Central nervous system prophylaxis in diffuse large B-cell lymphoma: What does the evidence tell us?

Secondary involvement of the central nervous system (CNS) by diffuse large b-cell lymphoma (DLBCL) is a rare yet often catastrophic event for DLBCL patients. As standard first-line therapy for DLBCL with rituximab, cyclophosphamide, doxorubicin, vincristine, and prednisone (R-CHOP) does not cross the blood-brain barrier, one approach to lessen the risk of CNS relapse has been to include additional agents, primarily methotrexate, directed at the CNS with standard R-CHOP although the timing, dose, and mode of administration differs widely across treating physicians. This practice derives from decades of non-randomized, often retrospective data with inconsistent outcomes. The current available tools and risk models are imprecise in their ability to predict which patients are truly at risk of secondary CNS relapse and more recent, large-scale real-world analyses call into question these longstanding practices. In a field lacking any prospective, randomized studies, this review synthesizes the available data investigating the utility of CNS prophylaxis in patients with DLBCL receiving 1st line therapy.