Risk factors are patient and disease characteristics that clinical studies have linked to better or worse outcomes from treatment. Risk factors are also called prognostic factors. Doctors look at risk factors to try to predict how well a patient's disease will respond to treatment. This page focuses on some of the risk factors doctors may use to plan treatment for acute myelogenous leukemia (AML). For a more complete overview of AML symptoms and treatment options, see Acute Myelogenous Leukemia (AML).
Risk factors doctors may consider
For acute myelogenous leukemia (AML), doctors look at risk factors to try to predict how well a patient's disease will respond to chemotherapy, the standard first treatment. Patients with low-risk factors have a good chance of reaching long-term remission with chemotherapy alone. For patients with certain high-risk factors, a bone marrow or cord blood transplant (also called a BMT) may offer the best chance for a long-term remission.
Risk factors that doctors may look at when planning treatment for AML include:
- The patient's age (see discussion below)
- Changes to the chromosomes (cytogenetic factors — explained below)
- The subtype of AML
- Whether the patient had a blood disorder, such as myelodysplastic syndrome, before developing AML
- Whether the patient has received chemotherapy in the past
- Whether the AML has been treated before and relapsed
- Whether leukemia cells have spread to the central nervous system (brain and spinal cord)
- How well AML responds to early chemotherapy treatments
- Whether the patient has other health problems, such as diabetes or heart disease, that can affect his or her ability to tolerate some treatments
Cytogenetic factors are changes in the chromosomes of leukemia cells.
- There may be more or fewer chromosomes than normal.
- Part of one chromosome may move to another (chromosome translocation).
There are many chromosome changes that can occur with AML. Some changes are linked with better outcomes (low-risk changes) and others are linked with worse outcomes (high-risk changes). If you have AML, ask your doctor to explain your cytogenetic risk factors to you.
- Examples of low-risk cytogenetic changes for AML include a translocation between chromosomes 15 and 17, a translocation between chromosomes 8 and 21, and certain changes to chromosome 16.
- Examples of high-risk cytogenetic changes for AML include changes to chromosome 5 or chromosome 7.
- Example of high-risk genetic change, FLT3 positive
- Example of low-risk genetic change, NPM 1 positive
High-risk factors for adults
The National Marrow Donor Program® (NMDP)* and American Society for Blood and Marrow Transplantation (ASBMT) recommend adult patients with AML be referred to a transplant doctor for consultation if they have any of the following high-risk factors:
- Previous myelodysplastic syndrome or other blood-related disease
- AML that may have developed because of previous chemotherapy treatments
- No remission after induction treatment
- High-risk cytogenetics — refer at first remission
- Relapse — refer at second or later remission
Complete NMDP and ASBMT recommendations are available in the Physician Resources section of this website: Recommended Timing for Transplant Consultation (PDF).
*The NMDP, which operates Be The Match®, also conducts research to learn how to improve patient outcomes.
Children with AML
Treatment for children age 17 or younger is similar to treatment for adults, but there are some differences. Children have different risk factors than adults. They also have a higher overall survival rate — about 50% to 60%. Children also generally have a better chance of a good outcome from an allogeneic transplant, so transplant may be used more often for children with AML than for adults.
The NMDP and ASBMT guidelines — Recommended Timing for Transplant Consultation (PDF) — recommend children with AML be referred to a transplant doctor for consultation if they have any of the following high-risk factors:
- If the child is 2 years old or younger when diagnosed with AML
- If induction chemotherapy does not bring a remission
- If the leukemia cells show only one chromosome 5 or chromosome 7 (high-risk cytogenetic factors)
- As soon as the child reaches a first remission if he or she has a suitable sibling donor
- At a second remission after a relapse — using either a related or unrelated donor or cord blood unit
Children have a higher risk than adults of leukemia spreading to the central nervous system (brain and spinal cord). Most children are treated to prevent this spread. Treatment is usually intrathecal chemotherapy — injecting chemotherapy drugs into the spinal fluid. Treatment may also include radiation therapy to the head.
Adults age 60 and older
More than half of people diagnosed with AML are age 60 or older. These older adults are more likely than younger adults to have high-risk disease factors. Older adults are less likely to respond well to treatment and may be less able to tolerate some treatments. Only 5% to 15% of adults age 60 or older are likely to survive without relapse for the long term. However, many factors affect a person's chances of long-term remission, so it is important to talk with your doctor about your own situation.
If you are age 60 or older, it is a good idea to talk with your doctor about a range of treatment options. Ask about the chances of long-term remission, possible side effects and the quality of life you can expect with different treatments. It is important to have complete information so that you and your doctor can choose an approach that is right for you. Options may include:
- Standard treatment options — chemotherapy or a transplant. To learn about these standard treatment options, see Acute Myelogenous Leukemia (AML).
- Reduced-intensity transplant — Many adults age 60 and older may be unable to tolerate a standard transplant, but a reduced-intensity transplant may be an option.
- Other newer treatments recently developed and/or being studied in clinical trials.
- Supportive care to maintain a good quality of life without trying to bring the AML into remission. Supportive care may include antibiotics to prevent infection and transfusions of red blood cells and platelets.
C. F. LeMaistre, M.D., Southwest Texas Methodist Hospital, San Antonio, Texas
Paul Shaughnessy, M.D., Texas Transplant Institute, San Antonio, Texas
Anthony S. Stein, M.D., City of Hope National Medical Center, Duarte, Calif.