Impact of Socioeconomic Status and Distance from Treatment Center on Survival in Patients Receiving Remission Induction Therapy for Newly Diagnosed Acute Myelogenous Leukemia (AML).

Background: Socioeconomic status (SES) and distance from a treatment center are prognostic factors in chronic malignancies, such as head and neck or breast cancer, where relative disease latency enables patients with greater means to travel to receive their care. Little is known about the influence of these demographics on patient outcomes in rapidly-growing cancers, such as AML.

Methods: We conducted a retrospective review of all patients receiving remission induction therapy for AML at the Cleveland Clinic between January 1997 and December 2005. Race and residential zipcodes were obtained from information disclosed by patients in their electronic medical records. Average annual household income in a zipcode and distance from the treatment center were obtained using web-based databases (www.melissadata.com, www.zip-codes.com). Data on known prognostic factors (age, WBC at diagnosis, cytogenetic risk groups (as defined by CALGB 8461) and AML etiology (de novo vs. secondary AML)) were collected and controlled for in multivariable analyses. Survival was estimated using the Kaplan-Meier method, and the association between distance and income assessed using the Spearman rank correlation.

Results: Anthracycline-based remission induction chemotherapy was administered to 281 patients: 132 (47%) were female, with a median age at diagnosis of 60 years (range 17–80). Median WBC at diagnosis was 9.9 k/uL (range:0.4–550 k/uL). Cytogenetics were favorable in 33 patients (11.7%, 10 of whom had t(15;17)), intermediate in 137 (48.8%), unfavorable in 73 (26%), and unknown in 38 (13.5%). Ninety patients (32%) had secondary AML. The ethnic distribution was consistent with other AML series: 252 (90.6%) were Caucasian (C), 22 (7.9%) were African American (AA), and 4 (1.4%) were neither (non-AA non-C). The median distance from the treatment center was 24.4 miles (range: 0.9–2058), and median average household income was $38,972 (range: $17,496-$143,220). Overall survival (OS) was 30.2% at a median of 22.6 months of follow-up. There was no significant correlation between distance and income. In both univariable and multivariable analyses, age ≥60 years, unfavorable cytogenetics, increased WBC count at presentation and secondary AML were all found to adversely affect survival (p<0.001, p<0.001, p=0.035, and p=0.010, respectively). OS was similar for AA and non-AA non-C patients compared to C (HR=1.12 [95% CI=.61–2.07, p=.71], and HR=.87 [CI=.21–3.62, p=.84], respectively). Neither distance from treatment facility (HR=1.00 [95%CI = .98–1.02 p =.96] for every 20 mile increase in distance) nor SES (HR=1.02 [95%CI=.92–1.13, p=.77] per $10000 increase) had an impact on OS. Similar findings held for CR rates.

Conclusion: Contrary to their impact on chronic malignancies, neither SES nor distance from treatment facility affect outcome in patients with AML treated at the same hospital. This supports referring patients for treatment to tertiary facilities skilled at managing AML, even when they live at great distances from those facilities.