A novel prognostic model makes it possible to stratify the majority of elderly patients with acute myeloid leukemia (AML) into two prognostic groups with significant implications for the therapeutic strategy.
As reported in the August issue of Blood, use of the additive model, which integrates the well-established cytogenic risk system, allowed stratification of elderly AML patients with intermediate-risk karotype into good intermediate risk and adverse intermediate risk groups with distinctly different prognoses.
Christoph Röllig, of the University of Dresden, Germany, and his fellow researchers analyzed prognostic factors derived from the AML96 trial, which included 909 patients ranging from 61 to 87 years of age. The patients received cytarabine-based induction therapy followed by 1 year of consolidation; median follow up was 5.7 years. Of 909 patients, 454 achieved complete remission. Five-year OS and disease-free survival were 9.7% and 14%, respectively.
On multivariate analysis, the researchers found that karotype, age, NPM1 mutation status, white blood cell count, lactate dehydrogenase level, and CD34 expression were independent prognostic factors for OS. They then developed an additive risk score based on the multivariate Cox model. Using this score, they identified four prognostic groups: favorable risk, good intermediate risk, adverse intermediate risk, and high risk, with corresponding 3-year OS rates of 39.5%, 30%, 10.6%, and 3.3%, respectively.
In the favorable and high-risk cytogenetic groups, the presence or absence of risk factors did not influence OS, indicating that in these groups, the karototype is the dominant prognostic factor. However, 76% of the patients fell into the intermediate-risk group, and in these patients, applying the identified risk factors made it possible to distinguish two distinct prognostic groups.
According to the authors, the ability to accurately identify the subset of older AML patients who can benefit from current treatment approaches and those who cannot “is of critical importance.” They say that for patients in the adverse intermediate and high-risk groups, who constitute the majority of elderly patients with AML, alternative or investigational therapies should be considered. For those in the favorable or good intermediate risk groups, intensive chemotherapy should be recommended.
They conclude that the prognostic model developed in this study “could serve as a tool for prospective treatment decisions in clinical trials with elderly AML patients and could be used in addition to or as an alternative to other comorbidity scores.”