Extended survival in women with brain metastases from HER2 overexpressing breast cancer

Brain metastases (BM) are a significant complication of metastatic breast cancer (MBC). The high incidence of BM in HER2 overexpressing MBC is now well recognized, however, the optimal management of such patients is not yet clearly defined. We aimed to analyze factors affecting survival after diagnosis of BM in patients treated in our center.

Retrospective analysis of survival in all patients treated with antineoplastic therapy for BM from MBC in our institution between May 1st 2002 and April 30th 2005, according to HER2 expression and use of trastuzumab after diagnosis of BM.

The median survival of the 26 patients with HER2 overexpressing disease after diagnosis of BM was significantly longer than that of the 60 patients with HER2 nonoverexpressing disease (6.2 vs. 3.8 months, P = 0.027). Further analysis revealed that this seems to be due to the favorable outcome of the 70% (n = 18) of HER2 overexpressing patients who received trastuzumab after BM were diagnosed. Median survival of this group was 11.9 months, compared with 3.8 months (HER2 nonoverexpressing disease, P = 0.002) and 3.0 months (HER2 overexpressing disease not treated with trastuzumab after development of BM, P = 0.05).

Patients with HER2 overexpressing MBC who received trastuzumab after diagnosis of BM survived longer than expected. This finding justifies an active therapeutic approach: disease progression within central nervous system does not preclude benefit from trastuzumab treatment.