In the Journals

Socioeconomic status affects OS, time to relapse in pediatric ALL

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February 23, 2016

Children with acute lymphoblastic leukemia who reside in high-poverty areas appeared at higher risk for early relapse than patients living in affluent areas, according to study results.

These associations persisted regardless of treatment uniformity, researchers found.

Kira Bona

Kira Bona, MD, MPH

“These children are getting the same best possible care at well-resourced institutions from highly trained clinicians, and we’re still seeing disparities,” Kira Bona, MD, MPH, instructor of pediatrics at Harvard Medical School and oncologist at Dana-Farber/Boston Children’s Cancer and Blood Disorders Center, said in a press release. “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 detriments.”

Prior research has demonstrated an association between lower socioeconomic status and poorer OS in children with leukemia; however, the relationship between wealth disparities and treatment-related mortality, relapse and time to relapse has not been studied, according to study background.

Thus, Bona and colleagues sought to evaluate OS, EFS, and the cumulative incidence and timing of relapse based on community-level poverty in children with ALL. They evaluated data from 575 children (54% boys; 75% white) aged 1 year to 18 years (median age at diagnosis, 5 years) with newly diagnosed ALL.

All patients were treated on two consecutive phase 3 multicenter Dana-Farber Cancer Institute ALL Consortium Protocols between 2000 and 2010.

The researchers used U.S. Census data to categorize patient zip codes as low- or high-poverty areas.

Fifteen percent of patients (n = 87) resided in high-poverty areas. Children in the lowest quartile (Q1, n = 144) were compared with children from three other quartiles (Q 2-4, n = 431).

Children of minority race or ethnicity tended to be in lower socioeconomic groups (P < .0001 for both).

Median follow-up was 5.8 years.

A significantly smaller proportion of children who lived in high-poverty areas achieved 5-year OS rate than children in low-poverty areas, despite uniform treatment with the trial protocol (85% vs. 92%; P = .02). Five-year OS also appeared worse among patients of Hispanic/Latino ethnicity (P = .008).

Ninety five percent of children (n = 545) achieved complete remission at the end of their first month of treatment, with no significant differences in rates of induction death, induction failure or attainment of remission.

The researchers did not observe differences in EFS or cumulative incidence of relapse based on poverty area.

However, of the children who relapsed, those who lived in high-poverty areas appeared more likely to relapse within 3 years of complete remission than children from low-poverty areas (92% vs. 48%; P = .008). This trend also occurred for relapse within 18 months from complete remission, but the difference did not reach statistical significance (33% vs. 12%).

Fifty two children died, representing 9% of the cohort. Fifteen percent of children from high-poverty areas died (n = 13 of 87), compared with 8% (n = 39 of 488) from low-poverty areas.

The researchers acknowledged limitations of their study, including the retrospective design and the inability to fully identify mechanisms that might underlie the connection between community-level poverty and time or relapse.

“In this country, 20% of children live in poverty,” Bona said. “Furthermore, we know that the costs of having a child treated for cancer force higher-income families into poverty. 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 socioeconomic disparities in outcomes.” – by Cameron Kelsall

Disclosure: The researchers report no relevant financial disclosures.

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