Income Inequality Contributes to Pediatric ALL Relapse

Survival in children with acute lymphoblastic leukemia (ALL), the most common pediatric cancer (responsible for 75 to 80% of childhood leukemia), could be significantly influenced by their family’s socioeconomic status, a new study conducted by researchers at the Dana-Farber Cancer Institute has found.

Children between the ages of 1 and 18 years, who were treated for ALL on the Dana-Farber Cancer Institute ALL Consortium Protocols between 2000 and 2010, were included in a study published in Pediatric Blood and Cancer. The researchers used zip codes of the areas where the families resided as a surrogate for poverty level, with high-poverty areas defined as ones where 20% or more residents had income below the federal poverty level (annual income of less than or equal to $24,250 for a family of 4).

Rationalizing the hypothesis of their study, lead author Kira Bona, MD, MPH, a pediatric oncologist at Dana-Farber/Boston Children’s Cancer and Blood Disorders Center said in a press release, “These children are getting the same best possible care at well-resourced institutions from highly trained clinicians, and we’re still seeing disparities. In trying to improve cure rates, we, as a field, have focused almost exclusively on biology. If we want to move forward, we also have to look at social determinants.”

Among the 575 children included in the study, overall rates of relapse were similar between the 2 groups being compared: high-poverty and low-poverty. However, 92% of children included in the lower economic strata group relapsed much earlier (less than 36 months following complete remission) compared with 48% of the remaining children. Further, residents of high-poverty areas had a 5-year overall survival (OS) of 85%, compared with 92% for those in low-poverty areas (P = .02). Statistical significance of the OS data, however, was lost after adjusting for immunophenotype, age, and white blood cell count. It is important to note that although OS was the same between the 2 groups, ALL that relapses early is harder to treat successfully, which underscores the significance of the study’s findings.

According to Bona, 20% of children live in poverty in the United States. “If we can devise successful interventions, that’s at least 20% of children with cancer whose outcomes we can potentially impact. Any 'moon shot' to cure cancer must include interventions that target socio-economic disparities in outcomes,” she added.

Future studies by these researchers will identify associations between disease outcomes and the socioeconomic status of patients’ families, using a targetable measure of socioeconomic status termed material hardship. They also plan to conduct interviews with family members to identify factors that possibly influence patient outcomes, with the anticipation of developing targeted interventions.

Reference

Bona K, Blonquist TM, Neuberg DS, Silverman LB, Wolfe J. Impact of socioeconomic status on timing of relapse and overall survival for children treated on Dana-Farber Cancer Institute ALL Consortium Protocols (2000—2010) [published online February 23, 2016]. Pediatr Blood Cancer. doi:10.1002/pbc.25928.