Acute myeloid leukemia is a curable disease; the chance of cure for a specific patient depends on a number of prognostic factors.
Cytogenetics
The single most important prognostic factor in AML is cytogenetics, or the chromosomal structure of the leukemic cell. Certain cytogenetic abnormalities are associated with very good outcomes (for example, the (15;17) translocation in acute promyelocytic leukemia). About half of AML patients have "normal" cytogenetics; they fall into an intermediate risk group. A number of other cytogenetic abnormalities are known to associate with a poor prognosis and a high risk of relapse after treatment.
The first publication to address cytogenetics and prognosis was the MRC trial of 1998:
| Risk Category | Abnormality | 5-year survival | Relapse rate |
|---|
| Good | t(8;21), t(15;17), inv(16) | 70% | 33% |
| Intermediate | Normal, +8, +21, +22, del(7q), del(9q), Abnormal 11q23, all other structural or numerical changes | 48% | 50% |
| Poor | -5, -7, del(5q), Abnormal 3q, Complex cytogenetics | 15% | 78% |
|
Later, the Southwest Oncology Group and Eastern Cooperative Oncology Group and, later still, Cancer and Leukemia Group B published other, mostly overlapping lists of cytogenetics prognostication in leukemia.
Myelodysplastic syndrome
AML which arises from a pre-existing myelodysplastic syndrome or myeloproliferative disease (so-called ''secondary AML'') has a worse prognosis, as does ''treatment-related AML'' arising after chemotherapy for another previous malignancy. Both of these entities are associated with a high rate of unfavorable cytogenetic abnormalities.
Other prognostic markers
In some studies, age >60 years and elevated lactate dehydrogenase level were also associated with poorer outcomes. As with most forms of cancer, performance status (i.e. the general physical condition and activity level of the patient) plays a major role in prognosis as well.
''FLT3'' internal tandem duplications (ITDs) have been shown to confer a poorer prognosis in AML. Treating these patients with more aggressive therapy, such as stem-cell transplantation in first remission, has not been shown to enhance long-term survival, so this prognostic feature is of uncertain clinical significance at this point. ITDs of FLT3 may be associated with leukostasis.
Researchers are investigating the clinical significance of ''c-KIT'' mutations in AML. These are prevalent, and clinically relevant because of the availability of tyrosine kinase inhibitors, such as imatinib and sunitinib that can block the activity of ''c-KIT'' pharmacologically.
Other genes being investigated as prognostic factors or therapeutic targets include ''CEBPA'', ''BAALC'', ''ERG'', and ''NPM1''.
Overall expectation of cure
Cure rates in clinical trials have ranged from 20–45%; however, it should be noted that clinical trials often include only younger patients and those able to tolerate aggressive therapies.
The overall cure rate for all patients with AML (including the elderly and those unable to tolerate aggressive therapy) is likely lower. Cure rates for promyelocytic leukemia can be as high as 98%.
Further Reading
This article is licensed under the Creative Commons Attribution-ShareAlike License.
It uses material from the Wikipedia article on
"Acute myeloid leukemia"
All material adapted used from Wikipedia is available under the terms of the
Creative Commons Attribution-ShareAlike License.
Wikipedia® itself is a registered trademark of the Wikimedia Foundation, Inc.