Abstract：
OBJECTIVE: The discovery of novel human epidermal growth factor receptor 2 (HER2)-directed antibody‒drug conjugates has accelerated the identification of the HER2-low subtype. However, the biological significance of low HER2 expression in breast cancer brain metastasis (BCBM) is unclear.
METHODS: Patients with HER2-negative BC and brain metastasis were retrospectively screened between February 2012 and November 2023. Brain metastasis-free survival (BMFS) and survival after brain metastasis (SABM) were analyzed according to HER2 expression.
RESULTS: A total of 201 female patients, 84 of whom were HER2-low and 117 of whom were HER2-zero, were evaluated. The median BMFS in the entire cohort was 35.6 months (95% CI 29.8-41.4). Although HER2-low patients had numerically longer median BMFS than HER2-zero patients (43.7 m vs. 30.1 m, p = 0.025), multivariate analysis revealed that the difference was not significant (p = 0.167). BMFS between the HER2-low and HER2-zero groups was similar in the hormone receptor (HR)-positive (52.8 m vs. 47.6 m, p = 0.276) and HR-negative (15.3 m vs. 19.7 m, p = 0.930) cohorts. The median SABM in the entire cohort was 6.0 months (95% CI 3.8-8.1). HER2-low and HER2-zero patients had similar median SAMB (5.4 m vs. 6.1 m, p = 0.816). The SABM between the HER2-low and HER2-zero groups was similar in the HR-positive (6.3 m vs. 8.7 m, p = 0.375) and HR-negative (3.3 m vs. 4.2 m, p = 0.783) cohorts.
CONCLUSIONS: Low HER2 expression does not affect BMFS or SAMB in brain metastatic breast cancer patients in this real-world population.
METHODS: Patients with HER2-negative BC and brain metastasis were retrospectively screened between February 2012 and November 2023. Brain metastasis-free survival (BMFS) and survival after brain metastasis (SABM) were analyzed according to HER2 expression.
RESULTS: A total of 201 female patients, 84 of whom were HER2-low and 117 of whom were HER2-zero, were evaluated. The median BMFS in the entire cohort was 35.6 months (95% CI 29.8-41.4). Although HER2-low patients had numerically longer median BMFS than HER2-zero patients (43.7 m vs. 30.1 m, p = 0.025), multivariate analysis revealed that the difference was not significant (p = 0.167). BMFS between the HER2-low and HER2-zero groups was similar in the hormone receptor (HR)-positive (52.8 m vs. 47.6 m, p = 0.276) and HR-negative (15.3 m vs. 19.7 m, p = 0.930) cohorts. The median SABM in the entire cohort was 6.0 months (95% CI 3.8-8.1). HER2-low and HER2-zero patients had similar median SAMB (5.4 m vs. 6.1 m, p = 0.816). The SABM between the HER2-low and HER2-zero groups was similar in the HR-positive (6.3 m vs. 8.7 m, p = 0.375) and HR-negative (3.3 m vs. 4.2 m, p = 0.783) cohorts.
CONCLUSIONS: Low HER2 expression does not affect BMFS or SAMB in brain metastatic breast cancer patients in this real-world population.
摘要：
目的：新型人表皮生长因子受体2（HER2）定向抗体药物偶联物的发现加速了对HER2低亚型的鉴定。然而,HER2低表达在乳腺癌脑转移（BCBM）中的生物学意义尚不清楚。
方法：2012年2月至2023年11月对HER2阴性BC和脑转移患者进行回顾性筛查。根据HER2表达分析无脑转移生存期(BMFS)和脑转移后生存期(SABM)。
结果：共201名女性患者，其中84人HER2低，117人HER2零，进行了评估。整个队列的BMFS中位数为35.6个月（95％CI29.8-41.4）。尽管低HER2患者的中位BMFS在数字上长于零HER2患者（43.7mvs.30.1米,p=0.025),多变量分析显示差异不显著(p=0.167)。低HER2组和零HER2组之间的BMFS在激素受体（HR）阳性中相似（52.8mvs.47.6米,p=0.276）和HR-负（15.3m与19.7米,p=0.930)队列。整个队列的SABM中位数为6.0个月（95％CI3.8-8.1）。低HER2和零HER2患者的中位SAMB相似（5.4mvs.6.1米,p=0.816)。HER2低组和HER2零组之间的SABM在HR阳性中相似（6.3mvs.8.7米,p=0.375）和HR-负（3.3mvs.4.2m,p=0.783)队列。
结论：低HER2表达不影响实际人群中脑转移性乳腺癌患者的BMFS或SAMB。
方法：2012年2月至2023年11月对HER2阴性BC和脑转移患者进行回顾性筛查。根据HER2表达分析无脑转移生存期(BMFS)和脑转移后生存期(SABM)。
结果：共201名女性患者，其中84人HER2低，117人HER2零，进行了评估。整个队列的BMFS中位数为35.6个月（95％CI29.8-41.4）。尽管低HER2患者的中位BMFS在数字上长于零HER2患者（43.7mvs.30.1米,p=0.025),多变量分析显示差异不显著(p=0.167)。低HER2组和零HER2组之间的BMFS在激素受体（HR）阳性中相似（52.8mvs.47.6米,p=0.276）和HR-负（15.3m与19.7米,p=0.930)队列。整个队列的SABM中位数为6.0个月（95％CI3.8-8.1）。低HER2和零HER2患者的中位SAMB相似（5.4mvs.6.1米,p=0.816)。HER2低组和HER2零组之间的SABM在HR阳性中相似（6.3mvs.8.7米,p=0.375）和HR-负（3.3mvs.4.2m,p=0.783)队列。
结论：低HER2表达不影响实际人群中脑转移性乳腺癌患者的BMFS或SAMB。
