Prognosis and survival for acute myelogenous leukemia
People with acute myelogenous leukemia (AML) may have questions about their prognosis and survival. Prognosis and survival depend on many factors. Only a doctor familiar with a person’s medical history, type of cancer, stage, characteristics of the cancer, treatments chosen and response to treatment can put all of this information together with survival statistics to arrive at a prognosis.
A prognosis is the doctor’s best estimate of how cancer will affect a person and how it will respond to treatment. A prognostic factor is an aspect of the cancer or a characteristic of the person that the doctor will consider when making a prognosis. A predictive factor influences how a cancer will respond to a certain treatment. Prognostic and predictive factors are often discussed together and they both play a part in deciding on a treatment plan and a prognosis.
The following are prognostic and predictive factors for AML.
Many chromosome changes, or abnormalities, are linked with AML and some of them are used as prognostic factors.
Good-risk chromosome changes
Good, or favourable, risk means that the person with AML has the following chromosome abnormalities:
- translocation (part of a chromosome is transferred to another chromosome) between chromosomes 8 and 21
- inversion of chromosome 16
- translocation between chromosomes 15 and 17
Poor-risk chromosome changes
Poor, or less-favourable, risk means that the person with AML has the following chromosome changes:
- deletion of part of chromosome 5 or 7
- translocation between chromosomes 9 and 11
- translocation or inversion of chromosome 3
- translocation between chromosome 6 and 9
- translocation between chromosome 9 and 22
- abnormalities of chromosome 11
- complex changes involving several chromosomes
Intermediate-risk chromosome changes
Doctors consider people with normal chromosomes or chromosome changes that do not fall into the good- or poor-risk categories as intermediate risk. They have a prognosis that is in between good and poor.
Some people with AML have certain gene mutations. Doctors use these gene mutations as prognostic factors for people with AML.
About 30% of people with AML have a mutation (internal tandem duplication) in the FMS-like tyrosine kinase 3 (FLT3) gene. This FLT3 gene mutation is linked with a less favourable prognosis.
Up to 50% of people with AML have a mutation in the nucleophosmin (NPM1) gene. The NPM1 gene mutation is linked with a more favourable prognosis if there are no other abnormalities.
Changes to the CEBPA gene are linked to a more favourable prognosis.
Overexpression of the ERG gene in people with AML points to a less favourable prognosis.
Younger adults, usually those younger than 60 years of age, have a more favourable prognosis than older adults. This may be because chromosomal abnormalities can happen as a person gets older. Older people may also have other health conditions that make it difficult for them to cope with the side effects of treatments for AML.
White blood cell count
A white blood cell (WBC) count of more than 100,000 at the time of diagnosis is linked with a less favourable prognosis.
Response to chemotherapy
People who reach complete remission after induction chemotherapy have a more favourable prognosis than those who have refractory disease that does not respond to treatment.
The response to chemotherapy is measured as the time it takes to reach a complete remission, or complete response. When a complete remission is reached within 4 weeks of starting chemotherapy, the prognosis is more favourable. The prognosis is less favourable when it takes longer to reach complete remission. The prognosis is poorer in people who don’t reach a complete remission after chemotherapy.
Minimal residual disease (MRD) means that there are leukemia cells, or blasts, in the bone marrow, but they can only be seen using very sensitive tests, such as flow cytometry or polymerase chain reaction (PCR). The cancer cells can’t be seen with standard tests, such as looking at the cells under a microscope. In general, people with AML who have MRD any time after the start of consolidation therapy (the continued treatment given to keep leukemia from coming back) have a higher risk of relapse and a poorer prognosis.
An early relapse means that the leukemia returns soon after treatment. It is linked with a less favourable prognosis.
Previous blood disorders
People who already had a blood disorder, such as a myelodysplastic syndrome (MDS), usually have a less favourable prognosis.
Previous treatment for cancer
AML that develops after treatment for another cancer usually has a less favourable prognosis.
A serious, uncontrolled infection at the time of diagnosis is a less favourable prognostic factor.
Leukemia cells in the central nervous system
Spread of AML to the brain and spinal cord (called the central nervous system, or CNS) is a poor prognostic factor.
Research at the Canadian Centre for Applied Research in Cancer Control led to a new standard in leukemia testing.
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