Brain metastasis in patients with metastatic breast cancer in the real world: a single-institution, retrospective review of 12-year follow-up.

PURPOSE

The data of 589 metastatic breast cancer (MBC) patients in a single institution were reviewed to determine the outcomes of patients with brain metastasis (BM) and assess the efficacy of BM screening.

METHODS

The patients with BM among the 589 MBC patients who underwent treatment at Shizuoka Cancer Center (Shizuoka, Japan) from 09/2002 to 03/2014 were retrospectively analyzed.

RESULTS

During the study period, BM developed in 187 (31.7%) patients. The tumor subtypes were as follows: luminal (hormone receptor [HR]+, HER2-), 44.9%; luminal-HER2 (HR+, HER2+), 14.9%; HER2 (HR-, HER2+), 21.3%; and triple-negative (TN), 16.0%. BM was detected in 48.6% of the patients by screening MRI. While 137 of 187 patients underwent local therapy, whole-brain irradiation was the most frequently applied therapy (63.5%). The median overall survival from the diagnosis of BM was as follows: luminal, 7.0 months (M); luminal-HER2, 13.3 M; HER2, 17.7 M; TN, 4.2 M. The HER2 status (hazard ratio [HR]: 0.58, 95% confidence interval [CI] 0.38-0.88) and nonprogressive extracranial lesion(s) (HR: 0.45, 95% CI 0.29-0.71) were identified as prognostic factors in a multivariate analysis. When limited to HER2-overexpressed MBC patients, the multivariate analysis revealed that non-progressive extracranial lesion(s) (HR: 0.20, 95% CI 0.088-0.47) and stereotactic irradiation (STI) as an initial treatment (HR: 0.18, 95% CI 0.061-0.56) were prognostic factors.

CONCLUSIONS

Our retrospective review showed that early detection of BM by screening MRI, followed by STI, improved the prognosis of HER2-overexpressed MBC patients with BM. A further prospective randomized study is needed to confirm our findings.