Disparities in cancer outcomes not fully explained by race and socioeconomic factors
Enrollment in clinical trials failed to overcome factors leading to worse survival of Hispanic children with high-risk neuroblastoma, a large retrospective analysis showed.
The Hispanic subgroup had a 5-year overall survival (OS) rate of 47%, compared to more than 60% for whites and non-Hispanic blacks. A similar disparity was observed for children in the racial/ethnic category of non-Hispanic others.
Children living in poverty also had lower OS, but socioeconomic differences did not fully explain the lower OS in Hispanic children, said Puja J. Umaretiya, MD, of the Dana-Farber Cancer Institute and the Boston Children’s Hospital, at a press briefing ahead of the American Society for Clinical Oncology (ASCO) Annual Meeting.
“Our data showed that Hispanic children with high-risk neuroblastoma have lower overall survival than other children, despite having access to the same clinical trials and the same consistent treatment plan and after controlling for associated factors. disease,” Umaretiya said. “We recognize that describing disparities is simply not enough. We must strive to identify the mechanisms that lead to inequitable outcomes.”
“In this cohort, we’re starting to do that by looking at things like early trial termination, treatment delays, and increased relapse rates, none of which seem to account for the differences in survival we’re seeing. by race and ethnicity,” she continued. . “Indirect exposures to poverty did not remain significantly associated with survival after adjusting for other factors, such as race, ethnicity, and disease-associated factors, recognizing the intersectionality of these three factors at United States because of structural racism.”
Rather than offering possible explanations for disparate results, the study raised new questions for future study, said ASCO President Everett Vokes, MD, of the University of Chicago, who moderated the press conference.
“It’s really important work,” Vokes said. “We encourage patients to enroll in clinical trials, and that’s what really happened here. This was a cohort of patients whose treatment was governed by these clinical trials, and that should have led to similar results, but it didn’t. Of course, leaves the questions open.”
“We are seeing differences in overall survival…of about 8-10% at longer follow-up periods, and they seem to correlate with socioeconomic factors and race, but specific causes of death, the increase in deaths in these groups, are not yet elucidated. I think it will be an important job moving forward,” he added.
The presentation was one of four in the opening press conference, which focused on the theme of the 2022 annual meeting, “Advancing Equitable Care Through Innovation.” Umaretiya presented the results of a review of the results of three clinical trials from the Children’s Oncology Group involving newly diagnosed high-risk neuroblastoma. The trials included a cumulative total of 696 pediatric patients with a racial/ethnic breakdown of 69% non-Hispanic white, 16% non-Hispanic black, 11% Hispanic, and 4% other non-Hispanic.
Previous studies have shown that black children with neuroblastoma have an increased rate of late relapse and that children covered by public insurance have an increased relapse rate and risk of death when treated with immunotherapy. Explanations for the disparities remained unclear, Umaretiya said. Clinical trials provide an ideal setting to study disparities because children received highly standardized care that should produce similar results in all patients.
The analysis had two main objectives: to identify associations between race, ethnicity, socioeconomic status and survival; and explore potential mechanisms of survival deterioration, particularly early trial termination, delays in induction treatment, and relapse.
Investigators compared survival by two different proxy measures of poverty: public insurance coverage and living in a ZIP code where more than 20% of residents have a household income below the federal poverty level . A third of children enrolled in the trials met the household poverty criteria, a fourth the neighborhood (zip code) poverty criteria, and 15% lived in rural areas, another potential source of disparities in outcomes.
The analysis showed that non-Hispanic black and non-Hispanic white patients had a 5-year OS of 61–62%, compared to 47% for Hispanic patients and 50% for other non-Hispanic patients (P=0.047). The relative risk of death was 1.78 for Hispanic patients compared to non-Hispanic whites and 1.45 for other non-Hispanic whites compared to non-Hispanic whites (P=0.01). Non-Hispanic black patients had a similar mortality risk as non-Hispanic white patients (HR 0.98).
Children covered by public insurance had a 5-year OS rate of 53% versus 63% in patients with private insurance (P=0.036). Living in a high-poverty neighborhood was associated with a 5-year OS of 54% versus 62% in patients living in more affluent areas (P=0.050). Children living in more rural areas did not have worse survival.
Examination of potential mechanisms or explanations for OS less than 5 years revealed no significant association with treatment delays by race/ethnicity (median 167-169 days, P=0.91) or early termination of trials (32-43% P=0.81 and P=0.97). Hispanic patients tended to have a higher relapse rate (57% versus 48-49%) and other non-Hispanic patients had a numerically lower relapse rate (30%), but the relapse rate did not differ significantly between the subgroups (P=0.11).
Umaretiya said he has no relevant relationship with the industry. One or more co-investigators disclosed relationships with Novartis, Exelixis, Genentech, Roche, Amgen, Bayer, Bristol Myers Squibb, Curis, Eisai, Lilly, Loxo, Merck, Pfizer, Salarius Pharmaceuticals, Turning Point Therapeutics and Y-mAbs Therapeutics .