We aimed to compare the therapeutic effect of radiotherapy (RT) plus systemic therapy (ST) with RT alone in patients with simple brain metastasis (BM) after first-line treatment of limited-stage small cell lung cancer (LS-SCLC). The patients were treated at a single center from January 2011 to January 2022. BM only without metastases to other organs was defined as simple BM. The eligible patients were divided into RT alone (monotherapy arm) and RT plus ST (combined therapy arm). Univariate and multivariate Cox proportional hazards analyses were used to examine factors associated with increased risk of extracranial progression. After 1:1 propensity score matching analysis, two groups were compared for extracranial progression-free survival (ePFS), PFS, overall survival (OS), and intracranial PFS (iPFS). 133 patients were identified and 100 were analyzed (monotherapy arm: n = 50, combined therapy arm: n = 50). The ePFS of the combined therapy was significantly longer than that of the monotherapy, with a median ePFS of 13.2 months (95% CI, 6.6–19.8) in combined therapy and 8.2 months (95% CI, 5.7–10.7) in monotherapy (P = 0.04). There were no statistically significant differences in PFS (P = 0.057), OS (P = 0.309), or iPFS (P = 0.448). Multifactorial analysis showed that combined therapy was independently associated with better ePFS compared with monotherapy (HR = 0.617, P = 0.034); more than 5 BMs were associated with worse ePFS compared with 1–5 BMs (HR = 1.808, P = 0.012). Compared with RT alone, combined therapy improves ePFS in patients with simple BM after first-line treatment of LS-SCLC. Combined therapy and 1–5 BMs reduce the risk of extracranial recurrence.

中文翻译：

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局限性期小细胞肺癌一线治疗后单纯性脑转移患者放疗联合全身治疗与单纯放疗的疗效比较：回顾性研究

我们的目的是比较放疗（RT）加全身治疗（ST）与单独放疗对局限性小细胞肺癌（LS-SCLC）一线治疗后的单纯性脑转移（BM）患者的治疗效果。患者于2011年1月至2022年1月在单一中心接受治疗。仅无转移至其他器官的BM被定义为单纯BM。符合条件的患者被分为单独RT（单一治疗组）和RT加ST（联合治疗组）。使用单变量和多变量 Cox 比例风险分析来检查与颅外进展风险增加相关的因素。经过1:1倾向评分匹配分析后，比较两组的颅外无进展生存期（ePFS）、PFS、总生存期（OS）和颅内PFS（iPFS）。确定了 133 名患者并分析了 100 名患者（单一治疗组：n = 50，联合治疗组：n = 50）。联合治疗的 ePFS 显着长于单药治疗，联合治疗的中位 ePFS 为 13.2 个月（95% CI，6.6-19.8），单药治疗的中位 ePFS 为 8.2 个月（95% CI，5.7-10.7）（P = 0.04）。 PFS (P = 0.057)、OS (P = 0.309) 或 iPFS (P = 0.448) 没有统计学上的显着差异。多因素分析显示，与单药治疗相比，联合治疗与更好的 ePFS 独立相关（HR = 0.617，P = 0.034）；与 1-5 个 BM 相比，超过 5 个 BM 与较差的 ePFS 相关（HR = 1.808，P = 0.012）。与单独放疗相比，联合治疗可改善 LS-SCLC 一线治疗后单纯性 BM 患者的 ePFS。联合治疗和 1-5 次 BM 可降低颅外复发的风险。