Dr Wang on the Efficacy of CNS Bridging Radiotherapy Prior to CAR T in B-Cell Lymphoma

“Patients who received partial brain radiation had good outcomes. We demonstrated that whole brain radiation is not needed for those patients with 1 to 2 lesions.”

Pule Wang, MD, a radiation oncology fellow in the Department of Radiation Oncology at City of Hope, discussed the key efficacy findings from a retrospective study which evaluated the role of bridging radiation therapy prior to CAR T-cell therapy in patients with central nervous system (CNS) involvement from relapsed/refractory B-cell lymphomas.

The study included 26 patients with relapsed/refractory B-cell lymphoma involving the CNS who were treated with bridging radiation therapy followed by CAR T-cell therapy at City of Hope. It included patients with diffuse large B-cell lymphoma (n = 22) and mantle cell lymphoma (n = 4). All patients had secondary CNS lymphoma and received brain radiation therapy to a median total dose of 25 Gy (range, 4.0-37.5) in 8 fractions (range, 1-15).

Findings from the study, which were presented by Wang during the 2025 American Society for Radiation Oncology (ASTRO) Annual Meeting, demonstrated that patients who received partial brain radiation (n = 18) achieved good efficacy outcomes, indicating that whole brain radiation is not needed for patients with a maximum of 1 to lesions, she explained. Patients who received partial brain radiation had a median gross tumor volume of 19.38 cc (range, 4.42-51.02) and achieved a mean decrease of lesion size prior to CAR T-cell therapy of 43.0% (95% CI, 22.2%-63.8%).

Moreover, patients with brain parenchymal disease (n = 14) experienced a markedly better median overall survival with partial brain radiation compared with those who received whole brain radiation, Wang noted. These findings suggest that in select patients with parenchymal disease, partial brain radiation as bridging therapy to CAR T-cell therapy can provide durable CNS disease control and spare patients from the long-term cognitive risks that are associated with whole-brain treatment, she concluded.