PURPOSE To identify risk factors for developing symptomatic brain metastases and evaluate the impact of prophylactic cranial irradiation (PCI) on brain metastasis-free survival (BMFS) and overall survival (OS) in extensive disease small cell lung cancer (ED-SCLC). MATERIALS AND METHODS Among 190 patients diagnosed with ED-SCLC who underwent FDG PET/CT and brain Magnetic Resonance Imaging (MRI) prior to treatment, 53 (27.9%) received PCI while 137 (72.1%) did not. Prognostic index predicting a high risk of symptomatic brain metastases was calculated for the group without receiving PCI (observation group, n = 137) with Cox regression model. RESULTS Median follow-up time was 10.6 months. Multivariate Cox regression showed that the following three factors were associated with a high risk of symptomatic brain metastases: the presence of extrathoracic metastases (p = 0.004), hypermetabolism of bone marrow or spleen on FDG PET (p < 0.001), and high neutrophil-to-lymphocyte ratio (p = 0.018). PCI significantly improved BMFS in high-risk patients (1-year rate: 94.7% vs. 62.1%, p = 0.001), but not in low-risk patients (1-year rate: 100.0% vs. 87.7%, p = 0.943). However, PCI did not improve OS in patients at high risk for symptomatic brain metastases (1-year rate: 65.2% vs. 50.0%, p = 0.123). CONCLUSION Three prognostic factors (the presence of extrathoracic metastases, hypermetabolism of bone marrow or spleen on FDG PET, and high neutrophil-to-lymphocyte ratio) were associated with a high risk of symptomatic brain metastases in ED-SCLC. PCI was beneficial for patients at a high risk of symptomatic brain metastases in terms of BMFS, but not OS. Thus, selective use of PCI in ED-SCLC according to the risk stratification is recommended.

中文翻译：

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通过临床和 FDG PET 参数对有症状的脑转移风险分层，用于选择性使用预防性颅脑照射治疗广泛型小细胞肺癌患者

目的 确定发生有症状的脑转移的危险因素，并评估预防性颅脑照射 (PCI) 对广泛疾病小细胞肺癌 (ED-SCLC) 脑转移生存 (BMFS) 和总生存 (OS) 的影响。材料与方法 190 名诊断为 ED-SCLC 且在治疗前接受 FDG PET/CT 和脑磁共振成像 (MRI) 的患者中，53 名 (27.9%) 接受了 PCI，137 名 (72.1%) 未接受。使用 Cox 回归模型计算未接受 PCI 的组（观察组，n = 137）的预测有症状脑转移高风险的预后指数。结果 中位随访时间为 10.6 个月。多变量 Cox 回归显示以下三个因素与有症状的脑转移的高风险相关：胸外转移的存在 (p = 0.004)，FDG PET 上骨髓或脾的代谢亢进 (p < 0.001)，以及高中性粒细胞与淋巴细胞的比率 (p = 0.018)。PCI 显着改善了高风险患者的 BMFS（1 年率：94.7% 对 62.1%，p = 0.001），但在低风险患者中没有改善（1 年率：100.0% 对 87.7%，p = 0.943 ）。然而，PCI 并未改善有症状的脑转移高危患者的 OS（1 年率：65.2% 与 50.0%，p = 0.123）。结论 三个预后因素（胸外转移的存在、FDG PET 显示的骨髓或脾脏代谢亢进以及高中性粒细胞与淋巴细胞的比率）与 ED-SCLC 中症状性脑转移的高风险相关。就 BMFS 而言，PCI 对有症状性脑转移风险高的患者有益，但对 OS 无益。因此，