High-Grade B-Cell Lymphoma, Not Otherwise Specified: CNS Involvement and Outcomes in a Multi-Institutional Series.

Little is known about the central nervous system (CNS) risk in high-grade B-cell lymphoma, not otherwise specified (HGBL, NOS). Hence, we sought to describe the rates of baseline CNS involvement, risk of CNS recurrence after primary therapy, and management strategies in HGBL, NOS. In this multicenter retrospective study, we included 160 adults with newly diagnosed HGBL, NOS treated between 2016 and 2021 at 20 US institutions. Eleven patients (7%) had baseline CNS involvement at diagnosis (leptomeningeal=6, parenchymal=4, and both=1). Baseline CNS involvement was significantly associated only with MYC rearrangement (OR=3.5) and testicular (in men) or female pelvic (in women) involvement (OR=8.1). There was no significant difference in survival outcomes between HGBL, NOS patients with (median PFS=4 years) or without (median PFS=2.4 years) baseline CNS involvement (p=0.45). The cumulative incidence of CNS recurrence at 3 years was 11%. Patients with baseline CNS involvement were at the highest risk (48.5% versus 8% for those without baseline CNS involvement) and were excluded from the risk factors analysis for CNS recurrence. The risk for CNS recurrence was significantly associated with blood or bone marrow involvement, CD5 expression, non-GCB subtype, and DEL phenotype, however, high CNS-IPI was not. The prognosis of relapsed HGBL, NOS was poor, regardless of whether recurrence was systemic or limited to the CNS, and with currently available salvage strategies, including autologous transplantation and CAR T-cell modalities, almost all patients with CNS recurrence ultimately succumbed to their disease. These patients represent an unmet need and should be prioritized for experimental approaches.