Systemic immune modulation by stereotactic radiotherapy in early-stage lung cancer

We performed a prospective study of circulating immune cell changes after stereotactic body radiotherapy (SBRT) in 50 early-stage NSCLC patients. We found no significant increase in CD8 + cytotoxic T lymphocytes at first follow-up (the primary endpoint) but detected a significant increase in expanding Ki-67 + CD8 + and Ki-67 + CD4 + T-cell fractions in patients treated with 10 Gy or less per fraction. SBRT can induce significant expansion in circulating effector T-cells immediately post-treatment.