Abstract P6-16-06: Impact of early detection of brain metastasis in metastatic breast cancer patients: A single institutional experience
Authors: Matsuo Satomi , Watanabe Junichiro , Mitsuya Koichi , Nakasu Yoko 
Published: May 2015

Abstract
Background/Introduction
Since brain metastasis (BM) is commonly seen in metastatic breast cancer (MBC) patients (pts), it may be an important prognostic factor. It has been believed that screening MRI would not improve a pt’s outcome, however, an appropriate diagnosis and early initiation of therapy, especially screening MRI followed by stereotactic irradiation (STI), might contribute to a pt’s survival.
Patients and methods
We reviewed our medical records for 589 MBC pts who were treated between September 2002 and March 2014. COX regression analyses were applied to identify the survival risk factors, and the Kaplan-Meier method with a log-rank test was utilized to evaluate the survival rates.
Results
Upon checking our medical records, 187 pts, or 37.1% of MBC pts, developed BM with the median time to BM of 585.0 days (95% confidence interval [CI] 501.0-647.0). The tumor subtypes of primary lesion were luminal, 44.9%; luminal-HER2, 14.9%; HER2+, 21.3%; triple-negative (TN), 16.0% and unavailable, 2.6%. The median overall survival (OS) from the diagnosis of BM was as follws: all pts, 292.0 days (95%CI 220.0-345.0); luminal, 212.0 days (150.0-293.0); luminal-HER2, 400.0 days (258.0-613.0); HER2+, 531.0 days (423.0-670.0) and TN, 127.0 days (43.0-185.0). Accompanying visceral and/or bone lesion(s) at the diagnosis of BM were as follows: lung, 49.7%; liver, 45.9% and bone, 64.7%. The development of BM in the HER2+ pt was significantly less frequently associated with progression of known visceral/bone lesions than other subtypes (HER2+ 41.0% versus luminal 64.2% or TN 70.0%; P&lt;0.01, Chi-square test), and the pts who developed BM without progression of other lesion(s) showed a significantly superior OS (hazard ratio [HR] 0.48, 95%CI 0.32-0.70, P&lt;0.001) regardless of the subtype. The 91 pts with BM (48.6%) whose lesions were detected by screening MRI showed a significantly superior OS from BM than did the pts with BM with any symptoms (median 359.0 days, 95%CI 249.0-439.0 versus 222.0 days, 95%CI 159.0-292.0; P&lt;0.05). STI was performed as initial therapy in 20.3% of pts, and improved their OS from BM in all subtypes (median 439.0 days with STI, 293.0 days without STI; P&lt;0.05), STI or the use of a tyrosine kinase inhibitor (TKI) significantly improved the OS from BM in HER2+ pts (median 661.0 days with STI versus 423.0 days without STI; P&lt;0.05, median 622.0 days with TKI versus 287.0 days without TKI; P&lt;0.01) The univariate COX analysis indicated that HER2+, 2&gt;ECOG performance status at the diagnosis of BM, no other progressive lesions at the diagnosis of BM, &lt;5 brain lesions and STI were favorable factors for the OS. When limited to HER2+ pts, the multivariate COX analysis showed that the lack of other progressive lesions at the diagnosis of BM (HR 0.20, 95%CI 0.09-0.47, P&lt;0.001) and STI (HR 0.18, 95%CI 0.06-0.56, P&lt;0.01) markedly decreased the risk of death for HER2+ pts.
Conclusions
From our institutional review, there seemed to be no special strategy for improving the OS of luminal or TN pts, however, HER2+ pts showed an improved OS after BM following the early detection and appropriate therapies for the BM. We conclude that HER2+MBC pts are good candidates for a BM screening program.
Citation Format: Satomi Matsuo, Junichiro Watanabe, Koichi Mitsuya, Yoko Nakasu. Impact of early detection of brain metastasis in metastatic breast cancer patients: A single institutional experience [abstract]. In: Proceedings of the Thirty-Seventh Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2014 Dec 9-13; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2015;75(9 Suppl):Abstract nr P6-16-06.