The contemporary spectrum of radiotherapy for hematologic malignancies involving the central nervous system: From focal therapy to craniospinal.

The contemporary landscape of systemic therapy options for hematologic malignancies involving the central nervous system (CNS-HM) is rapidly evolving; a key question is how radiotherapy (RT) can be optimally integrated to improve patient outcomes. Historically, use of RT to treat CNS-HM was defined by broad fields and high doses. While effective, this approach raised concerns of potential neurotoxicity which significantly decreased RT utilization. RT was replaced by high-dose, CNS-penetrant, systemic therapies that offered durable control with lower perceived neurotoxic risk. But, as the therapeutic toolbox for CNS-HM expands, so too does the complexity and diversity of potential clinical scenarios where RT should be considered. In this review, we describe both well-established and emerging opportunities for RT integration, emphasizing how dose selection and field design could balance neurotoxicity risk and disease control. We propose an anatomical framework that captures the diverse utilization of RT for CNS-HM and serves as a practical guide for RT volume and dose design.