Prognostic significance of HER-2/neu over-expression on the incidence of brain metastasis in newly diagnosed breast cancer

Abstract

649 Background: As systemic therapy improves, brain metastases (BM) from breast cancer are becoming increasingly evident. An increased risk of BM in HER-2/neu over-expressing metastatic breast cancer patients has been suggested. However, the relationship between HER-2/neu over-expression and the risk of BM in newly diagnosed breast cancer patients is unknown. Methods: To determine incidence of BM in HER-2/neu over-expressing breast cancer patients, a cohort of patients between 01/1998 and 12/2003 with uniform HER-2/neu testing were identified from a cancer registry. A total of 460 patients with HER-2/neu over-expression and 500 patients with HER-2/neu negative disease were reviewed. Patients were excluded if there was breast cancer diagnosed before 01/1998 or others cancer. A total of 301 HER-2/neu over-expressing and 363 HER-2/neu negative patients were included for this analysis. The association between histological features and the occurrence of BM were evaluated with univariate and multivariate analyses. Results: BM were identified in 8% (24 patients) of HER-2/neu over-expressing breast cancer patients compared to only 1.7% (6 patients) in the HER-2/neu negative patients (hazard ratio 5.15 [2.079–12.78], p=0.0001). In patients with recurrent disease, the proportion of BM for HER-2/neu over-expressing patients was 24% compared to 10% in HER-2/neu negative patients. HER-2/neu over-expression, tumor size >2cm, ≥ 4 nodes positive and grade 2/3 were predictors of BM in univariate analysis. In multivariate analysis, HER-2/neu over-expression and tumor size>2cm were an independent prognostic factors for the development of BM, while hormone receptors expressions was protective (p=0.02). Conclusions: Our population based study show that newly diagnosed HER-2/neu over-expressing breast cancer patients are at significantly increased risk for BM. As most BM occur in HER-2/neu over-expressing patients with systemic metastatic disease, these findings could prompt consideration of brain prophylaxis strategies and/or serial radiologic screening to detect asymptomatic BM. No significant financial relationships to disclose.