Stereotactic Ablative Radiation Therapy Induces Systemic Differences in Peripheral Blood Immunophenotype Dependent on Irradiated Site.

Purpose: Despite the strong interest in combining stereotactic ablative radiation therapy (SAR) with immunotherapy, limited data characterizing the systemic immune response after SAR are available. We hypothesized that the systemic immune response to SAR would differ by irradiated site owing to inherent differences in the microenvironment of various organs.

Methods And Materials: Patients receiving SAR to any organ underwent prospective blood banking before and 1 to 2 weeks after SAR.