The short answer
AML is not staged like a solid tumor. Doctors sort it into favorable, intermediate, or adverse risk groups using chromosome changes and gene variants in the leukemia cells. That grouping drives one decision more than any other: whether a stem cell transplant is offered in first remission.
AML has no stage I to IV. It is risk-stratified using cytogenetics and gene variants in the leukemia cells.
Favorable factors include t(8;21), inv(16), a normal karyotype with an NPM1 variant and no FLT3 variant, and a normal karyotype with double CEBPA variants.
Adverse factors include deletions of 5q, 7q, or 17p, complex or monosomal karyotype, KMT2A variants, and TP53, RUNX1, or ASXL1 variants.
A normal karyotype without those markers puts a case in the intermediate group.
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The full explanation.
Why AML has no stage number
A stage answers two questions: how big, and how far. Neither works for AML. At diagnosis the leukemia is already through the blood and bone marrow.
So hematologists sort AML a different way. They read the genetics of the leukemia cells themselves. NCI's clinical summary puts it directly: cytogenetic information can define subsets of patients with predictable better or worse outcomes.
The result is three groups. Favorable. Intermediate. Adverse.
What the testing looks at
Two kinds of results build the risk group.
Cytogenetics looks at whole chromosomes. It finds pieces that are missing, doubled, flipped, or swapped between chromosomes. Notation like t(8;21) means a translocation, an exchange of material between chromosomes 8 and 21. inv(16) means part of chromosome 16 is flipped end for end. del(5q) means a piece of the long arm of chromosome 5 is gone.
Molecular testing looks at single genes. NPM1, FLT3, CEBPA, TP53, RUNX1, ASXL1, and KMT2A all appear on the risk lists.
Both sets of results usually appear on the pathology report. Our page on AML pathology and molecular results walks through reading that report.
The favorable group
NCI lists four favorable-risk factors:
- t(8;21).
- inv(16).
- A normal karyotype with an NPM1 variant, when no FLT3 variant is present.
- A normal karyotype with double CEBPA variants.
Two of those carry conditions worth reading twice.
The NPM1 finding only counts as favorable when FLT3 is not also altered. That is why both genes are tested together, and why an NPM1 result alone does not settle the question.
CEBPA has to be altered in both copies of the gene. Biallelic CEBPA is independently linked to a favorable outlook. Single-copy, or monoallelic, CEBPA is not. That distinction was firm enough that the WHO revised its definition of the subtype in 2016 around it.
The adverse group
The adverse list is longer. NCI includes:
- Deletion of 5q, 7q, or 17p.
- Inversion of chromosome 3, or t(3;3).
- Abnormality of 17p.
- Trisomy 8.
- t(6;9).
- t(9;22).
- Most translocations involving chromosome 11q23.
- KMT2A variants.
- A complex karyotype, meaning three or more abnormalities, or a monosomal karyotype.
- A history of myelodysplasia or another blood disorder before the AML.
- TP53, RUNX1, or ASXL1 variants.
- A normal karyotype with a FLT3 variant.
Note the last two lines. Adverse risk is not only about chromosomes. A gene variant on a normal-looking karyotype, or a prior blood disorder, can move a case into this group on its own.
The intermediate group
Normal cytogenetics without any of the markers above lands a case in the intermediate group. NCI's guidance here is deliberately open. Consolidation should be individualized using additional molecular markers, other health conditions, and patient preference, or ideally handled within a clinical trial.
That is not vagueness. It reflects a real gap where the evidence does not yet point one way.
What the risk group actually decides
The practical stakes come down to one question. Should an allogeneic stem cell transplant happen during the first complete remission, or should it wait?
A meta-analysis pulled data from 18 prospective trials that used a donor versus no-donor design. Patients in remission were HLA typed; those with a matched sibling or unrelated donor went to the transplant arm, and outcomes were analyzed by intention to treat. Trials enrolled adults aged 60 and under between 1982 and 2006.
Across all risk groups, transplant reduced death or relapse. The combined hazard ratio was 0.80 for relapse-free survival and 0.90 for overall survival.
The subgroup results are what matter here:
- Favorable risk. No benefit. Relapse-free survival hazard ratio 1.07 (95% CI 0.83 to 1.38, P = .59). Overall survival hazard ratio 1.06 (95% CI 0.64 to 1.76, P = .81).
- Intermediate risk. Benefit. Relapse-free survival hazard ratio 0.83 (P < .01). Overall survival hazard ratio 0.84 (P = .03).
- Adverse risk. Larger benefit. Relapse-free survival hazard ratio 0.73 (P < .01). Overall survival hazard ratio 0.60 (P = .01).
