Treatment patterns and outcomes in adolescents and young adults with Hodgkin lymphoma in pediatric versus adult centers: An IMPACT Cohort Study

Hodgkin lymphoma (HL) is a common adolescent and young adult (AYA) cancer. While outcome disparities between pediatric vs. adult centers [locus of care (LOC)] have been demonstrated in other AYA cancers such as acute lymphoblastic leukemia, they have not been well studied in HL. We therefore compared population-based treatment patterns and outcomes in AYA HL by LOC. The IMPACT Cohort includes data on all Ontario, Canada AYA (15-21 years) diagnosed with HL between 1992 and 2012. Linkage to population-based health administrative data identified late effects. We examined LOC-based differences in treatment modalities, cumulative doses, event-free survival (EFS), overall survival (OS), and late effects. Among 954 AYA, 711 (74.5%) received therapy at adult centers. Pediatric center AYA experienced higher rates of radiation therapy but lower cumulative doses of doxorubicin and bleomycin. 10-year EFS did not differ between pediatric vs. adult cancer vs. community centers (83.8% +/- 2.4% vs. 82.8% +/- 1.6% vs. 82.7%+/- 3.0%; P = .71); LOC was not significantly associated with either EFS or OS in multivariable analyses. Higher incidences of second malignancies in pediatric center AYA and of cardiovascular events in adult center AYA were observed, but were not significant. In conclusion, while pediatric and adult centers used different treatment strategies, outcomes were equivalent. Differences in treatment exposures are however likely to result in different late-effect risks. Protocol choice should be guided by individual late-effect risk.