PD-L1 Expression Level of Primary Tumor as a Predictor of Local Control and Symptomatic Radiation Necrosis in Patients With Brain Metastases Undergoing SRS/fSRT With Concurrent Immunotherapy

Abstract

PD-L1 is often overexpressed in the tumor microenvironment to dampen host immune response and allow tumor proliferation. Radiation works partially through the immune system, but the correlation between PD-L1 expression in primary tumors and oncologic outcomes for metastatic lesions treated with SRS with concurrent immunotherapy (ICI) is unknown. We seek to evaluate the association of PD-L1 expression level of the primary tumor in patients undergoing SRS/fSRT with local control and symptomatic radiation necrosis.