Transplant-related mortality ran 5% to 42% in the donor groups and 3% to 27% in the no-donor groups. That range is why the favorable-risk result is not a footnote. Transplant carries real cost, and in the group that does well on chemotherapy it did not buy anything.
NCI states the resulting practice plainly. Most leukemia physicians agree transplant should be offered in first remission for adverse-risk cytogenetics and should not be offered in first remission for favorable-risk cytogenetics. Our page on stem cell transplant covers what the procedure involves.
The exceptions inside the rule
Two caveats follow immediately, and both are in the same NCI summary.
Older patients with favorable-risk AML who are unlikely to tolerate intensive cytarabine-based consolidation can still be considered for allogeneic transplant. The reason is not the leukemia's biology. It is that the alternative treatment may not be deliverable.
And even with transplant, adverse-risk outcomes are hard. NCI reports 5-year disease-free survival of 8% to 30% for patients with treatment-related leukemia or myelodysplasia.
Where the framework comes from
The favorable, intermediate, and adverse structure is set out in guidance from the European LeukemiaNet, an international expert panel. The current version is the 2022 recommendations published in Blood by Döhner and colleagues.
Risk group also interacts with drug choice. In a meta-analysis of more than 3,000 patients, adding gemtuzumab ozogamicin to induction improved 5-year overall survival across all ages, but the effect was largest in favorable-risk cytogenetics, at 76.3% versus 55.2%.
What a risk group is not
These groups summarize how large numbers of past patients fared. They are a planning tool, not a verdict on any one person. Age, other health conditions, and how the leukemia responds to the first round of treatment all carry weight alongside the genetics. Two people in the same group can end up with different, equally reasonable plans.
Sources
- National Cancer Institute, Acute Myeloid Leukemia Treatment (PDQ) - Health Professional Version, accessed August 6, 2026
- Döhner H, Wei AH, Appelbaum FR, et al., Diagnosis and management of AML in adults: 2022 recommendations from an international expert panel on behalf of the ELN, Blood 2022;140(12):1345-1377, accessed August 6, 2026
Words to know
Tap any term to see what it means.
Common questions
Why isn't AML staged like breast or colon cancer?
Solid tumor stages describe size and spread. AML is already throughout the blood and bone marrow at diagnosis, so that question does not apply. What predicts behavior is the genetics of the leukemia cells, and NCI's clinical summary states that cytogenetic information defines subsets with predictable better or worse outcomes.
What is cytogenetics?
Cytogenetics is the study of chromosomes, the structures inside cells that carry DNA. A cytogenetic test examines blood or bone marrow for broken, missing, rearranged, or extra chromosomes. In AML, specific patterns such as t(8;21) or inv(16) carry established meaning.
What does favorable risk actually change?
It changes the transplant conversation. NCI states that favorable-risk patients have a reasonable chance of cure with intensive consolidation chemotherapy, and that deferring transplant until early first relapse may be reasonable. A meta-analysis found no survival benefit from transplant in first remission for this group.
What does adverse risk mean for treatment?
NCI states that the adverse-risk group is highly unlikely to be cured with consolidation chemotherapy alone, and that allogeneic transplant in first complete remission is a reasonable option. Even then, outcomes are difficult: 5-year disease-free survival runs 8% to 30% for treatment-related leukemia or myelodysplasia.
Can the risk group change over time?
The group assigned at diagnosis comes from the original cytogenetic and molecular testing. Response to initial treatment is tracked separately and is itself an important signal. Relapsed AML and treatment-related AML are assessed on their own terms.
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Last updated: 2026-08-06Next planned review: 2027-08-03
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How this page was created
Cancer Explained does not originate medical claims. Every page restates guidance already published by the National Cancer Institute, the CDC, the USPSTF and the FDA, in plain language, with the source cited so you can check the original yourself. AI does the translating and organizing; automated checks test claims, citations, clarity and safety before anything publishes. We do not employ clinicians and do not intend to — our work is translation and navigation, not clinical judgment. Nothing here is personal medical advice, and no page can account for your particular situation.
Editorial status: Source checked — This page was written with AI assistance and checked line by line against the sources listed on it. That confirms the sources support what the page says. It is not a medical review, and it does not confirm the page is complete or right for your situation.
Human medical review: not completed. Pages here are not signed off by a clinician before they publish. That is not an oversight we are quietly working around: we restate published guidance and cite it, so the authority belongs to the source rather than to us, and every page names where its claims come from — you can verify us instead of trusting us. Where a volunteer clinician has reviewed a page, their name and credentials appear on it; where no name appears, no clinician has checked it. We are glad to have reviewers and are recruiting them, and we do not hold pages back waiting for one. Use this site to understand your situation and to ask better questions of the people treating you.
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