Survival by Race and Ethnicity in Children and Adolescents/Young Adults With Relapsed/Refractory Hodgkin Lymphoma: A Pooled Analysis of Children's Oncology Group Trials

PURPOSE: Despite 5-year survival rates of over 90% among children and adolescents/young adults (CAYAs) with classic Hodgkin lymphoma (cHL), 15%-20% relapse after frontline therapy. Prior analysis of frontline Children's Oncology Group (COG) clinical trials demonstrated that, despite similar rates of relapse, non-Hispanic Black (NHB) and Hispanic (vs. non-Hispanic White [NHW]) patients experienced higher post-relapse mortality. It is unknown whether post-relapse disparities persist when second-line treatment is delivered in a cooperative group trial setting. We examined overall survival (OS) by race and ethnicity in CAYAs enrolled in COG trials for relapsed/refractory (r/r) cHL. METHODS: A pooled analysis of individual-level data from CAYAs (≤ 29 years) receiving therapy for r/r cHL on COG clinical trials (2001-2016) was conducted. The Kaplan-Meier method estimated 3-year OS by racial and ethnic groups. Cox regression models examined associations of race and ethnicity and OS, adjusted for age, insurance, first versus ≥2 relapse, and time from initial diagnosis to relapse trial enrollment. RESULTS: Among 175 CAYAs treated on COG trials for r/r cHL (5.7% Asian or Pacific Islander, 14.9% Hispanic, 14.3% NHB, 61.7% NHW, 3.4% other), at median follow-up of 4.9 years, 3-year OS was 82.1% (95% confidence interval [CI], 75.3%-87.1%) and did not differ by race and ethnicity (p = 0.36). In multivariable analyses, shorter time from diagnosis to relapse trial enrollment (p = 0.01) and ≥2 relapses (vs. first, p = 0.004) conferred worse OS, with no significant effect of race and ethnicity (p = 0.43). CONCLUSION: Post-relapse survival did not differ by race and ethnicity among CAYAs enrolled in COG trials for r/r cHL, suggesting access to clinical trials may mitigate OS disparities.