鉴于有关广泛期小细胞肺癌（ES-SCLC）患者放疗（RT）联合免疫治疗的数据有限，本研究旨在确定不同治疗阶段放射免疫疗法对不同部位的免疫激活效应以及存活结果。本回顾性分析纳入了45例ES-SCLC患者。我们收集了患者的总生存期（OS），记录了RT之前、期间和之后的血细胞计数，并推算出血液指标比值，如中性粒细胞与淋巴细胞比值（NLR），血小板与淋巴细胞比值（PLR）和全身免疫炎症指数（SII）。采用Spearman秩相关检验、Kruskal-Wallis秩和检验和Logistic回归对数据集进行分析。在所选的血液指标中，Δ-NLR/PLR/SII与不同放疗器官相关，并且在免疫治疗期间，这三个指标的平均秩在脑放疗组中最低。此外，与二线或三线治疗和随后的治疗相比，辅助一线免疫治疗与RT显示出显著改善。我们的研究结果表明，与其他器官相比，脑放疗具有最强的免疫激活效应，并且早期接受放射免疫疗法（RIT）的ES-SCLC患者获得了更高的OS率。 © 2023. BioMed Central Ltd., part of Springer Nature.

In view of the limited data on radiotherapy (RT) combined with immunotherapy in patients with extensive-stage small cell lung cancer (ES-SCLC), this study aimed to identify the immune activation effect on different sites and the survival outcomes of radioimmunotherapy at different treatment stages.Forty-five patients diagnosed with ES-SCLC were included in this retrospective analysis. We collected the overall survival (OS) of the patients,, recorded the blood cell counts before, during, and after RT, and derived blood index ratios such as the neutrophil-to-lymphocyte ratio (NLR), platelet-to-lymphocyte ratio (PLR), and systemic immune-inflammation index (SII). The datasets were analyzed using the Spearman rank correlation test, Kruskal-Wallis rank sum test and logistic regression.Among the selected blood indices, the delta-NLR/PLR/Sll correlated with different irradiated organs, and the mean ranks of these three indices were the lowest in the brain-irradiated group during immunotherapy. Additionally, adjunct first-line immunotherapy with RT demonstrated a significant improvement compared to second- or third-line therapy and subsequent therapies.Our findings suggest that compared to other organs, the strongest immune activation effect occurs with brain RT, and ES-SCLC patients who received radioimmunotherapy (RIT) earlier achieved higher OS rates.© 2023. BioMed Central Ltd., part of Springer Nature.