Prognostic relevance of the neurological symptom burden in brain metastases from breast cancer.

Background: Existing prognostic models for breast cancer (BC) brain metastases (BM) overlook neurological symptoms. Thus, we explored the incidence and prognostic relevance of neurological symptoms in a real-world cohort of BC patients with BM.

Methods: The Vienna Brain Metastasis Registry identified BC patients with BM between 1992 and 2020, categorised by subtype: hormone receptor-positive/human epidermal growth factor receptor 2-negative (HR+/HER2-), HER2 overexpressing (HER2+), and triple-negative (TN).

Results: A total of 716 patients with BM from BC were included. In total, 80% (573/716) of the patients presented with neurological symptoms at BM diagnosis. Across all BC subtypes, asymptomatic patients presented with a significantly longer median OS from diagnosis of BM compared to symptomatic patients (p < 0.05; log-rank test; HR+ BC 29 vs. 9 months; HER2+ BC 24 vs. 12 months; TN 12 vs. 6 months). In multivariate analysis with the BC-specific Graded Prognostic Assessment (Breast-GPA: HR:1.4; 95% CI:1.3-1.5; p < 0.001), the presence of neurological symptoms at diagnosis (HR:1.6; 95% CI: 1.4-1.9; p < 0.001) presented as independently associated with OS from time of BM diagnosis, respectively.

Conclusions: Neurological burden at BM diagnosis independently predicts survival in BC patients. Our findings emphasise incorporating the symptom status in the prognostic evaluation and reassessing BM screening in high-risk patients during prospective clinical trials.