The Impact of Distance to Treatment Center on the Outcome of AML

While the distance patients travel to a treatment center (DTC) adversely impacts survival of patients with trauma, cardiac, or neurological disorders, as well as certain solid tumors, less is known of its influence in acute myeloid leukemia (AML). Care for patients with AML involves frequent emergent and urgent management, often complicating primary therapy provided in distant tertiary referral centers. We therefore hypothesized that increased DTC has a negative impact on outcome. We tested this hypothesis by assessing the effect of DTC on survival of patients with AML receiving care at a single institution.

Within the Stanford Leukemia Database, we identified 884 consecutive adult patients between 1993 and 2009 meeting the following criteria: age >=18, newly diagnosed AML (excluding APL), clinical management at Stanford University Medical Center (SUMC), and verified residence location available for DTC determination. Of these, 571 were deemed fit by the admitting physician to receive myelosuppressive induction chemotherapy. DTC was calculated by straight-line journey distance between home address at the time of diagnosis and treatment center.

The median age for the entire cohort is 55 years and 322 patients (36%) are older than 60 years of age. Median survival for the entire cohort was 14.0 months. DTC was not univariately associated with outcome as a continuous variable. When testing for a critical DTC threshold impacting outcomes across the entire cohort, we found a significant correlation between longer DTC and adverse outcomes, shorter DTC was associated with lower OS. Patients living within 20 miles of SUMC had a worse median overall survival (10.4 months versus 15.0 months, HR 1.23, corrected p-value 0.02). However, when adjusted for administration of induction chemotherapy (p<0.0001), age at presentation (p<0.0001) and karyotype at diagnosis (CBF vs other; p-value- 0.92), the negative impact of DTC was lost (p=0.08).

After accounting for confounding factors, DTC has no significant impact on the outcome of newly diagnosed AML patients receiving care at our institution. Unlike non-hematologic malignancies, distance to treatment center likely does not adversely influence outcomes for patients with AML.

No relevant conflicts of interest to declare.