therapy can include:
- antibiotics and antifungals to prevent or fight infections
- transfusions of blood products to replace blood cells when counts are low or if there is bleeding
- growth factors such as filgrastim (Neupogen) to stimulate the body to make white blood cells
- drugs to bring down high levels of some chemicals in the blood that increase when many cancer cells die at the beginning of treatment (called tumour lysis syndrome)
- leukapheresis to remove large numbers of white blood cells from the blood
Response to treatment
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.
Follow-up after treatment is an important part of cancer care. You will need to have regular follow-up visits for many years after treatment, even if there are no signs of disease. The time between exams will become longer as time goes on, but you will need to have follow-up exams for a long period of time. These visits allow your healthcare team to monitor your progress and recovery from treatment.
Some clinical trials in Canada are open to people with CML. Clinical trials look at new and better ways to prevent, find and treat cancer. Find out more about clinical trials.
Questions to ask about treatment
To make the decisions that are right for you, ask your healthcare team questions about treatment.
The organ on the upper-left side of the abdomen near the stomach that makes lymphocytes (a type of white blood cell that fights germs, foreign substances or cancer cells), stores blood cells, filters the blood and destroys old blood cells.
A procedure that uses a special machine (pheresis machine) to separate and collect specific white blood cells from withdrawn blood. The remaining blood is then returned to the body.
Leukapheresis is used to lower a very high white blood cell count in people with cancer (leukemia) or to remove white blood cells for transfusion.
An abnormality called a translocation where part of chromosome 9 is switched with a part of chromosome 22. This makes chromosome 22 shorter than normal. This type of chromosome abnormality happens in our cells during our lifetime, it is not inherited from our parents.
The Philadelphia chromosome is found in the leukemia cells of almost all people diagnosed with chronic myelogenous leukemia. Some people with acute lymphoblastic leukemia may also have the Philadelphia chromosome in their leukemia cells.
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