局限期小细胞肺癌不同脑转移风险人群脑预防照射的价值

The value of prophylactic cranial irradiation in patients with limited-stage small cell lung cancer at different risk of brain metastasis

目的建立根治性放化疗后达到完全缓解(CR)或部分缓解(PR)的局限期小细胞肺癌(LS-SCLC)脑转移(BM)风险预测模型,探讨不同风险分层人群脑预防照射(PCI)的价值。方法回顾性分析天津医科大学肿瘤医院2010年1月至2021年12月行根治性放化疗后达到CR/PR的274例LS-SCLC患者的临床资料,其中PCI组144例,非PCI组130例。在非PCI组中,应用单因素及多因素分析筛选相关变量并构建BM风险预测模型,并应用受试者操作特征(ROC)曲线、校准曲线及决策曲线分析进行模型评估。根据风险得分,将所有患者划分为BM高、低风险组,使用单因素log-rank比较BM高、低风险组中有无PCI治疗患者的无脑转移生存(BMFS)期、无进展生存(PFS)期、无颅外进展生存(ePFS)期和总生存(OS)期的差别。结果最终纳入模型的变量包括系统性免疫炎症指数(SII)、淋巴细胞/单核细胞比值(LMR)、胃泌素释放肽前体(ProGRP)、神经元特异烯醇化酶(NSE)及血钙。该模型预测1、2年BMFS率的ROC曲线下面积分别为0.761和0.822。在BM低风险组中,有无PCI治疗的BMFS(P=0.374)、PFS(P=0.551)、ePFS(P=0.508)及OS(P=0.767)均差异没有统计学意义;在BM高风险组中,PCI显著改善了患者的BMFS(P<0.001)和PFS(P=0.022),而ePFS(P=0.963)和OS(P=0.632)差异没有统计学意义,倾向评分匹配后再分析得到相似的结果。结论无论BM高、低风险人群,PCI没有延长LS-SCLC患者的OS期,但PCI显著延长了BM高风险人群的BMFS期和PFS期。

Objective To establish a brain metastasis(BM)prediction model for limited-stage small cell lung cancer(LS-SCLC)patients who achieved complete response(CR)or partial response(PR)after thoracic chemoradiotherapy,and to explore the value of prophylactic cranial irradiation(PCI)in different risk groups.Methods Clinical data of 274 patients with LS-SCLC who achieved CR/PR after thoracic chemoradiotherapy in Tianjin Medical University Cancer Institute&Hospital from January 2010 to December 2021 were retrospectively analyzed,including 144 cases in the PCI group and 130 in the non-PCI group.The nomogram was developed based on variables determined by univariate and multivariate analyses in the non-PCI group.The bootstrap method,receiver operating characteristics(ROC)curve,calibration curve and decision curve analysis(DCA)were employed to evaluate the predictive power and clinical benefits of the model.Patients were stratified into high-and low-risk groups based on risk scores.The brain metastases-free survival(BMFS),progression-free survival(PFS),extracranial progression-free survival(ePFS)and overall survival(OS)were compared between patients with and without PCI in different risk-stratified populations using the log-rank test.Results The nomogram included five variables:systemic immune inflammation index(SII),lymphocyte-to-monocyte ratio(LMR),pro-gastrin-releasing peptide precursor(ProGRP),neuron-specific enolase(NSE),and blood calcium.The area under the ROC curve(AUC)of the nomogram in predicting 1-and 2-year BMFS was 0.761 and 0.822.In the low-risk group,there was no significant difference in the BMFS(P=0.374),PFS(P=0.551),ePFS(P=0.508)and OS(P=0.767)between the PCI and non-PCI groups.In the high-risk group,PCI could significantly increase the BMFS(P<0.001)and PFS(P=0.022),while there was no significant difference in the ePFS(P=0.963)and OS(P=0.632).And propensity score-matching(PSM)analysis showed similar results.Conclusions PCI does not improve OS in LS-SCLC patients regardless of high or low risk of BM.However,PCI significantly prolong the BMFS and PFS in patients at a high risk of BM.