脑转移瘤（BM）是最常见的中枢神经系统肿瘤，但其患病率难以确定。大多数研究仅报告同步转移瘤，而同步转移瘤只占所有BM的一小部分。本文报告了十年期间同步和异时性BM患者的发生率和预后情况。研究数据来自TriNetX研究网络。如果患者在2013年1月1日至2023年1月1日期间确诊原发癌症和BM，将其纳入研究。异时性BM定义为BM在原发癌症后超过2个月诊断的情况。通过倾向性评分匹配年龄、颅外转移和抗肿瘤或放射治疗，使队列达到平衡。采用Kaplan-Meier图评估同步和异时性BM的存活差异以及与临床情况的相关性。采用log-rank检验评估异时性BM的BM无生存期和所有BM的总生存期（OS）。计算了风险比值和95%置信区间。 在确定的11,497,663例已确认的15种原发癌症患者中，300,863例（2.6%）发展为BM。BM最常见于肺癌、乳腺癌和黑色素瘤。所有BM中，113,827例（37.8%）是同步发生的，187,036例（62.2%）是异时性发生的。肺和支气管癌的转移率最高（11.0%），同步发生率最高（51.0%）。对于异时性发病，从原发诊断到转移的时间范围为1.3至2.5年，平均为1.8年。异时性BM诊断与从原发诊断开始的时间相比，存活时间更长（11.54 vs 37.41个月，p < 0.0001），但比没有BM的颅外转移存活时间更短（38.75 vs 69.18个月，p < 0.0001）。BM出现前的抗肿瘤治疗与BM无生存期（4.46 vs 17.80个月，p < 0.0001）和总生存期（25.15 vs 42.26个月，p < 0.0001）有关。放射治疗对BM无生存期（5.25 vs 11.44个月，p < 0.0001）和总生存期（30.13 vs 32.82个月，p < 0.0001）具有类似的效果，具有统计学上显著但适度的影响。 大多数BM是异时性出现的，且出现于原发癌症诊断后2年内。原发癌症诊断后6个月内BM的相当比率，特别是肝癌、肺癌和胰腺癌，可以为颅内分期的未来建议提供指引。在BM发展之前进行抗肿瘤治疗可能延长转移前的时间并改善生存。进一步对这一人群进行表征可以更好地指导筛查、预防和治疗工作。

Brain metastases (BMs) are the most common CNS tumors, yet their prevalence is difficult to determine. Most studies only report synchronous metastases, which make up a fraction of all BMs. The authors report the incidence and prognosis of patients with synchronous and metachronous BMs over a decade.Study data were obtained from the TriNetX Research Network. Patients were included if they had a primary cancer diagnosis and a BM diagnosis, with primary cancer occurring between January 1, 2013, and January 1, 2023. Metachronous BM was defined as BM diagnosed more than 2 months after the primary cancer. Cohorts were balanced by propensity score matching for age, extracranial metastasis, and antineoplastic or radiation therapy. Kaplan-Meier plots were used to evaluate survival differences between synchronous and metachronous BMs and associations with clinical conditions. A log-rank test was used to evaluate BM-free survival for metachronous BM and overall survival (OS) for all BMs. Hazard ratios and 95% CIs were calculated.Of the 11,497,663 patients with 15 primary cancers identified, 300,863 (2.6%) developed BMs. BMs most commonly arose from lung and breast cancers and melanoma. Of all BMs, 113,827 (37.8%) presented synchronously and 187,036 (62.2%) presented metachronously. Lung and bronchial cancer had the highest metastasis rate (11.0%) and the highest synchronous presentation (51.0%). For metachronous presentations, the time from primary diagnosis to metastasis ranged from 1.3 to 2.5 years, averaging 1.8 years. Metachronous BM diagnosis was associated with longer survival over synchronous BM from primary diagnosis (11.54 vs 37.41 months, p < 0.0001), but shorter survival than extracranial metastases without BM (38.75 vs 69.18 months, p < 0.0001). Antineoplastic therapy prior to BM was associated with improved BM-free survival (4.46 vs 17.80 months, p < 0.0001) and OS (25.15 vs 42.26 months, p < 0.0001). Radiotherapy showed a similar effect that was statistically significant but modest for BM-free survival (5.25 vs 11.44 months, p < 0.0001) and OS (30.13 vs 32.82 months, p < 0.0001).The majority of BMs present metachronously and arise within 2 years of primary cancer diagnosis. The substantial rate of BMs presenting within 6 months of primary cancer, especially liver, lung, and pancreatic cancer, may guide future recommendations on intracranial staging. Antineoplastic therapy prior to the development of BM may prolong the time before metastasis and improve survival. Further characterization of this population can better inform screening, prevention, and treatment efforts.