预防性颅脑照射（PCI）是小细胞肺癌（SCLC）患者的一种伴随治疗选择，然而，其疗效和相关危险因素尚未明确定义。本研究旨在系统评估PCI在SCLC治疗方案中的有效性和作用。使用以下关键词及其相应的等效词，在PubMed、Scopus、Web of Science和Cochrane数据库中进行了检索：“brain”、“radiotherapy”、“metastases”、“prophylactic”和“small cell lung cancer”。符合条件的研究包括比较接受PCI和不接受PCI的患者的总生存期（OS）、无进展生存期（PFS）、无脑转移生存期（BMFS）和脑转移发生率。使用非随机研究干预（ROBINS-I）工具评估偏倚风险。对上述结果进行了亚组分析，基于不同因素进行分组。作者鉴定了74项在1983年至2022年间发表的研究，包括31,551例SCLC患者，其中有26.7%接受了PCI。这些研究包括前瞻性随机和回顾性观察性研究。有限期患者接受PCI治疗的OS、PFS和BMFS均优于未接受PCI治疗的患者。接受PCI治疗的患者的OS时间显著延长，且脑转移的发生时间显著延迟。然而，关于广泛期SCLC的发现不那么乐观。PCI对有限期SCLC患者是一种有效的选择。它能提高OS和PFS，延迟脑转移，并减少脑转移的发生。然而，在进行MRI监测的情况下，对广泛期SCLC患者可能没有益处。最后，本研究的主要局限性是包括的研究的异质性和出版偏倚。

Prophylactic cranial irradiation (PCI) is a companion treatment option for small cell lung cancer (SCLC) patients. However, its efficacy and associated risk factors have not been clearly defined. In this study, the authors aimed to systematically assess the effectiveness and role of PCI in the treatment plan of SCLC.The PubMed, Scopus, Web of Science, and Cochrane databases were searched using the following key terms and their equivalents: "brain," "radiotherapy," "metastases," "prophylactic," and "small cell lung cancer." Studies comparing overall survival (OS), progression-free survival (PFS), brain metastasis-free survival (BMFS), and incidence of brain metastases between patients receiving PCI and those not receiving it were considered eligible. Risk of bias was assessed using the Risk of Bias in Non-Randomized Studies-of Interventions (ROBINS-I) tool. Meta-analysis was conducted on the mentioned outcomes with subgrouping based on different factors.The authors identified 74 studies published between 1983 and 2022 with 31,551 SCLC patients, of whom 26.7% received PCI. The studies were a mix of prospective randomized and retrospective observational studies. Patients with limited-stage disease receiving PCI had better OS, PFS, and BMFS than those not receiving PCI. Patients receiving PCI also had significantly longer OS times and developed brain metastases significantly later. However, findings regarding extensive-stage SCLC were not as promising.PCI is an effective option for limited-stage SCLC patients. It improves OS and PFS, delays brain metastases, and reduces the incidence of brain metastases. However, it might not benefit patients with extensive-stage SCLC under adequate follow-up with MRI surveillance. Finally, the heterogeneity of the included studies and publication bias were the main limitations of this study.