When you receive a diagnosis of CML, your doctor will monitor abnormal cells in your blood and bone marrow to see how well you’re responding to treatment. Treatment milestones are achieved by reducing levels of abnormal cells within specific time frames.
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Once you begin treatment, your doctor will perform regular blood tests and bone marrow tests to monitor how many abnormal cells are in these tissues. They will likely want to perform these tests at least every
Treatment milestones are when the number of abnormal cells in your blood or bone marrow are reduced to certain cut-off values within certain time frames. Achieving milestones means you have a better chance of having a good outlook and longer survival.
Read on to learn more about treatment milestones and how doctors use them to guide your treatment.
When you receive a diagnosis of CML, your doctor will order blood and bone marrow tests to see how many abnormal cells are in these tissues. The number of abnormal cells is higher in people with more advanced CML.
Your doctor will compare baseline test results with the results of follow-up tests to judge whether treatment is working. The primary treatment for CML is a group of targeted therapy medications called tyrosine kinase inhibitors.
Doctors consider three types of treatment responses when judging the effectiveness of your treatment:
- Molecular response: A molecular response is a measurement of how much of the gene BCR-ABL is detected in your blood or bone marrow.
- Cytogenetic response: A cytogenetic response is a measurement of the number of cells in your bone marrow that have the Philadelphia chromosome. The Philadelphia chromosome is a particular genetic change found in CML cells.
- Hematologic response: A hematologic response is a measurement of abnormal cells in your blood that have returned to normal. It’s measured with a complete blood count.
Molecular response
A molecular response is a measure of how much of the BCR-ABL gene that appears on CML cells is present in your blood or bone marrow. This gene forms when a part of chromosome 22 trades places with part of chromosome 9.
Levels of this gene are measured using a laboratory test called a real-time quantitative polymerase chain reaction (qPCR) test. Doctors classify your response as one of the following milestones depending on how much BCR-ABL is detected during your follow-up tests.
| Molecular response | Description |
|---|---|
| Early molecular response | Less than 10% BCR-ABL1 is detectable compared with baseline within 3 to 6 months. |
| Major molecular response | Less than 0.01% BCR-ABL1 is detectable compared with baseline. |
| Complete (deep) molecular response | Less than 0.0032% BCR-ABL1 is detectable compared with baseline. |
| Undetectable BCR-ABL1 | Less than 0.001% BCR-ABL1 is detectable compared with baseline |
Receiving a complete molecular response of 0.01% BCR-ABL1 is now considered the goal of CML therapy by many doctors and it’s often used as the endpoint milestone in clinical trials.
Doctors consider the following the
| Time frame | Treatment milestone | Treatment failure |
|---|---|---|
| 3 months | less than 10% | greater than 10% |
| 6 months | less than 1% | greater than 10% |
| 12 months | less than 0.1% | greater than 1% |
| Any time | less than 0.1% | greater than 1% with resistance mutations |
Cytogenetic response
Doctors measure your cytogenetic response with a bone marrow sample. They analyze your sample in a laboratory to see how many of your cells have a genetic mutation called the Philadelphia chromosome.
The
Your level of cytogenetic response can be useful for doctors but isn’t enough by itself to sufficiently monitor your treatment response.
Doctors classify cytogenetic response in the following way:
| Type of response | Features |
|---|---|
| Minor cytogenetic response | More than 35% of your cells have the Philadelphia chromosome. |
| Partial cytogenetic response | 1% to 35% of your cells have the Philadelphia chromosome. |
| Major cytogenetic response | 35% or fewer of your cells have the Philadelphia chromosome. |
| Complete cytogenetic response | No Philadelphia chromosome is detected. |
Hematologic response
Your doctor will monitor your blood cell counts about
A complete hematologic response is characterized by:
- blood count returning to normal
- no abnormal and immature blood cells in your blood
- no signs or symptoms of the disease
- spleen returning to its normal size
Ongoing monitoring of whether you’re achieving treatment milestones is crucial for determining whether your treatment is working. Your doctors may recommend changing your treatment if you haven’t reached a complete molecular response under
According to the
Treatment-free remission is the
Doctors perform regular blood and bone marrow tests after you’ve received a diagnosis of CML to monitor how well you’re responding to treatment.
Achieving certain levels of abnormal cells in your blood and bone marrow within certain time frames is known as treatment milestones.
Achieving milestones early in your treatment is linked to better outcomes. Your doctor may recommend switching your medications if you don’t achieve these milestones.