The prognostic contribution of clinical breast cancer subtype, age, and race among patients with breast cancer brain metastases

Background: Brain metastases (BM) arising from triple-negative breast cancer (TNBC) portend a poor prognosis. TNBC is more common in premenopausal and African-American (AA) patients; both of these characteristics also confer a poor prognosis. In a single-institution cohort study, the authors attempted to determine whether the inferior outcome noted with TNBC brain metastases is more reflective of a higher risk population or the subtype itself.

Methods: The University of North Carolina Breast Cancer Database identified patients with BC brain metastases who were diagnosed between 1988 and 2008. BC subtype was assigned by immunohistochemistry: hormone receptor (HR) positive (+);(HR, estrogen receptor [ER]+ and/or progesterone receptor [PR]+)/human epidermal growth factor receptor 2 (HER2) negative (-), HR+/HER2+, HR-/HER2+, and TN (ER-/PR-/HER2-). Survival and disease recurrence patterns were evaluated by subtype, patient age (<40 years vs ≥40 years), and race (AA vs non-AA) using the Kaplan-Meier method and Cox regression analysis.

Results: Among 119 patients with BC brain metastases, 33% were AA and 31% were aged <40 years. BC subtype was confirmed in 98 patients (30% with HR+/HER2-, 21% with HR+/HER2+, 18% with HR-/HER2+, and 31% with TNBC). Survival after BM was found to be impacted by subtype (P = .002), and was shortest for patients with TNBC (0.24 years; 95% confidence interval, 0.17 years-0.48 years). There were no age-specific (P = .84) or race-specific (P = .09) differences in survival noted after brain metastases; stratification of BC subtypes by age and race revealed no difference (all, P > .1). The receipt of systemic therapy after BC brain metastases was found to be an important predictor of survival after BC brain metastases (hazard ratio, 0.29; P = .002) when adjusted for race, age, number of central nervous system lesions, and BC subtype.

Conclusions: TNBC confers a high risk of death after brain metastases regardless of patient race and age, supporting the need for novel agents capable of controlling both intracranial and extracranial TNBC across all races and ages.