Living with CML - Treatment Goals / Progress

The 3 goals of treating CML include having a:

Hematologic response
A complete hematologic response means WBC, platelet, and RBC counts must have returned to a normal range, which should happen within the first 3 months of therapy.
Cytogenetic response
A complete cytogenetic response means that, using currently available tests, no cells with the Ph chromosome are found in the bone marrow sample or blood sample.
A major cytogenetic response means that no more than 35% of the cells in the bone marrow sample or blood sample have the Ph chromosome.
Molecular response
A complete molecular response means that, using currently available tests, there is no Bcr-Abl protein found in the bone marrow sample or blood sample.
A major molecular response means that the amount of Bcr-Abl protein found in the bone marrow sample or blood sample is very low.

To check your progress and see how well your treatment is working to meet your goals, your doctor will do regular tests. The tests will also show if you develop a resistance to the treatment.

Understanding resistance

There are 2 types of resistance: primary resistance (a patient is not responding to the treatment from the beginning) and a secondary or acquired resistance (a patient initially responds to the treatment but later stops responding)

A primary resistance means:

not getting a complete hematologic response within 3 months on treatment or
not getting a cytogenetic response within 6 months on treatment or
not getting a major cytogenetic response at 12 months on treatment

A secondary resistance means:

a prior hematologic or cytogenetic response that was obtained while on treatment is lost, regardless of using the recommended dose of medicine

For further information about resistance, click here.

Any combination of these tests may be used to track your response to treatment:
(Click here to learn more)

Hematologic testing—This is a simple blood test to see whether your WBCs, RBCs, and platelets have returned to normal levels. If they have, you have achieved a complete hematologic response. Even when your blood counts return to normal, you can still have undetectable levels of abnormal WBCs containing the Ph chromosome in your body. Therefore, you may need other tests to check your progress.
Cytogenetic testing—There are two types of cytogenetic testing:
- Karyotyping—Is done on bone marrow cells and WBCs to look at a small number of cells (about 20) to see whether they still contain the Ph chromosome. When the test shows that the number of Ph+ cells is decreasing, it is called a cytogenetic response.
- FISH (fluorescence in situ hybridization)—This test, which can be done on either blood or bone marrow cells, looks for abnormal cells that contain the bcr-abl gene, which is located on the Ph chromosome. This test can find 1 abnormal cell out of a background of up to 500 normal cells. Even when cytogenetic tests find no Ph cells, you can still have undetectable levels of abnormal WBCs containing the Ph chromosome in your body. These cells can be found using the most sensitive testing, molecular testing.
Molecular testing-RT-PCR (reverse transcriptase-polymerase chain reaction)—This is the most sensitive test for monitoring Ph+ CML. It is capable of finding 1 cell with the bcr-abl gene out of 1 million normal cells, and it can be done on either blood or bone marrow cells. If the test shows a significant decrease in the number of cells with the bcr-abl gene, as compared with a previous level of cells, it is called a molecular response.

Perform hematologic, FISH, and RT-PCR (if available) testing at diagnosis. At 3 months, check for a hematologic remission*. At 3 to 6 months, perform karyotyping to check for cytogenetic response and/or RT-PCR for molecular response. If in a complete cytogenetic remission, FISH or RT-PCR testing can be done on blood only, not on bone marrow. Bone marrow testing is done every year for cytogenetic response if RT-PCR does not increase or FISH is negative. Repeat bone marrow testing every 3 to 6 months for cytogenetic response if RT-PCR increases or FISH is positive.

Check Your Progress
Knowing how you are responding to treatment can help you feel more in control. Download the Tracking Treatment Progress chart to help track your treatment results. Be sure to talk with your treatment team about any questions or concerns you have about your test results and what they mean. Your treatment team can tell you whether your results mean that you are moving in the right direction.

Explaining remission in Ph+ CML
Talking about response and remission in Ph+ CML can be confusing. With most types of cancer, "remission" means that the cancer can no longer be detected. In Ph+ CML, though, there are 3 different types of remission your medical team may refer to:

Hematologic remission*—On regular blood testing (hematologic testing), WBC, RBC, and platelet counts have returned to normal, and the number of leukemia cells has decreased
Cytogenetic remission—On cytogenetic testing, none of the cells in the sample has the Ph+ chromosome. Even when cytogenetic tests find no Ph+ cells, you can still have undetectable levels of abnormal WBCs containing the Ph chromosome in your body
Molecular remission—On molecular (RT-PCR) testing, no cells containing the bcr-abl gene are detected. Although this is an excellent response, some undetectable leukemia cells (called minimal residual disease) may still remain and can cause relapse. That is why it is so important to continue treatment.

Next: Sticking with Treatment

*Even if your WBC count returns to normal, your CML has not been cured.