Hodgkin lymphoma in adolescent and young adults: Insights from an adult tertiary single-center cohort of 349 patients

Background: Adolescent and young adults (AYA) represent one third of patients affected by Hodgkin lymphoma (HL). These patients are frequently treated either with pediatric or adult protocol depending on their physician background. This population has been understudied so far, in terms of HL characteristics and treatment-associated outcomes. Aim: We aimed to extensively describe HL features in the AYA population including HL characteristics, progression-free (PFS) and overall survival (OS). Methods: From 1979 to 2013, consecutive patients with HL aged between 15 to 25 years and followed at Saint-Louis Hospital were prospectively enrolled. Survivals were estimated using the Kaplan-Meier method. Results: 349 patients were included and studied, with a median follow-up of 7 years. The majority of patients were treated with adult protocols (mainly ABVD and BEACOPP). They presented adverse clinical characteristics with a high proportion of stage III and IV according to Ann Arbor classification (45 %), a high rate of B symptoms (46 %) and extra-nodal involvement (36 %). Despite these pejorative clinical features, the prognosis remains good with a 10-year PFS and OS estimated at 81.0 % (95%CI [76.7-85.5]) and 90.7% (95%CI [87.2-94.4]), respectively. In multivariate analysis, stages III and IV according to Ann Arbor classification, mixed cellularity histology, elevated neutrophils and LDH above range were independently associated with a worse PFS. We identified a subgroup of 11 primary refractory patients with a particularly poor prognosis. The toxicity rate was low (7.4 %). Conclusion: Despite their baseline pejorative features, AYA with HL have a good prognosis. Progresses are still needed in order to reduce toxicities. Primary refractory patients with a particularly poor prognosis should be detected early in order to quickly introduce new targeted therapies.