Department of Radiation Oncology and Image-Applied Therapy, Graduate School of Medicine, Kyoto University, Kyoto 606-8507, Japan.
Department of Respiratory Medicine, Graduate School of Medicine, Kyoto University, Kyoto 606-8507, Japan.
J Radiat Res. 2022 Jul 19;63(4):636-645. doi: 10.1093/jrr/rrac035.
Prophylactic cranial irradiation (PCI) is recommended for patients with limited-stage small-cell lung cancer (LS-SCLC) who respond well to initial treatment. However, PCI is often omitted because of its potential neurotoxicity in the era of modern diagnostic imaging devices. In the present study, we aimed to investigate the risk factors for brain metastasis (BM) in patients eligible for PCI and who may benefit more from it. Patients with LS-SCLC who responded well to definitive thoracic chemoradiotherapy were included in the present study. Competing risk regression was used to identify factors associated with BM, and the Kaplan-Meier method was used to assess overall survival (OS). Between 2004 and 2017, 62 patients were eligible for PCI and were analyzed. Of these, 38 (61.3%) underwent PCI. Overall, 17 patients (27.4%) developed BM, with a 2-year cumulative incidence of 22.8%. Multivariate analysis (MVA) revealed that pretreatment elevated pro-gastrin-releasing peptide (ProGRP) levels were associated with an increased risk for BM (HR, 7.96, P = 0.0091). PCI tended to reduce the risk of BM (HR, 0.33; P = 0.051). The use of PCI was associated with improved OS in patients with ProGRP levels > 410 pg/mL (P = 0.008), but not in those with ProGRP ≤ 410 pg/mL (P = 0.9). Pretreatment ProGRP levels may be useful in predicting the development of BM in patients with LS-SCLC who achieved a good response to initial therapy and to determine which patients should undergo PCI.
预防性颅脑照射（PCI）推荐用于初始治疗反应良好的局限期小细胞肺癌（LS-SCLC）患者。然而，由于现代诊断成像设备的潜在神经毒性，PCI 常被忽略。在本研究中，我们旨在研究有资格接受 PCI 且可能从中获益更多的患者发生脑转移（BM）的危险因素。本研究纳入了对确定性胸部放化疗反应良好的 LS-SCLC 患者。采用竞争风险回归分析确定与 BM 相关的因素，并采用 Kaplan-Meier 法评估总生存期（OS）。2004 年至 2017 年期间，共纳入 62 例符合 PCI 条件的患者进行分析。其中，38 例（61.3%）接受了 PCI。共有 17 例（27.4%）患者发生 BM，2 年累积发生率为 22.8%。多变量分析（MVA）显示，治疗前升高的胃泌素释放肽前体（ProGRP）水平与发生 BM 的风险增加相关（HR，7.96，P = 0.0091）。PCI 有降低 BM 风险的趋势（HR，0.33；P = 0.051）。对于 ProGRP 水平>410 pg/mL 的患者（P = 0.008），接受 PCI 与改善 OS 相关，但对于 ProGRP ≤410 pg/mL 的患者（P = 0.9）则不然。治疗前 ProGRP 水平可用于预测初始治疗反应良好的 LS-SCLC 患者发生 BM 的情况，并确定哪些患者应接受 PCI。
