Inflammatory breast cancer and development of brain metastases: risk factors and outcomes.

Abstract

Brain metastases are associated with significant morbidity. Minimal research has been conducted on the risk factors for and incidence of brain metastases in women with inflammatory breast cancer (IBC). 210 women with Stage III or IV IBC diagnosed from 1997-2011 were identified. Competing risk analysis and competing risks regression were used to calculate the incidence of brain metastases and identify significant risk factors. After a median follow-up in surviving patients of 2.8years (range 0.6-7.6) and 3.3years (range 0.2-14.5) in the 47 and 163 patients with (MET) and without (non-MET) metastatic disease at diagnosis, 17 (36%) and 30 (18%) developed brain metastases, respectively. The cumulative incidence at 1, 2, and 3years was 17% [95% confidence interval (CI), 8-30], 34% (95% CI, 20-48), and 37% (95% CI, 22-51) for the MET cohort. The corresponding non-MET values were 4% (95% CI, 2-8), 8% (95% CI 5-13), and 15% (95% CI, 10-22). Once non-MET patients developed extracranial distant metastases, the subsequent 1, 2, and 3years cumulative incidence of brain metastases was 18% (95% CI, 10-28), 25% (95% CI, 15-36), and 31% (95% CI, 20-43). On multivariate analysis, brain metastases were associated with younger age [hazard ratio (HR), 0.73; 95% CI, 0.53-1.00; P=0.05] and distant metastases at diagnosis (HR, 2.33; 95% CI, 1.11-4.89; P=0.03). The incidence of brain metastases is high in women with IBC. Particularly for patients with extracranial distant metastases, routine screening with magnetic resonance imaging should be considered.