The overall prognosis for most acute myeloid leukemia (AML) patients remains poor with only 50-55% of patients achieving durable remission. The majority of adult patients (pts) who do achieve remission, will ultimately need allogeneic stem cell transplant (allo-SCT) to achieve long term survival. Treatment of AML requires intensive therapy, transfusion support, antimicrobials, and repeated admissions to the hospital. Limited data is available comparing epidemiology and treatment according to the distance from patient residence to treatment center. Oklahoma University Health Sciences Center (OUHSC) is the major tertiary center for Oklahoma residents to receive treatment for AML. Few patients receive AML treatment from distant states or oversea areas. We describe a retrospective analysis of adult pts with AML treated at our institution evaluating impact on distance from center.
From January 2000 to June 2011,we identified a total of 269 patients with 217 meeting inclusion criteria for the study. We then performed an analysis of variance (ANOVA) on the relationship between distance to treatment center (in miles) and relapse rate or remission rates. Kaplan-Meier method was used to estimate survival rates. Age and cytogenetics were identified as the major confounders. A Cox Proportional Hazards model on overall survival (OS) was implemented using the independent variables age category ( ≤60 and > 60), cytogenetic risk status (groups were divided into favorable, intermediate and unfavorable risks), and distance to treatment center. Statistical analysis was performed using SAS 9.2 software (SAS Institute Inc.). Fisher’s exact test was used to compare patients in the different groups.
Of the 217 pts (52.2% Males, 47.8% Females) included in the study, 81.5% were white, 9.0% African American, and 6.2% Native American. Median age at diagnosis was 51.0 years. Median distance to treatment center was 62 miles (range: 0-420). Distance of residence to treatment center was significantly related to complete remission rates, with patients living at longer distances having lower chances of achieving complete remission( p = 0.03). Distance from residence to treatment center however was not related to the risk of having relapsed disease (p = 0.22). A Cox proportional hazard model was performed including distance to travel, age and cytogenetic risks (unfavorable versus intermediate or favorable) and revealed that all three variables are associated with a trend towards shorter overall survival (p <0.1).
In this present study, we have identified that distance from residence to treatment center as a risk factor for achieving lower complete remission rate with no significant effect on the risk of relapse. There was a trend toward lower overall survival for those who live at longer distance from center. Further analysis of this dataset will identify the impact of other pretreatment variables on the distance to treatment center by performing a multivariate analysis. Larger studies are needed to further explore the impact of distance to treatment center on outcome in patients with AML.
No relevant conflicts of interest to declare.
Asterisk with author names denotes non-ASH members.