Pattern of brain metastatic disease according to HER-2 and ER receptor status in breast cancer patients

Abstract

Aims: To document the type, location, extent, and complications of brain metastases in patients with breast cancer and identify associations with oestrogen receptor (ER) negative and human epidermal growth factor receptor 2 (HER-2) receptor expression.

Materials and methods: Breast cancer patients with known brain metastases were included in this retrospective study, if cross-sectional imaging of the brain [computed tomography (CT)] was available to review and HER-2 and ER status was known. Two neuroradiologists, who were blinded to the receptor status, separately and for each patient, documented on a proforma the location, number, and dimensions of the deposits and the presence or absence of hydrocephalus. Adjudication was sought where there was discrepancy between the two reports. ER status, HER-2 receptor status, and patient age were also documented. The results were analysed using two-sided Fisher's exact tests with Lancaster's mid-P correction and associations were sought between the tumour characteristics and the pattern of brain disease.

Results: Sixty patients were included in the study. There was an association between young age (<40 years) and HER-2 positivity [10 of 24 (41.7%) versus three of 36 (8.3%); p = 0.002]. In ER-negative women, HER-2 positivity was found to be associated with a larger number (six or more) of metastases [11 of 18 (61%) versus nine of 25 (36%); p = 0.049], more brain stem metastases [11 of 18 (61%) versus three of 26 (11.5%); p = 0.035], more frequent occurrence of hydrocephalus [7 of 12 (36.8%) versus three of 26 (11.5%); p = 0.049], and a higher incidence of occipital metastases [12 of 18 (66.7%) versus eight of 26 (30.8%); p = 0.029].

Conclusion: ER-negative HER-2-positive women are more likely to present with a larger number of lesions, more brain stem/occipital metastases, and hydrocephalus, which may predispose them to unfavourable outcomes following treatment.