Children from lower-income neighborhoods were 2.4 times more likely to die during treatment for acute myeloid leukemia (AML) than children from middle- and high-income neighborhoods, according to findings from a study that analyzed nearly 1,500 clinical trial participants. While previous research has pointed to racial disparities in cancer survival, the new study is the first to identify socioeconomic status as a key contributor to disparities among children with AML who were enrolled in clinical trials. These results were presented by Winestone et al at the 2019 American Society of Hematology (ASH) Annual Meeting & Exposition (Abstract 703).

Researchers explained the findings are especially alarming, given that clinical trials are designed to provide consistent treatment across all participant groups. The fact that disparities were found despite the rigorous setting of clinical trials suggests that these disparities arise from factors outside of the specific chemotherapy used.

“We expected there to be a difference, but the degree of difference is quite substantial,” said lead study author Lena E. Winestone, MD, of the University of California, San Francisco (UCSF) Benioff Children’s Hospital. “The more people are cognizant about the disparities that exist, the better positioned we’ll be to ameliorate them.”

Methods and Results

Researchers at UCSF Benioff Children’s Hospital and the Children’s Hospital of Philadelphia examined clinical trial data from children enrolled on two recent trials, AAML1031 and AAML0531, and used U.S. census data to determine the median income and educational attainment in patients’ neighborhoods. They found that neighborhood socioeconomic factors were significant predictors of survival—even after accounting for insurance type, race, and known biologic risk factors.

About 68% of patients from middle or high-income areas survived for 5 years following an AML diagnosis. However, that proportion was 61% among patients from low-income areas and 43% among patients living in poverty.

A significantly higher proportion of African American and Hispanic patients lived in poverty, low-income, and low-education areas. Researchers found that the racial disparity persisted even after accounting for neighborhood socioeconomic factors, suggesting African American patients face a significantly higher risk of death than white children living in areas of the same socioeconomic level.

Why the Increase in Risk?

The study did not determine the reasons behind the increased risk of death. One possibility is that toxic stress—which has been linked with lower socioeconomic status—may impact responses to chemotherapy or immune recovery following chemotherapy, noted Dr. Winestone. The researchers plan to further examine when patients died and the cause of death in the hopes of gaining insights as to whether the risks are connected to treatment-related causes or to the cancer itself.

In addition to drawing attention to persistent racial and socioeconomic disparities in cancer outcomes, the results also highlight potential additional data to be collected as part of clinical trials. Rather than relying on neighborhood data as a proxy, Dr. Winestone said it would be helpful if future clinical trials collected individual data on participants’ socioeconomic status at the time of enrollment.

“If we could gather that information, it would allow us to dig deeper into the question of how someone’s circumstances outside of the clinical aspects of their disease impact their health outcomes,” she concluded.

Disclosure: This study was funded by National Institutes of Health/National Cancer Institute (NIH/NCI) grants to the Children’s Oncology Group, a member of the NCI National Clinical Trials Network. For full disclosures of the study authors, visit ash.confex.com.