Pediatric patients with acute lymphoblastic leukemia (ALL) living in extreme poverty and undergoing maintenance therapy may have almost a twofold greater risk of relapse compared with pediatric patients who weren’t living in extreme poverty, according to a new study published by Wadhwa et al in Blood. The findings also revealed that a higher proportion of these patients may have had difficulty adhering to treatment, though this may only partially explain the link between poverty and the risk of relapse.
Background
About 60% of cases of ALL—the most common pediatric cancer—occur in pediatric patients. Although 5-year survival rates are now approaching 90% as a result of advances in treatment, these survival rates may not be experienced equitably across all pediatric patients.
The new study is one of the first to examine the consequences of individual-level poverty using annual household income and its effects on the relapse rates among this patient population. Previous studies have relied on community measures of poverty—including zip codes that may have consisted of wide variations in socioeconomic status—or health insurance status.
“ALL is a curable disease, so while we observed relatively few relapses in total, [pediatric patients] living in extreme poverty—those whose families were really stretched thin and not able to make ends meet—had a significantly higher risk of relapse, even after controlling for all other biologic and prognostic factors,” stressed lead study author Aman Wadhwa, MD, MSPH, Assistant Professor of Pediatric Hematology and Oncology at the University of Alabama at Birmingham. “These [patients] were also much less likely to be able to maintain [the] critical level of adherence needed for sustained remission during maintenance therapy. These findings underscore an urgent need to identify patients with this level of financial hardship and connect them to resources, even if finite, to help,” he added.
For example, the researchers explained that for patients who face obstacles in transportation, supplying gas cards or ride shares can make a difference. Providing plain language education about the importance of adhering to maintenance therapy may also help.
Study Methods and Results
In the new secondary analysis of the Children’s Oncology Group Study—which examined adherence to oral mercaptopurine during maintenance therapy in patients with ALL—the researchers included 592 patients with a median age of 5 to 6 years, about 67% of whom were male.
The researchers further reported that 35% of the patients who participated in the study identified as Hispanic, 32.4% pf them identified as non-Hispanic White, 18.2% identified as Black, and 14.4% identified as Asian. Overall, 34.8% of the patients’ parents reported their highest level of education as high school or lower.
The researchers collected self-reported individual income information at the start of the study and used data from the U.S. Census Bureau to group the patients as living above or below the federal poverty threshold. Among those living in poverty, the patients were additionally characterized as living in extreme poverty if the federal poverty threshold was over 120% of the yearly household income—and more than 12% of the patients were identified as living in these conditions. Those living in extreme poverty were more likely to report being Hispanic or Black and have more household members (six vs four members). There researchers recorded no differences in disease or treatment intensity by poverty status.
After a median follow-up of 7.9 years, the researchers discovered that pediatric patients living in extreme poverty experienced nearly double the rates of relapse at 3 years after enrollment compared with those living above the federal poverty threshold (14.3% vs 7.6%). In addition, those living in poverty were significantly more likely to be nonadherent to prescribed treatment (57.1% vs 40.9%).
Study Implications
The researchers suggested that extreme poverty, like other social determinants of health, was on par with some clinical measures used in risk stratification.
“When [we] see [a pediatric patient] with a new diagnosis of ALL, we look at biological factors that a patient walks in with to determine if they have standard or high-risk disease. Patients at high risk are 2.5 times more likely to relapse. [T]hat’s similar to the risk of relapse that we are finding with extreme poverty and other social determinants of health,” Dr. Wadhwa emphasized.
“If we are going to risk stratify patients and give different treatments based on certain biological factors, then why not design interventions and treat these social factors that are also increasing their risk of relapse? There are only so many gains we may be able to make by continuing to intensify therapy. We can come up with the best treatment in the world, but if the patient doesn’t get it, then of what use was it?” he noted.
To date, poverty and other barriers to optimal care may not be routinely assessed or considered as part of treatment planning, but the researchers underscored that this may be necessary in order to improve patient outcomes among certain populations. They highlighted the need for interventions that assess and develop tailored solutions to make sure patients have equitable access to care.
Although this study was limited in its relatively small sample size and was conducted before measurable residual disease was a routine part of clinical care, the researchers hope that the findings lay the foundation for future research analyzing other social determinants of health and their potential role in pediatric cancers as well as inform interventions addressing these health-care barriers.
Disclosure: For full disclosures of the study authors, visit ashpublications.org.
