Acute myeloid leukemia (AML)

Diagnosis usually starts with a blood test called a complete blood count (CBC). It counts red cells, white cells and platelets. In AML, the CBC often shows too few red cells and platelets, and the white cell count may be high, normal or low. Looking at the blood under a microscope (a blood smear) can show immature cells called blasts. To confirm AML, doctors take a small sample of bone marrow with a hollow needle from the hip bone or breastbone (bone marrow aspiration and biopsy).

The marrow and blood then go through more tests. A marker test (flow cytometry or immunophenotyping) shows which kind of leukemia it is. Chromosome tests (cytogenetics) and gene tests (molecular testing) look for the changes that set the AML subtype and risk group. Some of these changes can be targeted by specific medicines. A spinal tap (lumbar puncture) may check the fluid around the brain and spinal cord. Children may also have a chest x-ray.

Chromosome and gene results take time. One U.S. trial, Beat AML, was set up for fast testing in adults aged 60 and older. From 2016 to 2019, results came back within 7 days of the sample for about 95 of every 100 people. U.S. transplant guidelines also advise detailed tissue typing (HLA typing) at diagnosis for everyone with AML. That way a donor search can start early if one is needed.

Treatment may use intensive chemotherapy, lower-intensity drug combinations such as a hypomethylating medicine with venetoclax, and medicines directed at particular leukemia mutations. The choice depends on the subtype, medical fitness and treatment goals. Acute promyelocytic leukemia is treated differently.

Remission means that standard assessments no longer show active leukemia at the previous level; sensitive measurable residual disease (MRD) tests may still detect leukemia. Treatment after remission reduces relapse risk. Some people can have lasting remission with drug treatment without a transplant.

Allogeneic transplantation uses another person’s blood-forming cells and can offer a chance of cure when relapse risk justifies its risks. It is often considered for eligible people with higher-risk AML, persistent MRD or relapsed disease. HLA typing, transplant consultation and donor searching can begin early, while initial treatment is underway.

When a transplant from a donor is planned, the team usually tests brothers and sisters first. Each full sibling has about a one in four chance of being a full match.

Most patients do not have a matched relative. In the words of NMDP, the U.S. registry, “75% of patients don’t have a fully matched donor in their own family.” The team then searches registries of volunteer donors around the world and banks of donated cord blood. In some transplants, a half-matched parent, child or sibling can also be the donor.

Matching depends on inherited tissue markers called HLA, so a patient is most likely to match someone who shares their ancestry. Every person who joins makes the search a little more likely to succeed, especially for patients from groups that are underrepresented on registries.

The outlook for AML differs a great deal from one person to the next. NCI says the leukemia's chromosome and gene changes give the strongest clues. Age and overall health matter too. Older adults are less likely to reach remission and have more complications during early treatment. AML that follows an earlier blood disorder, such as myelodysplastic syndrome (MDS), or earlier cancer treatment has a poorer outlook.

The response to first treatment is the next big clue. NCI says about 60 to 70 of every 100 adults with AML reach complete remission after the first phase of treatment (induction). Sensitive tests for measurable residual disease (MRD) can show whether hidden leukemia remains. When the chance of relapse is high, a donor stem cell transplant can offer a chance of cure. MedlinePlus notes that if AML has not come back within 5 years of diagnosis, the person is likely cured.

Children with AML tend to do better than older adults. St. Jude reports that about 90 of every 100 children have no leukemia cells in their blood after first treatment. About 30 of every 100 have leukemia that comes back or does not respond. Every one of these numbers describes a group. None can say what will happen to one person.