September 2020: Clinical Outcome of Breast Cancer Patients with asymptomatic brain metastases.

Brain metastases have become a major challenge in patients with metastatic breast cancer. A retrospective analysis has showed that 24.6% of patients with metastatic breast cancer develop brain metastases in the course of the disease (Darlix et al. 2019). The survival rates of patients with brain metastases did not improve over the last decades and differ significantly depending on the subtype of breast cancer. Indeed, analysis of the Brain Metastases in Breast Cancer (BMBC) registry has shown shorter survival between the time periods 2010-2015 compared to 2000-2009 (median survival of 5.8 months versus 7.6 months, p<0.001) (Witzel et al. 2018). The aim of this retrospective analysis was to characterize a cohort of breast cancer patients with asymptomatic brain metastases at diagnosis (N=580) as well as to compare the overall survival (OS) of patients with and without neurological symptoms of brain metastases in the overall cohort of 2,589 patients with brain metastases from BMBC registry.
Asymptomatic patients were slightly younger at diagnosis (median age: 55.5 vs. 57.0 years, p=0.01), had a better performance status at diagnosis (Karnofsky index 80–100%: 68.4% vs. 57%, p<0.001), a lower number of brain metastases (>1 brain metastases: 56% vs. 70%, p=0.027), and a smaller diameter of brain metastases (median: 1.5 vs. 2.2 cm, p<0.001) compared to symptomatic patients. A higher rate of extracranial metastases (86.7% vs. 81.5%, p=0.003) but lower rate of leptomeningeal metastasis (6.3% vs. 10.9%, p<0.001) was observed in asymptomatic compared to symptomatic patients. Furthermore, asymptomatic patients underwent less intensive brain metastases therapy but had a longer median OS (statistically significant for a cohort of HER2-positive patients) compared to symptomatic patients (10.4 vs. 6.9 months, p<0.001).
These findings demonstrated that asymptomatic patients have less severe metastatic brain disease and despite less intensive local brain metastasis therapy still have a better outcome, especially for HER2-positive patients compared to patients with symptomatic brain metastases, although a lead time bias of the earlier diagnosis cannot be ruled out. In addition, this analysis is of clinical relevance in the context of potential trials examining the benefit of early detection and treatment of brain metastases.

Laakmann E, Witzel I, Neunhöffer T, et al. Characteristics and Clinical Outcome of Breast Cancer Patients with Asymptomatic Brain Metastases. Cancers (Basel). 2020 Sep 28;12(10):E2787. doi: 10.3390/cancers12102787.

• Link in PubMed: https://pubmed.ncbi.nlm.nih.gov/32998430/
• Open Access Full Text doi:10.3390/cancers12102787