Abstract P092

CNS Involvement in Pediatric Hodgkin Lymphoma: A Retrospective Analysis of AHOD1331, EuroNet-PHL-C1 and EuroNet-PHL-C2 from SEARCH for CAYAHL

Background: Hodgkin lymphoma (HL) accounts for approximately 7% of childhood cancer, the majority of which occurs in adolescents and young adults (AYA). HL involving the central nervous system (CNS) is exceedingly rare, with an estimated incidence of <0.5%. Information regarding the presentation, management, treatment and outcome of patients with CNS HL is limited to case reports or small series.

Methods: We performed a retrospective analysis of COG AHOD1331 (NCT02166463), EuroNet-PHL-C1 (NCT00433459, EudraCT 2006-000995-33) and C2 (NCT02684708, EudraCT 2012-004053-88). Patients had morphologic (CT) and metabolic (FDG-PET) imaging at baseline, and response assessment after 2 cycles. Evaluated variables included: Ann Arbor stage, histology, symptoms at presentation, number and location of CNS lesions, anatomic description of CNS lesions, number and location of other E-lesions, FDG tracer intensity at diagnosis, metabolic and morphologic response of CNS lesions after 2 cycles, if relapse occurred and in which location. CNS involvement was defined as either: (1) lesions originating within the CNS parenchyma (intra-axial) or (2) lesions extending into the extra-axial CNS.

Results: We identified 45 HL patients with 55 CNS lesions extending into the extra-axial CNS at diagnosis from a cohort of 4995 patients; an overall incidence of 0.9%. 82.2% of patients had a single lesion in the thoracic, lumbar or sacral spine. Lesions extended into the extra-axial CNS space from adjacent soft tissue or bone, and never directly infiltrated through the dura into the brain or spinal cord. Patients with CNS involvement had a 2x greater incidence of E-lesions than previously reported cohorts without CNS involvement. 89.1% of CNS lesions demonstrated a complete metabolic response and a >75% decrease in volume after 2 cycles. Thirteen CNS lesions (23.6%) received irradiation; none were sites of disease relapse.

Conclusions: We present the largest reported cohort of pediatric and AYA HL involving the CNS at diagnosis, demonstrating that these lesions originate from surrounding tissues, extend into the extra-axial CNS space, and respond similarly to treatment as other nodal and extra-nodal disease. Our study is limited by the retrospective nature and that our cohort only includes patients enrolled on clinical trials. Despite these limitations, this study helps to describe a rare and important patient presentation.

Authors

Reena Pabari, Kathleen McCarten, Jamie E. Flerlage, Hollie Lai, Christine Mauz-Körholz, Karin Dieckmann, Monica Palese, Sue C. Kaste, Sharon M. Castellino, Kara M. Kelly, Dietrich Stoevesandt, Lars Kurch